Extracellular Amylase Is Required for Full Virulence and Regulated by the Global Posttranscriptional Regulator RsmA in Xanthomonas campestris Pathovar campestris
Extracellular Amylase Is Required for Full Virulence and Regulated by the Global Posttranscriptional Regulator RsmA in Xanthomonas campestris Pathovar campestris
复制标题
细胞外淀粉酶是油菜黄单胞菌具有完全毒力所必需的，并受到全局转录后调节因子 RsmA 的调节
DOI：
10.1094/phyto-08-20-0372-r
复制
发表时间：
2021-07-01
期刊：
影响因子：
3.2
通讯作者：
Tang, Dong-Jie
中科院分区：
文献类型：
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作者：
Lin, Yan;Liao, Yong-Yan;Tang, Dong-Jie
与许多植物病原细菌一样，野油菜黄单胞菌致病变种（Xanthomonascampestris pv.）十字花科植物中黑腐病的病原体campestris依赖于一系列胞外酶的分泌，所述胞外酶包括纤维素酶（内切葡聚糖酶）、果胶酶、蛋白酶和淀粉酶。虽然已经评估了这些酶在毒力中的作用，但淀粉酶对X。野油菜致病变种油菜毒力尚未确定。在这项工作中，我们研究了胞外淀粉酶在X。野油菜致病变种油菜毒力及其表达调控。XC 3487（在此更名为amyA（XCC）），一个假定的淀粉酶编码基因从X.野油菜致病变种campestris菌株8004，导致胞外淀粉酶活性的完全丧失和毒力的显著降低。amyA（XCC）突变体的胞外淀粉酶活性和毒力通过amyA（XCC）的反式表达而恢复到野生型水平。野油菜致病变种campestris的胞外淀粉酶活性，表明胞外淀粉酶在X.野油菜致病变种油菜毒力我们还发现，amyA（XCC）的表达强烈诱导淀粉，需要激活的全球转录后调节RsmA。RsmA特异性结合amyA（XCC）转录物的5 '-非翻译区，表明RsmA直接在转录后水平调节amyA（XCC）。出乎意料的是，除了转录后调控，使用的转录报告表明，RsmA也调节amyA（XCC）的表达在转录水平上，可能是通过间接的机制。
As with many phytopathogenic bacteria, the virulence of Xanthomonas campestris pv. campestris, the causal agent of black rot disease in cruciferous plants, relies on secretion of a suite of extracellular enzymes that includes cellulase (endoglucanase), pectinase, protease, and amylase. Although the role in virulence of a number of these enzymes has been assessed, the contribution of amylase to X. campestris pv. campestris virulence has yet to be established. In this work, we investigated both the role of extracellular amylase in X. campestris pv. campestris virulence and the control of its expression. Deletion of XC3487 (here renamed amyA(XCC)), a putative amylase-encoding gene from the genome of X. campestris pv. campestris strain 8004, resulted in a complete loss of extracellular amylase activity and significant reduction in virulence. The extracellular amylase activity and virulence of the amyA(XCC) mutant could be restored to the wild-type level by expressing amyA(XCC) in trans. These results demonstrated that amyA(XCC), is responsible for the extracellular amylase activity of X. campestris pv. campestris and indicated that extracellular amylase plays an important role in X. campestris pv. campestris virulence. We also found that the expression of amyA(XCC) is strongly induced by starch and requires activation by the global posttranscriptional regulator RsmA. RsmA binds specifically to the 5'-untranslated region of amyA(XCC) transcripts, suggesting that RsmA regulates amyA(XCC) directly at the posttranscriptional level. Unexpectedly, in addition to posttranscriptional regulation, the use of a transcriptional reporter demonstrated that RsmA also regulates amyA(XCC) expression at the transcriptional level, possibly by an indirect mechanism.