Safeguarding UK hop production from Verticillium nonalfalfae: Using genomics to develop race-specific diagnostics and generate Verticillium resistant

理性：土传真菌农艺黄萎菌的高度毒性小种在很大程度上导致了英国啤酒花产业的衰落。一旦这种致命的疾病在田间形成，就只能通过使用抗病品种来防治，因为没有有效的化学防治手段。据了解，英国有四个非阿尔法利弧菌小种(轻度、PV1、PV2、PV3)，其中两个是专门在英国进化的。已发表的工作主要集中在鉴定引起感病品种‘藤壶’的致病因子，这是欧洲大陆的一个重要问题。相比之下，本博士将研究在抗病品种‘Wye Challenger’(PV2)和‘Wye Target’(PV3)上造成致死性枯萎病的抗病英国小种。方法：WP1根据毒力特征确定非苜蓿弧菌种群结构WP2真菌种群基因组学与英国和欧盟毒力图谱WP3通过比较基因组学鉴定用于诊断的小种特异致病因子WP4通过敲除候选基因和寄主诱导基因沉默(HIGS)影响对致病因子进行验证：识别每个非苜蓿弧菌小种结构所特有的基因组区域，将允许生成土壤诊断工具，为啤酒花生产中的种植和管理决策提供信息。而HIGS和基因敲除的使用将验证致病因子，并允许产生抗黄萎病的啤酒花品种。现有的资金已经被确保通过QTL定位来表征酒花黄萎病抗性的新来源。然而，了解UK V.non alfae的小种结构将使怀伊啤酒花育种公司能够开发出强大的抗病啤酒花品种。该项目将补充目前的东道主工作，并有助于了解啤酒花育种者和黄萎病之间的军备竞赛。

Rational: Highly virulent races of the soil borne fungus Verticillium nonalfalfae have substantially contributed to the decline of the UK hop industry. Once this lethal disease has established within a field it can only be combatted through this use of resistant varieties as there are no effective chemical means for control. Four V. nonalfalfae UK races have been characterised (mild, PV1, PV2, PV3), with two understood to have evolved exclusively in the UK. Published work has focused on identifying pathogenicity factors causing lethal wilt (PV1) on the susceptible cultivar 'Fuggle', a significant problem in continental Europe. By contrast, this PhD will investigate the resistance breaking UK races causing lethal wilt on the resistant cultivars 'Wye Challenger' (PV2) and 'Wye Target' (PV3).Approaches: WP1 Determining V. nonalfalfae population structure in terms of virulence characteristicsWP2 Fungal population genomics in relation to UK and EU virulence profiles WP3 Identification of race specific pathogenicity factors through comparative genomics for use in the development of diagnosticsWP4 Validation of pathogenicity factors through knockouts of candidate genes and Host Induced Gene Silencing (HIGS)Impact: Identifying regions of the genome unique to each V. nonalfalfae race structure will allow the generation of soil diagnostic tools to inform planting and management decisions in hop production. Whereas the use of HIGS and gene knockouts will validate pathogenicity factors and allow the generation of Verticillium resistant hop varieties. Existing funding has been secured to characterise novel sources of Verticillium resistance in hop through QTL mapping. However, understanding the race structure of UK V. nonalfalfae will allow the Wye Hops breeding company to develop robust disease resistant hop varieties. This project will complement current host work and contribute to understanding of the arms race between hop breeders and Verticillium.