Download 22_CePACT on the movement of Germplasm material

“Role of the Centre for Pacific Crops and Tree’s in the sustainable conservation and the
safe movement of plant material”
Valerie Saena Tuia, Logotonu Meleisea Wainaqabete, Amit Sukal, Sainimili Baculacula, Ulamila Lutu, Arshni
Shandil, Unaisi Davete and Rohini Prasad
Centre for Pacific Crops and Trees, Secretariat of the Pacific Community, Suva, Fiji
Abstract: The Centre for Pacific Crops and Trees (CePaCT), a Pacific Genebank, based in Narere
Fiji is an investment by the Secretariat of the Pacific Community established in response to the
Heads of Agriculture and Forestry Meeting (HOAFS, 1996) recommendation to put in place policies
to conserve, protect, and best utilize plant genetic resources in countries and through regional
cooperation. CePaCT assists Pacific island countries (PICs) to sustainably conserve and utilize their
plant genetic resources as well as sourcing improved crop diversity to address food and nutritional
security and for improved resilience to climate change. The Centre uses in vitro technology to
conserve collections of some of the Pacific’s important staple crops, and such as taro (Colocasia
esculenta) and other edible aroids (alocasia (Alocasia macrorrhizos), swamp taro (Cyrtosperma
merkusii), xanthosoma (Xanthosoma sagittifolium)), banana (Musa sp), breadfruit (Artocarpus altilis),
cassava (Manihot esculenta), sweet potato (Ipomoea batatas) and yam (Dioscorea sp). Other collections
conserved by the Centre include kava (Piper methysticum), potato (Solanum tuberosum), vanilla
(Vanilla fragrans) and some selected tree species (Pandanus tectorius and Santalum sp). CePaCT
conserves a unique global collection of taro, largest in the world, comprising of over 1,100 taro
accessions from the Pacific and Asia. CePaCT has a “state of the art” virus indexing facilities that
virus test germplasm using internationally approved protocols in order to facilitate distribution of
crop diversity (improved and traditional) to farmers. The Centre does virus indexing on aroids,
banana, sweet potato and yam. Over 56,000 tissue culture plantlets from 14 crops have been
distributed by the CePaCT from January 2001 to June 2012, to 46 countries including 24 PICs. In
vitro technology is considered one of the safest and efficient methods available for the international
movement of germplasm.
Key words: CePaCT, edible aroids, virus indexing, in vitro conservation, resilience, crop diversity
1. Background:
The establishment of the Centre for Pacific Crops (CePaCT) by the Secretariat of the Pacific
Community (SPC) is a result of all the past and ongoing efforts that started in early 1990 under a
European Union project titled “The provision of tissue culture services to the Pacific region” that
was based at the University of the South Pacific in Samoa. The importance of the tissue culture
services was further strengthened when the taro industry of both Samoas was devastated by the
outbreak of taro leaf blight (TLB) disease in 1993, has resulted in the loss of food security, export
market, increased erosion of susceptible traditional varieties and increased vulnerability of other
Pacific countries to TLB. The importance of sharing tolerant genetic diversity from outside of
Samoa was also realized and taro varieties from Philippines, Palau and Federated State of
Micronesia were brought in as tissue culture material to help restored food security. These TLB
tolerant lines have formed the basis of new breeding programs to generate new diversity of taro in
Samoa as a long term solution to TLB and sustainable food security. The Samoa TLB disaster has
also prompted a 5 year AusAID Taro Genetic Resources: Conservation and Utilisation (TaroGen)
that began in 1998 and coordinated by SPC. The aim was to re-collect all taro genetic resources
of the Pacific, have them characterized, DNA fingerprinted for selection of a core collection and
have it virus indexed for sharing by all partners. Capacity building on DNA fingerprinting and
virus indexing was provided for regional staff and technology transfer was also part of the
project. With funding provided by the AusAID, the Regional Germplasm Centre (RGC) was
established, however the RGC has its name changed to CePaCT in 2007 recognizing the
importance of trees in the food supply systems and other income generation activities. The initial
SPC’s global taro collection comprises of taro established under this AusAID TaroGen regional
project. Through importance of SPC networking and sharing of germplasm, the EU Taro
Network for the South-east Asia and Oceania (TANSAO) enabled the Pacific countries to access
new diversed genepool of Asian taro with tolerant traits to TLB. These new TLB lines progenies
of Pacific and Asian parentage are widely distributed within the Pacific for evaluation. The
importance of sharing and accessing new diversity outside the region, Pacific countries through
SPC have agreed to place Annex 1 regional crop collections held in trust by SPC CePaCT into the
Multilateral System (MLS) of the International Treaty for Plant Genetic Resources for Food and
Agriculture (ITPGRFA). In June 2009, Hon Taua Kitiona Seuala, a Samoan Agricultural Minister
then on behalf of Pacific Ministers of Agriculture and Forestry has signed the agreement at the 3rd
Session of the Treaty Governing Body. All germplasm exchange and distribution from SPC have
to be accompanied by the Standard Material Transfer Agreement provided under the ITPGRFA.
