Download CAMo: from molecules to modeling PROVISIONAL Abstract Collection

International Workshop
CAMo: from molecules to modeling
Università di Torino, Italy
September 14th–15th, 2015
PROVISIONAL Abstract Collection
FA COST Action FA1405 Using three-way interactions between plants, microbes
and arthropods to enhance crop protection and production
July 15th, 2015
Editors:
ii
Simona Bonelli∗ , Roberto Cavoretto† , Alessandra De Rossi† , Ezio Venturino†
∗ Dipartimento di Scienze della Vita e Biologia dei Sistemi,
via Accademia Albertina 13,
† Dipartimento di Matematica “Giuseppe Peano”,
Università di Torino,
via Carlo Alberto 10,
10123 Torino, Italy.
Contents
Ofir Bahar: Molecular mechanisms of Insect-vectored-bacterial diseases . . . . . . . . . . .
Paula Baptista: Role of endophytes and epiphytes microorganisms in the mediation of
olive tree resistance to plant pathogens . . . . . . . . . . . . . . . . . . . . . . . . . .
Alison Bennett: Arbuscular mycorrizal fungi influence plant-insect interactions . . . . . .
Arjen Biere: Effects of soil biota on aboveground plant-insect interactions . . . . . . . . .
Aleksandra Bulajić: Quarantine and economically important plant viruses in Serbia: detection, characterization and epidemiology . . . . . . . . . . . . . . . . . . . . . . . .
Henryk Czosnek: Expression of whitefly primary endosymbiotic GroEL in plants provides
tolerance to several virus families . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maria Cristina Digilio: Trichoderma and insect control . . . . . . . . . . . . . . . . . . . .
Tomas Erban: The role of pathogenesis-related proteins in defense against fungal diseases
and insect pests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Enric Frago: Insect symbionts mediate interactions at the community level . . . . . . . . .
David Giron: Insect Reprogrammers and associated bacterial symbionts: From Strategies
for Manipulating Plants to Agriculture . . . . . . . . . . . . . . . . . . . . . . . . . .
Kristina Gruden: Potato Virus Y infection hinders potato defence response and renders
plants more vulnerable to Colorado potato beetle attack . . . . . . . . . . . . . . . .
Barbara H. Łabanowska: Insect Reprogrammers and associated bacterial symbionts: From
Strategies for Manipulating Plants to Agriculture . . . . . . . . . . . . . . . . . . . .
Anna-Liisa Laine: How sensitive are species interactions to stressful environmental conditions? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brian R. Murphy: Translating from 2-way interactions to 3-way interaction research with
fungal endophytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Photini Mylona: Enhancement of pollination services as a measure of biodiversity improvement in Mediterranean cropping systems . . . . . . . . . . . . . . . . . . . . .
Kalliope Papadopoulou: Tripartite interactions of fungal endophytes and arbuscular mycorrhizal fungi (AMF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Eduardo de la Peña: Induced plant defences mediated by glandular trichomes in tomato:
mechanism of induction and implications for plant-insect-natural enemy interactions
Sergio Rasmann: Genetic variation drives ecological outcomes of the three-way interaction
between plant herbivores and microorganisms . . . . . . . . . . . . . . . . . . . . . .
Jaka Razinger: Utilizing rhizosphere competence of entomopathogenic or insect associated
fungi to enhance crop production and resistance to soil pests . . . . . . . . . . . . . .
Kari Saikkonen: Trophic interactions mediated by fungal endophytes . . . . . . . . . . . .
Carolin Schneider: Beneficial endophytes: Development of biofertilizers and biocontrol
products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Jean-Christophe Simon: Aphid-plant-microbe interactions: from ecological to functional
studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ayco Tack: Plant-microbe-insect interactions across space . . . . . . . . . . . . . . . . . .
Radomira Vankova: Hormonal dynamics in the roots of Brassica napus during infection
with Plasmodiophora brassicae - comparison of tolerant and sensitive cultivar . . . .
Maria Carlota Vaz Patto: Biotic-abiotic interactions in Portuguese common bean. A case
study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ezio Venturino: Pathogens influence on interacting populations . . . . . . . . . . . . . . .
K. Vrandečić: Plant pathogenic fungi in Croatia . . . . . . . . . . . . . . . . . . . . . . . .
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Molecular mechanisms of Insect-vectored-bacterial diseases
Ofir Bahar
Dept. Of Plant Pathology and Weed Science
Agricultural Research Organization, Volcani Center
POB 155, Bet-Dagan, 5025001,
ISRAEL
Email: ofi[email protected]
Many arthropod insects are major agricultural pests causing severe crop damage and loss. Some of
these pests directly damage crop plants by feeding of them, but some convey their damage mainly
by transmitting plant disease agents. These agents belong to different classes of microorganisms
and viruses. Our focus in the lab is on bacterial diseases of plants, vectored by insect. These include
the bacterial species Ca. Phytoplasma, Spiroplasma and Ca. Liberibacter. These disease agents
are the cause of many agriculturally important diseases such as yellows disease of multiple crops,
greening disease (Huanglongbing) of citrus, Zebra-chip disease of potatoes and more. On top of
the complexity of working with three interacting organisms, many of these disease agents cannot be
grown in axenic culture or be inoculated onto the plant artificially and therefore pose great challenge
when it comes to study them in the lab. Our research goals focus on understanding the molecular
dialog between the three interacting partners in order to gain insight to the molecular mechanisms
that enable successful transmission of the pathogen and disease. Understanding the very basis of
these mechanisms can allow us to think of and generate new approaches to be added to the very
limited toolbox of management of insect-vectored diseases. More specifically, we work on yellows
disease of grapevines, carrots and sesame and also on citrus greening and olive quick decline.
Role of endophytes and epiphytes microorganisms in the mediation of olive tree
resistance to plant pathogens
Paula Baptista
Mountain Research Centre (CIMO),
School of Agriculture,
Polytechnic Institute of Bragança,
Campus Sta Apolónia,
5300-253 Bragança,
PORTUGAL
Email: [email protected]
Keywords: Olive tree, diseases, epiphytes, endophytes, sustainable agriculture, biocontrol.
Olive (Olea europaea L.) is one of the most important crops in the Mediterranean region, where
95% of the world’s olive production is located. Several insect pests and diseases attack the olive
crop, reducing its production by 30%. Among diseases, anthracnose (caused mostly by the airborne
fungi Colletotrichum acutatum), olive knot (caused by the bacterium Pseudomonas savastanoi pv.
