Lipps Sarah, Lipka Alexander E, Mideros Santiago, Jamann Tiffany
Department of Crop Sciences, University of Illinois, Urbana, IL, United States.
Front Plant Sci. 2023 Oct 6;14:1272951. doi: 10.3389/fpls.2023.1272951. eCollection 2023.
Northern corn leaf blight (NCLB) is an economically important disease of maize. While the genetic architecture of NCLB has been well characterized, the pathogen is known to overcome currently deployed resistance genes, and the role of hormones in resistance to NCLB is an area of active research. The objectives of the study were (i) to identify significant markers associated with resistance to NCLB, (ii) to identify metabolic pathways associated with NCLB resistance, and (iii) to examine role of ethylene in resistance to NCLB. We screened 252 lines from the exotic-derived double haploid BGEM maize population for resistance to NCLB in both field and greenhouse environments. We used a genome wide association study (GWAS) and stepwise regression to identify four markers associated with resistance, followed by a pathway association study tool (PAST) to identify important metabolic pathways associated with disease severity and incubation period. The ethylene synthesis pathway was significant for disease severity and incubation period. We conducted a greenhouse assay in which we inhibited ethylene to examine the role of ethylene in resistance to NCLB. We observed a significant increase in incubation period and a significant decrease in disease severity between plants treated with the ethylene inhibitor and mock-treated plants. Our study confirms the potential of the BGEM population as a source of novel alleles for resistance. We also confirm the role of ethylene in resistance to NCLB and contribute to the growing body of literature on ethylene and disease resistance in monocots.
北方玉米叶斑病（NCLB）是玉米的一种具有重要经济影响的病害。虽然NCLB的遗传结构已得到充分表征，但已知该病原菌会克服目前所使用的抗性基因，并且激素在NCLB抗性中的作用是一个活跃的研究领域。本研究的目的是：（i）鉴定与NCLB抗性相关的显著标记；（ii）鉴定与NCLB抗性相关的代谢途径；（iii）研究乙烯在NCLB抗性中的作用。我们在田间和温室环境中筛选了来自外来衍生双单倍体BGEM玉米群体的252个株系对NCLB的抗性。我们使用全基因组关联研究（GWAS）和逐步回归来鉴定四个与抗性相关的标记，随后使用途径关联研究工具（PAST）来鉴定与病情严重程度和潜伏期相关的重要代谢途径。乙烯合成途径对病情严重程度和潜伏期具有显著影响。我们进行了一项温室试验，在试验中抑制乙烯以研究乙烯在NCLB抗性中的作用。我们观察到，用乙烯抑制剂处理的植株与模拟处理的植株相比，潜伏期显著延长，病情严重程度显著降低。我们的研究证实了BGEM群体作为新型抗性等位基因来源的潜力。我们还证实了乙烯在NCLB抗性中的作用，并为单子叶植物中乙烯与抗病性方面不断增加的文献做出了贡献。
