PDF(Pubmed)
Abstract：
Mulberry crinkle leaf virus (MCLV) is a member of the genus Mulcrilevirus, family Geminiviridae. The expression and functions of the V4 and V5 genes encoded by the MCLV genome remain unknown. Here, we confirmed the expression of V4 and V5 by analyzing the V4 and V5 mRNAs and the promoter activity of individual ORFs upstream sequences. The functions of V4 and V5 were investigated by constructing Agrobacterium-mediated infectious clones of wild-type MCLV variant П (MCLV vII), MCLVwt and MCLV vП mutants, such as MCLVmV4 (start codon of V4 ORF mutated), MCLVdV4 (5\'-end partial deletion of V4 ORF sequence) and MCLVmV5 (V5 ORF start codon mutated). Although MCLVwt, MCLVmV4, and MCLVdV4 could infect natural host mulberry and experimental tomato plants systematically, the replication of the MCLVmV4 and MCLVdV4 genomes was obviously reduced compared to MCLVwt in both mulberry and tomato plants. MCLV vП expressing V5 could infect Nicotiana benthamiana plants systematically, but MCLVmV5 could not, implying that V5 is needed for MCLV vП to infect N. benthamiana plants. Taken together, V4 is involved in replication of the MCLV genome in host plants, and V5 potentially might extend the host range. Our findings lay a foundation for in-depth insight into the functions of MCLV-encoded proteins and provide a novel perspective for the subsequent study of MCLV-host plant interactions.
摘要：
桑树皱叶病毒（MCLV）是Mulcrilevirus属的成员，双子病毒科。由MCLV基因组编码的V4和V5基因的表达和功能仍然未知。这里,我们通过分析V4和V5mRNA以及单个ORF上游序列的启动子活性来确认V4和V5的表达。通过构建野生型MCLV变异型（MCLVvII）的农杆菌介导的感染性克隆，研究了V4和V5的功能，MCLVwt和MCLVvver突变体，例如MCLVmV4（V4ORF突变的起始密码子），MCLVdV4(V4ORF序列的5'端部分缺失)和MCLVmV5(V5ORF起始密码子突变)。虽然MCLVwt,MCLVmV4和MCLVdV4可以系统地感染天然寄主桑树和实验番茄植株，在桑树和番茄植物中，与MCLVwt相比，MCLVmV4和MCLVdV4基因组的复制明显减少。表达V5的MCLVver可以系统地感染本氏烟草植物，但是MCLVmV5不能，这意味着MCLV需要V5来感染N.benthamiana植物。一起来看,V4参与宿主植物中MCLV基因组的复制，和V5可能会扩展主机范围。我们的发现为深入了解MCLV编码蛋白的功能奠定了基础，并为随后研究MCLV与宿主植物相互作用提供了新的视角。