savastanoi), Verticillium wilt (caused by the fungus Verticillium dahliae) and olive leaf spot (caused
by the fungus Spilocaea oleaginea), are considered to be the major cause of olive-crop damage
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worldwide. No effective biological or cultural controls are available against these diseases; therefore,
protection relies on chemical control. However, many of the chemical products currently used cause
a variety of health problems and environmental impacts. During the last three years we have been
carried out studies aiming to explore plant-associated microorganisms, in an integrative perspective,
in order to designed new strategies for the control of these diseases. Specifically, we intend to
disclose the role of microorganisms (both endophytes and epiphytes) inhabiting olive trees in the
mediation of plant defense against the aforementioned diseases, under field conditions, and select the
strains with the greatest biocontrol potential. For this, both epi- and endophyte bacteria and fungi
inhabiting olive trees from five cultivars (Cobrançosa, Madural, Verdeal Transmontana, Picual and
Galega) with different susceptibilities to the aforementioned diseases have been isolated, and further
identified by sequencing the 16S (for bacteria) and the ITS region (for fungi) of rRNA genes. Since
this approach only detects cultivable microorganisms (uncultured ones will not be represented) the
diversity will be additionally assessed recurring to next generation sequencing approaches that allow
metabarcoding (in an illumina platform). Disease incidence and severity as well as several chemical
and physical factors of the phyllosphere will be evaluated for each olive tree cultivar, and the results
obtained will be related with their microbial composition. These results are expected to clarify
microbiome mediated beneficial effects on plant protection and also to identified the isolates that
appear to be most correlated with disease biological control. The real capability of those isolates
to reduce disease symptoms and proliferation of plant pathogens will be studied for selecting the
most efficient BCA, by using “in vitro” and “in planta” assays. The results from this study will form
the basis for the identification of olive tree microorganisms for the biological control of these four
diseases. Results will also uncover previously unrecorded mechanisms of microorganism-olive tree
and microorganism-microorganism relationships, which may be of relevance for plant health and for
designing a new strategy for the biological control of these diseases.
Acknowledgements: This work is supported by FEDER funds through the COMPETE (Operational Programme for Competitiveness Factors) and by National funds through the FCT (Foundation for Science and Technology) in the framework of the projects PTDC/AGR-PRO/4354/2012
and EXCL/AGR-PRO/0591/2012.
Arbuscular mycorrizal fungi influence plant-insect interactions
Alison Bennett
Ecological Sciences
James Hutton Institute
Errol Road
Invergowrie, Dundee
DD2 5DA
UK
Email: [email protected]
044 (0) 1382 568700 ext 7567
In our group we research the influence of arbuscular mycorrhizal (AM) fungi on plant-insect interactions above and belowground. AM fungi are plant mutualists that uptake nutrients (predominantly
P) in return for carbon, and prime the salicyclic acid pathway in plants potentially leading to greater
and faster responses by plants to antagonists. We study a wide variety of herbivores and pollinators
visiting different plant hosts, and apply our results to both natural and managed systems. We are
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particularly interested in replicating actual systems and assessing the generality of the influence of
AM fungi on insects.
Effects of soil biota on aboveground plant-insect interactions
Arjen Biere
Dept. Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW)
Droevendaalsesteeg 10, 6708 PB Wageningen,
The NETHERLANDS
Email: [email protected]
The Department of Terrestrial Ecology of the Netherlands Institute of Ecology (Wageningen, NL)
broadly studies biotic interactions in terrestrial ecosystems. In particular we study how plants
mediate multi-trophic interactions between above- and belowground organisms and how these interactions are affected by (human induced) changes in climate, land use and species invasions.
One of the topics that we focus on is so-called “plant soil feedback”. During plant growth, plants
change the composition of the community of soil biota in their rhizosphere. These changes (“soil
legacies”) subsequently affect the performance of the same plant, its conspecifics, or heterospecific
plants that grow in that same soil later in time, e.g. in the next season (“soil feedback”). Such
feedbacks can be either positive or negative, and can play an important role in processes such
as succession, species invasions, and the outcome of multitrophic interactions. For instance, soil
legacies not only affect the performance of ensuing plants, but also that of the insects that feed on
their leaves. Strikingly, we have shown that insect feeding modifies the type of soil legacy that their
host plants leave in the soil in a way that it benefits conspecific insects that feed on (the offspring
of) their host plants grown in that soil in the ensuing year (facilitation)([1]). We could view this as
a form of “delayed” three-way interaction between plants, microbes and insects.
At a more mechanistic level we try to unravel how plant symbionts (mycorrhizae) in roots and
rhizosphere affect plant interactions with arthropods feeding on their leaves. Mycorrhizae can
affect interactions with aboveground arthropods in a variety of ways. For instance, they can alter
plant size, phenology and primary chemistry, induce or prime plants for systemic resistance or
susceptibility, alter plant tolerance, and modulate plant indirect defense by altering the blend of
herbivore-induced plant volatiles emitted upon herbivory (affecting the attraction of the natural
enemies of the herbivores and hence the efficacy of their biocontrol). We are interested in the role
of secondary metabolites mediating such interactions ([2]), whether there is genetic variation in
these three-way interactions, the raw material for selection ([3]), and how their outcome depends
on environmental conditions (context-dependency).
References
[1] Kostenko O, van de Voorde TFJ, Mulder PPJ, Van der Putten WH, Bezemer TM (2012) Legacy
effects of aboveground-belowground interactions. Ecol. Lett. 15: 813-821
[2] De Deyn GB, Biere A, van der Putten WH, Wagenaar R, Klironomos JN (2009) Chemical
defense, mycorrhizal colonization and growth responses in Plantago lanceolata L. Oecologia
160: 433-442.
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[3] Biere A, Tack AJM (2013) Evolutionary adaptation in three-way interactions between plants,
microbes and arthropods. Funct. Ecol. 27: 646-660.
Quarantine and economically important plant viruses in Serbia: detection, characterization and epidemiology
A. Bulajić, I. Stanković, A. Vučurović, D. Nikolić, K. Milojevi, B. Krstić
Institute of Plant Protection,
Department of Phytopathology,
University of Belgrade,
Faculty of Agriculture,
Nemanjina 6,
11080 Belgrade,
SERBIA
Email: [email protected]
Viruses cause many important plant diseases with significant agricultural and economic losses, and
also have consequences for biodiversity conservation. Vast majority of plant viruses are completely
dependent on their vectors, mainly insects for their epidemiology, spreading and infecting susceptible
host plants. Changes in vector diversity, efficacy, or epidemiology, as well as changes in interactions
between vectors and host plants, determine the population structure of all plant viruses and their
capability of spatial-temporal spreading. Understanding of virus–vector interactions as epidemiological information is essential to develop effective integrated management strategies designed for
viruses transmitted by vectors. During past decade, our team has developed expertise in research
of detection of new viruses for our country which is in close correlation with the emergence of their
vectors or changes in vector-plant interactions. Our realized and future research topics include
several viruses as model organisms and clarification on their epidemiology throughout investigation
of interactions among viruses, insect vectors and host plants, including thrips transmitted Iris yellow spot virus (IYSV), aphid transmitted cucurbit viruses (Zucchini yellow mosaic virus (ZYMV),
Watermelon mosaic virus (WMV), Cucumber mosaic virus, CMV), etc. Our research objective will
focus on IYSV, Thrips tabaci as its vector, and onion and other known and unknown host plants
in Serbia, and their interaction. The first occurrence of IYSV on onion in Serbia was documented
in 2007 at two localities. In the years following the first outbreak (2008-2013), IYSV was not
detected in any of the tested plants and was, thus, regarded as eradicated. During 2014, serious
outbreaks of IYSV in onion crops planted from true seed were observed in eight locations. Infected
plants showed symptoms suggestive of IYSV infection, with high incidence estimated at over 90%,
leading to nearly total crop failure. A large population of T. tabaci was also noted. Our future
research focus is to identify natural reservoir hosts of the virus, alternative host plants supporting
thrips population, and the most important to determine what triggered such sudden and epidemic
occurrence of the virus in order to contribute in prevention similar outbreaks. Insecticides have
been the primary tactic for T. tabaci management; however, repeated applications often lead to
resistance in the thrips population, suppression of natural enemies, and unsustainable management.
