Download out line of plant communication

Bio communication in plants: Who is talking, who is listening?
COMMUNICATION

What is communication?

The term communication covers just about any interaction with another person it
includes sharing information, ideas and feelings between people.

Communication is a two way process when you communicate you perceives the other
persons responses and react with your thought and feelings.

Necessity of communication:
 For proper growth, development and survival communication is must needed.
 Communication leads to co operation and co operation is a very genuine instinct in all living
creatures which help the cycle of life running.
 Communication helps keeping a range of relationship from a individual to species level.
 Communication is essential for defend enemies.
 Communication (both above ground and under ground ) is much needed to cope with change
in external environment.

IS PLANT COMMUNICATE? IF YES HOW?
 As in all organism the evolution, development and growth of plant depend on complex
communication process.
 These communication processes are primarily sign mediated interactions not only simply an
exchange of information and also they involve active co ordination and active organizational
signal transduction.
 Simply a wide range of chemical substances and physical influences serves as signs.

WHAT ARE SIGNS? HOW THEY PLAY ROLE IN PLANT COMMUNICATION
 Signs may be signals or symbols. It’s most oftenly chemical molecules (secondary metabolites)
produced by plants.
 The sign is used to obey semiotic rules
VOCABULARY OF PLANT COMMUNICATION

As from last slide discussion we were little aware that communication process in plants are
signals or signs, so its obvious the vocabularies used by plants must be chemically origin or
chemical related.

NEURO TRANSMITTERS IN PLANT COMMUNICATION
 Only vocabulary is not sufficient for proper communication, along with vocabularies some
neuro transmitters which play role in information processing, sensing, growth, development
and storage of information is needed.
 Interestingly among the metabolic neuro transmitters acetylcholine, catecholamines,
histamines, serotonin, dopamine, melatonin, GABA and glutamate which are most common in
animal nervous system is present in plant often at high concentration as noted by scientists.

SOME STRONG EVIDENCES OF NEURO TRANSMITTERS
 Among all these neuro transmitters, strong evidence now supports glutamate as a signaling
molecule in plants, due to discovery of some glutamate receptors in Arabidopsis.
 A glutamate receptor (BMAA) served as a useful compound for morphogenesis in plant.
 Several tryptophan derivatives investigated for their role in signaling and storage of
information such as serotonin and melatonin.
 The role of auxin as a neuro transmitter is not forgettable is plays a regulatory role in plant
growth and development.
PLANT MEMORY
 The detection of resources and their periodic cyclic availability plays a key role in plant
memory, planning, growth and development.
 For example young trees of arid region obtain water only once a season in a year, they
learned to adjust to the following seasons and concentrate their entire growth and
development precisely on that expected period of water availability.
 Some chemicals are also found plays a major role in plant memory. These are tryptophan
derivatives such as serotonin and melatonin.

TYPES OF PLANT COMMUNICATION

INTERPRETATION OF MECHANICAL INFLUENCES
 Mechanical contact has influence on the over all organism in the cell level in plants, it includes
contact and wounding.
 Responds to contact involve signal molecules and hormones along with intra cellular calcium
reactive oxygen species, octadeconoids and ethylene.
 Some of genes also expressed in relation to contact for example genes codes for calcium
binding proteins, cell wall changes, defence, transcription factor and kinase proteins.

PHENOMENON OCCUR INSIDE A PLANT DUE TO MECHANICAL INTERPRETATION:
 Change in osmotic condition (e.g.venus fly trap, Mimosa pudica).
 Immediate drop in electrical resistant in stem.
 Callose synthesis.
 Localized block of phloem transport.
 Increase in ethylene production.
 Discardation of pollens.
 Growing towards sunlight.

PLANT COMMUNICATION WITH NON PLANT ORGANISM

INTERACTION OF PLANT WITH INSECTS

INTERACTION OF PLANT WITH INSECTS
 When plants are attacked by pest they emit volatiles which allows them to attack parasites
either directly by producing substances that deterred them .
 Indirectly attracting other insects or parasites which are natural enemies of the attacking
species.
 When plants attacked by pests they produce aromatic substances that warn other plants then
the uninjured plant rapidly produce enzymes that makes leaves unpalatable for insects.

CASE STUDY IN LIMABEAN AND TOMATO

In lima bean and tomato a total number of three defence strategies have been discovered.

CHEMICALS INVOLVED IN DEFENCE

CO ORDINATION OF DEFENCE AGAINST PESTS
 COMMUNICATIVE CO –ORDINATION OF SYMBIOSIS
 Simply symbiosis is a phenomenon of relationship between two organisms in which both are
benefited and no one is harmed.
 Plants depends on ability of root to communicate with microbes ,the converse is also true t
hat is many bacteria & fungi also depends on plant root or root exudates for their successive
life process.
 A chemotactic response to wards root secreted organic & amino acid is the first step in
symbiosis.

TYPES OF COMMUNICATIVE SYMBIOSIS IN PLANT

SYMBIOSIS OF RHIZOBIUM WITH LEGUMES
 Rhizobium is free living bacteria in soil, but when they approach the plant root they are
assume to be an alien invader.
 The plants response with an oxidative burst producing a mixture that contains super oxide
radical, hydrogen peroxide and NO2.
 This redox based oxidative burst involving glutathion and homoglutathion is critical for
determining the fate of infection process and influences whether further steps occur or not.

