South African Grape and Wine Research Institute, Department of Viticulture and Oenology, Stellenbosch University, South Africa.
Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark.
Ann Bot. 2021 Sep 7;128(5):527-543. doi: 10.1093/aob/mcab086.
The necrotrophic fungus Botrytis cinerea infects a broad range of fruit crops including domesticated grapevine Vitis vinifera cultivars. Damage caused by this pathogen is severely detrimental to the table and wine grape industries and results in substantial crop losses worldwide. The apoplast and cell wall interface is an important setting where many plant-pathogen interactions take place and where some defence-related messenger molecules are generated. Limited studies have investigated changes in grape cell wall composition upon infection with B. cinerea, with much being inferred from studies on other fruit crops.
In this study, comprehensive microarray polymer profiling in combination with monosaccharide compositional analysis was applied for the first time to investigate cell wall compositional changes in the berries of wine (Sauvignon Blanc and Cabernet Sauvignon) and table (Dauphine and Barlinka) grape cultivars during Botrytis infection and tissue maceration. This was used in conjunction with scanning electron microscopy (SEM) and X-ray computed tomography (CT) to characterize infection progression.
Grapes infected at veraison did not develop visible infection symptoms, whereas grapes inoculated at the post-veraison and ripe stages showed evidence of significant tissue degradation. The latter was characterized by a reduction in signals for pectin epitopes in the berry cell walls, implying the degradation of pectin polymers. The table grape cultivars showed more severe infection symptoms, and corresponding pectin depolymerization, compared with wine grape cultivars. In both grape types, hemicellulose layers were largely unaffected, as was the arabinogalactan protein content, whereas in moderate to severely infected table grape cultivars, evidence of extensin epitope deposition was present.
Specific changes in the grape cell wall compositional profiles appear to correlate with fungal disease susceptibility. Cell wall factors important in influencing resistance may include pectin methylesterification profiles, as well as extensin reorganization.
腐生性真菌 Botrytis cinerea 可感染包括栽培葡萄 Vitis vinifera 品种在内的广泛的水果作物。该病原体造成的损害对鲜食葡萄和酿酒葡萄产业危害极大，导致全球范围内的大量作物减产。质外体和细胞壁界面是许多植物-病原体相互作用发生的重要场所，也是一些与防御相关的信使分子产生的场所。已有研究有限地调查了感染 Botrytis cinerea 后葡萄细胞壁组成的变化，其中许多是从其他水果作物的研究中推断出来的。
本研究首次应用综合微阵列聚合物分析与单糖组成分析，调查了在酿酒葡萄（Sauvignon Blanc 和 Cabernet Sauvignon）和鲜食葡萄（Dauphine 和 Barlinka）品种浆果感染 Botrytis 和组织捣碎过程中细胞壁组成的变化。结合扫描电子显微镜（SEM）和 X 射线计算机断层扫描（CT）用于表征感染进展。
在转色期感染的葡萄未出现可见的感染症状，而在转色后期和完熟期接种的葡萄则显示出明显的组织降解迹象。后者的特征是浆果细胞壁中果胶表位信号减少，暗示着果胶聚合物的降解。与酿酒葡萄品种相比，鲜食葡萄品种表现出更严重的感染症状和相应的果胶解聚。在两种葡萄类型中，半纤维素层基本不受影响，阿拉伯半乳糖蛋白含量也不受影响，而在中度至重度感染的鲜食葡萄品种中，存在伸展素表位沉积的证据。
葡萄细胞壁组成特征的特定变化似乎与真菌病易感性相关。影响抗性的细胞壁因素可能包括果胶甲酯化谱以及伸展素的重组。
