[Molecular markers linked to mono-dominant genic male sterile gene in rapeseed (Brassica napus L.)].

Bulked segregant analysis (BSA) was used to identify randomly amplified polymorphic DNA (RAPD) markers linked to the MS gene in mono-dominant GMS of rapeseed (Brassica napus L.), which was bred by Hybrid Rapeseed Research Center of Shaanxi Province. A total of 300 random 10-mer oligonucleotide primers were screened on the DNA from fertile and sterile bulks. Primer S(243) (5'CTATGCCGAC3') gave identical 1.5 kb DNA polymorphic segment OPU-03(1500) in the bulk S, but not in the bulk F (Fig.2). The DNAs from individual plants of each bulk and from their sister lines, which were generated from the same original crossing, were then screened with the primer S(243), and the same results were obtained (Figs.3,4). Other types of GMS and CMS were analyzed using primer S(243), and the specific 1.5 kb DNA segment was not found (Fig.5). Therefore, the RAPD marker OPU-03(1500) is linked to the mono-dominant GMS trait in rapeseed. This RAPD marker OPU-03(1500) was cloned into a T-easy vector and sequenced. The sequence here obtained was highly homologous to one of the Arabidopsis DNA sequences. According to this DNA conserved region in different species, we designed a pair of specific primers P1 (5'ATGTCGCTGAGGCCG-AGCAC3') and P2 (5'GGCACACTGTCACG-ATCCTTGG3') and amplified only one specific 2.3 kb DNA fragment in each bulk. There are two mutant loci between the two DNA fragments after sequencing. We designed another pair of specific primers P3 (5'CTCCAGCAGCAGCAGC-AGCCT3') and P4 (5'GCAGGAATGAGAA-CCGTAGG3') according to the DNA sequence at the mutant loci. A specific DNA segment was amplified only in the fertile line but not in the sterile line using the primers P3 and P4 (Fig.6). Therefore the RAPD marker were converted into SCAR marker. Moreover, the SCAR marker detection method was improved (Fig.7).