Unraveling the complex story of intergenomic recombination in ABB allotriploid bananas

TitleUnraveling the complex story of intergenomic recombination in ABB allotriploid bananas
Publication TypeJournal Article
Year of Publication2020
AuthorsCenci A, Sardos J, Hueber Y, Martin G, Breton C, Roux N, Swennen R, Carpentier SChristian, Rouard M
JournalAnnals of Botany
Date Published02/2020
Type of Articlejournal arcticle
Keywordsgenetic diversity, homoeologous exchanges, meiosis, Musa, polyploids, subgenomes
Abstract

Bananas (Musa spp.) are a major staple food for hundreds of millions of people in developing countries. The cultivated varieties are seedless and parthenocarpic clones of which the ancestral origin remains to be clarified. The most important cultivars are triploids with an AAA, AAB, or ABB genome constitution, with A and B genomes provided by M. acuminata and M. balbisiana, respectively. Previous studies suggested that inter-genome recombinations were relatively common in banana cultivars and that triploids were more likely to have passed through an intermediate hybrid. In this study, we investigated the chromosome structure within the ABB group, composed of starchy cooking bananas that play an important role in food security.
Methods

Using SNP markers called from RAD-Seq data, we studied the chromosome structure of 36 ABB genotypes spanning defined taxonomic subgroups. To complement our understanding, we search for similar events within nine AB hybrid genotypes.

Recurrent Homoeologous Exchanges (HEs), i.e. chromatin exchanges between A and B subgenomes were unraveled with at least 9 founding events (HE patterns) at the origin of the ABB bananas prior to the clonal diversification. Two independent founding events were found for Pisang Awak genotypes. Two HE patterns, corresponding to genotypes Pelipita and Klue Teparod, show an overrepresentation of B genome contribution. Three HE patterns mainly found in Indian accessions share some recombined regions and two additional patterns did not correspond to any known subgroups.
Conclusions

The discovery of the nine founding events allowed an investigation of the possible routes that led to the creation of the different subgroups, which resulted in new hypotheses. Based on our observations, we suggest different routes that gave rise to the current diversity in the ABB cultivars, routes involving primary AB hybrids, routes leading to shared HEs and routes leading to a B excess ratio. Genetic fluxes took place between M. acuminata and M. balbisiana, particularly in India, where these unbalanced AB hybrids and ABB allotriploids originated, and where cultivated M. balbisiana are abundant. The result of this study clarifies the classification of ABB cultivars, leading possibly to the revision of the classification of this subgroup.

URLhttps://academic.oup.com/aob/advance-article/doi/10.1093/aob/mcaa032/5760888
DOI10.1093/aob/mcaa032
Showing 40 of 43 accessions
Accession Name Pictures Accession number Species / Group SubSpecies / SubGroup Origin Collection Available for distribution
Kluai Tiparot ITC0652 ABB Unknown Unknown ITC
Safet Velchi ITC0245 AB subgr. Ney Poovan Unknown ITC
Namwa Khom ITC0659 ABB subgr. Pisang Awak Thailand ITC
Balonkawe ITC0473 AAB subgr. Plantain Philippines ITC
Cachaco ITC0643 ABB subgr. Bluggoe Unknown ITC
Kunnan ITC1034 AB subgr. Ney Poovan Unknown ITC
Pelipita ITC0472 ABB Unknown Philippines ITC
Kayinja ITC0087 ABB subgr. Pisang Awak Unknown ITC
Saba ITC1138 ABB subgr. Saba Unknown ITC
Cachaco Enano ITC0632 ABB subgr. Bluggoe Unknown ITC
Sabra ITC0026 ABB Unknown Gabon ITC
Blue Java ITC0361 ABB subgr. Ney Mannan Unknown ITC
Dole ITC0767 ABB subgr. Bluggoe Unknown ITC
Simili Radjah ITC0123 ABB subgr. Peyan Unknown ITC
Auko ITC0983 AB Unknown Papua New Guinea ITC
Fougamou 1 ITC0101 ABB subgr. Pisang Awak Gabon ITC
Vunapope ITC0990 AB Unknown Papua New Guinea ITC
Auko ITC0987 AB Unknown Papua New Guinea ITC
Chuoi mit
ITC1682 AB Unknown Vietnam ITC
Mu'u Pundi
ITC1880 AB Unknown Indonesia ITC
Pelipita
ITC0396 ABB Unknown Unknown ITC
Pelipita Majoncho
ITC0397 ABB Unknown Unknown ITC
Sambrani Monthan
ITC1728 ABB subgr. Bontha India ITC
Ney Vannan
ITC1750 ABB subgr. Bontha India ITC
Kyauk Sein Phee Kyan
ITC1738 Unknown Unknown Myanmar ITC
Padali Moongil
ITC1729 AB subgr. Kunnan India ITC
Agniswar
ITC1747 AB subgr. Kunnan India ITC
Adukka Kunnan
ITC1751 AB subgr. Kunnan India ITC
Poovilla Chundan
ITC1752 AB subgr. Kunnan India ITC
Monthan
ITC1483 ABB subgr. Monthan Unknown ITC
Kambani Zambia/Gurutu/Blokeni
ITC1599 ABB subgr. Pisang Awak Tanzania ITC
Chinia
ITC1719 ABB subgr. Pisang Awak India ITC
Karpuravalli
ITC1721 ABB subgr. Pisang Awak India ITC
Ya Khine
ITC1737 ABB subgr. Pisang Awak Myanmar ITC
Bankel
ITC1746 ABB subgr. Pisang Awak India ITC
Boddida Bukkisa
ITC1748 ABB subgr. Pisang Awak India ITC
Vananthpurani
ITC1749 ABB subgr. Pisang Awak India ITC
Pisang Awak
ITC0339 ABB subgr. Pisang Awak Unknown ITC
Kluai Namwa Khom
ITC0526 ABB subgr. Pisang Awak Unknown ITC
Bom
ITC0053 ABB subgr. Pisang Awak Unknown ITC

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