New Phytologist (2018) 218, 1570-1585

Xuan Zhang, Kai Dong, Kai Xu, Kun Zhang, Xuejiao Jin, Meng Yang, Yongliang Zhang, Xianbing Wang, Chenggui Han, Jialin Yu and Dawei Li (2018)
Barley stripe mosaic virus infection requires PKA-mediated phosphorylation of γb for suppression of both RNA silencing and the host cell death response
New Phytologist 218 (4), 1570-1585
Abstract: - The Barley stripe mosaic virus (BSMV) γb protein is a viral suppressor of RNA silencing (VSR) and symptom determinant. However, it is unclear how post-translational modification affects the different functions of γb.
- Here, we demonstrate that γb is phosphorylated at Ser-96 by a PKA-like kinase in vivo and in vitro. Mutant viruses containing a nonphosphorylatable substitution (BSMV_S96A or BSMV_S96R) exhibited reduced viral accumulation in Nicotiana benthamiana due to transient induction of the cell death response that constrained the virus to necrotic areas. By contrast, a BSMV_S96D mutant virus that mimics γb phosphorylation spread similarly to the wild-type virus.
- Furthermore, the S96A mutant had reduced local and systemic γb VSR activity due to having compromised its binding activity to 21-bp dsRNA. However, overexpression of other VSRs in trans or in cis failed to rescue the necrosis induced by BSMV_S96A, demonstrating that suppression of cell death by γb phosphorylation is functionally distinct from its RNA silencing suppressor activities.
- These results provide new insights into the function of γb phosphorylation in regulating RNA silencing and the BSMV-induced host cell death response, and contribute to our understanding of how the virus optimizes the balance between viral replication and virus survival in the host plants during virus infection.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Dawei Li, Jia-Lin Yu

Research topic(s) for pests/diseases/weeds:
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Barley stripe mosaic virus