Phytopathology. 1999 Aug;89(8):687-94. doi: 10.1094/PHYTO.1999.89.8.687.
ABSTRACT Among the 171 strains of Xanthomonas oryzae pv. oryzae (the bacterial blight pathogen of rice) collected from eight rice-producing zones in Nepal, 31 molecular haplotypes were distinguished using two polymerase chain reaction-based assays. Six common haplotypes represented nearly 63% of the strains, and some haplotypes were geographically dispersed. Multiple correspondence analysis divided the collection into five putative genetic lineages. Lineages 1, 2, and 4 were the most frequently detected and occurred in diverse geographic populations. Twenty-six pathotypes (virulence phenotypes) of X. oryzae pv. oryzae were identified using 11 near-iso-genic rice lines, each containing a single gene for resistance. The 26 pathotypes grouped into five clusters, and cluster 1 contained wide virulence spectrum strains from all geographic populations. Although molecular variation was greatest between strains of different virulence phenotypes, some variation was observed among strains with identical virulence. There was a weak correlation (r = 0.52) between molecular haplotypes and virulence phenotypes. There are two major groups of X. oryzae pv. oryzae in Nepal. One group consists of strains with high molecular polymorphism and many pathotypes that are either virulent to the 11 major resistance genes or avirulent only to Xa21. Strains in the second group have low molecular polymorphism and are avirulent to Xa4, xa5, Xa7, and Xa21.
摘要 在从尼泊尔八个水稻种植区采集的 171 株稻黄单胞菌（水稻细菌性条斑病病原菌）菌株中，使用两种基于聚合酶链反应的检测方法区分了 31 个分子单倍型。 6 个常见单倍型代表了近 63%的菌株，并且一些单倍型在地理上分散。多元对应分析将采集的样本分为五个假定的遗传谱系。谱系 1、2 和 4 是最常检测到的，并且存在于不同的地理种群中。使用 11 个近等基因水稻系鉴定了 26 个稻黄单胞菌 pv.oryzae 的致病型（毒性表型），每个系都含有一个抗性基因。这 26 个致病型分为五个聚类，聚类 1 包含来自所有地理种群的广谱毒性菌株。尽管不同致病型菌株之间的分子变异最大，但在具有相同致病型的菌株中也观察到了一些变异。分子单倍型与致病型之间存在弱相关性（r = 0.52）。尼泊尔有两个主要的稻黄单胞菌 pv.oryzae 群体。一组由具有高分子多态性和许多致病型的菌株组成，这些菌株要么对 11 个主要抗性基因具有毒性，要么仅对 Xa21 无毒。第二组菌株的分子多态性较低，对 Xa4、xa5、Xa7 和 Xa21 无毒。
