National Citrus Engineering and Technology Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing 400712, China.
Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China.
Plant Dis. 2020 Nov;104(11):3010-3018. doi: 10.1094/PDIS-12-19-2597-RE. Epub 2020 Sep 3.
Paper mulberry () is a perennial woody plant used as source material for Cai Lun paper making, in traditional Chinese medicine, and as livestock feed. To identify the presence of viruses in paper mulberry plants affected by a disease with leaf curl symptoms, high-throughput sequencing of total RNA was performed. Analysis of transcriptome libraries allowed the reconstruction of two geminivirus-like genomes. Rolling-circle amplification and PCR with back-to-back primers confirmed the presence of two geminiviruses with monopartite genomes in these plants, with the names paper mulberry leaf curl virus 1 and 2 (PMLCV-1 and PMLCV-2) proposed. The genomes of PMLCV-1 (3,056 nt) and PMLCV-2 (3,757 to 3,763 nt) encode six proteins, with the V4 protein of PMLCV-1 and the V3 proteins of both viruses having low similarities to any known protein in databases. Alternative splicing of an intron, akin to that of mastre-, becurto-, capula-, and grabloviruses, was identified by small RNA (sRNA)-seq and RNA-seq reads mapping to PMLCV-1 and PMLCV-2 antisense transcripts. Phylogenetic analyses and pairwise comparisons showed that PMLCV-1 and PMLCV-2 are most closely related to, but distinct from, two unassigned geminiviruses, citrus chlorotic dwarf associated virus and mulberry mosaic dwarf associated virus, suggesting that they are two new members of the family . Field investigation confirmed the close association of the two viruses with leaf curl symptoms in paper mulberry plants and that coinfection can aggravate the symptoms.
构树是一种多年生木本植物，可用作蔡伦造纸的原料，在中药中也可用作牲畜饲料。为了鉴定受一种卷叶症状疾病影响的构树植物中是否存在病毒，对总 RNA 进行了高通量测序。转录组文库的分析允许重建两个类似双生病毒的基因组。滚环扩增和带有背靠背引物的 PCR 证实了这两种具有单分体基因组的双生病毒的存在，在这些植物中分别命名为构树卷叶病毒 1 和 2（PMLCV-1 和 PMLCV-2）。PMLCV-1 的基因组（3056nt）和 PMLCV-2 的基因组（3757 至 3763nt）编码六个蛋白，其中 PMLCV-1 的 V4 蛋白和两种病毒的 V3 蛋白与数据库中任何已知蛋白的相似度都很低。通过小 RNA（sRNA）-seq 和 RNA-seq 读取与 PMLCV-1 和 PMLCV-2 反义转录物的映射，鉴定了类似于 mastre-、becurto-、capula-和 grabloviruses 的内含子的选择性剪接。系统发育分析和成对比较表明，PMLCV-1 和 PMLCV-2 与两种未分配的双生病毒（柑橘褪绿矮化相关病毒和桑花叶矮化相关病毒）最为密切相关，但又有所不同，这表明它们是家族的两个新成员 。田间调查证实了这两种病毒与构树植物卷叶症状的密切关联，并且合并感染会加重症状。