The use of tissue culture technology by CePaCT involves the growing of crops under aseptic
controlled conditions and is widely used for commercial propagation of many plants (Dodds and
Lorin., 1982). There are multiple advantages of the in vitro system: [i] as a safe method for
preservation and conservation of plants for future use, [ii] all year production of planting material,
[iii] plant can be manipulated for increased multiplication rates, [iv] virus-indexed status of the
crops allows for safe distribution without any quarantine risks, [v] sterility state of plant material
provides for easier access to diversity from within and outside of the region and [vi] cost-effective
method for distribution of plant material due to small size, easier and cheaper.
The CePaCT continues to provide services to the region through sustainable conservation and
utilization of their plant genetic resources as well as sourcing improved crop diversity to address
food and nutritional security and for improved resilience to climate change.
2. Conservation:
The Centre uses in vitro technology to conserve over 2,000 accessions of some of the Pacific’s
important staple crops, and such as taro and other edible aroids (alocasia, swamp taro,
xanthosoma), banana, breadfruit, cassava, sweet potato and yam. Other collections conserved by
the Centre include kava (Piper methysticum), potato (Solanum tuberosum), vanilla (Vanilla
fragrans) and some selected tree species (Pandanus tectorius and Santalum sp). SPC is a current
recipient of a long term funding by the Global Crop Diversity Trust (the Trust) recognizing
CePaCT asone of the leading Worlds Genebank Centre for conserving a unique in vitro global
taro collection of over 1,100 accessions from the Pacific and Asia. SPC is the first non-CGIAR
Centre to have received this funding from the Trust.
At the request of the countries, the Centre also conserves important cultural collections such as
the unique collection of yam (D.alata) from the Federated State of Micronesia, New Caledonia
unique fei and maoli popoulu banana collection, taro and banana from French Polynesia as well
as swamp taro from Kiribati, Federated State of Micronesia and Tuvalu.
The Centre repatriates lost accessions from their traditional collections in the countries from its
in vitro master collections for countries such as Cook Islands, Fiji, New Caledonia, Niue, Palau,
PNG, Solomon Islands and Samoa.
SPC collaborates with the University of the South Pacific (USP) on the conservation and safety
duplication of the CePaCT Pacific collection as a backup to its main master collections
conserved at CePaCT in Fiji.
3. Utilisation:
The HOAFS 1996 recommendation (Taylor et al., 2003) encourages utilization and sharing of
plant genetic resources, thus CePaCT should not be seen as just a museum of plants. CePaCT has
been distributing over 56,000 tissue culture plantlets (36,922 tubes) from January 2001 to June
2012, of 14 crops to 46 countries including 24 Pacific island countries (PICS). Crops being
distributed to PICs include aroids, banana, bele, breadfruit, cassava, cowpeas, potato, kava, sweet
potato and yam. The following PICs that have received germplasm from SPC namely American
Samoa, Cook Islands, Fiji, Federated State of Micronesia, Guam, Hawaii, Kiribati, Marshall
Islands, New Caledonia, Nauru, Niue, Norfolk Islands, Northern Marianas, Palau, Papua New
Guinea, Pitcairn Islands, Samoa, Solomon Islands, French Polynesia, Tokelau, Tonga, Tuvalu,
Vanuatu and Wallis and Futuna.
