Open AccessNitrate‐inducible MdBT2 acts as a restriction factor to limit apple necrotic mosaic virus genome replication in Malus domestica
Author(s) -
Zhang Zhenlu,
Xie YinHuan,
Sun Ping,
Zhang FuJun,
Zheng PengFei,
Wang XiaoFei,
You ChunXiang,
Hao YuJin
Publication year - 2022
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.13166
Subject(s) - biology , ubiquitin , viral replication , proteasome , virus , viral protein , virology , rna , tobamovirus , tobacco mosaic virus , plant virus , microbiology and biotechnology , gene , genetics
Apple necrotic mosaic virus (ApNMV) is highly associated with the occurrence of apple mosaic disease in China. However, ApNMV–host interactions and defence mechanisms of host plants against this virus are poorly studied. Here, we report that nitrate treatment restrains ApNMV genomic RNA accumulation by destabilizing viral replication protein 1a through the MdBT2‐mediated ubiquitin‐proteasome pathway. MdBT2, a nitrate‐responsive BTB/TAZ domain‐containing protein, was identified in a yeast two‐hybrid screen of an apple cDNA library using viral protein 1a as bait, and 1a was further confirmed to interact with MdBT2 both in vivo and in vitro. It was further verified that MdBT2 promoted the ubiquitination and degradation of viral protein 1a through the ubiquitin‐proteasome pathway in an MdCUL3A‐independent manner. Viral genomic RNA accumulation was reduced in MdBT2 ‐overexpressing transgenic apple leaves but enhanced in MdBT2 ‐antisense leaves compared to the wild type. Moreover, MdBT2 was found to interfere with the interaction between viral replication proteins 1a and 2a pol by competitively interacting with 1a. Taken together, our results demonstrate that nitrate‐inducible MdBT2 functions as a limiting factor in ApNMV viral RNA accumulation by promoting the ubiquitination and degradation of viral protein 1a and interfering with interactions between viral replication proteins.