Beijing Key Laboratory of New Technology in Agricultural Application, National Demonstration Center for Experimental Plant Production Education, Beijing University of Agriculture, Beijing, China.
Key Laboratory for Northern Urban Agriculture of Ministry of Agriculture and Rural Affairs, Beijing University of Agriculture, Beijing, China.
BMC Microbiol. 2019 Nov 21;19(1):260. doi: 10.1186/s12866-019-1636-y.
Cannas are popular ornamental plants and widely planted for the beautiful foliage and flower. Viral disease is a major threaten to canna horticulture industry. In the city of Beijing, mosaic disease in canna was frequently observed, but the associated causal agent and its biological characterization is still unknown.
After small RNA deep sequencing, 36,776 contigs were assembled and 16 of them shared high sequence identities with the different proteins of Sugarcane mosaic virus (SCMV) of the size ranging from 86 to 1911 nt. The complete genome of SCMV isolate (canna) was reconstructed by sequencing all cDNA clones obtained from RT-PCR and 5'\3' RACE amplifications. SCMV-canna isolate showed to have a full RNA genome of 9579 nt in length and to share 78% nt and 85% aa sequence identities with SCMV isolates from other hosts. The phylogenetic tree constructed based on the full genome sequence of SCMV isolates allocated separately the canna-isolate in a distinct clade, indicating a new strain. Recombination analyses demonstrated that SCMV-canna isolate was a recombinant originating from a sugarcane-infecting isolate (major parent, acc. no. AJ310103) and a maize-infecting isolate (minor parent, acc. no. AJ297628). Pathogenicity test showed SCMV-canna could cause typical symptoms of mosaic and necrosis in some tested plants with varying levels of severity but was less virulent than the isolate SCMV-BJ. Field survey showed that the virus was widely distributed.
This study identified SCMV as the major agent causing the prevalent mosaic symptom in canna plants in Beijing and its genomic and biological characterizations were further explored. All these data enriched the knowledge of the viruses infecting canna and would be helpful in effective disease management in canna.
美人蕉是一种受欢迎的观赏植物，因其美丽的叶片和花朵而被广泛种植。病毒病是美人蕉种植业的主要威胁。在北京，美人蕉花叶病经常发生，但相关的致病因子及其生物学特性仍不清楚。
通过小 RNA 深度测序，共组装了 36776 个 contigs，其中 16 个与甘蔗花叶病毒（SCMV）的不同蛋白具有高度的序列同一性，大小从 86 到 1911nt 不等。通过对从 RT-PCR 和 5'3' RACE 扩增获得的所有 cDNA 克隆进行测序，重建了 SCMV 分离物（美人蕉）的全长基因组。SCMV-canna 分离物显示具有全长 9579nt 的 RNA 基因组，与来自其他宿主的 SCMV 分离物具有 78%的 nt 和 85%的 aa 序列同一性。基于 SCMV 分离物全长基因组序列构建的系统发育树将美人蕉分离物分别分配到一个独特的分支中，表明这是一个新的分离物。重组分析表明，SCMV-canna 分离物是一种由甘蔗侵染分离物（主要亲本，acc. no. AJ310103）和玉米侵染分离物（次要亲本，acc. no. AJ297628）重组而来的重组病毒。致病性试验表明，SCMV-canna 能够引起一些受测植物出现典型的花叶和坏死症状，但其毒力比 SCMV-BJ 分离物弱。田间调查表明，该病毒广泛分布。
本研究鉴定出 SCMV 是引起北京美人蕉普遍花叶症状的主要病原体，并进一步探讨了其基因组和生物学特性。所有这些数据丰富了感染美人蕉的病毒知识，有助于美人蕉的有效病害管理。