For the first time SPC has distributed improved crop diversity (banana, cassava, sweet potato and
taro) to Pitcairn Islands in May 2012 after several years of delays due to isolation, irregular boat
travel schedules and New Zealand biosecurity regulations restricting transit of some of other
improved material listed as risky bound for Pitcairn Islands. CePaCT works closely with countries
on the evaluation of this germplasm using new evaluation forms developed and information of
crops that performed well under local conditions is fed into the Pacific Genetic Resources Database
(PacGen) developed by the Centre.
The activities of the Centre have expanded dramatically over the years taken on board new projects
encompassing food security, trade components and climate change adaptation. With funding by
AusAid climate change project, CePaCT is actively working closely with the Pacific countries in
evaluating its climate ready collection comprising of seven crops namely taro, banana, cassava,
swamp taro, sweet potato, cassava and yam which have been indentified to have demonstrated
tolerance to drought, salt, waterlogged, windy conditions and acid soils. The number of
accessions will increase with time after evaluation information is received from the countries.
4. Sourcing of improved diversity
The CePaCT continues to source new diversity from within and outside of the Pacific. The 1993
TLB scenario has proven Samoas taro genetic pool is very narrow and vulnerable. The new taro
diversity is robust against TLB, an indication of broadened genetic base enhanced by integrated
TLB tolerant genes contributed by Asian taro. It is also likely limited genetic pool also exists for
other crops in the Pacific. Bringing diversity that exists outside of the Pacific is the long term
solution to sustainable food security.
In collaboration with International Genebank Centres, CePaCT sources improved crop diversity
from the International Institute of Tropical Agriculture (IITA), Nigeria for yams, with Bioversity
International, Belgium and Department of Employment, Economic Development and Innovation
(DEEDI), Australia on banana, sweet potato is obtained from the Centre Internacional de la Papa
(CIP), Peru and cassava acquired from the Centro Internacional de Agricultura Tropical (CIAT),
Columbia. The accessions imported from these Genebanks are virus indexed material and SPC
accessed them as in vitro cultures for further mass propagation and distribution. The PICs have
limited resources and facilities to establish and virus test their germplasm, and this service is
provided by SPC. CePaCT imports treated vegetative plant material from countries for
establishment in the Biosecurity of Fiji approved screenhouse prior to establishment in tissue
culture.
5. Virus Indexing
The Centre houses a virus indexing laboratory which enables SPC to facilitate distribution and
sharing of crop diversity both local and improved varieties to the Pacific and SPC partners. The
improved diversity sourced from the region either sent as vegetative or as tissue cultures, is virus
indexed by the Centre. The Centre can virus test for aroids, banana, sweet potato and yam using
internationally approved protocols. There are several stages of the process, includes screening of
the accessions at the in vitro stage, only those tested negative will be tested at the three and six
month stage of crop growth in the post-entry quarantine (PEQ) screen house. This is a prolonged
process and requires about 6-10 months until any accession can be declared clean and available
for distribution, whilst those infected have to go through the cleaning process again until viruses
are eliminated.
Three types of indexing technologies used involves the application of (1) molecular techniques,
(2) serological and (3) symptomatology: molecular methods, namely polymerase chain reaction
(PCR), Reverse transcriptase (RT) PCR, Immunocapture (IC)-PCR and Rolling Circular
Amplification (RCA); serological techniques such as the double antibody sandwich enzymelinked immunosorbent assay (DAS-ELISA), triple antibody sandwich ELIZA (TAS-ELISA) and
nitrocellulose membranes ELISA (NCM-ELISA), and symptomatology using grafting
techniques as used in sweet potato virus diagnostics.
The collection to date has 554 accessions of aroids, banana, potato, sweet potato, vanilla and
yam already indexed to known crop viruses and available for distribution. The number of the
collection will also increase with time once more accessions are tested negative to certain known
crop viruses. For infected material, CePaCT has been investigating three methodologies for
eliminating viruses as part of a Masters research, namely thermotherapy, electrotherapy and virus
therapy (chemotherapy). The research has initially focused on yam viruses, in particular,
Dioscorea badna virus (DBV) and Dioscorea alata virus (DAV).
