单 位：
Chinese Acad Agr Sci, Oil Crops Res Inst, Key Lab Biol & Genet Improvement Oil Crops, Minist Agr, Wuhan 430062, Peoples R China
摘 要：
DNA sequences of fatty acid elongase 1 genes FAE1.1 (E-A) and FAE1.2 (E-C) were isolated and characterized for 30 commercialized low erucic acid rapeseed (LEAR) cultivars in China. Four types of independent mutation leading to low erucic acid trait were found, i.e., a single-base transition (e(A1)), a two-base deletion (e(C2)) and four-base deletion (e(C4)) as well as single-base transition with a four-base deletion (e(A*)). Three genotypes, i.e., e(A1)e(A1)e(C2)e(C2), e(A1)e(A1)e(C4)e(C4) and e(A*)e(A*)e(C4)e(C4) were responsible for LEA content in storage lipids of different rapeseed cultivars. Most of the LEAR cultivars had a genotype of e(A1)e(A1)e(C2)e(C2), which were descended from the first LEAR cultivar, Oro. Yeast expression analysis revealed that two-base-pair (AA) deletion (e(C2)) at the base sites of 1 422-1 423 in the C genome FAE1 gene resulted in the absence of the condensing enzyme and led to the failure to produce erucic acid. Coexpression of FAE1 and ketoacyl-CoA reductase (KCR) or enoyl-CoA reductase (ECR) was found in high erucic acid rapeseed (HEAR) but not in LEAR (e(A1)e(A1)e(C2)e(C2) or e(A1)e(A1)e(C4)e(C4)). Moreover, KCR and ECR were still coordinately regulated in e(A1)e(A1)e(C2)e(C2) or e(A1)e(A1)e(C4)e(C4) genotypes, suggesting that the expression of two genes was tightly linked. In addition, specific detection methods were developed by high-resolution melting curve analysis in order to detect e(A1) and e(C4).
