Collinearity between AFLP markers flanking dominant genic male sterility gene in Brassica napus and homologous loci in Arabidopsis thaliana

摘要

Two patterns for restoration of dominant genic male sterility (DGMS) in Brassica napus have been proposed: an unlinked dominant gene or a dominant allele at the very locus of DGMS gene (Ms) restores the male fertility. The later cannot even exclude the possibility of a tightly linked gene or pseudoallele. Therefore, there will not a final explanation until the cloning and function analysis of relevant genes are achieved. Arabidopsis thaliana is a model plant with a complete sequenced genome. B. napus is closely related to it, and both belong to Cruciferae. Moreover, comparative genome analysis has revealed wide collinear relationship between them and conservativity of gene organization during evolution. The present study was focused on collinearity analysis between flanking markers tightly-linked to the Ms and correspondent homologous loci in A. thaliana so as to facilitate fine mapping and cloning. Seven AFLP marker fragments were cloned and sequenced, and the flanking regions of 3 small size fragments were obtained by PCR walking. BLAST search results showed that 6 of the 7 marker sequences had their corresponding homologous loci in A. thaliana, and that all these loci were located in a 2Mb region between 1g04950 and 1g10400.Collinearity was evident between the Ms markers and the corresponding homologous loci. Combined with our studies on inheritance and the previous studies on comparative mapping between Brassica A genome and A. thalian genome, the Ms was inferred to be likely on the short arm of Chromosome 1, the long arm of Chromosome 5, or the long arm of Chromosome 8 in Brassica A genome.