Pseudomonas syringae Hrp type III secretion system and effector proteins
Pseudomonas syringae Hrp type III secretion system and effector proteins
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DOI：
10.1073/pnas.97.16.8770
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发表时间：
2000-08-01
影响因子：
11.1
通讯作者：
Alfano, JR
中科院分区：
文献类型：
--
作者：
Collmer, A;Badel, JL;Alfano, JR
丁香假单胞菌是动植物中一类重要的革兰氏阴性细菌，依赖III型分泌系统将毒力效应蛋白注入宿主细胞。在丁香假单胞菌中，hrp/hrc基因编码hrp(Ⅲ型分泌系统)，avr和hrp依赖的外蛋白(Hop)基因编码效应蛋白，丁香假单胞菌hrp/hrc基因编码丁香假单胞菌61，P，丁香属丁香假单胞菌B728a和P。紫丁香科光伏番茄DC3000在一个三分体马赛克HRP致病岛(PAI)上含有一个可互换的效应区和一个保守的效应区，PAI与tRNA(Leu)基因连锁，但不与HRP系统基因连锁。CosmidPHIR11携带菌株61 HRP致病岛的一部分，足以指示大肠杆菌和荧光假单胞菌将HopemoA注射到烟草细胞中，从而引发通常只由植物病原体触发的超敏反应。DC3000菌株的大量缺失表明，保守的效应子基因对致病性是必需的，但可交换的效应子基因对番茄的生长只起到很小的作用。在与致病相关的pH和温度条件下，紫丁香假单胞菌以一种依赖于HRP的方式在培养中分泌HopQiA和AvrPto。AvrPto也是由小肠结肠炎耶尔森菌分泌的。AvrPto的分泌依赖于前15个密码子，这些密码子也足以指导来自小肠结肠炎Y的NPT报告基因的分泌，这表明植物和动物病原体的III型分泌系统都识别通用的靶向信号。
Pseudomonas syringae is a member of an important group of Cram-negative bacterial pathogens of plants and animals that depend on a type III secretion system to inject virulence effector proteins into host cells, In P. syringae, hrp/hrc genes encode the Hrp (type III secretion) system, and avirulence (avr) and Hrp-dependent outer protein (hop) genes encode effector proteins, The hrp/hrc genes of P. syringae pv syringae 61, P, syringae pv syringae B728a, and P, syringae pv tomato DC3000 are flanked by an exchangeable effector locus and a conserved effector locus in a tripartite mosaic Hrp pathogenicity island (Pai) that is linked to a tRNA(Leu) gene found also in Pseudomonas aeruginosa but without linkage to Hrp system genes. Cosmid pHIR11 carries a portion of the strain 61 Hrp pathogenicity island that is sufficient to direct Escherichia coli and Pseudomonas fluorescens to inject HopPsyA into tobacco cells, thereby eliciting a hypersensitive response normally triggered only by plant pathogens. Large deletions in strain DC3000 revealed that the conserved effector locus is essential for pathogenicity but the exchangeable effector locus has only a minor role in growth in tomato. P. syringae secretes HopPsyA and AvrPto in culture in a Hrp-dependent manner at pH and temperature conditions associated with pathogenesis. AvrPto is also secreted by Yersinia enterocolitica. The secretion of AvrPto depends on the first 15 codons, which are also sufficient to direct the secretion of an Npt reporter from Y, enterocolitica, indicating that a universal targeting signal is recognized by the type III secretion systems of both plant and animal pathogens.