Boyce Thompson Institute for Plant Research, Ithaca, NY 14853, USA.
Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA.
New Phytol. 2010 Sep;187(4):969-982. doi: 10.1111/j.1469-8137.2009.03175.x. Epub 2010 Jan 28.
*The Pseudomonas syringae pv. tomato type III effector protein AvrPto has two functional domains that contribute additively to its ability to promote pathogen virulence in susceptible tomato plants and also defense responses in resistant tomato and tobacco genotypes. Here, we test the hypothesis that key amino acid residues in these two domains will be conserved even in sequence-divergent AvrPto proteins expressed by diverse P. syringae pathovars. *We cloned avrPto homologs from diverse P. syringae pathovars and characterized the four most diverse homologs from P. syringae pathovars mori, lachrymans, myricae and oryzae for their virulence activity and ability to elicit resistance in tomato and tobacco. *Key residues within the two AvrPto domains are conserved in three of the four homologs and are required for virulence activity and defense elicitation. AvrPto(oryzae), lacks conserved residues in each domain, but was found to be recognized by a previously unknown resistance gene in both tomato and tobacco. *Our results indicate that the two virulence domains of AvrPto are conserved in diverse pathovars despite the fact these domains are recognized by certain plant species. AvrPto may therefore function in pathovars infecting diverse plant species by targeting conserved host processes.
译文：丁香假单胞菌 pv.番茄的 III 型效应蛋白 AvrPto 有两个功能域，这两个功能域共同作用，有助于其在易感番茄植株中促进病原菌的毒力，也有助于在抗番茄和烟草基因型中诱导防御反应。在这里，我们测试了一个假设，即这些两个结构域中的关键氨基酸残基即使在由不同丁香假单胞菌致病变种表达的序列差异的 AvrPto 蛋白中也将保守。我们从不同的丁香假单胞菌致病变种中克隆了 avrPto 同源物，并对来自于 mori、lachrymans、myricae 和 oryzae 等不同致病变种的四个最具多样性的同源物的毒力活性及其在番茄和烟草中诱导抗性的能力进行了表征。在这两个 AvrPto 结构域中的关键残基在四个同源物中的三个中是保守的，并且是毒力活性和防御诱导所必需的。AvrPto(oryzae) 缺失每个结构域中的保守残基，但在番茄和烟草中都被一个以前未知的抗性基因所识别。我们的结果表明，尽管这些结构域被某些植物物种识别，但 AvrPto 的两个毒力结构域在不同的致病变种中是保守的。因此，AvrPto 可能通过靶向保守的宿主过程在感染不同植物物种的致病变种中发挥作用。
