Abstract
Nitrogen is an essential element for plant growth, and low nitrogen stress significantly restricts crop yield. Therefore, cultivating crop varieties that are tolerant to low nitrogen is crucial for agricultural production. The AT-hook motif nuclear localization protein (AHL) family is vital for plant stress resistance. To investigate the potential regulatory mechanisms of the AHL family in maize under low nitrogen stress, 35 ZmAHL genes were identified from the maize genome using bioinformatics methods. The results indicated that these genes encode proteins with lengths ranging from 203 to 573 amino acids, with relative molecular weights between 20.68 and 59.68 kDa, and they are unevenly distributed across 10 chromosomes. Most proteins encoded by these genes are alkaline hydrophilic proteins, primarily localized in the nucleus. Family expansion occurred through tandem and fragment repeats, which exhibited evolutionary conservation with rice homologous genes. Transcriptome analysis revealed that the majority of ZmAHL genes in drought-tolerant maize inbred lines were significantly up-regulated under drought and low nitrogen stress, with the ZmAHL10 gene displaying the most pronounced response to low nitrogen conditions. Experiments involving transgenic Arabidopsis thaliana further confirmed that the growth status, nitrogen uptake, and photosynthetic pigment content of ZmAHL10 overexpression strains under low nitrogen conditions were superior to those of the wild type, while the mutant exhibited significant growth inhibition. Overall, this study delineated the fundamental characteristics of the maize ZmAHL gene family and established that ZmAHL10 enhances low nitrogen tolerance in plants by improving nitrogen absorption capacity and maintaining the stability of the photosynthetic system. This research provides candidate genes and a theoretical foundation for the molecular breeding of maize with enhanced low nitrogen tolerance.