Interactions between the Powdery Mildew Effector BEC1054 and Barley Proteins Identify Candidate Host Targets

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• 作者：Helen G. Pennington ; Dana M. Gheorghe ; Annabelle Damerum ; Clara Pliego ; Pietro D. Spanu ; Rainer Cramer ; Laurence V. Bindschedler
• 刊名：Journal of Proteome Research
• 出版年：2016
• 出版时间：March 4, 2016
• 年：2016
• 卷：15
• 期：3
• 页码：826-839
• 全文大小：788K
• ISSN：1535-3907

文摘

There are over 500 candidate secreted effector proteins (CSEPs) or Blumeria effector candidates (BECs) specific to the barley powdery mildew pathogen Blumeria graminis f.sp. hordei. The CSEP/BEC proteins are expressed and predicted to be secreted by biotrophic feeding structures called haustoria. Eight BECs are required for the formation of functional haustoria. These include the RNase-like effector BEC1054 (synonym CSEP0064). In order to identify host proteins targeted by BEC1054, recombinant BEC1054 was expressed in E. coli, solubilized, and used in pull-down assays from barley protein extracts. Many putative interactors were identified by LC-MS/MS after subtraction of unspecific binders in negative controls. Therefore, a directed yeast-2-hybrid assay, developed to measure the effectiveness of the interactions in yeast, was used to validate putative interactors. We conclude that BEC1054 may target several host proteins, including a glutathione-S-transferase, a malate dehydrogenase, and a pathogen-related-5 protein isoform, indicating a possible role for BEC1054 in compromising well-known key players of defense and response to pathogens. In addition, BEC1054 interacts with an elongation factor 1 gamma. This study already suggests that BEC1054 plays a central role in barley powdery mildew virulence by acting at several levels.