白菜型油菜srb多室性状的遗传分析与分子鉴定

油菜多室角果是一种高产相关性状,本研究对桑日白油菜(srb)多室性状的遗传调控机制进行研究。性状分析表明,该突变体具有稳定的多室角果表型,单株多室角果比例为94.7%~100.0%,每角果平均3.5个心皮。遗传上srb突变体中的多室性状受1对隐性核基因控制。比较测序分析发现,srb中BrCLV3基因的CLE motif中存在一种新的单核苷酸突变(C/G),可导致其保守结构域的第12位组氨酸突变为天冬氨酸,将该位点命名为Brclv3Asp12。利用SNP标记进行分离群体的鉴定,证实Brclv3Asp12中的C/G单核苷酸变异与多室表型共分离。转基因互补测验和体外多肽的处理试验进一步证实,该材料中控制多室性状位点Brclv3Asp12突变导致了CLV3多肽活性的减弱,是形成多室角果性状的原因。本研究初步阐明了白菜型油菜srb多室性状形成的机制。

Genetic analysis and molecular characterization of multilocular trait in the srb mutant of Brassica rapa L.

Multilocular silique is considered as a trait associated with high yield in rapeseed,and we studied the genetic regulation of the multilocular trait in B.rapa var.srb.This mutant showed a stable multilocular phenotype,ranging from 94.7%to 100%multilocular siliques per plant and 3.5 carpels per silique.Genetic analyses showed that the multilocular trait was monogenically governed by a recessive nuclear gene.Comparative sequencing analysis revealed that there was a novel C-to-G single-nucleotide mutation in the core CLE motif of BrCLV3,leading to histidine mutation at position 12 in conserved domain to aspartic acid,which was named Brclv3Asp12.The analysis of segregated population by SNP marker showed that the C/G single-nucleotide variation in Brclv3Asp12 was co-segregated with the multilocular phenotype.Transgenic complementation studies and in vitro peptide assays further confirmed that the Brclv3Asp12 allelic mutation in srb could lead to reduced activity of the CLV3 peptide,resulting in the formation of multilocular phenotype.Therefore,the study preliminarily clarified the mechanism involved in multilocular silique formation in srb mutant.