单个氨基酸的变化改变了多基小麦茎耐性位点SR9的特异性
Jianping Zhang1,2,3, Jayaveeramuthu Nirmala4, Shisheng Chen5
1CSIRO Agriculture & Food, Canberra, ACT, 2601, Australia.
Nature communications
|November 14, 2023
概括
研究人员分离了小麦茎抗基因局部SR9的多个等位基因. 这些等位基对核酸结合点白丰富重复 (NB-LRR) 免疫受体进行编码,提供针对小麦茎生的多样性抵抗光谱.
科学领域:
- 植物遗传学 植物遗传学
- 分子生物学分子生物学
- 农作物科学 农作物科学
背景情况:
- 小麦茎生,由Puccinia graminis f. sp. 引起的 三,对全球粮食安全构成重大威胁.
- 现有的小麦生抗性基因往往具有有限的等位基因多样性,需要发现新的抗性来源.
- SR9位点是理解和增强小麦对茎生的防御的关键目标.
研究的目的:
- 隔离和表征小麦茎抗基因位点SR9.9中的功能性基因.
- 为了研究不同SR9等位基因所赋予的抗性的分子基础.
- 了解SR9基因家族内抗性机制的进化多样化.
主要方法:
- 七个之前报告的SR9等位基因 (Sr9a,Sr9b,Sr9d,Sr9e,Sr9f,Sr9g和Sr9h) 的隔离和表征.
- 利用功能丧失突变体和转基因补充来确认基因功能.
- 采用比较序列分析来研究蛋白质结构和进化关系.
主要成果:
- 在SR9位点成功分离和表征了多个功能性等位基因.
- 每个等位基因编码一个核酸结合部位白丰富重复 (NB-LRR) 免疫受体,具有不同的抗性谱.
- 确定了特定的氨基酸变异,包括单氨基酸变化,负责功能多样化和改变病原体识别.
- SR9H 赋予了对 Ug99 (TTKSK) 茎生种族的抗性,而 SR9B 和 SR9G 的区别在于单一的氨基酸.
- 在B亚基因组中的SR9等位基因与A亚基因组中的Sr21是正基因,共享大约85%的蛋白质序列相同性.
结论:
- SR9等位基因的功能多样化是由NB-LRR受体内的单个和多个氨基酸替代驱动的.
- 在SR9位点提供了一个有价值的资源,用于育种小麦品种,具有持久的耐药性,多种不同的干病原体分离.
- 了解SR9的等位基变异有助于应对不断变化的小麦生威胁的策略.
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