Genome-Wide Identification of a Large Repertoire of Ralstonia solanacearum Type III Effector Proteins by a New Functional Screen
Genome-Wide Identification of a Large Repertoire of Ralstonia solanacearum Type III Effector Proteins by a New Functional Screen
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DOI：
10.1094/mpmi-23-3-0251
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发表时间：
2010-03-01
影响因子：
3.5
通讯作者：
Iwabuchi, Masaki
中科院分区：
文献类型：
--
作者：
Mukaihara, Takafumi;Tamura, Naoyuki;Iwabuchi, Masaki
革兰氏阴性植物病原细菌青枯雷尔氏菌（Ralstonia solanacearum）利用过敏反应和致病性（Hrp）III型分泌系统（T3SS）在植物中引起疾病。为了确定R.利用转座子介导的钙调素依赖性腺苷酸环化酶报告基因，构建了一个转座子，通过监测插入突变体接种的植物叶片中cAMP水平，特异性检测rip（Ralstonia protein injected into plant cell）基因。从使用该转座子的新功能筛选中，我们鉴定了38个新的Rip蛋白通过Hrp T3SS易位到植物细胞中。此外，RS1000的34个已知效应子中的大多数都可以通过屏幕检测到，除了三个看起来尺寸很小或仅弱表达的效应子。最后，我们在RS1000中鉴定了72个Rip，其中包括68个效应蛋白，分为50多个家族和Hrp T3SS的4个胞外组分。有趣的是，三分之一的效应子是R所特有的。青枯菌属许多效应蛋白含有各种重复的氨基酸序列或已知的酶基序。我们还表明，大部分的R。青枯菌效应蛋白，而不是Hrp胞外组分，需要Hrp相关蛋白HpaB，用于其有效易位到植物细胞中。
The gram-negative plant-pathogenic bacterium Ralstonia solanacearum utilizes the hypersensitive response and pathogenicity (Hrp) type III secretion system (T3SS) to cause disease in plants. To determine the entire repertoire of effector proteins possessed by R. solanacearum RS1000, we constructed a transposon carrying a calmodulin-dependent adenylate cyclase reporter that can be used to specifically detect rip (Ralstonia protein injected into plant cells) genes by monitoring the cAMP level in plant leaves inoculated with insertion mutants. From the new functional screen using this transposon, we identified 38 new Rip proteins translocated into plant cells via the Hrp T3SS. In addition, most of the 34 known effectors of RS1000 could be detected by the screen, except for three effectors that appear to be small in size or only weakly expressed. Finally, we identified 72 Rips in RS1000, which include 68 effector proteins classified into over 50 families and four extracellular components of the Hrp T3SS. Interestingly, one-third of the effectors are specific to R. solanacearum. Many effector proteins contain various repeated amino acid sequences or known enzyme motifs. We also show that most of the R. solanacearum effector proteins, but not Hrp extracellular components, require an Hrp-associated protein, HpaB, for their effective translocation into plant cells.