USDA-ARS Plant Disease Resistance Research Unit, University of Wisconsin, 53706, Madison, WI, USA.
Theor Appl Genet. 1994 Sep;88(8):901-8. doi: 10.1007/BF00220794.
Magnaporthe grisea causes rice blast, the most important fungal disease of rice. The segregation of genes controlling virulence of M. grisea on rice was studied to establish the genetic basis of cultivar specificity in this host-parasite interaction. Full-sib progeny and parent isolates Guy11 and 2539 of M. grisea were inoculated onto rice (Oryza sativa) cultivar 'CO39' and five near-isogenic lines (NILs) of CO39. Each NIL contained a different single gene affecting resistance to specific isolates of M. grisea. No differential interactions between NILs and progeny or parents were observed; parents and progeny pathogenic on CO39 were pathogenic on all five NILs. Segregation ratios of 101 full-sib progeny, 117 progeny from full-sib parents, and 109 backcross progeny, indicated a common single gene affecting pathogenicity on CO39 and the five NILs. A subset of the above 327 isolates (43 fullsib progeny, 37 progeny from full-sib parents, and 32 backcross progeny) were inoculated onto rice cultivar '51583'; all were pathogenic, indicating that cultivar specificity to CO39 was segregating in this population of isolates. The locus controlling cultivar specificity, named avrCO39, was mapped to chromosome 1 using a subset of the progeny previously used to construct an RFLP map of M. grisea. The closest reported RFLP markers were 11.8 (estimated 260 kb) and 17.2 cM (estimated 380 kb) away and provide starting points on either side of the locus for a "chromosome walk" to clone the locus.
稻瘟病菌引起稻瘟病，是水稻最重要的真菌病害。本研究旨在解析稻瘟病菌在水稻上的致病基因的分离规律，从而阐明这种寄主-病原互作的遗传基础。将稻瘟病菌的全同胞后代及亲本菌株 Guy11 和 2539 接种到水稻品种 CO39 及其五个近等基因系（NILs）上。每个 NIL 都含有一个影响对特定稻瘟病菌株抗性的单一基因。未观察到 NILs 与后代或亲本之间存在差异互作；对 CO39 致病的亲本和后代菌株也对所有五个 NILs 致病。101 个全同胞后代、117 个全同胞亲本后代和 109 个回交后代的分离比例表明，有一个单一的基因共同影响 CO39 和五个 NILs 的致病性。上述 327 个菌株中的一部分（43 个全同胞后代、37 个全同胞亲本后代和 32 个回交后代）被接种到水稻品种 51583 上；所有这些菌株都致病，表明 CO39 的品种特异性在该菌株群体中是分离的。该控制品种特异性的基因座命名为 avrCO39，利用先前用于构建稻瘟病菌 RFLP 图谱的后代中的一部分，将其定位到 1 号染色体上。最近报道的 RFLP 标记位于 11.8（估计 260kb）和 17.2cM（估计 380kb）处，为该基因座两侧的“染色体步移”克隆提供了起点。
