The effect of the barley pathogen Ramularia collo-cygni on the quality of malt and the potential to control the disease through host resistance

在整个谷物部门，人们对谷物健康和种子携带的病原体的存在非常感兴趣，特别是在用于麦芽制造的大麦中。在苏格兰的主要经济大麦疾病之一是柱隔孢叶斑病（RLS），其由dothidiomycete真菌，柱隔孢collo-cygni引起。这种真菌已被证明会降低谷物产量和质量。它在其生命周期中也有一个种子繁殖阶段。这个BARITONE博士项目建立在以前的研究基础上，通过调查（1）R。在麦芽和sprit上收获的谷物中存在的collo-cygni（2）利用先前的全基因组分析（其鉴定了与田间抗性相关的候选基因区域），我们将使用从地方品种和优良栽培品种发育的多亲本群体遗传地剖析该区域（3）这些杂交表现出对病原体增加的抗性的潜力将在受控条件和田间实验中得到验证。该项目与减少投入的主题密切相关，因为RLS控制依赖于在抽穗前喷洒杀真菌剂。为了解决这三个目标，该项目将结合联合收割机生物化学，遗传学，基因组学和现场表型在以下实验方法：生物化学方法。对受感染的样品进行微制麦芽以确定具有不同水平的Rcc的谷物样品（包括具有增强的耐受性/抗性的一些品系）中的麦芽质量（预测的烈酒产量）、糖化力和麦芽汁粘度。然后是由该麦芽生产的烈酒的酒精产率、同类物特征和风味特征。这将为真菌对产品质量的影响以及抗性育种对谷物质量的影响提供强有力的证据。 遗传学和基因组学方法。最近的全基因组关联分析突出了大麦染色体上与田间试验中的抗病性相关的候选基因。将对更广泛的基因型组进行分析，包括来自遗产收集的地方品种，以确定携带候选基因的基因型，并开发新的种质，用于控制和田间研究的验证。 田间病害表型分析和验证方法。i）测试预测的抗性。第2部分分析的基因型组中的抗性水平将在受控条件和田间试验中进行测试，以确定对症状表达的抗性水平。ii）将测试抗性和敏感品系的质外体渗漏水平和角质层厚度，以确定它们对疾病水平的潜在影响。 在整个研究计划中，学生将有机会参与更广泛的作物健康和改良战略研究。

Across the cereals sector, there is much interest in grain health and the presence of seed borne pathogens, especially in barley for malting. One of the major economic barley diseases in Scotland is Ramularia leaf spot (RLS), caused by the dothidiomycete fungus, Ramularia collo-cygni . This fungus has been shown to reduce grain yield and quality. It also has a seed borne stage in its life cycle. This BARIToNE PhD project builds on previous research by investigating (1) the effect of R. collo-cygni presence in harvested grain on malting and sprit (2) utilising previous genome wide analysis, which identified candidate gene regions associated with field resistance, we will genetically dissect this region using multi-parent populations developed from landraces and an elite cultivar (3) the potential for these crosses to display increased resistance to the pathogen will be validated in controlled condition and field experiments. The project relates strongly to the reduced input theme as RLS control relies on fungicide sprays just before head emergence. To address these three objectives, the project will combine biochemistry, genetics, genomics and field phenotyping in the following experimental approaches: Biochemical approaches. Micromalting of infected samples to determine malt quality (predicted spirit yield), diastatic power and wort viscosity in grain samples with varying levels of Rcc (including some lines with enhanced tolerance/resistance) . Then alcohol yield, congener profile and flavour profile of spirit produced from that malt. This will provide robust evidence on the impact of the fungus on product quality and also the impact of breeding for resistance on grain quality. Genetics and genomic approaches. A recent genome wide association analysis has highlighted candidate genes on the barley chromosomes which are associated with disease resistance in field experiments. An analysis will be conducted on a wider panel of genotypes including landrace accessions from a legacy collection, to identify genotypes which carry the candidate genes and develop novel germplasm for validation in controlled and field studies. Field disease phenotyping and validation approaches. i) Testing predicted resistance. The levels of resistance in the panel of genotypes analysed in part 2 will be tested in controlled conditions and field experiments to determine levels of resistance to symptom expression. ii) Resistant and susceptible lines will be tested for levels of apoplastic leakage and cuticle thickness to determine their potential influence on disease levels. Throughout the research programme, the student will have opportunity to engage with broader strategic research on crop health and improvement.