Gupta V, Mukhopadhyay A, Arumugam N, Sodhi Y S, Pental D, Pradhan A K
Centre for Genetic Manipulation of Crop Plants and Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India.
Theor Appl Genet. 2004 Feb;108(4):743-9. doi: 10.1007/s00122-003-1481-z. Epub 2003 Oct 16.
Molecular mapping and tagging of the erucic acid trait (C22:1) in Brassica juncea was done by a candidate gene approach. Two QTLs underlying the variation of seed erucic acid content were assigned to two linkage groups of a B. juncea map using a doubled haploid (DH) mapping population derived from high x low erucic acid F(1) hybrid. Two consensus primers corresponding to the full-length Fatty Acid Elongase 1 ( FAE1) gene, reported to be involved in the elongation of C18:1 to C22:1, were designed. PCR amplification and subsequent cloning and sequencing identified two FAE1 genes ( FAE1.1 and FAE1.2) in both high and low erucic acid mustard lines. Sequence alignment of corresponding FAE1 genes between high and low erucic acid mustard lines identified four substitution type single nucleotide polymorphisms (SNPs) in FAE1.1 and three in FAE1.2. Using the SNuPE method of SNP genotyping, these two genes were mapped to two independent loci that co-segregated with the two QTLs governing the erucic acid trait. Association of wild ( E1E2) and mutant ( e1e2) haplotypes of two FAE1 genes with erucic acid variation in two segregating populations revealed that the e1e1e2e2 genotype identified low erucic acid individuals (<2%) and E1E1E2E2 identified individuals with highest erucic acid content (>40%). The E1e1E2e2 heterozygote was found to be intermediate in phenotype. The applicability of these SNPs in marker-assisted manipulation of the erucic acid trait was verified by genotyping a set of contrasting germplasm of B. juncea belonging to two distinct gene pools (Indian and east European) and other oil-yielding Brassica species.
通过候选基因法对芥菜型油菜中芥酸性状（C22:1）进行了分子定位和标记。利用高芥酸与低芥酸F(1)杂种衍生的双单倍体（DH）作图群体，将控制种子芥酸含量变异的两个QTL定位到芥菜型油菜图谱的两个连锁群上。设计了两个与全长脂肪酸延长酶1（FAE1）基因对应的共有引物，据报道该基因参与C18:1到C22:1的延长。通过PCR扩增以及随后的克隆和测序，在高芥酸和低芥酸芥菜品系中均鉴定出两个FAE1基因（FAE1.1和FAE1.2）。高芥酸和低芥酸芥菜品系中相应FAE1基因的序列比对在FAE1.1中鉴定出4个替换型单核苷酸多态性（SNP），在FAE1.2中鉴定出3个。利用SNP基因分型的单核苷酸引物延伸（SNuPE）方法，将这两个基因定位到与控制芥酸性状的两个QTL共分离的两个独立位点。两个FAE1基因的野生型（E1E2）和突变型（e1e2）单倍型与两个分离群体中芥酸变异的关联分析表明，e1e1e2e2基因型鉴定出低芥酸个体（<2%），E1E1E2E2鉴定出芥酸含量最高的个体（>40%）。发现E1e1E2e2杂合子表型为中间型。通过对属于两个不同基因库（印度和东欧）的一组芥菜型油菜对比种质以及其他产油油菜物种进行基因分型，验证了这些SNP在芥酸性状标记辅助操作中的适用性。
