Type IV Pili Are Required for Virulence, Twitching Motility, and Biofilm Formation of Acidovorax avenae subsp citrulli
Type IV Pili Are Required for Virulence, Twitching Motility, and Biofilm Formation of Acidovorax avenae subsp citrulli
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DOI：
10.1094/mpmi-22-8-0909
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发表时间：
2009-08-01
影响因子：
3.5
通讯作者：
Burdman, Saul
中科院分区：
文献类型：
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作者：
Bahar, Ofir;Goffer, Tal;Burdman, Saul
燕麦酸腐病菌亚种西瓜是细菌性果斑病(BFB)的病原，是西瓜、甜瓜和其他葫芦科的重要病害。尽管BFB具有重要的经济意义，但人们对该病原菌生物学的基本方面及其与寄主植物相互作用的分子基础知之甚少。对燕麦亚种进行鉴定。为了获得与致病力相关的甜瓜基因，我们以燕麦亚种I群菌株M6为背景构建了一个转座子(Tn5)突变文库。并通过甜瓜种子传播试验对其进行减毒筛选。在这里，我们报告了一个毒力降低的TN5突变体的鉴定，该突变体在PilM中受损，它编码一种参与IV型菌毛组装(TFP)的蛋白质。对该突变体的进一步鉴定表明，该突变株为燕麦亚种。瓜子需要TFP来进行抽动运动和野生型生物膜的形成。在其他TFP基因影响的插入突变体中，也观察到毒力和生物被膜形成的显著减少以及抽动的取消。我们还首次提供了第一组燕麦亚种的证据。瓜子可以在寄主木质部导管中定植和移动。
Acidovorax avenae subsp. citrulli is the causal agent of bacterial fruit blotch (BFB), a threatening disease of watermelon, melon, and other cucurbits. Despite the economic importance of BFB, relatively little is known about basic aspects of the pathogen's biology and the molecular basis of its interaction with host plants. To identify A. avenae subsp. citrulli genes associated with pathogenicity, we generated a transposon (Tn5) mutant library on the background of strain M6, a group I strain of A. avenae subsp. citrulli, and screened it for reduced virulence by seed-transmission assays with melon. Here, we report the identification of a Tn5 mutant with reduced virulence that is impaired in pilM, which encodes a protein involved in assembly of type IV pili (TFP). Further characterization of this mutant revealed that A. avenae subsp. citrulli requires TFP for twitching motility and wild-type levels of biofilm formation. Significant reductions in virulence and biofilm formation as well as abolishment of twitching were also observed in insertional mutants affected in other TFP genes. We also provide the first evidence that group I strains of A. avenae subsp. citrulli can colonize and move through host xylem vessels.