Genetic Analysis and Identification of Amplified Fragment Length Polymorphism Markers Linked to the alm1 Avirulence Gene of Leptosphaeria maculans

ABSTRACT A gene-for-gene interaction was previously suggested by mapping of a single major locus (LEM 1) controlling cotyledon resistance to Leptosphaeria maculans isolate PHW1245 in Brassica napus cv. Major. In this study, we obtained further evidence of a gene-for-gene interaction by studying the inheritance of the corresponding avirulence gene in L. maculans isolate PHW1245. The analysis of segregating F(1) progenies and 14 test crosses suggested that a single major gene is involved in the interaction. This putative avirulence gene was designated alm1 after the resistance locus identified in B. napus. Amplified fragment length polymorphism (AFLP) markers were used to generate a rudimentary genetic linkage map of the L. maculans genome and to locate markers linked to the putative avirulence locus. Two flanking AFLP markers, AC/TCC-1 and AC/CAG-5, were linked to alm1 at 3.1 and 8.1 cM, respectively. Identification of markers linked to the avirulence gene indicated that the differential interaction is controlled by a single gene difference between parental isolates and provides further support for the gene-for-gene relationship in the Leptosphaeria-Brassica system.     

甘蓝型油菜显性无蜡粉基因的染色体组定位

为给克隆无蜡粉基因提供理论依据,减少无蜡粉基因分子标记的工作量,对用白菜型油菜有蜡粉材料Ｃ１－３３与甘蓝型油菜无蜡粉材料１０４７种间杂交获得的Ｆ１,自交所得Ｆ２,以及与Ｃ１－３３回交获得的ＢＣ１,ＢＣ２代的蜡粉性状分离进行了观察。结果表明,１０４７中显性无蜡粉基因位于甘蓝型油菜的Ａ染色体组上。