Characterisation of a genetic region that conditions resistance to viral fungal and plasmodiophorid plant pathogens

植物抗性(R)基因是病虫害综合管理策略的重要组成部分，减少了对杀菌剂和杀虫剂治疗的依赖。我们联盟最近的工作已经确定了一个R基因区域，该区域控制着对甜菜病毒、真菌和原生孢类病原体的抗性。这种广谱抗性可能是由多个紧密连锁的R基因或单个新基因引起的。随后对基因组的扫描发现了一些与广谱R基因位点相互作用的基因座，以降低疾病水平。该项目的目的是从结构、与次级遗传位点的相互作用以及在田间控制病害的能力等方面描述甜菜染色体IV参与抗病的区域。预计在该项目中产生的信息和材料将用于甜菜育种家的标记辅助选择，并可能在后续工作中用于抗病基因(S)的图位克隆。因此，该项目的另一个目标是促进对这一耐药基因的进一步开发。在第一年，对不同病原体进行抗性分离的大型植物种群将在受控环境测试中进行抗病能力评估。行业合作伙伴将对这些群体进行分子标记分析，以便生成QTL图谱。这些图谱将被用来识别次要的相互作用的基因座，并定义包含抗性等位基因的第四染色体区域。在该地区表现重组的单株将被用来生成测交家系以进行精细定位。在第二年，将在感兴趣的区域内生成和绘制一组多态的SNP标记。在第三年，将对测交家系在田间生长季节的抗病能力进行评估，以便确定随着时间的推移对第四染色体抗病的效果。这些表型信息将与SNP标记数据相结合，生成精细的广谱抗性基因图谱。这项工作的结果和解释将提交给同行评议期刊。

Plant resistance (R) genes form an important component of integrated pest management strategies, decreasing reliance on fungicide and insecticide treatments. Recent work within our consortium has resulted in the identification of an R gene region that conditions resistance to viral, fungal and plasmodiophorid pathogens of sugar beet. This broad-spectrum resistance could be conferred by a number of tightly-linked R genes or by a single, novel gene. Subsequent scans of the genome revealed a number of loci that interacted with the broad-spectrum R gene locus to reduce disease levels. The aim of the project is to characterise the region of Beta vulgaris chromosome IV involved in resistance to diverse pathogens, in terms of its structure, its interaction with secondary genetic loci and its ability to control disease in the field. It is anticipated that the information and materials generated within the project will be used for marker assisted selection by sugar beet breeders and potentially for map-based cloning of the resistance gene(s) in subsequent work. A further aim of the project therefore is to facilitate further exploitation of this resistance locus. In year 1, large plant populations which segregate for resistance to diverse pathogens will be evaluated for disease resistance in controlled environment tests. Industry partners will conduct molecular marker analysis on these populations so that QTL maps can be generated. These maps will be used to identify secondary, interacting loci and to define a region of chromosome IV that contains the resistance alleles. Individual plants that show recombination in this region will be used to generate testcross families for fine mapping. In year 2, a set of polymorphic SNP markers will be generated and mapped within the region of interest. In year 3, the testcross families will be evaluated for disease resistance over a growing season in the field, allowing the efficacy of chromosome IV resistance through time to be determined. This phenotypic information will be combined with the SNP marker data to generate Mendelised, fine maps of the broad-spectrum resistance locus. The results and interpretation of this work will be submitted to peer review journals.