RT Journal Article
SR Electronic
T1 Maximizing genetic representation in seed collections from populations of self and cross-pollinated banana wild relatives
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2021.05.25.445549
DO 10.1101/2021.05.25.445549
A1 Simon Kallow
A1 Bart Panis
A1 Toan Vu Dang
A1 Tuong Vu Dang
A1 Janet Paofa
A1 Arne Mertens
A1 Rony Swennen
A1 Steven B. Janssens
YR 2021
UL http://biorxiv.org/content/early/2021/05/26/2021.05.25.445549.abstract
AB Background Conservation of plant genetic resources, including the wild relatives of crops, plays an important and well recognised role in addressing some of the key challenges faced by humanity and the planet including ending hunger and biodiversity loss. However, the genetic diversity and representativeness of ex situ collections, especially that contained in seed collections, is often unknown. This limits meaningful assessments against conservation targets, impairs targeting of future collecting and limits their use.We assessed genetic representation of seed collections compared to source populations for three wild relatives of bananas and plantains. Focal species and sampling regions were Musa acuminata subsp. banksii (Papua New Guinea), M. balbisiana (Viet Nam) and M. maclayi s.l. (Bougainville, Papua New Guinea). We sequenced 445 samples using suites of 16-20 existing and newly developed taxon-specific polymorphic microsatellite markers. Samples of each species were from five populations in a region; 15 leaf samples and 16 seed samples from one infructescence (‘bunch’) for each population.Results Allelic richness of seeds compared to populations was 51%, 81% and 93% (M. acuminata, M. balbisiana and M. maclayi respectively). Seed samples represented all common alleles in populations but omitted some rarer alleles. The number of collections required to achieve the 70% target of the Global Strategy for Plant Conservation was species dependent, relating to mating systems. Musa acuminata populations had low heterozygosity and diversity, indicating self-fertilization; many bunches were needed (>15) to represent regional alleles to 70%; over 90% of the alleles from a bunch are included in only two seeds. Musa maclayi was characteristically cross-fertilizing; only three bunches were needed to represent regional alleles; within a bunch, 16 seeds represent alleles. Musa balbisiana, considered cross-fertilized, had low genetic diversity; seeds of four bunches are needed to represent regional alleles; only two seeds represent alleles in a bunch.Conclusions We demonstrate empirical measurement of representation of genetic material in seeds collections in ex situ conservation towards conservation targets. Species mating systems profoundly affected genetic representation in seed collections and therefore should be a primary consideration to maximize genetic representation. Results are applicable to sampling strategies for other wild species.Competing Interest StatementThe authors have declared no competing interest.ARallelic richnessCITESConvention on International Trade in Endangered Species of Wild Fauna and Flora (1973)CWRsCrop wild relativesdfdegrees of freedomDNADeoxyriboNucleic AcidE5evenness indexFisinbreeding coefficientGPSglobal positioning systemH’Shannon:Weiner diversity indexHexpNei’s gene diversity (expected heterozygosity)Hoobserved heterozygosityMLGmultilocus genotypesMusa acuminataMusa acuminata subsp. banksiiMusa maclayiMusa maclayi s.l.Nnumber of samplesPAprivate allelesPCRPolymerase chain reactionPNGPapua New GuineaSpeciesspecies and infraspecificsΛSimpson’s index