We hope that we will be able to contribute to the efficient control of IYSV and T. tabaci by defining elements in their interaction and thus to prevent substantial onion yield losses in Serbia and
worldwide.
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Expression of whitefly primary endosymbiotic GroEL in plants provides tolerance to several virus families
Henryk Czosnek
Institute of Plant Sciences and Genetics in Agriculture
The Robert H. Smith Faculty of Agriculture, Food and Environment
The Hebrew University of Jerusalem,
Rehovot 76100
ISRAEL
Email: [email protected]
The whitefly Bemisia tabaci is a major pest to agriculture because of its feeding habits and because
it transmits many families of viruses, the begomoviruses being one of the most deleterious. B.
tabaci harbors a diverse fauna of endosymbionts housed in specialized cells called bacteriocytes, including the primary endosymbiont Portiera aleyrodidarum, and several other facultative secondary
symbionts: in Israel, in addition to Portiera, the B biotype harbors Hamiltonella, and the Q biotype Wolbachia and Arsenophonus [1]. The facultative B. tabaci endosymbiont Rickettsia can be
found free in the insect digestive tract of both biotypes. A chaperone GroEL protein produced by
Hamiltonella in B. tabaci B biotype was shown to be essential for the transmission of the begomovirus Tomato yellow leaf curl virus TYLCV to tomato by interacting with the virus coat protein
CP. In contrast, GroEL proteins produced by secondary endosymbionts do not interact with the
TYLCV CP [2]. The facultative endosymbiont Rickettsia found free in B. tabaci and its presence
was correlated with increased amounts of TYLCV associated with the insect digestive tract [3]. The
CP-binding property of GroEL was exploited to engineer tomato and Nicotiana benthamiana plants
expressing the B. tabaci GroEL gene resistant to TYLCV. In these plants, GroEL trapped the virus
in the phloem [4, 5]. The GroEL-producing plants may be used as rootstock to confer resistance to
grafted susceptible plants.
References
[1] Chiel E, Gottlieb Y, Zchori-Fein E, Mozes-Daube N, Katzir N, Inbar M and Ghanim M (2007).
Biotype-dependent secondary symbiont communities in sympatric populations of Bemisia tabaci.
Bull. Entomol. Res. 97:407-413.
[2] Gottlieb Y, Zchori-Fein E, Mozes-Daube N, Kontsedalov S, Skaljac M, Brumin N, Sobol I,
Czosnek H, Vavre F, Fleury F and Ghanim M (2010) The transmission efficiency of Tomato
yellow leaf curl virus is correlated with the presence of a specific symbiotic bacterium species.
J. Virology 84:9310-9317.
[3] Kliot A, Cilia M, Czosnek H and Ghanim M (2014) Implication of the bacterial endosymbiont
Rickettsia spp. in the whitefly Bemisia tabaci interactions with Tomato yellow leaf curl virus. J.
Virology 88:5652-5660.
[4] Akad F, Eybishtz A, Edelbaum D, Gorovits R, Dar-Issa O, Iraki N and Czosnek H (2007) Making
a friend from a foe: Expressing a GroEL gene from the whitefly Bemisia tabaci in the phloem
of tomato plants confers resistance to Tomato yellow leaf curl virus. Arch. Virol. 152:1323-1339.
[5] Edelbaum D, Gorovits R, Sasaki S, Ikegami M and Czosnek H (2009) Expressing a whitefly
GroEL protein in Nicotiana benthamiana plants confers tolerance to Tomato yellow leaf curl
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virus (TYLCV) and Cucumber mosaic virus (CMV), but not to Grapevine virus A (GVA) and
Tobacco mosaic virus (TMV). Arch. Virol. 154:399-407.
Trichoderma and insect control
Maria Cristina Digilio
Laboratorio di Entomologia “E. Tremblay”
Dipartimento di Agraria
Università degli Studi di Napoli "Federico II"
Via Università 100,
Portici,
ITALY
Email: [email protected]
Soil microorganisms living in symbiosis with plant roots can be beneficial, either by promoting plant
growth and its defense response against biotic stressors. PGPFs (Plant Growth Promoting Fungi)
belonging to the genus Trichoderma are among the most widespread soil symbionts, which are effective biocontrol agents of plant pathogens. However, their impact on insect pests is still controversial.
In fact, while several mechanisms active against pathogenic fungi have been described, in the case of
phytophagous insects the increase of plant defense responses can be, in some cases, counterbalanced
by plant growth promotion which may have positive effects on feeding insects. Therefore, it is of
pivotal importance to understand the mechanisms underpinning the plant-Trichoderma interaction
and how this complex symbiosis is modulated by environmental factors. Our group focuses on this
research issue, looking at the symbiosis between tomato plants and Trichoderma, which appears to
be strain-specific. Root colonization by T. harzianum strain T22 results in effective control against
two tomato pests with different plant attack strategies, the aphid Macrosiphum euphorbiae and the
caterpillar Spodoptera littoralis. However, other strains supported aphid growth (T. longibrachiatum MK1) or had an intermediate effect (T. atroviride P1). It is interesting to note that all the
strains considered induce an enhanced production of volatile compounds, reinforcing the indirect
defense barriers as a result of a more intense attraction towards aphid parasitoids. Collectively,
these results indicate that selected Trichoderma strains may offer interesting tools for developing
new IPM protocols against insects.
The role of pathogenesis-related proteins in defense against fungal diseases and
insect pests
Tomas Erban, Bronislava Hortova
Crop Research Institute,
Drnovska 507/73,
Prague,
CZECH REPUBLIC, CZ-16106
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Email: [email protected]; [email protected]
Keywords: pathogenesis-related proteins; proteomics; chitinase; thaumatin; mass spectrometry;
allergen
Plant pathogenesis-related (PR) proteins are produced in plants in the event of a pathogen attack such as bacteria, viruses, fungi or invertebrates. The PRs according to their enzymatic
properties suggested to act against fungi are: PR-2 (β-1,3-glucanases) and PR-3, -4, -8 and -11
(chitinases). Both β-1,3-glucanases and chitinases are able to hydrolyze components of fungal cell
walls β-1,3-glucans and chitin. Also some lipid transfer proteins (PR-14) exhibit the antifungal
activity. Proteinase-inhibitory properties of PR-6 (protease inhibitor) may confer anti-insect and
anti-nematode effects, inactivating the proteins secreted by these pests in the invaded plant tissues. Another candidate for the anti-invertebrate activity is thaumatin, i.e. it has been shown that
maize protein homological to thaumatin is potent in vitro inhibitor of trypsin and α-amylase. We
analyzed storage disease of apple caused by Neofabraea and Alternaria using mass-spectrometry
based proteomics approach. Overall, four proteins were identified after the non-redundant (nr)
NCBI database search: β-1,3-glucanases (PR-2), Mal d 2 and Pru p 2.01B (PR-5), and proteins
of class PR-8. Both pathogenic fungi showed similar proteins identified; the exception was protein
homological to Pru p 2.01B detected only in Alternaria disease. The detected apple proteins belong
to group of proteins with antifungal activity that could play also role in the defense against insects.
