Rep-PCR技术对中国水稻条斑病菌的遗传多样性初析

PRELIMINARY ANALYSIS OF GENETIC DIVERSITY OF Xanthomonas oryzae pv.oryzicola AND Xanthomonas leersiae STRAINS IN CHINA BY Rep-PCR

采用 Rep- PCR技术 ,对 30个水稻细菌性条斑病菌株 (Xanthomonas oryzae pv.oryzicola)进行遗传多样性分析 ,同时对李氏禾条斑病菌等其它 10个参试菌株也进行了比较。 Rep- PCR是利用一些基于细菌的短的重复序列引物 (ERIC和 BOX)的 DNA扩增特性 ,2种引物组合的电泳图谱结合并分析 ,以水稻细菌性条斑病菌各自的指纹谱型在相似率 80 %时可分为 6簇 ,初步表明我国水稻细菌性条斑病菌群体的遗传分化明显 ;发现自然界存在的弱或无毒性菌株与毒性菌株的 Rep- PCR指纹图谱差异很大 ;毒性菌株的遗传分簇与其致病性具有一定的相关性。用 ERIC扩增水稻条斑病菌基因组DNA的指纹比 BOX更为多样 ,两者对菌株的分辨率不同。因此 ,Rep- PCR技术可有效地用于监测水稻细菌性条斑病菌的遗传变异 ,还可应用于菌株的鉴定和分类学研究。

Rep PCR was used to analyze the genetic diversity in a population of 40 Xan thomonas strains. These strains included 30 Xanthomonas oryzae pv. oryzicola isolates from different rice regions in China and 10 reference strains of other Xanthomonas spp. Rep PCR was performed using DNA amplification with primers based on short bacterial repetitive elements(ERIC, BOX).The combination of results from Rep PCR with the two primers demonstrated a higher diversity than either one primer; The results indicated that significant genetic diversity exists within the population of X.o. pv. oryzicola in China. All strains of X.o. pv. oryzicola were clustered into 6 groups at a level of 80% similarity. In addition, strains from infected rice plants were recovered with a number of naturally occurring avirulent or weak virulent strains with Rep PCR fingerprints different to those of virulent ones; There was a high degree of correlation between strains groupings generated by Rep PCR and pathogenicity analysis. It suggested that there are different distributions of BOX and ERIC in genomic DNA of several rice leaf streak pathogen. The results suggested that Rep PCR technique may be a useful tool for detecting genetic variation among strains of X.o. pv. oryzicola and identification of strains as well as classification studies.