The C-Terminal Transmembrane Domain of Cowpea Mild Mottle Virus TGBp2 Is Critical for Plasmodesmata Localization and for Its Interaction With TGBp1 and TGBp3

Chong Jiang; Shiqi Shan; Yue Huang; Chenyang Mao; Hehong Zhang; Yanjun Li; Jianping Chen; Zhongyan Wei; Zongtao Sun

doi:10.3389/fmicb.2022.860695

The C-Terminal Transmembrane Domain of Cowpea Mild Mottle Virus TGBp2 Is Critical for Plasmodesmata Localization and for Its Interaction With TGBp1 and TGBp3

Front Microbiol. 2022 Apr 15:13:860695. doi: 10.3389/fmicb.2022.860695. eCollection 2022.

Authors

Chong Jiang¹, Shiqi Shan¹, Yue Huang¹, Chenyang Mao¹, Hehong Zhang¹, Yanjun Li¹, Jianping Chen¹, Zhongyan Wei¹, Zongtao Sun¹

Affiliation

¹ State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo, China.

Abstract

The movement of some plant RNA viruses is mediated by triple gene block (TGB) proteins, which cooperate to transfer the viral genome from cell to cell through plasmodesmata. Here, we investigated the function of the TGB proteins of cowpea mild mottle virus (CPMMV; genus Carlavirus, family Betaflexiviridae), which causes severe damage to soybean production. Subcellular localization experiments demonstrated that TGBp1 and TGBp3 were localized to the endoplasmic reticulum (ER), plasmodesmata (PD) and nucleus in Nicotiana benthamiana leaves. TGBp2 was unusually localized to PD. In protein interaction assays TGBp2 significantly enhanced the interaction between TGBp3 and TGBp1. Interaction assays using deletion mutants showed that the C-terminal transmembrane (TM) domain of TGBp2 is critical for its localization to PD and for its interaction with TGBp1 and TGBp3.

Keywords: cowpea mild mottle virus; intercellular movement; plasmodesmata targeting; transmembrane domain; triple gene block proteins.