PDF(Pubmed)
Abstract：
Leaf sheath blight disease (SB) of rice caused by the soil-borne fungus Rhizoctonia solani results in 10-30% global yield loss annually and can reach 50% under severe outbreaks. Many disease resistance genes and receptor-like kinases (RLKs) are recruited early on by the host plant to respond to pathogens. Wall-associated receptor kinases (WAKs), a subfamily of receptor-like kinases, have been shown to play a role in fungal defense. The rice gene WAK91 (OsWAK91), co-located in the major SB resistance QTL region on chromosome 9, was identified by us as a candidate in defense against rice sheath blight. An SNP mutation T/C in the WAK91 gene was identified in the susceptible rice variety Cocodrie (CCDR) and the resistant line MCR010277 (MCR). The consequence of the resistant allele C is a stop codon loss, resulting in an open reading frame with extra 62 amino acid carrying a longer protein kinase domain and additional phosphorylation sites. Our genotype and phenotype analysis of the parents CCDR and MCR and the top 20 individuals of the double haploid SB population strongly correlate with the SNP. The susceptible allele T is present in the japonica subspecies and most tropical and temperate japonica lines. Multiple US commercial rice varieties with a japonica background carry the susceptible allele and are known for SB susceptibility. This discovery opens the possibility of introducing resistance alleles into high-yielding commercial varieties to reduce yield losses incurred by the sheath blight disease.
摘要：
由土壤传播的真菌枯萎病引起的水稻叶鞘枯萎病（SB）每年导致10-30％的全球产量损失，在严重爆发时可达到50％。许多抗病基因和受体样激酶(RLK)在宿主植物早期被募集以响应病原体。壁相关受体激酶（WAKs），受体样激酶亚家族,已被证明在真菌防御中起作用。水稻基因WAK91(OsWAK91),共同位于9号染色体上主要的SB抗性QTL区域，被我们确定为防御水稻纹枯病的候选者。在易感水稻品种Cocodrie（CCDR）和抗性品系MCR010277（MCR）中鉴定出WAK91基因中的SNP突变T/C。抗性等位基因C的结果是终止密码子丢失，导致具有额外62个氨基酸的开放阅读框，携带更长的蛋白激酶结构域和额外的磷酸化位点。我们对父母CCDR和MCR以及双单倍体SB群体的前20名个体的基因型和表型分析与SNP强烈相关。易感等位基因T存在于粳稻亚种以及大多数热带和温带粳稻系中。具有粳稻背景的多个美国商业水稻品种携带易感等位基因，并且以SB易感性而闻名。这一发现开启了将抗性等位基因引入高产商业品种以减少纹枯病引起的产量损失的可能性。