The detected proteins are known human allergens; therefore their increased level in fruits means
higher allergy risks.
Insect symbionts mediate interactions at the community level
Enric Frago
Laboratory of Entomology, Wageningen University
Droevendaalsesteeg 1, Building 107
6708 PB Wageningen,
the NETHERLANDS
Email: [email protected]
It has long been known that insect mutualistic symbionts, and bacteria in particular, provide their
herbivorous hosts with nutrients that are missing in the diet. In the last decade, it has become
apparent that these symbionts can be important mediators of direct and indirect (i.e. separated
by more than one trophic link) interactions between insects, their host plants and their natural
enemies. For example, insect symbionts can directly influence host plant range, but also indirectly
through manipulation of plant state or physiology. Symbionts can also benefit their insect hosts
by protecting them from natural enemies. Currently I investigate these interactions using aphids
as a model system. I am particularly interested in the consequences these symbionts have for the
aphid’s host plants, and for aphid-parasitoid communities.
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Insect Reprogrammers and associated bacterial symbionts: From Strategies for
Manipulating Plants to Agriculture
David Giron
Institut de Recherche sur la Biologie de l’Insecte (IRBI)
UMR 7261
CNRS/Université François-Rabelais de Tours
Tours,
FRANCE
Email: [email protected]
Plants constitute key nutritional resources for many organisms on Earth and protect these resources
by enhancing interactions with mutualists while reducing interactions with antagonists. Interactions
with different members of their ecological community can lead to a profound metabolic reconfiguration of the plant’s physiology, which favors beneficial organisms like symbionts and harms antagonists like pathogens or herbivores. Among the insect herbivores that attack plants, some species
have evolved a peculiar feeding strategy that allows them to hijack the plant’s machinery for their
own benefit. By “reprogramming” the plant genome, the insect forces the plant to create specialized
nutritional resources that benefit the insect at the expense of the plant’s growth and reproduction.
This attack strategy can have serious economic consequences in agroecosystems by reducing crop
yield or quality. Mechanisms underlying this attack strategy and the plant’s options for effective
defense remain largely unknown. Our research focus on: 1. physiological modifications induced in
susceptible and resistant plants, 2. changes in phytohormones that accompany these modifications;
3. secreted salivary effectors that are produced by insect ’reprogrammers’ to suppress defense responses and alter plant metabolic processes; and 4. insect bacterial endosymbionts and their role in
the plant reconfiguration. Feeding strategies of a number of different plant-manipulating insects are
compared using an evolutionary framework to discover similarities and differences in their strategies for exploiting plants. Strategies used by insect “reprogrammers” are also compared to those
of antagonistic microbes and nematodes that “reprogram” the plant. Knowledge gained from this
research should contribute to new ideas for using natural plant traits to protect agricultural plants
from biotic stress.
Potato Virus Y infection hinders potato defence response and renders plants
more vulnerable to Colorado potato beetle attack
Kristina Gruden
National Institute of Biology
Večna pot 111,
1000 Ljubljana,
SLOVENIA
Email: [email protected]
In the field, plants are challenged by more than one biotic stressor at the same time. In the present
study, the molecular interactions between potato (Solanum tuberosum L.), Colorado potato bee8
tle (Leptinotarsa decemlineata Say; CPB), and Potato virus YNTN (PVYNTN) were investigated
through analyses of gene expression in the potato leaves and the gut of the CPB larvae, and of
the release of potato volatile compounds. CPB larval growth was enhanced when reared on secondary PVYNTN-infected plants, which was associated with decreased accumulation of transcripts
associated with the antinutritional properties of potato. In PVYNTN-infected plants, the ethylene
signalling pathway induction and induction of auxin response transcription factors was attenuated,
while no differences were observed in JA signalling pathway. Similarly to rearing on virus-infected
plants, CPB larvae gained more weight when reared on plants silenced in the JA receptor gene (coi1).
Although herbivore induced defence mechanism is regulated predominately by JA, response in coi1silenced plants only partly corresponds to the one observed in PVYNTN-infected plants, confirming
the role of other plant hormones in modulating response. The release of β barbatene and benzyl
alcohol was different in healthy and PVYNTN-infected plants before CPB larvae infestation, implicating the importance of PVYNTN infection in plant-to-plant communication. This was reflected
in gene expression profiles of neighbouring plants showing different degree of defence response. The
present study thus contributes to our understanding of plant responses in agro-ecosystems.
Insect Reprogrammers and associated bacterial symbionts: From Strategies for
Manipulating Plants to Agriculture
Barbara H. Łabanowska1 , Małgorzata Tartanus1 , Eligio Malusa1 , Cezary Tkaczuk2 ,
Loredana Canfora3
Research Institute of Horticulture,
Skierniewice,
POLAND
1
Siedlce University of Natural Science and Humanities,
POLAND
2
Council for Agricultural Research and Economics,
Rome,
ITALY
3
Email: [email protected]
Experiments on testing various species of entomopathogenic fungi and nematodes are performed in
our laboratory since several years. We have tested Beauveria bassiana (biopesticide Naturalis) to
control Phytonemus pallidus on strawberry, B. bassiana and Heterorhabditis megidis (as Larvanem)
against Otiorhynchus ovatus and O. sulcatus on strawberry and Beauveria brongniartii (biopesticide
Melocont) against “white grubs” larvae (Melolontha melolontha). The main results will be presented.
In the last two years, the fungi Beauveria bassiana, B. brongniartii (applied as an aqueous suspension
of conidia) and Metarhizium anisopliae (biopesticide Met 52 Granular used as granulate and mixed
with the soil), as well as entomopathogenic nematodes Heterorhabditis bacteriophora (as Nemasys G
and Larvanem applied as an aqueous suspension) and Seinernema kraussei (applied as an aqueous
suspension) have been used to control larvae and adults of O. sulcatus (laboratory experiments) and
to control larvae L1 −L4 of M. melolontha (laboratory and field experiments). The field experiments
have been carried out on strawberry organic plantations. Microorganisms were applied to the soil
before planting the plants and/or on plantations of different ages (one year old and older). The
efficacy of the treatments was assessed by visually checking the health condition of plants (healthy
9
and damaged by the larvae). Microorganisms used in the field reduced the number of damaged
plants at the level of about 50% in comparison to untreated plots. However, when they were
applied before establishing the plantation, the efficacy was 45-67%. The persistence and amount of
microorganisms in the soil was also assessed by DNA-based and microbiological analyses (number of
colony forming units - CFU). In all experiments, following the introduction of the microorganisms
into the soil an increase in the amount of CFU for the relevant species was recorded. We might
conclude that the results obtained in these initial experiments are promising, but the effects of the
treatments are not immediate.
How sensitive are species interactions to stressful environmental conditions?
