Quantitative cDNA-AFLP reveals the extent of transcriptional polymorphism in developing cotton fibres.

Genetic variability in fibre quality among the two major cultivated cotton species, Gossypium hirsutum (Gh) and G. barbadense (Gb), shows a complex multigenic inheritance. We developed a quantitative 3 targeting cDNA-AFLP analysis strategy in order to dissect transcriptional regulation differences between the developing fibres of these 2 species. Two studies were undertaken. In the first study the expression profiles of over 3000 transcripts from the 2 parental species were analysed by quantitative cDNA-AFLP during the time-course of fibre development, between 6 and 28 days post anthesis (dpa). The 2nd study (4400 transcripts profiled) focused on two key developmental stages of fibre development (10 and 22 dpa, respectively) at a population-wide level using an inter-specific RIL population. Major achievements include: (1) the partitioning of genes among significant expression profiles and its comparison between Gh and Gb; and (2) the mapping of a large (>5000) number of expression QTLs on the RIL genetic map and a comparison of their distributions with QTL for fibre phenotypic traits. This research is part of a larger project aimed at the genetic and genomic dissection of cotton fibre quality. (Résumé d'auteur