Elucidation of the hrp Clusters of Xanthomonas oryzae pv. oryzicola That Control the Hypersensitive Response in Nonhost Tobacco and Pathogenicity in Susceptible Host Rice
Elucidation of the hrp Clusters of Xanthomonas oryzae pv. oryzicola That Control the Hypersensitive Response in Nonhost Tobacco and Pathogenicity in Susceptible Host Rice
复制标题
DOI：
10.1128/aem.00511-06
复制
发表时间：
2006-09
影响因子：
4.4
通讯作者：
Lifang Zou;Xingsheng Wang;Y. Xiang;Bing Zhang;Yu-rong Li;You-lun Xiao;Jin-sheng Wang;A. Walmsley-A.-Walms
中科院分区：
文献类型：
--
作者：
Lifang Zou;Xingsheng Wang;Y. Xiang;Bing Zhang;Yu-rong Li;You-lun Xiao;Jin-sheng Wang;A. Walmsley-A.-Walms
摘要水稻白叶枯病菌Xanthomonas oryzae PV.水稻细菌性条斑病的病原菌oryzicola具有hrp基因簇，决定了其在非寄主烟草中诱导过敏反应(HR)和在寄主水稻中致病的能力。稻瘟病菌基因组的一个27kb的区域。对水稻RS105基因进行了鉴定和测序，发现了10个hrp、9个hrc(hrp保守)和8个hpa(hrp相关)基因和7个植物诱导的调控启动子框。Hpa2~hpaB区域和hrpF操纵子与其他黄单胞菌的相应基因相似，而hpaB-hrpF区域含有水稻白叶枯病菌所没有的hrpE3基因。米饭。我们发现一个hrpF突变体已经失去了在烟草中诱导HR和在成年水稻植株上致病的能力，但仍然在水稻幼苗上引起了浸水症状，并且Hpa1是非寄主烟草中的HR激发子，其表达受HRP调控因子HrpX的调控。通过HRP表型互补试验，我们鉴定了一个包含hrpG和hrpX调控基因的小HRP簇，它是从核心HRP簇中分离出来的。此外，我们还鉴定了一个基因prhA(植物调节的hrp)，它在水稻纹枯病菌的hrp表型中起着关键作用。Oryzicola，但既不在核心HRP组中，也不在HRP调控组中。一个prhA突变体未能降低烟草的致病力和水稻的致病力，但在水稻上引起了浸水症状。这是首次报道稻瘟病菌X.oryzae pv.水稻纹枯病菌在非寄主烟草上具有诱导HR和在寄主水稻上致病的三个不同的DNA区域，这将为了解水稻白粉病致病决定因素提供基础。Oryzicola与稻瘟病菌X.oryzae pv.米饭。
ABSTRACT Xanthomonas oryzae pv. oryzicola, the cause of bacterial leaf streak in rice, possesses clusters of hrp genes that determine its ability to elicit a hypersensitive response (HR) in nonhost tobacco and pathogenicity in host rice. A 27-kb region of the genome of X. oryzae pv. oryzicola (RS105) was identified and sequenced, revealing 10 hrp, 9 hrc (hrp conserved), and 8 hpa (hrp-associated) genes and 7 regulatory plant-inducible promoter boxes. While the region from hpa2 to hpaB and the hrpF operon resembled the corresponding genes of other xanthomonads, the hpaB-hrpF region incorporated an hrpE3 gene that was not present in X. oryzae pv. oryzae. We found that an hrpF mutant had lost the ability to elicit the HR in tobacco and pathogenicity in adult rice plants but still caused water-soaking symptoms in rice seedlings and that Hpa1 is an HR elicitor in nonhost tobacco whose expression is controlled by an hrp regulator, HrpX. Using an Hrp phenotype complementation test, we identified a small hrp cluster containing the hrpG and hrpX regulatory genes, which is separated from the core hrp cluster. In addition, we identified a gene, prhA (plant-regulated hrp), that played a key role in the Hrp phenotype of X. oryzae pv. oryzicola but was neither in the core hrp cluster nor in the hrp regulatory cluster. A prhA mutant failed to reduce the HR in tobacco and pathogenicity in rice but caused water-soaking symptoms in rice. This is the first report that X. oryzae pv. oryzicola possesses three separate DNA regions for HR induction in nonhost tobacco and pathogenicity in host rice, which will provide a fundamental base to understand pathogenicity determinants of X. oryzae pv. oryzicola compared with those of X. oryzae pv. oryzae.