CHEMICALS SIGNS USED BY PLANTS FOR SYMBIOSIS
 The plant roots also release flavonoid inducer molecules that stimulate rhizobial colonization.
 In response to that molecular message rhizobia produce their own signaling compound called
Nod factors.
 Upon receive of nod factor message gene expression in the outer cell (epidermal) is altered so
that root hair deformed and infection thread is formed and the process continued.

SYMBIOSIS WITH MYCORRHIZA
 Mycorrhiza (Greek- fungus root) formed mutualistic relationship with some limited species of
plant.
 Mycorrhiza can be broadly classified into endomycorrihza and ectomycorrihza.
 The development of ectomycorrihza starts with growth of a fungal mycelium around the root.
 Then it produce signaling molecule that limit the growth of root hair and fungus colonizes
around the root and extend hyphae to the soil forming hartig net.

SERVE FOR SERVE BETWEEN PLANT AND MYCORRHIZA
 Most of the Mycorrhiza associated plants synthesis sugars such as mannitol and trehalose that
can’t be used by the plant and can only be assimilated by Mycorrhiza.
 In return to that Mycorrhiza provide number of service to plant like nutrient uptake (N and P)
and resistant from drought and disease etc.
 Along with that some bacteria like organisms (BLO’s) Burkholdria cepacia interacts with plant
fungal communication and contribute nitrogen metabolism.

COMMUNIACATION OF PLANT WITH PATHOGENIC BACTERIA
 Genetics of plant bacterial communication
(gene for gene hyphothesis , Flor, 1940)
 Quorum sensing and signal transduction environment
Mechanism of ensuring that sufficient cell number of given species are present before
elicting a biological response( production of AHL).
 Some chemicals secreted by plant root to rhizosphere which has direct defence activity(Ferulic
acid, butanoic acid and p- coumaric acid).

COMMUNICATION OF PLANT WITH FUNGUS
 Several fungal proteinaceous and non proteinaceous elicitors are known to induce defense
responses of host plant. E.g. oligo N-acetyl glucosamine and oligogalactosamide

where as elicitors a type of protein (toxin) secreted by oomycetes are known to have specific
elicitor activity as a glycoprotein and heptaglucan from the oomycetes pathogens.
 In response to the fungal toxin a signal transduction occurs to host nucleus which stimulate
the secretion of enzyme chitinase & rapid oxidation of peroxidases & poly phenoxydases &
silicon linked cellulose occour which prevents pathogenicity.

MECHANISM OF COMMUNICATION WITH FUNGI & BACTERIA

SOME ANTIBACTERIAL AND ANTI FUNGAL SECONDARY METABOLITES

PLANT COMMUNICATE WITH OTHER PLANT
 Allelopethy:
the phenomenon of having one plant having detrimental effect on another through
the production and release of toxic chemicals is known as allelopathy.
 Allelochemicals:
these are the secondary metabolites in plant metabolism vary from simple molecule
such as ammonia to complex conjugated flavonoids such as phlorizin (extracted from apple roots and
heterocyclic alkaloid caffeine).

EXAMPLES OF SOME ALLELOCHEMICALS

EFFECTS OF ALLELOCHEMICALS

PROPERTIES OF ALLELOCHEMICALS
 These are plant root or above ground chemicals many of which are species specific.
 Many of these chemicals are exudates into the rhizosphere and can move at least decimeters
from their source.
 Chemicals in root exudates have powerful and apparently non controversial ecological effect
on animals, bacteria , virus and fungi.

BIOCOMMUNICATION OF PLANT WITHIN THEIR BODY
1.Intercellular communication:
 intercellular communication informs other plant parts about events in specific organs or
regions of plant E.g. sugar production in leaves, reproduction in flowers and resource
utilization by roots.
 Plant cell are connected by plasmodesmata. This connecting channels enable the flow of small
molecules as well as ions, metabolites and hormones and allow the selective exchange of
macro molecules.
2.Intracellular communication:

It indicates sign mediated interactions which occurs within the plant cell.

Intracellular communication in plant transforms and transmits external messages into internal
messages that exert a direct influence on DNA storage medium and trigger genetic process.

This leads to the production of signal molecule that generates a response behavior.

Intra cellular communication offers viruses the opportunity to integrate certain genetically
coded abilities of the host into their own genome or to inegrate their own genetic data sets
into the host genome.

ENVIRONMENTAL PLANT INTERACTION
The external environment and plant communication based on presence of hormones

1. plant bends towards light due to auxin.

2.seed germinate in presence of water due to gibberellins.

3.fruits ripe due to increase in respiration enhances by increase in temperature due to
ethylene.

4. flowers produced on plants in presence of appropriate photoperiod and thermo period due
to florigen.

ROLE OF HORMONES IN PLANT ENVIRONMENTAL INTRACTIONS

Auxin moves in response t light

Response of gibberellins to water

SOME HORMONES PLAYS A ROLE IN PLANT ENVIRONMENT INTRACTION

OVERALL MECHANISM OF PLANT COMMUNICATION

CONCLUSION

By studying the plant bio communication process we can solve various problems like

Genetic and physiological aspects of disease resistant.

extraction of green leaf chemicals

knowledge about interaction of plant and Mycorrhiza association

Finding of some novel chemicals and some unknown bio chemical pathways.