Abstract

MicroRNAs (miRNAs) are pivotal regulators of plant immunity. While our prior work implicated zma-miR169s in maize defence against Bipolaris maydis , its upstream regulation and downstream signalling mechanisms remained elusive. Here, we decipher a complete signalling pathway that confers resistance to B. maydis . We show that the transcription factor ZmWRKY92 directly binds to the promoter of zma-miR169s to suppress its transcription. Consistent with its role as a positive regulator, loss of ZmWRKY92 function increased maize susceptibility to the pathogen. We further delineate downstream of this pathway, demonstrating that ZmNF-YA13, a nuclear-localised target of zma-miR169s induced upon infection, is a positive defence regulator. Overexpression of ZmNF-YA13 enhanced resistance, whereas knockout mutants were more susceptible. Integrated multi-omics analysis further revealed that ZmNF-YA13 activates the flavonoid biosynthesis pathway, promoting the accumulation of antimicrobial compounds like gallocatechin, quercetin and chalcone. Collectively, our work establishes the ZmWRKY92–miR169s–ZmNF-YA13-flavonoid module as a key signalling pathway in maize antifungal immunity, providing novel targets for maize disease resistance improvement.