Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Fuzhou, Fujian, China.
Mol Plant Microbe Interact. 2011 Jan;24(1):13-7. doi: 10.1094/MPMI-10-09-0240.
Magnaporthe oryzae 2539 was previously found to be avirulent to most rice cultivars and, therefore, was assumed to carry many avirulence (AVR) genes. However, only one AVR gene, AVR1-CO39, which corresponds to a resistance (R) gene Pi-CO39(t) in rice cv. CO39, has been found from 2539 thus far. In order to identify more AVR genes, we isolated 228 progeny strains from a cross between 2539 and Guy11, an M. oryzae strain with strong virulence on rice, and inoculated these strains onto 23 rice accessions (22 individual cultivars and a mixture of 14 cultivars) that are all resistant to 2539 but susceptible to Guy11. Unexpectedly, the experimental results indicated that the avirulence of 2539 on these rice cultivars appeared to be controlled only by the AVR1-CO39 locus. Consistent with this result, we further found that all except one of the rice cultivars were resistant to two transformed Guy11 strains carrying a 1.05-kb fragment containing the AVR1-CO39 gene from 2539. These results suggest that AVR1-CO39 is a predominant locus controlling the broad avirulence of 2539 on cultivated rice. Based on the results of this study and other previous studies, we infer that AVR1-CO39 is a species-wise rather than a cultivar-wise host-specific AVR locus of M. oryzae for rice.
稻瘟病菌 2539 先前被发现对大多数水稻品种无毒，因此被认为携带许多无毒（AVR）基因。然而，迄今为止，仅从 2539 中发现了一个 AVR 基因 AVR1-CO39，它对应于水稻品种 CO39 中的抗性（R）基因 Pi-CO39(t)。为了鉴定更多的 AVR 基因，我们从稻瘟病菌 2539 和 Guy11 之间的杂交后代中分离出 228 个菌株，Guy11 对水稻具有很强的毒性，将这些菌株接种到 23 个水稻品种（22 个单一品种和 14 个品种的混合物）上，这些品种对 2539 均具有抗性，但对 Guy11 敏感。出乎意料的是，实验结果表明，2539 对这些水稻品种的无毒特性似乎仅由 AVR1-CO39 基因座控制。与这一结果一致，我们进一步发现，除了一个品种外，所有其他水稻品种都对携带来自 2539 的包含 AVR1-CO39 基因的 1.05kb 片段的两个转化 Guy11 菌株具有抗性。这些结果表明，AVR1-CO39 是控制 2539 在栽培稻上广泛无毒的主要基因座。基于这项研究和其他先前研究的结果，我们推断 AVR1-CO39 是稻瘟病菌对水稻的一种种属特异性而非品种特异性的 AVR 基因座。