Anna-Liisa Laine, Marjo Saastamoinen, Minna-Maarit Kytöviita, Stafva Lindström
Metapopulation Research Centre,
PO Box 65,
University of Helsinki,
FINLAND
Email: anna-liisa.laine@helsinki.fi
In their natural populations, plant individuals interact with a diverse community of species associated with either the above-ground (AG) or below-ground (BG) parts of the plant. Simultaneous or
sequential use of a shared host plant may generate a network of interactions whereby species may
affect each other either directly or through host mediated responses. We have studied whether AMF
colonization affects infection by a foliar pathogen of a shred host under natural epidemics. We then
measure rates of AMF colonization in natural populations of the host to understand whether there
is the potential for variation in AMF colonization to generate heterogeneity in disease dynamics, as
suggested by the experimental work. The work was carried out with host plant Plantago lanceolata
L. (Plantaginceae) and its powdery mildew pathogen in the Åland archipelago of Finland. Ongoing
work is focused on investigating the impact of AMF colonization on plant drought tolerance, and
how the effects of drought cascade to higher trophic levels including a specialist insect herbivore
and a powdery mildew pathogen.
Translating from 2-way interactions to 3-way interaction research with fungal
endophytes
Brian R. Murphy
Department of Botany
School of Natural Sciences
Trinity College Dublin,
Dublin 2,
IRELAND
10
Email: [email protected]
At Trinity College Dublin we have been working with novel fungal endophytes recovered from
a wild barley species (Hordeum murinum). We have tested the effects of these endophytes on
biotic and abiotic stress resistance in cultivated barley (Hordeum vulgare). During this research
we discovered that an endophyte related to the nematophagous Metarhizium anisopliae enhanced
several important agronomic traits in barley. We now aim to collaborate with other academic
institutions to research the effects of fungal endophytes on arthropod resistance in important forage
grasses. This research will focus on both root and shoot insect pests, and will form part of a whole
suite of research which aims to manipulate the fungal microbiome to improve forage crops. The
declared purpose of this experimental work is to reduce chemical use in grassland forage systems
through novel technological methods focusing on seed treatment with endophytes.
Enhancement of pollination services as a measure of biodiversity improvement
in Mediterranean cropping systems
Photini Mylona
Institute of Plant Breeding and Genetic Resources
HAO-DEMETER
57001 Thermi
GREECE
Email: [email protected]
In modern agriculture intensified weed management in association to farming practices and monocultures have led to a decline of both plant and invertebrate diversity in arable land and in the surrounding non-cropping areas. To counteract with this biodiversity loss a number of agro-ecological
schemes have been employed that led to the development of a set of measures in the current Common Agricultural Policy (CAP 2014-2020). In that respect border zones and field edges of cropping
systems are essential in enhancing ecosystem’s biodiversity and services, while providing key mitigation measures for buffering. Recent studies have shown that habitat manipulation including
intentional provisioning of natural vegetation along crop edges, and interventions of floral addition
have enhanced beneficial insect activity counting pollination in many agricultural settings, but little research has been conducted in Mediterranean arable land. Mediterranean agro-systems are
complex subjected to a variety of pressures including anthropogenic, natural disasters and environmental perturbations. To date our knowledge is limited of the network of interactions, associations
and mutualisms among agro-system participants, components in response to environmental perturbations. As climate changes will further intensify such perturbations, the need for a comprehensive
understanding of agro-systems interactions and mutualism will provide valuable knowledge and tools
for the development of sustainable management procedures to protect and enhance plant, animal
and microbial diversity in Mediterranean farming areas. The study is focused in enhancement of
ecosystem services by improving floral and plant diversity. In that respect the influences on crop
yield, the invertebrate and the soil microbial communities are explored.
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Tripartite interactions of fungal endophytes and arbuscular mycorrhizal fungi
(AMF)
Kalliope Papadopoulou
University of Thessaly,
Department of Biochemistry and Biotechnology,
Larissa,
GREECE
Email: [email protected]
We are interested to determine factors that act commonly during plant colonization by endophytic
fungi and distinguish key molecular components that lead to mutualistic and beneficial interactions.
We focus our studies on a proprietary endophytic Fusarium solani strain (FsK), which was shown
to be capable of promoting plant growth, protecting against root pathogens and eliciting induced
systemic resistance in tomato plants (1,2). On the basis of this disease protection capability, we
hold a Greek patent. Using a genetic approach of mutant tomato plant lines, we show that colonization and ingress of FsK in tomato roots is affected by ethylene and ABA signalling pathways.
Establishment of colonization is also studied in the model legume Lotus japonicus. The interaction
between FsK and AMF is investigated in L.japonicus roots, co-inoculated with both fungal strains.
Colonization patterns are recorded and quantitatively assessed. Genes involved in signaling during
AMF establishment are analysed. In addition, towards a more applied point of view, we perform a
series of experiments to examine effects on plant growth in various plants (tomato, lettuce, olive),
grown under normal or under abiotic stress conditions. A main focus is on osmotic stress alleviation effects (salinity and water stress). The mycorrhizal strains used in the latter studies also
include newly isolated strains from organically cultivated field sites or from marginal ecosystems in
Greece, that comprise a large collection available in our laboratory. Isolates from the same localities/rhizospheres are tested on their own or in combination (reconstructed communities) to assess
potential complementarity effects.
[1] Kavroulakis N, Ntougias S, Zervakis G, Ehaliotis C, Haralampidis K. Papadopoulou KK (2007)
Role of ethylene in the protection of tomato plants against fungal pathogens conferred by an endophytic Fusarium solani strain. Journal of Experimental Botany, 58 (14): 3853-3864
[2] Karpouzas DG, Karatasas A, Spiridaki E, Rousidou C, Bekris F, Omirou M, Ehaliotis C, Papadopoulou KK (2011) Impact of a beneficial and of a pathogenic Fusarium strain on the fingerprinting based structure of microbial communities in tomato (Lycopersicon esculentum Milll.)
rhizosphere. European Journal of Soil Biology, 47: 400-408.
Induced plant defences mediated by glandular trichomes in tomato: mechanism
of induction and implications for plant-insect-natural enemy interactions
Eduardo de la Peña
Ghent University,
Faculty of Science,
Department of Biology
K.L. Ledeganckstraat 35,
12
Ghent 9000
BELGIUM
Spanish National Research Council,
Institute for Mediterranean and Subtropical Horticulture
Finca Experimental La Mayora,
Algarrobo-Costa 29750,
SPAIN
Email: [email protected]
Tomato, Solanum lycopersicum is one of the most important crops worldwide, but its agricultural
production is often severely impaired by different insect species that adversely affect its growth
and productivity. Some species of aphids (Aphididae) and the whitefly (Bemisia tabaci) occupy
a prominent place as they not only limit the growth of the plant but are vectors of devastating
viruses and other plant-pathogens. On a global scale, the managing strategies for these insect pests
mainly rely on the use of insecticides which often result in the development of insect resistances.
This situation requires improving and developing alternative production methods that reduce the
use of phytochemicals. In this sense, there are two complementary lines: (1) the development of
crop varieties resistant to insects (2) improving biological control strategies using natural enemies of
insect pests. In either case, it is necessary to understand the defense mechanisms of the plant as they
mediate not only the interaction between plant and the insect herbivores, but also the interaction
with natural enemies. Glandular trichomes show a key role in the defense against herbivorous insects
as they are involved in direct defenses (by producing acylsucroses) and indirectly by producing other
allelochemicals that potentially mediate the interaction of the plant with the herbivorous insects and
their natural enemies. Moreover, induced defenses mediated by trichomes depend of other biotic
factors acting on the plant, such as the interactions of the plant with different groups occurring in
the soil (e.g. mycorrhizal fungi) and the genetic background of the tomato; since not all tomato
lines have the same natural defenses. During this meeting, the current research and knowledge gaps
regarding the mechanisms of defence in tomato in relation with multitrophic interactions will be
outlined.
