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

理性：土壤传播的真菌黄萎病的高毒力种族已经大大促进了英国啤酒花产业的衰落。这种致命疾病一旦在田间形成，就只能通过使用抗药品种进行防治，因为没有有效的化学控制手段。四种非苜蓿英国变种已被确定（轻度，PV1, PV2, PV3），其中两种被认为只在英国进化。已发表的工作集中在鉴定引起易感品种“Fuggle”致命枯萎病（PV1）的致病性因素，这是欧洲大陆的一个重大问题。相比之下，本博士将研究抗性突破英国种族对抗性品种“Wye挑战者”（PV2）和“Wye目标”（PV3）造成致命枯萎。方法：WP1根据毒力特征确定非紫花葡萄种群结构；swp2与英国和欧盟毒力谱相关的真菌种群基因组学；WP3通过比较基因组学鉴定种族特异性致病性因子，用于诊断；swp4通过敲除候选基因和宿主诱导基因沉默（HIGS）来验证致病性因子。确定每个非苜蓿品种结构的独特基因组区域将允许产生土壤诊断工具，为啤酒花生产的种植和管理决策提供信息。而使用HIGS和基因敲除将验证致病性因素，并允许产生抗黄萎病的啤酒花品种。现有的资金已经通过QTL定位来确定跳跃中黄萎病抗性的新来源。然而，了解英国V. nonalfalfae的品种结构将允许怀啤酒花育种公司开发健壮的抗病啤酒花品种。该项目将补充目前的宿主工作，并有助于了解啤酒花育种者和黄萎病菌之间的军备竞赛。

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.