Physiological and Transcriptomic Mechanisms of Exogenous Salicylic Acid-Induced Resistance to Ear Rot in Maize

Maize ear rot is an important fungal disease in maize production, mainly caused by pathogens such as Fusarium graminearum, which seriously affects the yield and quality of maize. This study investigated the changes in the activity of defense-related enzymes in maize grains and their transcriptome response characteristics after exogenous SA treatment under Fusarium graminearum stress. The results showed that treatment with 0.01 mmol/L salicylic acid (SA) significantly inhibited the growth of Fusarium graminearum hyphae, while enhancing the activities of phenylalanine ammonia-lyase (PAL), superoxide dismutase (SOD), β-1,3-glucanase (β-1,3-GA), and polyphenol oxidase (PPO) in maize grains, and reducing the content of malondialdehyde (MDA), effectively alleviating the damage of Fusarium graminearum to the maize grain membrane system. Transcriptome analysis identified multiple key genes involved in SA-mediated disease resistance pathways, including disease-related proteins (PR10), acidic terpenoids, aspartic proteases, proteins containing BTB/POZ and MATH domains (BPM4), and PPT3 transporters. This study reveals the physiological and molecular mechanisms by which exogenous SA enhances maize resistance to ear rot, providing an important theoretical basis for further understanding the regulatory network of SA in plant disease resistance.