Gonzalez Carolina, Szurek Boris, Manceau Charles, Mathieu Thierry, Séré Yacouba, Verdier Valérie
Laboratoire Génome et Développement des Plantes, IRD-CNRS-Universite de Perpignan, Centre IRD, 911 Av Agropolis, BP64501, 34394 Montpellier, France.
Mol Plant Microbe Interact. 2007 May;20(5):534-46. doi: 10.1094/MPMI-20-5-0534.
DNA polymorphism analysis and pathogenicity assays were used to characterize strains of Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola collected from rice leaves in West Africa. Restriction fragment length polymorphism (RFLP), repetitive sequence-based polymerase chain reaction, fluorescent amplified fragment-length polymorphism (FAFLP) analyses were assessed for molecular characterization, while pathogenicity was tested by leaf clipping and leaf infiltration. Dendrograms were generated for the data sets obtained from RFLP analysis and repetitive polymerase chain reaction suggesting that the interrelationships between strains were dependent on the technique used. In all cases, data showed that African strains of X. oryzae pv. oryzae form a group genetically distant from Asian strains. FAFLP analyses separated the X. oryzae strains into three groups with significant bootstrap values. A specific and intriguing feature of African strains of X. oryzae pv. oryzae is a reduction in the number of insertion sequence elements and transcription activator-like (avrBs3/pthA) effector genes, based on the molecular markers employed in the study. In addition, pathogenicity assays conducted with African strains of X. oryzae pv. oryzae on a series of nearly isogenic lines (NILs) identified three new races. Finally, leaf infiltration assays revealed the capacity of African strains of X. oryzae pv. oryzae to induce a nonhost hypersensitive response in Nicotiana benthamiana, in contrast with Asian X. oryzae pv. oryzae and X. oryzae pv. oryzicola strains. Our results reveal substantial differences between genomic characteristics of Asian and African strains of X. oryzae pv. oryzae.
采用DNA多态性分析和致病性检测方法，对从西非水稻叶片中采集的水稻白叶枯病菌（Xanthomonas oryzae pv. oryzae）和水稻条斑病菌（Xanthomonas oryzae pv. oryzicola）菌株进行特征分析。采用限制性片段长度多态性（RFLP）、基于重复序列的聚合酶链反应、荧光扩增片段长度多态性（FAFLP）分析进行分子特征鉴定，同时通过剪叶法和叶片浸润法检测致病性。对RFLP分析和重复聚合酶链反应获得的数据集生成聚类图，结果表明菌株之间的相互关系取决于所使用的技术。在所有情况下，数据显示水稻白叶枯病菌的非洲菌株形成了一个与亚洲菌株在遗传上距离较远的群体。FAFLP分析将水稻白叶枯病菌菌株分为三组，具有显著的自展值。基于本研究中使用的分子标记，水稻白叶枯病菌非洲菌株的一个特殊且有趣的特征是插入序列元件和转录激活样（avrBs3/pthA）效应子基因的数量减少。此外，对一系列近等基因系（NILs）进行水稻白叶枯病菌非洲菌株的致病性检测，鉴定出三个新小种。最后，叶片浸润试验表明，与亚洲水稻白叶枯病菌和水稻条斑病菌菌株相比，水稻白叶枯病菌非洲菌株能够在本氏烟草中诱导非寄主过敏反应。我们的结果揭示了水稻白叶枯病菌亚洲菌株和非洲菌株在基因组特征上的显著差异。
