College of Biotechnology, Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China.
Center for Circadian Clocks and School of Biology and Basic Medical Sciences, Medical College, Soochow University, Suzhou 215123, Jiangsu, China.
Plant Dis. 2023 Oct;107(10):2971-2977. doi: 10.1094/PDIS-08-22-1865-RE. Epub 2023 Sep 29.
To investigate the presence of hop stunt viroid (HSVd) in mulberry () plants in China, HSVd was detected by reverse transcription (RT)-PCR using dsRNAs extracted from symptomatic or asymptomatic mulberry leaf samples collected from a mulberry field located in Zhenjiang, China, as a template and the primer pairs for HSVd detection. The primer pairs were designed based on the conserved sequence of 25 HSVd variants deposited in the GenBank database. Four out of a total of 53 samples were HSVd-positive, confirming that HSVd is present in mulberry plants in China. The consensus full-length nucleotide (nt) sequence of two HSVd variants determined by sequencing the HSVd variants in these four HSVd-positive samples consisted of 296 nt and shared the highest nt identity of 96.8% with that from plum in Turkey but relatively low identity with those from mulberry in Iran (87.3 to 90.8%). Phylogenetic analysis showed that these HSVd variants clustered together with those of the HSVd-hop group. Analysis of the infectivity and pathogenicity to hosts by the constructed -mediated dimeric head-to-tail HSVd cDNA infectious clones demonstrated that one of the HSVd variants identified in this study infects the natural host, mulberry plants, and also infects experimental plants, cucumber, and tomato. It probably induces stunting symptoms in HSVd-infected tomatoes but does not induce symptoms on mulberry leaves or in cucumbers. Although HSVd infecting mulberry has been found in Iran, Italy, and Lebanon, this is the first study to report this viroid in naturally infected mulberry plants in China.
为了调查中国桑树上是否存在 hop stunt viroid（HSVd），我们使用从中国镇江的一个桑园采集的有症状或无症状的桑叶样本中提取的 dsRNA 作为模板，用针对 HSVd 检测的引物对通过反转录（RT）-PCR 检测 HSVd 的存在。这些引物对是基于保存在 GenBank 数据库中的 25 种 HSVd 变体的保守序列设计的。在总共 53 个样本中，有 4 个为 HSVd 阳性，证实 HSVd 存在于中国的桑树中。通过对这 4 个 HSVd 阳性样本中的 HSVd 变体进行测序确定的两种 HSVd 变体的全长核苷酸（nt）序列由 296nt 组成，与来自土耳其李的 HSVd 的 nt 同一性最高为 96.8%，但与来自伊朗的桑树的 HSVd 的 nt 同一性相对较低（87.3%至 90.8%）。系统发育分析表明，这些 HSVd 变体与 HSVd- hop 组的变体聚类在一起。通过构建的 -介导的二聚体从头至尾 HSVd cDNA 传染性克隆分析其对宿主的感染力和致病性表明，本研究中鉴定的一种 HSVd 变体感染天然宿主桑树，也感染实验植物黄瓜和番茄。它可能在感染 HSVd 的番茄中引起矮化症状，但不会在桑树叶或黄瓜中引起症状。尽管在伊朗、意大利和黎巴嫩已经发现了感染桑树的 HSVd，但这是首次在中国自然感染的桑树上报告这种类病毒。