Genetic variation drives ecological outcomes of the three-way interaction between plant herbivores and microorganisms
Sergio Rasmann
Institute of Biology
Université de Neuchâtel
CH-2000 Neuchâtel
SWITZERLAND
Email: [email protected]
Accumulating evidence indicates that arbuscular mycorrhizal fungi (AMF) can affect plant interactions with other organisms, including above- and belowground herbivores, but the mechanisms
underlying these effects remain unclear. I will here show that plant attractiveness and resistance to
foliar and root herbivores is mediated by intra and interspecific variation of plants and mycorrhizae.
13
First, I will show that AMF genotypic variation drives host plant selection for caterpillar larvae.
Similarly, root herbivores tend to differentially colonize different plant species, but this is mainly
mediated by the quantity of AMFs on the plants. Finally, I will show that deficient plants in phytohormonal production can benefit AMF colonization for better resisting herbivores. Taken together,
our findings suggest that AMF should be incorporated in future studies investigating ecology and
evolution of communities and biotic interactions.
Utilizing rhizosphere competence of entomopathogenic or insect associated fungi
to enhance crop production and resistance to soil pests
Jaka Razinger, Hans-Josef Schroers
Agricultural Institute of Slovenia
Hacquetova ulica 17,
Ljubljana, SI-1000
SLOVENIA
Email: [email protected]
Keywords: Agriotes spp., biological control, cabbage root fly, Delia radicum, endophytes, entomopathogenic fungi, plant-microbe interactions; rhizosphere, wireworms
Soil-borne microorganisms influence significantly abiotic and biotic stress tolerance of crops. Most
interactions between soil-borne microorganisms and plants take place in the rhizosphere presenting
one of the most complex ecosystems on Earth. Interactions are maintained through plant exudations/rhizodeposition, as up to 25% of the net carbon fixed during photosynthesis is released
into the rhizosphere. Rhizodeposits promote the growth and multiplication of microbial cells. We
hypothesized that an increased availability of nutrients (rhizodeposits) in the rhizosphere can be
utilized also by non-plant symbiotic microbial communities. The aim of our research is the development of protective microbial communities in the rhizosphere via bioaugmentation, i.e. the addition
of microbes with plant beneficial metabolic or ecological traits, specifically bioaugmentation with
entomopathogenic or insect associated fungi. Systems such as cabbage root fly (CRF) Delia radicum
(Diptera: Anthomyiidae) on brassicas or Agriotes spp. wireworms on maize and wheat are looked at.
The CRF is a major threat for many brassica crops in Europe; wireworms, the soil-burrowing larval
stages of click beetles (Coleoptera: Elateridae) are major pests of crops including wheat, maize,
and numerous vegetables in many parts of the world. The aim of our studies was to assess the virulence of several entomopathogenic or insect associated fungal strains against laboratory bred CRF
or field-collected wireworms. The fungi were also tested for their rhizosphere competence, plant
tissue colonization (endophytism) and potential growth stimulating effects to cauliflower or maize
and wheat. The following fungal species were tested: Trichoderma atroviride, T. koningiopsis, T.
gamsii, Beauveria brongniartii, B. bassiana, Metarhizium robertsii, M. anisopliae, Purpureocillium
lilacinum and Clonostachys solani. The presentation will show Abbott’s corrected mortality values
of a set of performed experiments. The results showed that rhizosphere competence of the tested
strains to cauliflower varied considerably, possibly due to the ecological preferences of the different
fungal species. Trichoderma spp. colonized the cauliflower rhizoplane most efficiently and were also
most often detected inside plant tissue. C. solani was not detected on the rhizoplane when added
through seed coating inoculation method, but was positively identified on roots inoculated with
colonized agar plugs. This indicates that the method of fungal exposure influences their colonization ability. Regarding maize and wheat, all strains colonized the rhizoplane, however to varying
extent. The isolates tested were not isolated as endophytes in maize and wheat. Some isolates
14
stimulated growth of maize and wheat seedling, whereas others decreased root or shoot length or
biomass. This effect was plant-fungus pair specific. On several occasions, contrasting results were
observed between maize and wheat and the same fungal isolate. We conclude that the ecological
preferences of the fungal species might influence their performance (i.e. virulence to insect pests)
in different environments, method of bioaugmentation influences the plant-microbe interaction, and
plant-microbe interactions can depend on the specific fungal strain and plant cultivar.
Acknowledgments The research was financed partly by the Crop production research group (0401009) of the Agricultural Institute of Slovenia and grant J4-5527 from the Slovenian Research Agency
(ARRS). It was realized in the frame of the EU FP7 Project CropSustaIn, grant agreement FP7REGPOT- CT2012-316205.
Trophic interactions mediated by fungal endophytes
Kari Saikkonen
Natural Resources Institute Finland (Luke)
Management and Production of Renewable Resources
Itäinen Pitkäkatu 3
20520 Turku
FINLAND
Tel. +358 29 532 6510
Email: kari.saikkonen@luke.fi
The ongoing research of my team focuses on ecological and evolutionary implications of genetic,
species and functional diversity of plants (both grasses and trees), microfungi and herbivores by
emphasizing importance of habitat diversity, consequences of human activities and climate change.
Majority of our recent research has concentrated on the role of extended asymptomatic (endophytic)
phase of foliar fungi, and how endophytes should be taken into account in agriculture. Historically
endophytes were found in agronomic arena in 1970’s when agricultural scientists demonstrated that
livestock disorders in USA and New Zealand were attributable to endophyte origin alkaloids.
Noteworthy is that nearly all fungi invading plant foliage have an asymptomatic period in their life
cycle. In the largest sense then, all internal plant fungi are endophytic. The length of asymptomatic
phase varies from an imperceptibly short period, as for many pathogens, to lifelong abeyance in
strictly asexual Epichloë edophytes in grasses. However, the majority of the interactions fall between
these extremes. Because of different viewpoints among the disciplines of natural sciences, endophytic
fungus-plant associations are generally treated separately from parasitic, pathogenic and saprophytic
interactions. However, such a functional distinction is erroneous and may be misleading. Niches
for these fungal groups are often indistinguishable, their ecological role appears to be complex and
labile, and functionally different fungi are sprinkled throughout phylogenetic lineages. Thus, we
propose that (1) the evolution of endophytic fungal life histories and their hosts, like any other
complex ecological interaction, is dynamic, and that (2) varying selection pressures, phylogenetic
constraints, and stochastic factors canalize fungal life history traits somewhere between the extremes
of sexuality and asexuality and pathogenic and mutualistic.
We want to emphasize that despite the seeming “endophyte” stamp of our research, our research
interests lie in the trophic interactions, with particular emphasis on the ecology and life history
evolution of foliar microfungi and their host plants. Throughout our research, common threads
have been (1) plant resistance to microfungi and other plant associated heterotrophic organisms (e.g.
