Study On The Polymorphism Of Wx Gene In Wild Rice

Wild rice are the ancestors of cultivated rice. It contains rich elite traits in the long time evolution course, and that is an important resource in the genetic development of cultivated rice. Amylose content of rice is one of the important physi-chemical trait in the evaluation of rice's cooking and eating quality. Previous researches had shown that granule-bound starch synthase I was the main effective gene to regulate the AC of rice.Therefor, in this study, wild rice was used as the research main objects. 22 accessions rice materials were selected, which including 10 wild rice accessions and 12 cultivated rice accessions. The polymorphism of Wx gene in wild rice was elucidated by the comparative analysis of nucleotide variation in genome DNA and cDNA sequences of Wx gene between wild rice and cultivated rice. The results showed:(i) The length of Wx gene genome DNA sequence(from the start codon to termination codon) was 3077 bp to 3480 bp in wild rice and 3476 bp to3481bp in cultivated rice. The length of Wx gene cDNA sequence was1818 bp to 1839 bp and 1830 bp in most of the cultivated rice.(ii) The proportion of nucleotide variation sites in wild rice Wx gene's genome DNA was 9.76593%, it was far more than 1.24321% in cultivated rice. Sequence polymorphism rate(?) in Wx gDNA of wild rice was 0.09360, which far more than 0.00275 in cultivated rice.(iii) The proportion of nucleotide variation sites in wild rice Wx cDNA was 5.7%, it was far more than0.32573% in cultivated rice. Sequence polymorphism rate(?) in Wx cDNA of wild rice was 0.02284, which far more than 0.00083 in cultivated rice.(iv) It showed a tight correlation between AC and single-nucleotide polymorphisms(SNPs) in Wx gene promoter regions-570bp(C/T) and CDS region exon 10 +1098(C/T).(v) The AC of wild rice may be more abundant polymorphism than cultivated rice based on the cluster analysis by Wx gene gDNA sequence variation information. The results indicated that Wx gene of wild rice have more abundant polymorphism than cultivated rice either in gDNA or in CDS levels,and that the wild rice resources may have more abundant AC polymorphism than cultivated rice.