大豆对大豆花叶病毒株系SC6和SC17抗病基因的精细定位

摘要

SMV strains SC6 and SC17 were prevalent in the North China and the Yangtze Valleys soybean production regions. Two soybean cultivars Q0926 and Zhongdou 35, which were resistant to SC6 and SC17, were respectively crossed with Nannong 1138-2 and Nannongcaidou 5, which were susceptible to SC6 and SC17, to determine inheritance of resistance to SC6 or SC17. Q0926 was also crossed with Zhongdou 35 to study allelic relationships of the resistance genes from the two soybean cultivars. On the basis of the results, the resistance genes to SC6 and SC17 were fine mapped. The results showed that the F1 plants pre-sented complete resistance, F2 population were segregated with a ratio of 3R:1S, F2:3 population were segregated with a ratio of 1R:2Seg:1S in resistant (R)×susceptible (S) crosses. These results indicated that the resistances of Q0926 and Zhongdou 35 to SC6 and SC17 were controlled by a single dominant gene respectively. The F1 plants displayed complete resistance, and F2 popu-lations of the crosses Q0926×Zhongdou 35 were not segregated, indicating that the resistance genes to SC6 and SC17 were alleles%　　针对我国北方和长江流域大豆产区广泛分布的SMV株系SC6和SC17,利用2个抗病大豆品种Q0926和中豆35分别与感病品种南农1138-2和南农菜豆5号配制2个抗感杂交组合Q0926×南农1138-2和中豆35×南农菜豆5号以及一个抗抗组合Q0926×中豆35,研究3个组合的F1、F2、F2：3抗性遗传规律,探讨Q0926对SC6和中豆35对SC17及2个抗病品种对同一SMV株系抗性基因的等位关系,并对大豆对2个株系的抗病基因进行了标记定位.结果显示, Q0926×南农1138-2和中豆35×南农菜豆5号2个抗感杂交组合在分别接种SC6和SC17后, F1表现抗病, F2呈3抗∶1感分离比例, F2：3家系呈1抗∶2分离∶1感病的分离比率,表明Q0926对SC6和中豆35对SC17的抗病性分别由1对显性基因控制；抗抗组合Q0926×中豆35的F1和F2在接种2个株系后均未发现感病单株,表明Q0926与中豆35对 SC6和 SC17株系的抗病基因分别是等位或紧密连锁的.分别利用2个抗感组合的 F2和 F2：3群体对2个抗病基因的定位结果显示,第2染色体上的25个SSR标记与抗 SC6的基因RSC6连锁,最近的2个标记与抗性基因RSC6的排列次序和遗传距离为BARCSOYSSR_02_0617(0.775 cM)-RSC6-BARCSOYSSR_02_0621(0.519 cM)；第2染色体上的38个SSR标记与抗SC17的基因RSC17连锁.最近的2个标记与抗性基因RSC17的排列次序和遗传距离为BARCSOYSSR_02_0622(0.264 cM)-RSC17-BARCSOYSSR_02_0627(0.262 cM),其对应的物理区间分别为52 kb和60 kb.抗性遗传研究为抗大豆花叶病毒育种的亲本选配、后代选择提供了理论指导,抗性基因的标记定位研究为抗性基因的分子标记辅助选择和抗病基因的图位克隆奠定了基础.