报告题目：The virus–chloroplast connection: Symptoms and defense 

报  告 人：Dr. Bong Suk Kim

  Purdue University

报告时间：2015年8月3日15:30

报告地点：新实验楼E202会议室

联  系 人：金京波研究员（jinjb@ibcas.ac.cn） 

报告摘要：

Alfalfa mosaic virus (AMV) coat protein (CP) is essential for many steps in virus replication from early infection to encapsidation. However, the identity and functional relevance of cellular factors that interact with CP remain unknown. In an unbiased yeast two-hybrid screen for CP-interacting arabidopsis proteins, we identified several novel protein interactions that could potentially modulate AMV replication.

One of the novel CP-binding partners was PsbP protein, which is a nuclear-encoded component of the oxygen-evolving complex of Photosystem II. We validated the protein interaction in vitro with pull-down assays, in planta with bimolecular fluorescence complementation assays, and during virus infection by co-immunoprecipitations. CP interacted with the chloroplast-targeted PsbP in the cytosol and mutations that prevented the dimerization of CP abolished this interaction. Importantly, PsbP overexpression markedly reduced virus accumulation in infected leaves. This suggests a potential sequestration strategy that may preempt the generation of any PsbP-mediated antiviral state. We have also determined that down-regulation of PsbP enhanced replication.

One of the fundamental strategies for virus survival relies on virus-host interactions that suppress host defenses. Preliminary experiments did not indicate that the salicylic acid defense pathway is compromised in PsbP down-regulated plants. This makes us reconsider of CP-PsbP interactions modify host basal defense to enhance AMV replication.

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                        中国科学院植物分子生理学重点实验室