Phylogeographic evidence of crop neodiversity in sorghum

De Alencar Figueiredo Lucio Flavio, Calatayud Caroline, Dupuits Céline, Billot Claire, Rami Jean-François, Brunel Denys, Perrier Xavier, Courtois Brigitte, Deu Monique, Glaszmann Jean-Christophe. 2008. Phylogeographic evidence of crop neodiversity in sorghum. Genetics, 179 (2) : 997-1008.

Résumé : Sorghum has shown the adaptability necessary to sustain its improvement during time and geographical extension despite a genetic foundation constricted by domestication bottlenecks. Initially domesticated in the northeastern part of sub-Saharan Africa several millenia ago, sorghum quickly spread throughout Africa, and to Asia. We performed phylogeographic analysis of sequence diversity for six candidate genes for grain quality (Shrunken2, Brittle2, Soluble starch synthaseI, Waxy, Amylose extender1, and Opaque2) in a representative sample of sorghum cultivars. Haplotypes along 1-kb segments appeared little affected by recombination. Sequence similarity enabled clustering of closely related alleles and discrimination of two or three distantly related groups depending on the gene. This scheme indicated that sorghum domestication involved structured founder populations, while confirming a specific status for the guinea margaritiferum subrace. Allele rooted genealogy revealed derivation relationships by mutation or, less frequently, by recombination. Comparison of germplasm compartments revealed contrasts between genes. Sh2, Bt2, and SssI displayed a loss of diversity outside the area of origin of sorghum, whereas O2 and, to some extent, Wx and Ae1 displayed novel variation, derived from postdomestication mutations. These are likely to have been conserved under the effect of human selection, thus releasing valuable neodiversity whose extent will influence germplasm management strategies.

Mots-clés Agrovoc : Sorghum bicolor, variation génétique, distribution géographique, biogéographie, phylogénie, domestication, séquence nucléotidique, qualité, grain, gène

Mots-clés géographiques Agrovoc : Afrique, Asie

Classification Agris : F70 - Taxonomie végétale et phytogéographie
F30 - Génétique et amélioration des plantes

Champ stratégique Cirad : Axe 1 (2005-2013) - Intensification écologique

Auteurs et affiliations

• De Alencar Figueiredo Lucio Flavio, CIRAD-BIOS-UMR DAP (FRA)
• Calatayud Caroline, CIRAD-BIOS-UMR DAP (FRA)
• Dupuits Céline, INRA (FRA)
• Billot Claire, CIRAD-BIOS-UMR DAP (FRA)
• Rami Jean-François, CIRAD-BIOS-UMR DAP (FRA) ORCID: 0000-0002-5679-3877
• Brunel Denys, INRA (FRA)
• Perrier Xavier, CIRAD-BIOS-UPR Multiplication végétative (FRA) ORCID: 0000-0002-0092-003X
• Courtois Brigitte, CIRAD-BIOS-UMR DAP (FRA) ORCID: 0000-0003-2118-7102
• Deu Monique, CIRAD-BIOS-UMR DAP (FRA)
• Glaszmann Jean-Christophe, CIRAD-BIOS-DIR (FRA) ORCID: 0000-0001-9918-875X

Source : Cirad - Agritrop (https://agritrop.cirad.fr/545324/)

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