Exploiting pathogenomics and resistance for control of Fusarium wilt of lettuce

由土传真菌尖孢镰刀菌引起的莴苣枯萎病。乳酸菌（FOL）对全球的保护和大田作物造成严重的经济损失。该病原体是尖孢镰刀菌物种复合体的一部分，该复合体包括多种适应宿主的致病形式（f.s spp.）以及非致病性分离物。因此，FOL是一种高度适应的宿主特异性病原体。已经培育出抗病莴苣品种以减少因FOL造成的损失，但新的病原体品种已经进化以克服这种抗性。最近，4号种族（FOL4）在欧洲出现，并在英国和爱尔兰造成了广泛的损失。到目前为止，FOL4仅限于受保护的生菜，但坊间证据表明，它可能比FOL1更具侵略性，尤其是在低温下；因此，户外生产存在重大风险。值得注意的是，在保护下广泛种植的莴苣类型对FOL4没有抗性，因此开发抗性品种是非常必要的。该项目的主要目的是确定生菜中抗FOL4的新来源，并确定与该性状相关的基因组区域或特定基因。进一步的工作将比较FOL1和FOL4的遗传学和生物学，以确定与生菜品种特异性相关的毒力基因补体和/或突变。此外，还将研究感染过程的生物学方面，包括FOL1和FOL4定殖和感染不同生菜品种的能力。非致病性的尖孢镰刀菌和木霉在减少FOL方面的潜力也可以探索。

Fusarium wilt disease of lettuce, caused by the soilborne fungus Fusarium oxysporum f.sp. lactucae (FOL), results in severe economic losses in protected and field-grown crops globally. The pathogen is part of the F. oxysporum species complex which comprises multiple host-adapted pathogenic formae speciales (f.spp.) as well as non-pathogenic isolates. FOL is therefore a highly adapted, host specific pathogen. Disease resistant lettuce cultivars have been bred to reduce losses due to FOL but new pathogen races have evolved to overcome this resistance. Recently, race 4 (FOL4) emerged in Europe and has caused extensive losses in the UK and Ireland. So far, FOL4 is confined to protected lettuce but anecdotal evidence suggests it may be more aggressive than FOL1, especially at low temperatures; hence there is a significant risk to outdoor production. Significantly, there is no lettuce resistance to FOL4 in the lettuce types widely grown under protection and hence development of resistant cultivars is highly desirable.The main aim of this project is to identify and characterise new sources of FOL4 resistance in lettuce and identify areas of the genome or specific genes associated with this trait. Further work will compare the genetics and biology of FOL1 and FOL4 to identify virulence gene complements and/or mutations related to lettuce cultivar specificity. In addition, biological aspects of the infection process will be examined including the ability of FOL1 and FOL4 to colonise and infect different lettuce cultivars. The potential of non-pathogenic F. oxysporum and Trichoderma spp. to reduce FOL may also be explored.