小麦慢条锈性品种抗病遗传解析及主效QTL定位

Stripe (or yellow) rust is a major air-born fungal disease, which has always been threating the security of wheat production in China. At present, the most critical control strategy for the disease is to develop resistance cultivars by mainly using major all-stage resistance (ASR) genes. This kind of complete plant disease resistance based on host hypersensitive responses is usually with higher level of race specificity and frequently ‘loses’ functions due to virulence variability of pathogen popular races. However, slow-rusting wheat cultivars often perform durable and stable resistance against stripe rust. It has been confirmed that adult-plant resistance (APR) is a key component for slow-rusting resistance and plays important roles for keeping durable and stable stripe rust resistance in wheat cultivars. But we know little about the genetic details of wheat slow rusting. In this proposal, we will characterize the genetics of stripe rust resistance in slow-rusting wheat cultivars with the methods such as general genetic analysis and genotyping by sequencing, to find out the number of resistance gene(s) and their genetic and resistant traits of 20 - 30 typical slow-rusting wheat cultivars, and to generalize their genetic models for slow rusting and its relationship with stripe rust resistance stability. In our plan four or five major slow-rusting resistance QTLs or major resistance genes will be genetically localized and their molecular markers will be developed. Base on the results, we will set up a primary model for utilizing the slow-rusting resistance genes in wheat breeding practice, and evaluate the method for testing the stripe rust resistance stability and durability of important wheat genotypes with predominant races out-breaking in several historical periods in China. There are 5 to 8 highly valuable slow-rusting offspring lines to be developed.

条锈病是威胁我国小麦安全生产的重要气传真菌病害，目前防控该病害的关键技术措施主要是利用全生育期主效抗病基因选育抗病品种。这种基于寄主过敏性坏死反应的完全抗病性具有较高水平的小种专化性，常因病原菌主要流行小种毒性变异“丧失”抗性，而慢锈性品种具有较持久稳定的抗病性。已发现成株抗性是慢锈性的重要组份，在维持小麦抗条锈病稳定性方面发挥了重要作用，但慢锈性的具体遗传学基础尚不清楚。本申请项目中采用常规遗传分析和基因组简化测序等技术，对具有慢锈性特点的小麦品种进行抗性遗传分析，明确20~30份慢锈性典型材料抗条锈病基因数目及遗传和抗性特点，解析慢条锈性遗传模式及其与抗性稳定性的关系；发掘4~5个慢条锈性主效QTL或主效基因，获其分子标记；初步建立慢锈性基因利用的模式和利用不同历史时期流行小种评估重要抗源抗条锈病稳定性的方法；创制有实用价值慢锈性中间抗源材料5~8份。

条锈病是重要气传真菌病害，大规模流行造成小麦严重减产。目前，使用主要含有全生育期抗病基因的主栽品种是防控条锈病关键措施，但这类抗病性常因条锈菌毒性变异和优势流行小种轮替而被克服。多数持久抗条锈病小麦品种具有慢锈性，成株抗性可能是其重要抗病遗传组分。本项目比较慢锈性品种抗病类型，解析抗病遗传模式，标记定位主效抗病基因，探讨持久抗性鉴定方法和利用途径。从持久抗病慢锈性品种和近年育成慢锈性品系中获得高抗CYR32或CYR34品种13个和品系10个，分别包括9个和8个材料属于成株抗性类型，说明持久抗病慢锈品种主要保留了成株抗病类型的遗传组分。验证了用一套不同时期关键小种分析苗期和成株期抗病谱，可以初步评价品种抗病持久性和稳定程度。分析和比较了10个持久抗病慢锈性和8个新育成品系抗病遗传组分，多数持久抗病慢锈性品种具有2个或多个隐性遗传抗病基因。标记定位了地方品种‘白芒麦’位于4BL主效成株抗病新基因YrBm，分子标记为Xgpw7272189和Xwmc652164，遗传距离为1.55 cM和3.03 cM；微效全生育期抗病基因YrBmm位于1DS，与BSR-Seq标记M1最近遗传距离为8.8 cM。获得4个代表性持久抗病慢锈性品种‘西农1367’、‘陕优225’、‘武都白茧麦’和‘长武131’重组自交系（RIL）群体F3:4或F4:5种子，用于标记主效抗病基因或QTL。创制中间抗源材料40份，将持久抗病慢锈性品种‘西农1367’、‘陕优225’、‘武都白茧麦’和‘长武131’主效抗基因及YrBm、Yr5、Yr15、Yr36、Yr46、Yr59、Yr62转育主栽品种中，获得重组自交系。YrBm转育到5个受体主栽品种；甘肃小麦育种单位将单株系NJ119-5（含YrBm）用作抗源，组配10个育种杂交组合，获得82个F3重组系。明确了不同类型抗病基因聚合有助于扩展谱抗病，全生育期抗病基因Yr1与高温成株抗病基因Yr36聚合重组系苗期抗病谱扩展最为明显。部分研究结果发表在遗传学领域顶级期刊Theoretical and Applied Genetics和中文核心期刊。本项目研究结果对揭示持久抗病慢锈性品种遗传组分、建立持久性鉴定方法具有重要意义，促进持久抗病慢锈性品种成株抗性基因的实际应用。