The New Zealand Institute for Plant and Food Research Limited (PFR), Private Bag 92169, Auckland 1142, New Zealand.
The New Zealand Institute for Plant and Food Research Limited (PFR), Private Bag 1401, Havelock North 4157, New Zealand.
Viruses. 2022 Jun 21;14(7):1348. doi: 10.3390/v14071348.
Grapevine leafroll disease (GLD) constrains wine production worldwide. In New Zealand, the main causal agent of GLD is grapevine leafroll-associated virus 3 (GLRaV-3). To control GLD, an integrated management program is used and includes removing (roguing) GLRaV-3-infected vines from the vineyard. The classical foliar symptoms from virus-infected red-berry cultivars are leaves with dark red intervein, green veins, and downward rolling of margins. Growers use these phenotypic cues to undertake visual symptom identification (VSI) for GLD. However, the influence of the known large genetic variation among GLRaV-3 isolates on the foliar symptoms from different grapevine cultivars remains undescribed, especially in cool-climate growing environments, such as New Zealand. Over three vintages (2015, 2016, and 2017), VSI for GLD was undertaken at three field sites in New Zealand (Auckland, Hawke’s Bay, and Marlborough), each including four cultivars (Merlot, Pinot noir, Sauvignon blanc, and Pinot gris) infected with three GLRaV-3 genotypes (Groups I, VI, and X) or GLRaV-3-uninfected control plants. Throughout this study, no visual symptoms were observed on white-berry cultivars infected with GLRaV-3. For red-berry cultivars, the greatest variability in observed foliar symptoms among regional study sites, cultivars, and GLRaV-3 genotypes was observed early in the growing season. In particular, Group X had significantly delayed symptom expression across all three sites compared with Groups I and VI. As the newly infected, young vines matured in years 2 and 3, the GLRaV-3 genotype, cultivar, region, and environmental conditions had minimal influence on the accuracy of VSI, with consistently high (>95%) within-vintage identification by the end of each vintage. The results from this study strongly support the use of VSI for the GLD management of red-berry cultivar grapevines, Merlot and Pinot noir, as a reliable and cost-effective tool against GLD.
葡萄卷叶病（GLD）在全球范围内限制了葡萄酒的生产。在新西兰，GLD 的主要病原体是葡萄卷叶伴随病毒 3（GLRaV-3）。为了控制 GLD，采用了综合管理计划，包括从葡萄园清除（铲除）感染 GLRaV-3 的葡萄藤。受病毒感染的红浆果品种的典型叶片症状是叶片上有暗红色叶脉、绿色叶脉和向下卷曲的边缘。种植者使用这些表型线索进行葡萄卷叶病的目视症状识别（VSI）。然而，GLRaV-3 分离株之间已知的大量遗传变异对不同葡萄品种叶片症状的影响仍未得到描述，特别是在新西兰等凉爽气候的生长环境中。在三个葡萄种植年份（2015 年、2016 年和 2017 年），在新西兰的三个田间地点（奥克兰、霍克斯湾和马尔堡）进行了葡萄卷叶病的 VSI，每个地点包括四个品种（梅洛、黑比诺、长相思和灰皮诺）感染了三种 GLRaV-3 基因型（I 组、VI 组和 X 组）或 GLRaV-3 未感染的对照植物。在整个研究过程中，感染 GLRaV-3 的白浆果品种没有观察到肉眼可见的症状。对于红浆果品种，在生长季节早期，观察到不同地区研究地点、品种和 GLRaV-3 基因型之间的叶片症状变化最大。特别是与 I 组和 VI 组相比，X 组在所有三个地点的症状表达明显延迟。随着新感染的年轻葡萄藤在第 2 年和第 3 年成熟，GLRaV-3 基因型、品种、地区和环境条件对 VSI 的准确性影响最小，每个葡萄种植年份结束时，准确性始终保持在较高水平（>95%）。这项研究的结果强烈支持使用目视症状识别来管理红浆果品种葡萄藤的葡萄卷叶病，梅洛和黑比诺，这是一种可靠且具有成本效益的防治葡萄卷叶病的工具。
