A phylogenetic framework of the legume genus Aeschynomene for comparative genetic analysis of the Nod-dependent and Nod-independent symbioses

Brottier, L.; Chaintreuil, C.; Simion, P.; Scornavacca, C.; Rivallan, R.; Mournet, P.; Moulin, L.; Lewis, G. P.; Fardoux, J.; Brown, S. C.; Gomez-Pacheco, M.; Bourges, M.; Hervouet, C.; Gueye, M.; Duponnois, R.; Ramanankierana, H.; Randriambanona, H.; Vandrot, H.; Zabaleta, M.; DasGupta, M.; d'Hont, A.; Giraud, E.; Arrighi, J.-F.

doi:10.1101/422956

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bioRxiv · 10.1101/422956

A phylogenetic framework of the legume genus Aeschynomene for comparative genetic analysis of the Nod-dependent and Nod-independent symbioses

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Abstract

SUMMARYO_LISome Aeschynomene legume species have the property of being nodulated by photosynthetic Bradyrhizobium lacking the nodABC genes. Knowledge of this unique Nod (factor)-independent symbiosis has been gained from the model A. evenia but our understanding remains limited due to the lack of comparative genetics with related taxa using a Nod-dependent process.\nC_LIO_LITo fill this gap, this study significantly broadened previous taxon sampling, including in allied genera, to construct a comprehensive phylogeny. This backbone tree was matched with data on chromosome number, genome size, low-copy nuclear genes and strengthened by nodulation tests and a comparison of the diploid species.\nC_LIO_LIThe phylogeny delineated five main lineages that all contained diploid species while polyploid groups were clustered in a polytomy and were found to originate from a single paleo-allopolyploid event. In addition, new nodulation behaviours were revealed and Nod-dependent diploid species were shown to be tractable.\nC_LIO_LIThe extended knowledge of the genetics and biology of the different lineages in the legume genus Aeschynomene provides a solid research framework. Notably, it enabled the identification of A. americana and A. patula as the most suitable species to undertake a comparative genetic study of the Nod-independent and Nod-dependent symbioses.\nC_LI

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Brottier, L., Chaintreuil, C., Simion, P., Scornavacca, C., Rivallan, R., Mournet, P., Moulin, L., Lewis, G. P., Fardoux, J., Brown, S. C., Gomez-Pacheco, M., Bourges, M., Hervouet, C., Gueye, M., Duponnois, R., Ramanankierana, H., Randriambanona, H., Vandrot, H., Zabaleta, M., DasGupta, M., d'Hont, A., Giraud, E., Arrighi, J.-F.. 2018-09-21. A phylogenetic framework of the legume genus Aeschynomene for comparative genetic analysis of the Nod-dependent and Nod-independent symbioses. https://doi.org/10.1101/422956

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