利用抗、染根肿病F2群体构建大白菜AFLP遗传连锁图谱

Constructed an AFLP Genetic Linkage Map of Chinese Cabbage with Resistant and Susceptible F_2 Lines

以易感染根肿病的大白菜(Brassica campestrisssp. pekinensis)自交系94SK和抗根肿病的CR Shinki DH系为亲本,通过杂交获得F1,并选择一株F1植株进行自交,构建了F2作图群体。利用扩增出与根肿病抗性基因CRb连锁标记的17对AFLP引物组合Pst+GNN/Mse+CNN构建大白菜遗传连锁图谱。这些AFLP引物组合共扩增出322个亲本间表现出多态性的AFLP标记。应用其中6个与CRb基因紧密连锁的AFLP标记转化成的SCAR标记和清晰可见的大于100 bp的211个AFLP标记构建了一张包含179个标记位点1、0个连锁群、覆盖长度为576 cM,平均图距3.3 cM的遗传图谱。抗根肿病基因CRb定位在第一条连锁群9 cM的范围内。研究表明,利用PstⅠ/MseⅠ和EcoRⅠ/MseⅠ引物组合以及其他分子标记类型构建遗传连锁图谱,并有效减少遗传图谱中聚集和间隙现象的产生提供了一定的科学依据。同时,该图谱的构建对在基因组范围内通过分子标记辅助选择选育大白菜根肿病抗性品种奠定了基础。

Clubroot disease, caused by Plasmodiophora brassicase War. is soil-born, obligate causes the development of galls on root tissue in Crucifer. The clubroot is one of the most damaging plant pathogen that diseases of brassica crops and is the most serious disease of cruciferous crops in the temperate zone. An F2 mapping population was developed from a cross between Chinese cabbage inbred line of 94 SK, a line susceptible to clubroot disease, and CR Shinki DH line, a line resistance to clubroot disease. Seventeen Pst ＋ GNN/Mse ＋ CNN primer combinations generating AFLP markers linked to clubroot resistance gene CRb were employed to construct a linkage map of Chinese cabbage. Of 322 polymorphic bands observed between two parental lines,211 AFLP and 6 SCRA marker conversed from AFLP marker linked to CRb were used for construction of linkage map. Most of polymorphic bands displayed normal segregation pattern in an F2 population. Only 4 markers were seriously distorted. Among 217 markers, 179 were mapped to ten linkage groups at LOD value of 4.3 using JoinMap version 3. The linkage map developed here covers a total map distance of 576 cM corresponding 3.3 cM per marker. The clubroot resistance gene CRb was mapped to the interval of 9 cM in linkage group 1. This result indicated Pst I/Mse I and EcoR I/Mse I primer combinations constructed linkage map with other types makers, and provided a certain amount of scientific evidence to effectively reduce the accumulation of genetic maps and the gener- ation gap. The construction of the map was the basic of breeding Chinese cabbage resistant to clubroot disease through the molecular marker-assisted selection in the range of the genome.