An atypical kinase under balancing selection confers broad-spectrum disease resistance in Arabidopsis.
An atypical kinase under balancing selection confers broad-spectrum disease resistance in Arabidopsis.
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DOI：
10.1371/journal.pgen.1003766
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发表时间：
2013
期刊：
影响因子：
4.5
通讯作者：
Roby D
中科院分区：
文献类型：
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作者：
Huard-Chauveau C;Perchepied L;Debieu M;Rivas S;Kroj T;Kars I;Bergelson J;Roux F;Roby D
基因对基因的抗性性状在农业环境中无法提供持久和广谱的抗性，这导致了对植物数量抗性基因的研究。这些基因仅在少数情况下被鉴定出来，所有这些基因都具有真菌或线虫抗性，并且编码多种分子功能。然而，对其他敌人的数量抗性变异的分子机制以及形成这种变异的相关进化力量的理解在很大程度上仍然未知。我们报道了QRX3 （RKS1，抗性相关激酶1）的鉴定，基于图谱的克隆和功能验证，赋予了对十字花科植物的破坏性细菌血管病原体Xanthomonas campestris （Xc）的广谱抗性。RKS1编码一种非典型激酶，通过限制细菌从感染部位扩散介导植物的数量抗性机制。巢式全基因组关联图谱在物种水平上揭示了RKS1等位基因序列对应的主要位点。在多种转基因品系和天然品种中发现了抗性变异与RKS1转录之间的关联，这表明RKS1表达的调控是对Xc定量抗性的主要组成部分。拟南芥中长寿的RKS1单倍型与多种参与病原体识别的基因共存，表明存在共同的选择压力。RKS1的鉴定是破解广谱定量抗病机制的起点，这种抗病机制对一种破坏性的维管作物病原体有效。由于在其他芸苔属植物中已经发现了推测的RKS1同源基因，因此RKS1为植物育种家提高作物对黑腐病的抗性提供了一个令人兴奋的机会。在植物与病原体相互作用的进化过程中，植物通过不同的重叠机制进化出了防御病原体感染的能力。抗病是由一个复杂的、多层次的防御系统构成的。在这些反应中，数量抗性是作物和天然植物群体中普遍存在的抗性形式，其遗传和分子基础在很大程度上仍然未知。因此，鉴定数量抗性背后的基因是植物育种和进化生物学中的一项重大挑战，并可能通过提高作物产量和质量对人类健康产生巨大的实际影响。我们的工作有助于了解油菜黄单胞菌（Xc）的数量抗性的分子基础，它是导致黑腐病的血管病原体，是世界上重要的十字花科植物疾病。通过多种方法，我们证明了RKS1是拟南芥中的一个定量抗性基因，具有对Xc的广谱抗性，并且这种抗性机制与RKS1的表达调控有关。我们还提供证据表明，RKS1等位基因变异是物种水平上对Xc数量抗性的主要组成部分。最后，与RKS1相关的长寿命多态性表明，拟南芥对Xc的进化稳定的广谱抗性可能在自然种群中实现。
The failure of gene-for-gene resistance traits to provide durable and broad-spectrum resistance in an agricultural context has led to the search for genes underlying quantitative resistance in plants. Such genes have been identified in only a few cases, all for fungal or nematode resistance, and encode diverse molecular functions. However, an understanding of the molecular mechanisms of quantitative resistance variation to other enemies and the associated evolutionary forces shaping this variation remain largely unknown. We report the identification, map-based cloning and functional validation of QRX3 (RKS1, Resistance related KinaSe 1), conferring broad-spectrum resistance to Xanthomonas campestris (Xc), a devastating worldwide bacterial vascular pathogen of crucifers. RKS1 encodes an atypical kinase that mediates a quantitative resistance mechanism in plants by restricting bacterial spread from the infection site. Nested Genome-Wide Association mapping revealed a major locus corresponding to an allelic series at RKS1 at the species level. An association between variation in resistance and RKS1 transcription was found using various transgenic lines as well as in natural accessions, suggesting that regulation of RKS1 expression is a major component of quantitative resistance to Xc. The co-existence of long lived RKS1 haplotypes in A. thaliana is shared with a variety of genes involved in pathogen recognition, suggesting common selective pressures. The identification of RKS1 constitutes a starting point for deciphering the mechanisms underlying broad spectrum quantitative disease resistance that is effective against a devastating and vascular crop pathogen. Because putative RKS1 orthologous have been found in other Brassica species, RKS1 provides an exciting opportunity for plant breeders to improve resistance to black rot in crops. During the evolution of plant-pathogen interactions, plants have evolved the capability to defend themselves from pathogen infection by different overlapping mechanisms. Disease resistance is constituted by an elaborate, multilayered system of defense. Among these responses, quantitative resistance is a prevalent form of resistance in crops and natural plant populations, for which the genetic and molecular bases remain largely unknown. Thus, identification of the genes underlying quantitative resistance constitutes a major challenge in plant breeding and evolutionary biology, and might have enormous practical implications for human health by increasing crop yield and quality. Our work contributes to understanding the molecular bases of quantitative resistance to the vascular pathogen Xanthomonas campestris (Xc), which is responsible for black rot, an important disease of crucifers worldwide. By multiple approaches, we demonstrate that RKS1 is a quantitative resistance gene in Arabidopsis thaliana conferring broad-spectrum resistance to Xc and that this resistance mechanism in plants is associated with regulation of RKS1 expression. We also provide evidence that RKS1 allelic variation is a major component of quantitative resistance to Xc at the species level. Finally, the long-lived polymorphism associated with RKS1 suggests that evolutionary stable broad-spectrum resistance to Xc may be achieved in natural populations of A. thaliana.
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影响因子：
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