Maina Solomon, Coutts Brenda A, Edwards Owain R, de Almeida Luis, Ximenes Abel, Jones Roger A C
School of Agriculture and Environment and Institute of Agriculture, Faculty of Science, The University of Western Australia, Crawley, WA 6009, Australia; and Cooperative Research Centre for Plant Biosecurity, Canberra, ACT 2617, Australia.
Department of Agriculture and Food Western Australia, South Perth, WA 6151, Australia.
Plant Dis. 2017 Jun;101(6):985-993. doi: 10.1094/PDIS-10-16-1499-RE. Epub 2017 Apr 4.
To examine possible genetic connectivity between crop viruses found in Southeast Asia and Australia, Papaya ringspot virus biotype W (PRSV-W) isolates from cucurbits growing in East Timor and northern Australia were studied. East Timorese samples from cucumber (Cucumis sativus) or pumpkin (Cucurbita moschata and C. maxima) were sent to Australia on FTA cards. These samples and others of pumpkin, rockmelon, honeydew melon (Cucumis melo), or watermelon (Citrullus lanatus) growing in one location each in northwest, north, or northeast Australia were subjected to high throughput sequencing (HTS). When the 17 complete PRSV genomic sequences obtained by HTS were compared with 32 others from GenBank, the five from East Timor were in a different major phylogroup from the 12 Australian sequences. Moreover, the East Timorese and Australian sequences each formed their own minor phylogroups named VI and I, respectively. A Taiwanese sequence was closest to the East Timorese (89.6% nt dentity), and Mexican and Brazilian sequences were the closest to the Australian (92.3% nt identity). When coat protein gene (CP) sequences from the 17 new genomic sequences were compared with 126 others from GenBank, three Australian isolates sequenced more than 20 years ago grouped with the new Australian sequences, while the closest sequence to the East Timorese was from Thailand (93.1% nt identity). Recombination analysis revealed 13 recombination events among the 49 complete genomes. Two isolates from East Timor (TM50, TM32) and eight from GenBank were recombinants, but all 12 Australian isolates were non-recombinants. No evidence of genome connectivity between Australian and Southeast Asian PRSV populations was obtained. The strand-specific RNA library approach used optimized data collection for virus genome assembly. When an Australian PRSV isolate was inoculated to plants of zucchini (Cucurbita pepo), watermelon, rockmelon, and honeydew melon, they all developed systemic foliage symptoms characteristic of PRSV-W, but symptom severity varied among melon cultivars.
为研究东南亚和澳大利亚发现的作物病毒之间可能存在的遗传联系，对来自东帝汶和澳大利亚北部葫芦科作物上的番木瓜环斑病毒生物型W（PRSV-W）分离株进行了研究。来自东帝汶黄瓜（Cucumis sativus）或南瓜（Cucurbita moschata和C. maxima）的样本通过FTA卡被送往澳大利亚。这些样本以及澳大利亚西北部、北部或东北部各一个地点种植的南瓜、网纹甜瓜、白兰瓜（Cucumis melo）或西瓜（Citrullus lanatus）的其他样本接受了高通量测序（HTS）。当将通过HTS获得的17个完整PRSV基因组序列与来自GenBank的其他32个序列进行比较时，来自东帝汶的5个序列与12个澳大利亚序列处于不同的主要系统发育组。此外，东帝汶和澳大利亚的序列分别形成了各自的名为VI和I的次要系统发育组。一个台湾序列与东帝汶序列最接近（核苷酸同一性为89.6%），墨西哥和巴西序列与澳大利亚序列最接近（核苷酸同一性为92.3%）。当将17个新基因组序列的外壳蛋白基因（CP）序列与来自GenBank的126个其他序列进行比较时，20多年前测序的三个澳大利亚分离株与新的澳大利亚序列归为一组，而与东帝汶序列最接近的序列来自泰国（核苷酸同一性为93.1%）。重组分析揭示了49个完整基因组中的13个重组事件。来自东帝汶的两个分离株（TM50、TM32）和来自GenBank的八个分离株是重组体，但所有12个澳大利亚分离株均为非重组体。未获得澳大利亚和东南亚PRSV种群之间基因组存在联系的证据。链特异性RNA文库方法为病毒基因组组装优化了数据收集。当将一个澳大利亚PRSV分离株接种到西葫芦（Cucurbita pepo）、西瓜、网纹甜瓜和白兰瓜植株上时，它们都出现了PRSV-W特有的系统性叶片症状，但症状严重程度在甜瓜品种间有所不同。
