Grapevine leafroll-associated virus-2 (GLRaV-2) and GLRaV-3 are both (+) ssRNA viruses of the family Closteroviridae and are involved in grapevine leafroll, the most destructive viral disease affecting the global grape/wine industry. Outbreaks of the disease were recently reported in Canada, causing serious concerns to the grape/wine industry. Reliable, sensitive and timely detection is key to the control of the disease. However, information on their seasonal dynamics and tissue distribution under cool climate conditions has been rather limited. We conducted a two-year comprehensive study to elucidate the temporal variation and spatial distribution of both viruses through symptom monitoring, Western blotting and RT-qPCR. Sampling was done monthly from commercial Cabernet Franc and Chardonnay vines from May to October in 2015 and 2016. Both viral RNA and capsid protein levels in leaves remained low during May and June, steadily increased from late July, and peaked in September or October. Interestingly, young berries collected in June contained high levels of viral RNA for both viruses. As expected, the viral RNA levels of GLRaV-2 detected by RT-qPCR using primers targeting the CP region were much higher than those by using primers targeting the genomic RNA. Surprisingly, virtually the same levels of viral RNA were detected for GLRaV-3 regardless of the targeted genomic regions. To ensure accurate detection of both viruses, we recommend using young berries early in the season and leaves and cambial scrapings from late July to harvest. To our knowledge, this is the first report on the seasonal dynamics and tissue distribution of two major grapevine viruses in Canada.

葡萄叶相关病毒2（GLRaV-2）和GLRaV-3均为Closteroviridae家族的（+）ssRNA病毒并参与了葡萄叶卷病，这是最具破坏力的病毒性疾病，影响了全球葡萄/葡萄酒产业。最近在加拿大报道了该病的暴发，引起了葡萄/葡萄酒行业的严重关注。可靠，敏感和及时的检测是控制疾病的关键。但是，有关它们在寒冷气候条件下的季节动态和组织分布的信息非常有限。我们进行了为期两年的综合研究，以通过症状监测，蛋白质印迹和RT-qPCR阐明这两种病毒的时间变化和空间分布。从2015年和2016年5月至10月，每月从商业赤霞珠和霞多丽葡萄中进行采样。5月和6月叶片中的病毒RNA和衣壳蛋白水平均保持较低水平，从7月下旬开始稳定增长，并在9月或10月达到顶峰。有趣的是，六月收​​集的幼浆果含有两种病毒的高水平病毒RNA。不出所料，通过RT-qPCR使用靶向CP区的引物检测到的GLRaV-2病毒RNA水平要远远高于使用靶向基因组RNA的引物。出乎意料的是，无论靶向基因组区域如何，对于GLRaV-3，实际上检测到了相同水平的病毒RNA。为确保准确检测这两种病毒，我们建议在季节初使用幼果，从7月下旬开始采摘叶子和叶子。据我们所知，这是加拿大两种主要葡萄病毒的季节性动态和组织分布的第一份报告。不出所料，通过RT-qPCR使用靶向CP区的引物检测到的GLRaV-2病毒RNA水平要远远高于使用靶向基因组RNA的引物。出乎意料的是，无论靶向基因组区域如何，对于GLRaV-3，实际上检测到了相同水平的病毒RNA。为确保准确检测这两种病毒，我们建议在季节初使用幼果，从7月下旬开始采摘叶子和叶子。据我们所知，这是加拿大两种主要葡萄病毒的季节性动态和组织分布的第一份报告。不出所料，通过RT-qPCR使用靶向CP区的引物检测到的GLRaV-2病毒RNA水平要远远高于使用靶向基因组RNA的引物。出乎意料的是，无论靶向基因组区域如何，对于GLRaV-3，实际上检测到了相同水平的病毒RNA。为确保准确检测这两种病毒，我们建议在季节初使用幼果，从7月下旬开始采摘叶子和叶子。据我们所知，这是加拿大两种主要葡萄病毒的季节性动态和组织分布的第一份报告。不论靶向的基因组区域如何，对于GLRaV-3几乎检测到相同水平的病毒RNA。为确保准确检测这两种病毒，我们建议在季节初使用幼果，从7月下旬开始采摘叶子和叶子。据我们所知，这是加拿大两种主要葡萄病毒的季节性动态和组织分布的第一份报告。不论靶向的基因组区域如何，对于GLRaV-3几乎检测到相同水平的病毒RNA。为确保准确检测这两种病毒，我们建议在季节初使用幼果，从7月下旬开始采摘叶子和叶子。据我们所知，这是加拿大两种主要葡萄病毒的季节性动态和组织分布的第一份报告。