槟榔坏死环斑病毒轻症型分离物(ANRSV-DAT)的基因组序列克隆及分析

 槟榔坏死环斑病(ANRSD)是近年来海南槟榔主产区发生广泛、危害严重的病毒病害,发病植株叶片表现严重坏死环斑、树势衰退,疑似与马铃薯Y病毒科(Potyviridae)槟榔坏死环斑病毒(areca palm necrotic ringspot virus, ANRSV)相关。本研究从海南定安槟榔种植区发现感病植株叶部表现轻微稀疏褪绿斑的病毒分离物(ANRSV-DAT),对其基因组序列全长克隆和分析。ANRSV-DAT与先前报道的强毒分离物ANRSV-XC1基因组核苷酸(nt)序列及其编码融合蛋白氨基酸(aa)序列的同源性分别为90.68%和97.91%;两者的融合蛋白之间存在63个aa变异,不同程度地分布在10个顺反子中(HCPro1、HCPro2、P3、7K、CI、9K、NIa-VPg、NIa-Pro、NIb和CP)。与ANRSV-XC1显著不同的是,ANRSV-DAT的5'非翻译区的5'末端缺失95-nt序列。该缺失序列是否导致ANRSV-DAT毒性弱化有待进一步研究。本研究报道的ANRSV轻症型分离株,以期为筛选弱毒株及后续交叉保护防治ANRSV提供重要宝贵材料。

The cloning and molecular characterization of full genome sequence of one mild isolate of areca palm necrotic ringspot virus (ANRSV-DAT)

In recent years, the wide occurrence of a viral disease termed as areca palm necrotic ringspot disease (ANRSD) has severely threaten the sustained production of areca palm industry in Hainan, China. Diseased plants usually display severe phenotype with symptoms of foliar necrotic ringspot and declined vigor. Previously, our research group identified a new virus species of the family Potyviridae (referred to as areca palm necrotic ringspot virus, ANRSV), and revealed a close correlation of ANRSV and ANRSD. In this study, we characte-rized a potential mild strain of ANRSV (named ANRSV-DAT) from an areca palm orchard in Dingan, Hainan. The complete genomic sequence of ANRSV-DAT was determined and analyzed. Subsequently, the genomic sequence comparison between ANRSV-DAT and ANRSV-XC1 (a severe ANRSV isolate recently reported by us) was conducted. Both ANRSV-DAT and ANRSV-XC1 shared 90.68% nucleotide (nt) identity in the whole genome, and 97.91% amino acid (aa) identity for the encoding large polyprotein. A total of 63 aa differences that distributed to a varied extent in ten putative cistrons (i.e., HCPro1, HCPro2, P3, 7K, CI, 9K, NIa-VPg, NIa-Pro, NIb and CP) were discriminated between them. Remarkably, in comparison to ANRSV-XC1, a 95-nt sequence is missing at the beginning of 5' untranslated region (UTR) in ANRSV-DAT. Whether this natural truncated 5'-UTR is responsible for toxicity attenuation of ANRSV-DAT needs to be further investigated. Altogether, ANRSV-DAT reported here might provide an essential practical resource for the control of ANRSV damage in the field through cross protection strategy.