Ralstonia solanacearum genes induced during growth in tomato:: an inside view of bacterial wilt
Ralstonia solanacearum genes induced during growth in tomato:: an inside view of bacterial wilt
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DOI：
10.1111/j.1365-2958.2004.04237.x
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发表时间：
2004-09-01
影响因子：
3.6
通讯作者：
Allen, C
中科院分区：
文献类型：
--
作者：
Brown, DG;Allen, C
植物病原菌青枯雷尔氏菌（Ralstonia solanacearum）有超过5000个基因，其中许多可能促进细菌性枯萎病的发展。利用体内表达技术（IVET）筛选了133 200个R.青枯菌菌株K60启动子融合体和分离的约900个融合体在番茄植物中细菌生长期间表达。对307个融合基因进行序列分析，发现153个独特的植物表达基因（ipx）。这些基因包括七个先前鉴定的毒力基因（pehR、vsrB、vsrD、rpoS、hrcC、pme和gspK）以及七个额外的推定毒力因子。大量的ipx基因可能反映了对寄主木质部环境的适应，19.6%的ipx基因编码具有代谢和/或运输功能的蛋白，9.8%的ipx基因编码可能参与胁迫反应的蛋白。许多ipx基因（18%）编码推定的跨膜蛋白。所分离的ipx基因大多编码功能未知的蛋白质，其中13%为R.青枯菌属ipx基因在植物中被诱导表达;对44个ipx融合体的一个子集的β-葡萄糖醛酸酶报告基因表达分析显示，在植物中的表达水平比培养中高2 - 37倍。许多ipx基因的表达受已知的R.青枯菌毒力调节因子32融合测试，28个至少有一个毒力调节器的影响，几个融合控制多个监管机构。两个ipx融合菌株分离在这个屏幕上的番茄的毒力降低，表明基因（S）的重要的细菌性枯萎病的发病机制被中断的IVET插入;在其他ipx基因的突变是必要的，以确定其在毒力和植物生长的作用。总的来说，ipx基因的这种分布表明，在其宿主中，R。青枯菌面临并克服了压力和营养不良的环境。
The phytopathogen Ralstonia solanacearum has over 5000 genes, many of which probably facilitate bacterial wilt disease development. Using in vivo expression technology (IVET), we screened a library of 133 200 R. solanacearum strain K60 promoter fusions and isolated approximate to 900 fusions expressed during bacterial growth in tomato plants. Sequence analysis of 307 fusions revealed 153 unique in planta-expressed (ipx) genes. These genes included seven previously identified virulence genes (pehR, vsrB, vsrD, rpoS, hrcC, pme and gspK) as well as seven additional putative virulence factors. A significant number of ipx genes may reflect adaptation to the host xylem environment; 19.6%ipx genes are predicted to encode proteins with metabolic and/or transport functions, and 9.8%ipx genes encode proteins possibly involved in stress responses. Many ipx genes (18%) encode putative transmembrane proteins. A majority of ipx genes isolated encode proteins of unknown function, and 13% were unique to R. solanacearum. The ipx genes were variably induced in planta; beta-glucuronidase reporter gene expression analysis of a subset of 44 ipx fusions revealed that in planta expression levels were between two- and 37-fold higher than in culture. The expression of many ipx genes was subject to known R. solanacearum virulence regulators. Of 32 fusions tested, 28 were affected by at least one virulence regulator; several fusions were controlled by multiple regulators. Two ipx fusion strains isolated in this screen were reduced in virulence on tomato, indicating that gene(s) important for bacterial wilt pathogenesis were interrupted by the IVET insertion; mutations in other ipx genes are necessary to determine their roles in virulence and in planta growth. Collectively, this profile of ipx genes suggests that in its host, R. solanacearum confronts and overcomes a stressful and nutrient-poor environment.