Dynamic evolution of pathogenicity revealed by sequencing and comparative genomics of 19 Pseudomonas syringae isolates.
Dynamic evolution of pathogenicity revealed by sequencing and comparative genomics of 19 Pseudomonas syringae isolates.
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DOI：
10.1371/journal.ppat.1002132
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发表时间：
2011-07
期刊：
影响因子：
6.7
通讯作者：
Dangl JL
中科院分区：
文献类型：
--
作者：
Baltrus DA;Nishimura MT;Romanchuk A;Chang JH;Mukhtar MS;Cherkis K;Roach J;Grant SR;Jones CD;Dangl JL
密切相关的病原体可能在宿主范围上有很大差异，但这些差异的分子、遗传和进化基础仍不清楚。在许多革兰氏阴性细菌中，包括植物病原体假单胞菌，III型效应子（TTE）对于致病性是必需的，有助于构建宿主范围，并且在菌株之间表现出广泛的多样性。为了捕获整个P. pastingae的毒力基因库的动态性质，我们筛选了11个不同的菌株的新型TTE家族，并将这种几乎饱和的筛选与来自广泛收集的患病宿主植物的14个遗传多样性分离株的测序和组装相结合。TTE库在所有P. erichingae进化枝中在大小和内容上显著变化;令人惊讶的是，很少TTE是保守的并且存在于所有菌株中。那些可能提供致病性的基本要求。我们证明了一个保守的基因座，hopM 1，功能的分歧，导致致病性的显着差异，我们表明，遗传学的信息诱变可用于确定功能关键的TTEs残基。TTE库的动态反映了影响分泌的植物毒素合成的途径的多样性，突出了两种类型的毒力因子在确定宿主范围中的可能作用。我们使用这14个基因组草图序列，加上之前报道的5个额外的基因组序列，来鉴定P. pseudingae的核心基因组，并将该核心基因组与两个密切相关的非致病性假单胞菌物种进行了比较。这些数据揭示了黄瓜病原体的一个亚支最近获得了1 Mb大质粒。这种大质粒编码IV型分泌系统和一组不同的未知蛋白质，这大大增加了这些菌株的基因组含量和物种的泛基因组。基因组学的突破性进展为研究不同细菌分离株表型差异的遗传基础提供了一套新的工具。在这里，我们分析了19个基因组的P. pastingae，许多作物物种的病原体，揭示了从水稻到枫树等宿主植物的毒力差异的遗传变化。令人惊讶的是，一对菌株通过获得约占基因组14%的1 Mb大质粒而显著分化。新型质粒和水平遗传交换对物种多样性做出了广泛贡献。III型效应蛋白是致病性所必需的，在菌株之间表现出广泛的多样性，并且在整个物种中以不同的更高水平模式存在。此外，我们使用进化背景下的序列比较，以确定多个毒力基因的功能变化。总的来说，我们的数据提供了一个独特的概述内的进化压力P. pastingae和植物病原体研究界的重要资源。
Closely related pathogens may differ dramatically in host range, but the molecular, genetic, and evolutionary basis for these differences remains unclear. In many Gram- negative bacteria, including the phytopathogen Pseudomonas syringae, type III effectors (TTEs) are essential for pathogenicity, instrumental in structuring host range, and exhibit wide diversity between strains. To capture the dynamic nature of virulence gene repertoires across P. syringae, we screened 11 diverse strains for novel TTE families and coupled this nearly saturating screen with the sequencing and assembly of 14 phylogenetically diverse isolates from a broad collection of diseased host plants. TTE repertoires vary dramatically in size and content across all P. syringae clades; surprisingly few TTEs are conserved and present in all strains. Those that are likely provide basal requirements for pathogenicity. We demonstrate that functional divergence within one conserved locus, hopM1, leads to dramatic differences in pathogenicity, and we demonstrate that phylogenetics-informed mutagenesis can be used to identify functionally critical residues of TTEs. The dynamism of the TTE repertoire is mirrored by diversity in pathways affecting the synthesis of secreted phytotoxins, highlighting the likely role of both types of virulence factors in determination of host range. We used these 14 draft genome sequences, plus five additional genome sequences previously reported, to identify the core genome for P. syringae and we compared this core to that of two closely related non-pathogenic pseudomonad species. These data revealed the recent acquisition of a 1 Mb megaplasmid by a sub-clade of cucumber pathogens. This megaplasmid encodes a type IV secretion system and a diverse set of unknown proteins, which dramatically increases both the genomic content of these strains and the pan-genome of the species. Breakthroughs in genomics have unleashed a new suite of tools for studying the genetic bases of phenotypic differences across diverse bacterial isolates. Here, we analyze 19 genomes of P. syringae, a pathogen of many crop species, to reveal the genetic changes underlying differences in virulence across host plants ranging from rice to maple trees. Surprisingly, a pair of strains diverged dramatically via the acquisition of a 1 Mb megaplasmid, which constitutes roughly 14% of the genome. Novel plasmids and horizontal genetic exchange have contributed extensively to species-wide diversification. Type III effector proteins are essential for pathogenicity, exhibit wide diversity between strains and are present in distinct higher-level patterns across the species. Furthermore, we use sequence comparisons within an evolutionary context to identify functional changes in multiple virulence genes. Overall, our data provide a unique overview of evolutionary pressures within P. syringae and an important resource for the phytopathogen research community.
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影响因子：
3.5
作者：
Chang, JH;Tobias, CM;Michelmore, RW
通讯作者：
Michelmore, RW
影响因子：
3.5
作者：
Chang, JH;Rathjen, JP;Michelmore, RW
通讯作者：
Michelmore, RW
DOI：
10.1073/pnas.0409660102
发表时间：
2005-02-15
影响因子：
11.1
作者：
Chang, JH;Urbach, JM;Dangl, JL
通讯作者：
Dangl, JL
DOI：
10.1073/pnas.1731982100
发表时间：
2003-09-02
影响因子：
11.1
作者：
Buell, CR;Joardar, V;Collmer, A
通讯作者：
Collmer, A
影响因子：
4.9
作者：
Ferrante, Patrizia;Clarke, Christopher R.;Vinatzer, Boris A.
通讯作者：
Vinatzer, Boris A.