Yao Lishan, Li Yanmei, Ma Chuanyu, Tong Lixiu, Du Feili, Xu Mingliang
State Key Laboratory of Plant Physiology and Biochemistry, College of Agronomy and Biotechnology, National Maize Improvement Center, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing, 100193, China.
J Integr Plant Biol. 2020 Oct;62(10):1535-1551. doi: 10.1111/jipb.12911. Epub 2020 Mar 23.
Fusarium ear rot, caused by Fusarium verticillioides, is a devastating fungal disease in maize that reduces yield and quality; moreover, F. verticillioides produces fumonisin mycotoxins, which pose serious threats to human and animal health. Here, we performed a genome-wide association study (GWAS) under three environmental conditions and identified 34 single-nucleotide polymorphisms (SNPs) that were significantly associated with Fusarium ear rot resistance. With reference to the maize B73 genome, 69 genes that overlapped with or were adjacent to the significant SNPs were identified as potential resistance genes to Fusarium ear rot. Comparing transcriptomes of the most resistant and most susceptible lines during the very early response to Fusarium ear rot, we detected many differentially expressed genes enriched for pathways related to plant immune responses, such as plant hormone signal transduction, phenylpropanoid biosynthesis, and cytochrome P450 metabolism. More than one-fourth of the potential resistance genes detected in the GWAS were differentially expressed in the transcriptome analysis, which allowed us to predict numbers of candidate genes for maize resistance to ear rot, including genes related to plant hormones, a MAP kinase, a PR5-like receptor kinase, and heat shock proteins. We propose that maize plants initiate early immune responses to Fusarium ear rot mainly by regulating the growth-defense balance and promoting biosynthesis of defense compounds.
由轮枝镰孢菌引起的玉米穗腐病是玉米中一种毁灭性的真菌病害，会降低产量和品质；此外，轮枝镰孢菌会产生伏马菌素霉菌毒素，对人类和动物健康构成严重威胁。在此，我们在三种环境条件下进行了全基因组关联研究（GWAS），并鉴定出34个与玉米穗腐病抗性显著相关的单核苷酸多态性（SNP）。参照玉米B73基因组，69个与显著SNP重叠或相邻的基因被鉴定为玉米穗腐病的潜在抗性基因。在对玉米穗腐病的极早期反应过程中，比较最抗病和最感病品系的转录组，我们检测到许多差异表达基因，这些基因富集于与植物免疫反应相关的途径，如植物激素信号转导、苯丙烷类生物合成和细胞色素P450代谢。在GWAS中检测到的潜在抗性基因中有超过四分之一在转录组分析中差异表达，这使我们能够预测玉米抗穗腐病的候选基因数量，包括与植物激素、一种促分裂原活化蛋白激酶、一种类PR5受体激酶和热休克蛋白相关的基因。我们提出，玉米植株主要通过调节生长 - 防御平衡和促进防御化合物的生物合成来启动对玉米穗腐病的早期免疫反应。
