The Pseudomonas viridiflava phylogroups in the P. syringae species complex are characterized by genetic variability and phenotypic plasticity of pathogenicity-related traits
The Pseudomonas viridiflava phylogroups in the P. syringae species complex are characterized by genetic variability and phenotypic plasticity of pathogenicity-related traits
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DOI：
10.1111/1462-2920.12433
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发表时间：
2014-07-01
影响因子：
5.1
通讯作者：
Morris, Cindy E.
中科院分区：
文献类型：
--
作者：
Bartoli, Claudia;Berge, Odile;Morris, Cindy E.
丁香假单胞菌是一种复杂的物种，存在于农业和天然水生生境中。据报道，该复合体的成员之一黄假单胞菌在表型上基本上是同质的。我们对来自不同栖息地的菌株进行了表征，这些菌株是根据它们与先前描述的P. viridiflava菌株的遗传相似性来选择的。我们发现了两个不同的系统群和两种不同的表型性状和基因组含量的变异性。菌株在马铃薯的致病性和软腐病等表型上表现出阶段性变化。我们发现，与之前的报道相反，III型分泌系统的两种构型[单（S-PAI）和三（T-PAI）致病性岛]的存在与致病性或诱导软腐病的能力无关。avrE效应基因的存在与否是我们发现的唯一与黄绿假单胞菌致病性相关的性状。其他III型分泌效应基因与致病性无相关性。在S-PAI菌株中发现了一个类似于交换效应位点（EEL）的基因组区域，并描述了两种pai之间可能的重组。在丁香假单胞菌的这些系统群中观察到的变异性的集合可能有助于它们适应致病性或腐生生存的交替机会。
As a species complex, Pseudomonas syringae exists in both agriculture and natural aquatic habitats. P. viridiflava, a member of this complex, has been reported to be phenotypically largely homogenous. We characterized strains from different habitats, selected based on their genetic similarity to previously described P. viridiflava strains. We revealed two distinct phylogroups and two different kinds of variability in phenotypic traits and genomic content. The strains exhibited phase variation in phenotypes including pathogenicity and soft rot on potato. We showed that the presence of two configurations of the Type III Secretion System [single (S-PAI) and tripartite (T-PAI) pathogenicity islands] are not correlated with pathogenicity or with the capacity to induce soft rot in contrast to previous reports. The presence/absence of the avrE effector gene was the only trait we found to be correlated with pathogenicity of P. viridiflava. Other Type III secretion effector genes were not correlated with pathogenicity. A genomic region resembling an exchangeable effector locus (EEL) was found in S-PAI strains, and a probable recombination between the two PAIs is described. The ensemble of the variability observed in these phylogroups of P. syringae likely contributes to their adaptability to alternating opportunities for pathogenicity or saprophytic survival.