玉米缺陷型籽粒突变体的遗传分析及突变基因dek1-T7的定位

Genetic Analysis of Defective Kernel Mutant and Mapping of the Mutant Gene dek1-T7 in Maize

突变体是功能基因组学研究和分子育种的重要材料。自然条件下,在玉米自交系M08649中发现一个突变穗,其突变表型表现为凹陷,没有胚以及胚乳,不能发芽并繁殖后代的缺陷型籽粒(defectivekernel)。利用出现籽粒突变自交系M08649的杂合体与正常自交系齐319构建分离群体对突变体进行遗传分析,共有85个F2代自交穗具有突变籽粒,38个F2代自交穗表现为正常,统计分析发现其符合2:1的分离比例。同时在85个具有突变籽粒的穗子中,共有9961粒正常籽粒和3217粒突变籽粒,符合3:1的分离比例,初步证实自交系M08649中控制籽粒发育的突变基因属于单个基因的隐性突变,暂命名为dek1-T7(t)。利用SSR分子标记将该基因初步定位在第1染色体的短臂上1.03区,位于SSR标记bnlg2204和Hkf1-3之间,两个标记之间的物理距离为1.78Mb。本研究结果为该基因的克隆和功能分析奠定了基础。

Mutant is an important material for the studies of functional genomics and molecular breeding. Underthe natural growth conditions, a mutant with defective kernels was found in the population of maize inbred lines M08649, which manifested the mutant phenotype of sunken seed without embryo and endosperm that can＇t becapable of germination and reproduction. In order to analyze the heredity of the mutant, we built a separate population derived fi＇om the cross made by heterozygote of inbred M08649 mutations and normal inbred linesQi319. There were 85 ears of F2 individuals with mutation phenotype and 38 ears of F2 individuals with normal phenotype, which was consistent with the ratio of 2 to 1 in segregation. Total of 9 961 normal kernels and 3 217sunken kernels occurred in the 85 ears with mutation phenotype, which was in line with 3 to 1 segregation ratio. The results preliminary confirmed that the mutant gene conferring the kernel growth in inbred M08649 would be asingle recessive gene, tentatively named as dekl-T7（t）. The tentative mutation gene was preliminary mapped in the bin of 1.03 on the short arm of chromosome one by using SSR markers, which was framed between SSR markersof bnlg2204 and Hkfl-3 that the physical distance is 1.78 Mb. The results of this study would be the foundations for further gene cloning and functional analysis.