中国、日本和菲律宾水稻白叶枯病菌的母株与单细胞系的遗传与致病性差异的分析

The Variation of Genetic and Virulent of Xanthomonas oryzae pv. oryzae Strains and Mono-cell-clones from China, Japan and the Philippines

以J3、IS1112、IS1113和ERIC为引物对17组（56株）来自中国、日本和菲律宾的水稻白叶枯病菌（Xanthomonas oryzae pv．oryzae）代表菌株和它们的单细胞系进行IS-PCR和Rep-PCR扩增以及田间致病性鉴定，研究母株和单细胞系之间的遗传和致病性变异。结果表明：1）母株与单细胞系属于同一分子谱型的比率依次为：52．9％（J3）、23．5％（IS1112）、29．4％（IS1113）和35．3％（ERIC）；2）综合4个引物的PCR扩增结果，采用UPGMA聚类，母株与其全部单细胞系相似率在90％以上的组群占29．4％，差异率达到30％～41％的组群占参试组群的52．9％；以带位相似率80％为簇界，参试菌可以划分为15簇，来自中国、日本和菲律宾的9个组的母株和单细胞系聚合在同一簇中，占参试菌的52．9％，说明三国病菌在遗传上存在高度相关性；三国病菌都存在簇群差异，以菲律宾菌系变异最大，如Pxo79和Pxo112母株和单细胞系各分在不同的3簇中，Pxo79、Pxo86、Pxo99和Pxo112等菌系的母株和单细胞系之间的差异率达到了41％；结果证明：母株是“由遗传上有不同程度差异的细胞”组成的混合体。3）田间致病性测定表明，母株与其单细胞系毒力不同的有15组，占88．2％，说明母株是由毒力不同的单细胞系组成的混合体，但病原菌的分子谱型以及遗传分簇与致病型之间没有相关性。

The primers J3, IS 1112, IS 1113, and ERIC were used to analyze 17 tested groups （56 strains and their mono-cell-clones） of Xanthomonas oryzae pv. oryzae from China, Japan and the Philippines. The result showed： 1） The percentage were 52.9%（J3）, 23.5%（IS1112）, 29.4%（IS1113） and 35.3%（ERIC） which strains and their mono-cell-clones were in one patten of each primer, respectively. 2） Percentage were 29.4% which the similarity were over 90% between strains and their mono-cell-clones of 17 tested groups, while 52.9% of dissimilarity were 30%-41%; at level of 80% similarity, 9 tested groups which strains and their mono-cell clones were in one cluster（52.9% of 17 tested groups）, these results suggested there were phylogenetic relationship between the strains. Also the differentiation were exits. Such as, Philippine strains, Pxo79 and Pxo112 were distributed into 3 clusters; the dissimilarity were 41% between strains and their mono-cellclones of Pxo79, Pxo86, Pxo99 and Pxo112. These results indicated the strains were combined by different cells. 3） There was only 11.8% of tested strains which virulence of strains were equal to their mono-cellclones in 17 tested groups. The result indicated that there were virulent difference between strains and their mono-cell-clones. No relationship were observed between UPGMA clusters and pathotypes.