Table_2_A Distinct Tobamovirus Associated With Trichosanthes kirilowii Mottle Mosaic Disease.XLS

Trichosanthes kirilowii is one of the most important perennial herbaceous vines that have been used in traditional Chinese medicine. In this study, a novel RNA virus was discovered in T. kirilowii plants showing leaf mottling and mosaic symptoms. The complete genome of this virus is 6,524 nucleotides long and encodes four open reading frames which are arranged in a manner typical of tobamoviruses. Phylogenetic analysis based on the complete genome sequence revealed that the virus was clustered into a branch with the tobamoviruses whose natural host are plants belonging to the family Cucurbitaceae. A full-length infectious cDNA clone was then constructed and demonstrated to establish a systemic infection with typical symptoms in Nicotiana benthamiana, T. kirilowii, and five other cucurbitaceous crops including Cucumis melo, C. lanatus, C. sativus, Luffa aegyptiaca, and Cucurbita pepo via agrobacterium-mediated infectivity assays. Further experiments provided evidence that the rod-shaped viral particles derived from the infectious clone could be mechanically transmitted and reproduce indistinguishable symptoms in the tested plants. Taken together, the mottle mosaic disease of T. kirilowii is caused by a distinct tobamovirus, for which the name Trichosanthes mottle mosaic virus (TrMMV) is proposed. As the infectious cDNA clone of TrMMV could also infect five other cucurbit crops, this distinct tobamovirus could be a potential threat to other cucurbitaceous crops.

绞股蓝 kirilowii 为我国传统中医药中极为重要的多年生草本藤本植物之一。本研究中，于绞股蓝 kirilowii 植物中发现了一种新型的RNA病毒，该病毒导致叶片出现斑驳和花叶症状。该病毒的全基因组长度为6,524个核苷酸，编码四个开放阅读框，其排列方式与番茄花叶病毒属（tobamoviruses）典型。基于全基因组序列的进化分析显示，该病毒与自然宿主为葫芦科植物的番茄花叶病毒属病毒聚集成一支。随后构建了全长感染性cDNA克隆，并通过农杆菌介导的感染性测试，证实其在烟草 benthamiana、绞股蓝 kirilowii 以及其他五种葫芦科作物（包括甜瓜 Cucumis melo、黄瓜 C. lanatus、南瓜 C. sativus、丝瓜 Luffa aegyptiaca 和西葫芦 Cucurbita pepo）中建立系统性感染，并表现出典型症状。进一步实验表明，源自感染性克隆的杆状病毒粒子可通过机械传播，并在测试植物中产生不可区分的症状。综上所述，绞股蓝 kirilowii 的斑驳花叶病是由一种独特的番茄花叶病毒引起的，因此建议将该病毒命名为绞股蓝花叶病毒（TrMMV）。鉴于TrMMV感染性cDNA克隆也能感染其他五种葫芦科作物，这种独特的番茄花叶病毒可能对其他葫芦科作物构成潜在威胁。