15
herbivores and mycorrhizae) and (2) fungal mediated trophic interactions in changing environments.
This has required a multidisciplinary approach combining both theory and experimental work, and
a good overall picture of ecosystem functions.
Indeed, we are convinced that more knowledge about multi-species interactions is required to fully
understand bilateral ecological interactions between plants and organisms subsisting on them. This
perspective provides novel insights into agricultural entomology in changing environmental conditions in the future.
References
[1] Saikkonen, K., S.H. Faeth, M.L. Helander and T.J. Sullivan (1998): Fungal endophytes: a
continuum of interactions with host plants. Annual Review of Ecology and Systematics 29:
319-343.
[2] Saikkonen K., U. Ahonen-Jonnarth, A.M. Markkola, M. Helander, J. Tuomi, M. Roitto and
H. Ranta (1999): Defoliation and mycorrhizal symbiosis: a functional balance between carbon
sources and below-ground sinks. Ecology Letters 2: 19-26.
[3] Ahlholm, J., M. L. Helander, P. Elamo, I. Saloniemi, S. Neuvonen, And S. Hanhimäki and
K. Saikkonen (2002): Micro-fungi and invertebrate herbivores on birch trees: fungal mediated
plant-herbivore interactions or responses to host quality? Ecology Letters 5: 648-655.
[4] Saikkonen K., Wäli P., Helander, M. and S.H. Faeth (2004) Evolution of endophyte-plant symbioses. Trends in Plant Science 9: 275-280.
[5] Lehtonen, P., M. Helander, M. Wink, F. Sporer and K. Saikkonen (2005) Transfer of endophyteorigin defensive alkaloids from a grass to a hemiparasitic plant. Ecology Letters 8: 1256-1263.
[6] Lehtonen, P., M. Helander, S. Siddiqui, K. Lehto and K. Saikkonen (2006) Endophytic fungus
decreases plant virus infections in meadow ryegrass (Lolium pratense). Biology Letters 2: 620623. (doi:10.1098/rsbl.2006.0499).
[7] Saari, S., J. Sundell, O. Huitu, M. Helander, E. Ketoja, H. Ylönen and K. Saikkonen (2010)
Fungal-mediated multitrophic interactions - do grass endophytes in diet protect voles from predators? PLoS ONE 5(3): e9845. doi:10.1371/journal.pone.0009845.
[8] Vesterlund, S.-R., M. Helander, S. H. Faeth, T. Hyvönen and K. Saikkonen (2011) Environmental
conditions and host plant origin override endophyte effects on invertebrate communities. Fungal
Diversity 47: 109-118.
[9] Saikkonen, K., K. Taulavuori, T. Hyvönen, P. E. Gundel, C. E. Hamilton, I. Vänninen, A.
Nissinen and M. Helander (2012) Climate change-driven species’ range shifts filtered by photoperiodism. Nature Climate Change 2: 239–242, Doi:10.1038/Nclimate1430
[10] Saikkonen, K., K. Ruokolainen, O. Huitu, P. E. Gundel, T. Piltti, C. E. Hamilton and M.
Helander (2013) Fungal endophytes help prevent weed invasions. Agriculture, Ecosystems and
Environment 165: 1-5.
[11] Wäli, P. P., P.R. Wäli, K. Saikkonen and J. Tuomi (2013) Is the pathogenic ergot
fungus a conditional defensive mutualist for its host grass? PLoS ONE 8(7): e69249.
doi:10.1371/journal.pone.0069249.
[12] Gundel, P. E., L. I. Pérez, M. Helander and K. Saikkonen (2013) Symbiotically modified organisms: non-toxic fungal endophytes in grasses. Trends in Plant Science 18: 420-427.
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[13] Saikkonen, K., P. E. Gundel and M. Helander (2013) Chemical ecology mediated by fungal
endophytes in grasses. Journal of Chemical Ecology 39: 962-968.
[14] Li, T., J. D. Blande, P. E. Gundel, M. Helander and K. Saikkonen (2014) Epichloë
endophytes alter inducible indirect defences in host grasses. PLoS ONE 9(6): e101331.
doi:10.1371/journal.pone.0101331.
[15] Saikkonen, K., J. Mikola and M. Helander (2015). Endophytic phyllospere fungi and nutrient
cycling in terrestrial ecosystems. Current Science 109: 121-126.
Beneficial endophytes: Development of biofertilizers and biocontrol products
Carolin Schneider
Institut für Pflanzenkultur e.K.,
Inoq GmbH,
GERMANY
Email: schneider@pflanzenkultur.de
Plants are colonized by diverse microbial communities containing of bacterial, archaeal, fungal and
protistic taxa. Some of these microbial endophytes promote plant growth and protection against
biotic and abiotic stress by triggering the host induced systemic resistance response, production of
antibiotics and other secondary metabolites, synthesis of phytohormones, ACC deaminase, solubilization of phosphor in soil, assimilation of nutrients and fixation of atmospheric nitrogen. These
beneficial characteristics render endophytes (well-known: mycorrhiza) attractive for biotech companies producing biofertilizers and biocontrol agents for agriculture, forestry and horticulture. But
the endophytic lifestyle also bears unknown facts: F.e. can phytopathogens change their liefstyle
and be “sleepers”? Some examples of our industrial and scientific work:
1. Endophytic bacteria from different excellent-growing in vitro clones of Prunus avium (Wild
cherry for timber or veneer) are isolated and cultivated. In a second step their ability to
produce auxin, ACC deaminase, siderophores and solubilize phosphor via spectrophotometric
measurements and plate assays as markers for plant growth promotion have been tested.
Inoculation of poorly growing cherry clones with bacterial suspensions of selected endophytes
improved plant quality.
2. A mycorrhizal inoculum manufacturer has to face that definition of quality in those products
is still controversial: Is it the richness of the inoculum (number of spores or propagules)?
Is it based on the tests of most probable number (MPN)? Quality could be also based on
the capacity of the inoculum to induce/elicitate the plant to establish mycorrhizal symbiosis.
With the use of different elicitors, applied both in leaves and in the substrate/soil, increased
mycorrhizal colonization rates and spore production are achieved.
3. There are observations that the phytopathogen Rhabdocline pseudotsugae can live latently
as endophyte in seeds and trees of Pseudotsuga menziesii (Douglas fir) without causing any
symptoms. With lightmicroscopy of callus, induced from seeds, specific fungal structures could
be discovered.
17
4. Finally the use of insects as vectors for inoculation of beneficial endophytes is promising in
future.
