Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA.
Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa, USA.
Nat Genet. 2017 Sep;49(9):1364-1372. doi: 10.1038/ng.3919. Epub 2017 Jul 24.
Alleles that confer multiple disease resistance (MDR) are valuable in crop improvement, although the molecular mechanisms underlying their functions remain largely unknown. A quantitative trait locus, qMdr, associated with resistance to three important foliar maize diseases-southern leaf blight, gray leaf spot and northern leaf blight-has been identified on maize chromosome 9. Through fine-mapping, association analysis, expression analysis, insertional mutagenesis and transgenic validation, we demonstrate that ZmCCoAOMT2, which encodes a caffeoyl-CoA O-methyltransferase associated with the phenylpropanoid pathway and lignin production, is the gene within qMdr conferring quantitative resistance to both southern leaf blight and gray leaf spot. We suggest that resistance might be caused by allelic variation at the level of both gene expression and amino acid sequence, thus resulting in differences in levels of lignin and other metabolites of the phenylpropanoid pathway and regulation of programmed cell death.
虽然赋予多种疾病抗性（MDR）的等位基因在作物改良中很有价值，但它们功能的分子机制在很大程度上仍然未知。一个与三种重要叶部玉米病害——南方叶斑病、灰斑病和北方叶斑病——抗性相关的数量性状位点 qMdr 已被定位在玉米 9 号染色体上。通过精细定位、关联分析、表达分析、插入诱变和转基因验证，我们证明 ZmCCoAOMT2 是 qMdr 中赋予南方叶斑病和灰斑病数量抗性的基因，它编码一个与苯丙烷途径和木质素合成有关的咖啡酰辅酶 A O-甲基转移酶。我们认为抗性可能是由基因表达和氨基酸序列水平的等位基因变异引起的，从而导致木质素和苯丙烷途径其他代谢物的水平以及程序性细胞死亡的调节存在差异。
