Zhang Jie, Shang Pengxiang, Yuan Linkai, Li Dingshan, Liu Shunmin, Du Zhenguo, Zhuang Jun, Wu Zujian
Fujian Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China.
State Key Laboratory for Ecological Pest Control of Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou, China.
Mol Plant Pathol. 2025 Jan;26(1):e70049. doi: 10.1111/mpp.70049.
The begomoviral V2 protein is known to be multifunctional, including its interaction with and inhibition of CYP1, a papain-like cysteine protease (PLCP). However, the effect of this interaction on viral pathogenicity remains unclear. Cotton leaf curl Multan virus (CLCuMuV), a typical monopartite begomovirus associated with a betasatellite, is one of the main pathogens responsible for cotton leaf curl disease. This study verifies the interaction between CLCuMuV V2 and NbCP15, a PLCP homologue in Nicotiana benthamiana. The results show that V2 can be cleaved by NbCP15 in vitro, with the N-terminal cleavage site located between the second and third amino acids. Using an Agrobacterium-mediated inoculation method, we investigated the influence of cleavage sites on viral pathogenicity. The findings indicate that mutation of the third amino acid in V2 (V2) reduced the pathogenicity of both heterologous PVX and CLCuMuV. Additionally, the NbCP15 gene mutation in N. benthamiana (nbcp15) also resulted in reduced CLCuMuV pathogenicity. These results suggest that CLCuMuV V2 may promote viral infection through its interaction with plant PLCPs.
已知双生病毒的V2蛋白具有多种功能，包括与类木瓜半胱氨酸蛋白酶（PLCP）CYP1相互作用并对其产生抑制作用。然而，这种相互作用对病毒致病性的影响仍不清楚。棉花曲叶木尔坦病毒（CLCuMuV）是一种典型的与β卫星相关的单组分双生病毒，是导致棉花曲叶病的主要病原体之一。本研究验证了CLCuMuV V2与本氏烟草中的PLCP同源物NbCP15之间的相互作用。结果表明，V2在体外可被NbCP15切割，N端切割位点位于第二个和第三个氨基酸之间。采用农杆菌介导的接种方法，我们研究了切割位点对病毒致病性的影响。研究结果表明，V2中第三个氨基酸的突变（V2）降低了异源PVX和CLCuMuV的致病性。此外，本氏烟草中的NbCP15基因突变（nbcp15）也导致CLCuMuV致病性降低。这些结果表明，CLCuMuV V2可能通过与植物PLCP相互作用促进病毒感染。