Aphid-plant-microbe interactions: from ecological to functional studies
Jean-Christophe Simon
INRA
Institute of Genetics, Environment and Plant Protection
UMR 1349, IGEPP,
FRANCE
Email: [email protected]
Aphids are engaged in multiple forms of interactions with micro-organisms. In addition to their
obligate symbiont (Buchnera aphidicola), these insects may harbour one to several heritable facultative bacterial symbionts from Proteobacteria and Mollicutes. While obligate symbionts supply
aphids with key nutrients, facultative symbionts influence their hosts in many ways such as protection against natural enemies, heat tolerance, color change and reproduction alteration. Besides
heritable symbionts, little is known about gut associates, the bacteria colonizing the aphid digestive tract. In my group, we are working on aphid-microbe-plant interactions with three types of
objectives: First, we analyse the diversity and structure of aphid microbial communities in relation
to host ecology. For that, we characterize microbial communities hosted by aphids by using with
and without a priori techniques (next generation sequencing) and attempt to link environmental
factors with aphid microbiota. Second, we study the influence of microbial communities on the
host. This is achieved by measuring different traits on natural and manipulated aphid lines with
different symbiotic composition and by carrying out the biological and functional validation of symbiont effects. Third, we wish to better understand the dynamics of symbiotic associations by gaining
knowledge in costs and benefits of symbiont infection, in within-host interactions, in acquisition and
loss events of microbial partners, and sources and routes of transmission of microbial communities
within ecological network. Most of these researches are performed on the pea aphid, Acyrthosiphon
pisum, and its microbial associates, in interaction with legume species and natural enemies (aphid
parasitoids and predators).
Plant-microbe-insect interactions across space
Ayco Tack
Department of Ecology, Environment and Plant Sciences
Stockholm University
Stockholm
SWEDEN
18
Email: [email protected]
Microbes and insects frequently interact within terrestrial food webs. Despite this, we know little
about i) their patterns of co-occurrence across spatial and temporal scales and ii) the impact of
their interactions on the structure of plant-based communities. In our study, we investigate the
metacommunity dynamics of specialist pathogens and insects sharing the same spatially fragmented
resource (the oak tree Quercus robur ). We focus on a target set of 89 oak trees on which we have
tracked spatial and temporal variation in the composition of the insect and pathogen community
for already 12 years. As of 2014, we have added the monitoring of microclimatic conditions. More
recently, we have started to explore the role of endosymbionts within this food web. Overall, our
findings indicate that knowledge on microbe-insect interactions may be crucial for understanding
the dynamics of plant-based food webs.
Hormonal dynamics in the roots of Brassica napus during infection with Plasmodiophora brassicae - comparison of tolerant and sensitive cultivar
Radomira Vankova
Institute of Experimental Botany AS CR
Rozvojova 263
165 02 Prague 6
CZECH REPUBLIC
Email: [email protected]
Plasmodiophora brassicae is a soil pathogen, which infects readily Brassica napus plants. Recently,
it has been spreading in a worldwide scale. As the resting spores of this pathogen can stay viable
in the soils for more than twenty years, the long-term contamination of soils has become a serious
problem. The aim of our study is to characterize differences in hormonal pools of resistant and
sensitive cultivars, both under control conditions and during the infection, in order to contribute
to the selection of more resistant cultivars. When sensitive cultivar Hornet was compared with
the resistant one Alister, we detected earlier elevation of cytokinins and auxins, plant hormones
involved in gall formation, in roots of sensitive cultivar. The increase in auxins and cytokinins was
accompanied (or followed) by elevation of gibberellin GA4 in both cultivars. In contrast, elevation
of the stress hormone salicylic acid was delayed and not so profound in Hornet. In this cultivar,
the early increase of abscisic acid was found. The achieved results indicate an intensive cross-talk
among plant hormones, as well as difference between the magnitude and dynamics of the response
among the sensitive and resistant cultivars.
Biotic-abiotic interactions in Portuguese common bean. A case study
Maria Carlota Vaz Patto
ITQB
Av. da Republica, EAN
Apartado 127
19
2781-901 Oeiras,
PORTUGAL
Email: [email protected]
Plants respond to multiple stresses in a different way from what they do to individual stresses, activating a specific programme of gene expression to the exact environmental conditions encountered.
These responses are very complex and involve changes in many levels such as physiological, cellular
and transcriptional. Understanding the molecular basis of multiple stress resistance is of primary
importance for the development of breeding approaches, since the combination of an abiotic stress
with a biotic stress can result in reduced or enhanced disease severity. Common bean (Phaseolus
vulgaris L.) has a history of more than five centuries of cultivation in Portugal. Diverse landraces are
still widely grown at farmers’ fields, commonly in intercropping systems, for example with maize.
These traditional landraces, well adapted to local environmental conditions and to quality farmers’ preferences, may represent important sources of biotic and abiotic resistance, not yet explored
in breeding programmes. Screening this germplasm for resistance against major diseases affecting
common bean, such as fusarium wilt and rust and simultaneously also for water deficit tolerance
may reveal new interesting sources common to all these stress factors. Through a Genome-Wide
Association Study, we are generating a comprehensive view of the genetic control of drought, rust
and fusarium wilt resistance in this germplasm, revealing their potential interactions. A subsequent
transcriptomic analysis of contrasting landraces will allow us to identify pathways and candidate
genes involved in the multiple-stress response. This approach, at the same time that will value this
national germplasm, will also provide novel molecular tools, such as functional markers for multiple
selection, to expedite common bean multiple stress resistance improvement.
Pathogens influence on interacting populations
Ezio Venturino
Dipartimento di Matematica “Giuseppe Peano”,
Università di Torino,
via Carlo Alberto 10,
10123 Torino,
ITALY
Email: [email protected]
In this talk I would like to briefly present the type of models that I study and how these investigations
can reveal phenomena that at first sight may be unforeseen. Mathematical modelling via dynamical
systems can help in assessing the future behavior of ecosystems. It is instrumental in planning
actions to possibly drive them toward the ultimate desired or expected configuration. Some examples
will be outlined involving: biological control in fruit orchards and vineyards; an epidemiological
model for goat breeding; the interplay of herbivores, grass and trees.
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Plant pathogenic fungi in Croatia
K. Vrandečić and J. Ćosić
J. J. Strossmayer University,
Faculty of Agriculture in Osijek,
Kralja Petra Svačića 1d,
31 000 Osijek,
CROATIA
Email: [email protected]
Most fungi are associated with plants as saprotrophs and decomposers but one very important
group is plant pathogenic fungi. Crop losses to pathogens continue to reduce available production
of food and the total global potential loss due to fungi and bacteria could be more than 80%. During past decade, our team has been focused in research of detection of new and emerging fungal
pathogens of arable crops (Alternaria helianthinficiens, Diaporthe phaseolorum etc.) cereals (Puccinia striiformis, Fusarium venenatum, Fusarium concolor etc.) vegetables (Fusarium oxysporum
f.sp. lycopersici, Uromyces lineolatus etc.) and ornamental plants (Septoria lavanulae, Fusarium
sporotrichioides etc.) for our country. Except that, one of our research objective was focused on
application of biofungicide based on Trichoderma harzianum spores against Pythium debaryanum
and Rhizoctonia solani in tomato, cauliflower and lettuce seedlings production. In all tested crops
biofungicide showed statistically significant reduction of diseases compared with untreated control
and application of two chemical fungicides. Boifungicide on the base of T. harzianum also showed
good results as growth promotor. Important part of our investigation was related with weeds as
alternative hosts for fungal pathogen. We found out that many fungi, known as crops pathogens are
developed on alternative hosts (e.g. Diaporthe helianthi, Diaporthe longicolla, Fusarium graminearum etc.). On the other hand they can also serve as host to mycopopulation, which usually does
not attacks cultivated plants (e.g. Alternaria crassa, Erysiphe convolvuli, Puccinia malvacearum
etc.) and many research are directed towards the use of fungi in biological control of weeds.
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