Marone Fassolo Elena, Lecchi Beatrice, Marcianò Demetrio, Maddalena Giuliana, Toffolatti Silvia Laura
Department of Agricultural and Environmental Sciences, University of Milan, 20133 Milano, Italy.
Plants (Basel). 2022 Oct 5;11(19):2619. doi: 10.3390/plants11192619.
Durable resistance is a key objective in genetic improvement for disease resistance in grapevines, which must survive for years in the field in the presence of adaptable pathogen populations. In this study, the adaptation of 72 Northern Italian isolates of Plasmopara viticola, the downy mildew agent, has been investigated into Bianca, possessing Rpv3-1, the most frequently exploited resistance locus for genetic improvement, and Mgaloblishvili, a Vitis vinifera variety possessing the newly discovered Rpv29 locus. Infection parameters (latency period, infection frequency, and disease severity) and oospore production and viability were evaluated and compared to those of Pinot noir, the susceptible reference. The expected levels of disease control were achieved by both resistant cultivars (>90% on Bianca; >25% on Mgaloblishvili), despite the high frequency of isolates able to grow on one (28%) or both (46%) accessions. The disease incidence and severity were limited by both resistant cultivars and the strains able to grow on resistant accessions showed signatures of fitness penalties (reduced virulence, infection frequency, and oospore density). Together, these results indicate an adequate pathogen control but suitable practices must be adopted in the field to prevent the diffusion of the partially adapted P. viticola strains to protect resistance genes from erosion.
持久抗性是葡萄抗病性遗传改良的关键目标，葡萄必须在田间存在适应性病原菌群体的情况下存活数年。在本研究中，对72株来自意大利北部的葡萄霜霉病菌（Plasmopara viticola）分离株在拥有Rpv3-1（遗传改良中最常利用的抗病位点）的比安卡（Bianca）以及拥有新发现的Rpv29位点的酿酒葡萄品种Mgaloblishvili上的适应性进行了研究。评估了感染参数（潜伏期、感染频率和病害严重程度）以及卵孢子的产生和活力，并与感病对照品种黑皮诺进行了比较。尽管能够在一个品种（28%）或两个品种（46%）上生长的分离株频率很高，但两个抗病品种均达到了预期的病害控制水平（比安卡上>90%；Mgaloblishvili上>25%）。抗病品种限制了病害发生率和严重程度，并且能够在抗病品种上生长的菌株表现出适应性代价的特征（毒力降低、感染频率降低和卵孢子密度降低）。总之，这些结果表明对病原菌有足够的控制，但在田间必须采用适当的措施来防止部分适应的葡萄霜霉病菌株扩散，以保护抗病基因不被侵蚀。
