A soybean cyst nematode resistance gene points to a new mechanism of plant resistance to pathogens
A soybean cyst nematode resistance gene points to a new mechanism of plant resistance to pathogens
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DOI：
10.1038/nature11651
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发表时间：
2012-12-13
期刊：
影响因子：
64.8
通讯作者：
Meksem, Khalid
中科院分区：
文献类型：
--
作者：
Liu, Shiming;Kandoth, Pramod K.;Meksem, Khalid
大豆（甘氨酸max (l)）小麦是一种重要的作物，在世界范围内提供可持续的蛋白质和油脂来源。大豆囊线虫（Heterodera glycines Ichinohe）是一种以大豆根部为食的微小蛔虫，是大豆生产的主要制约因素。仅在美国，这种线虫每年就造成超过10亿美元的产量损失(1)，使其成为大豆上最重要的经济病原体。尽管种植抗性品种是该病原体的核心管理策略，但对抗性的性质一无所知。此外，这种寄生虫在大多数已知耐药源上的毒性种群增加，需要开发新的控制方法。在这里，我们报道了在Rhg4位点上的一个基因的基于图谱的克隆，Rhg4位点是一个主要的数量性状位点，有助于抵抗这种病原体。突变分析、基因沉默和转基因互补证实该基因具有耐药性。该基因编码一种丝氨酸羟甲基转移酶，这种酶在自然界中普遍存在，并且在结构上保守。该酶负责丝氨酸和甘氨酸的相互转化，是细胞单碳代谢所必需的。赋予Rhg4抗性或易感性的等位基因通过改变酶的关键调控特性的两种遗传多态性而不同。我们的发现揭示了一种前所未有的植物对病原体的抗性机制。抗性基因的机制知识可以很容易地用于提高大豆的抗线虫性，这是一种日益重要的全球作物。
Soybean (Glycine max (L.) Merr.) is an important crop that provides a sustainable source of protein and oil worldwide. Soybean cyst nematode (Heterodera glycines Ichinohe) is a microscopic roundworm that feeds on the roots of soybean and is a major constraint to soybean production. This nematode causes more than US$1 billion in yield losses annually in the United States alone(1), making it the most economically important pathogen on soybean. Although planting of resistant cultivars forms the core management strategy for this pathogen, nothing is known about the nature of resistance. Moreover, the increase in virulent populations of this parasite on most known resistance sources necessitates the development of novel approaches for control. Here we report the map-based cloning of a gene at the Rhg4 (for resistance to Heterodera glycines 4) locus, a major quantitative trait locus contributing to resistance to this pathogen. Mutation analysis, gene silencing and transgenic complementation confirm that the gene confers resistance. The gene encodes a serine hydroxymethyltransferase, an enzyme that is ubiquitous in nature and structurally conserved across kingdoms. The enzyme is responsible for interconversion of serine and glycine and is essential for cellular one-carbon metabolism. Alleles of Rhg4 conferring resistance or susceptibility differ by two genetic polymorphisms that alter a key regulatory property of the enzyme. Our discovery reveals an unprecedented plant resistance mechanism against a pathogen. The mechanistic knowledge of the resistance gene can be readily exploited to improve nematode resistance of soybean, an increasingly important global crop.