6. Challenges in Distribution due to integrated badna viruses
The widespread presence of two major viruses in the Pacific especially the Dasheen Mosaic
Virus (DsMV) and Taro bacilliform virus (TaBV), an integrated badna virus (Secretariat of the
Pacific Community, 2004), have caused a major constraint in the distribution of accessions from
CePaCT. The new elite Cycle-7 breeding lines of taro from Samoa have all been tested positive
to TaBV. Based on Macanawai et al (2005), TaBV is transmissible and even through seed and
pollen. Other badna viruses infect banana namely the Banana streak virus (BSV). The effect of
badna viruses on plant growth is minimal and often a latent virus. This indeed can be a long term
constraint if no effective methodologies for eliminating integrated viruses from plant material are
available hence further research is urgently needed. CePaCT has looked at possible methods that
could help improved badna work, such as the use of BSV antibodies (Phillips et al., 1999) and
Dioscorea Badna Virus (DBV) antibodies for IC-PCR; Rolling Circular Amplification (RCA)
using new primers designed to detect episomal viruses (non integrated sequence); and the use of
internal primer controls NAD5 (Menzel et al., 2002) to check on integrity of nucleic acid
extraction for example, RNA. Through network collaboration, CePaCT collaborates with
virologists in IITA, Nigeria, Queensland University of Technology (QUT) and DEEDI,
Australia, and DSMZ, Germany on modification of protocols used on the IC-PCR protocol that
has been recommended to use with the DBV antibodies for detection.
The virus research on both taro and yam, is a time consuming process with a number of
challenges facing with badna viruses. The presence of badna viruses continue to hinder
accessibility of some of these unique varieties at CePaCT that have tolerant traits to drought and
TLB disease important for adaptive capacity to climate change variability. Viruses do evolve
with time, so as the new challenges on virus research, hence the need to develop more sensitive
tests that are efficient and cost-effective in the long run.
7. Possible consideration
Both DsMV and TaBV infect some of the known aroids and are widespread throughout Asia and
the Pacific. The impact of the two viruses on yield and plant growth could be less than 20% as
compared to Colocasia bobone disease virus (CBDV) confined to PNG and Solomon Islands
(Secretariat of the Pacific Community., 2004). All of the new collection of TLB resistant taro
varieties from Samoan (Cycle 7 breeding lines) and some of the aroids received from other PICs
are infected by these widespread viruses. The same scenario occurred with D.esculenta and
D.alata yams obtained from PICs are also infected with yam badna virus (DBV), but these
accessions have tolerant traits to drought important for climate change adaptation. Similarly,
some of the unique banana accessions such as the fei (soa’a), iholena and maoli popoulu types
from the Pacific are infected with BSV. CePaCT is unable to distribute this new diversity, and
therefore, farmers are denied the opportunity to access it. If this new diversity can’t be shared,
countries prone to TLB and to other climatic extremes such as drought will become very
vulnerable hence food security will be severly affected.Given that some of these viruses are
widespread in the Pacific, countries might like to consider an import risk assessment (IRA) to be
carried out on these common viruses (DsMV, TaBV, DBV, BSV) subject to country approval
before accessing this new diversity from CePaCT if they are already present in their respective
countries.
8. Conclusion
In line with the mission of the Pacific Plant Protection Organisation, SPC CePaCT is actively
distributing virus indexed germplasm within and outside of the Pacific as in vitro cultures. Not
only CePaCT is internationally recognized as a Pacific Genebank, but a Centre that conserves the
largest unique global collection of taro in the world. The establishment of the virus facility of the
Centre using internationally approved diagnostic methodologies facilitates access of PICs to
improved diversity at SPC. Countries also need to carry IRA on less harmful badna viruses as not
to deny access to unique accessions at CePaCT important for food security. Using in vitro
technology facilitates conservation and utilization of improved diversity through germplasm
sharing important for sustainable food and nutritional security, as well as building resilience of
communities to climate change through availability of climate ready crops that also have
commercial potential.
References
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2005
Dodds, John H. & Lorin W. Roberts, 1982. Experiments in Plant Tissue Culture Cambridge University Press,
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