Combining Biological Approaches to Shed Light on the Evolution of Edible Bananas

researchDeciphering the diversity of the banana complex needs a joint characterization and analysis of the original wild species and their relatives, primitive diploid forms and triploid derived varieties. Sexuality, the primary source of diversity, is strongly disrupted in the cultivated varieties (sterility, parthenocarpy and vegetative propagation) by human selection of vegetatively maintained punctuated mutations. Many biological tools are available for characterizing this diversity, each one illustrating some peculiar facets, and we show that their joint analysis enables an evolutionary reading of this diversity. We propose various scenarios regarding the structure of wild species, on the domestication of the edible diploids from hybrids between wild forms, on the direct ancestry of triploids from cultivated diploids, and on the ancient migrations dispersing cultivated forms around the world. The comparison with data from archaeology, linguistics and human genetics will enable the validation, refinement and dating of the proposed domestication process

Metabolic characterization of green pods from Vanilla planifolia accessions grown in La Reunion.

Large phenotypic variation has been observed between the cultivated vanillas since a single genetic source of Vanilla planifolia was spread to the Indian Ocean and the Indonesia in the 19th century. In order to differentiate the cultivated vanilla plants, genetic studies have been conducted in the past on the plants grown in various regions such as the French island, La Réunion. However, the genetic difference was not big enough to differentiate diverse accessions of V. planifolia. In this study, metabolomics, in which genetic variation could be amplified, was employed to delve into the variation between the cultivated vanilla plants. To obtain a broad view of the metabolome, nuclear magnetic resonance (NMR) spectroscopy was applied to the analysis of V. planifolia green pods. Principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) of the data showed that the accessions could be differentiated according to their glucovanillin and glucosides A and B contents. Furthermore, a correlation between the glucovanillin content and the pod length, number of flower and growth capacity of the accessions has been observed from the multivariate data analysis