Genome-Wide Analysis of YABBY Gene Family Reveals ZmYABBY8 as a Central Regulator Involved in Drought and Heat Stress Tolerance in Maize

The YABBY transcription factor family plays a critical role in the development of lateral organs and the establishment of polarity in plants. However, its evolutionary dynamics and regulatory functions in response to abiotic stress in maize (<i>Zea mays</i>) remain unclear. In this study, we conducted a genome-wide analysis of the maize YABBY gene family, employing phylogenetic analysis, transcriptomics, co-expression networks, and molecular experiments. A total of 12 <i>ZmYABBY</i> genes were identified from 26 maize inbred lines and classified into five conserved subfamilies. Evolutionary analysis indicated that the family is structurally stable, predominantly shaped by purifying selection, with limited lineage-specific variation among hybrid populations, highlighting its high evolutionary conservation. In contrast, transcriptomic analysis revealed functional diversification: <i>ZmYABBY</i> genes were preferentially expressed in floral organs and exhibited distinct response patterns under drought and heat stress. Notably, co-expression network analysis identified <i>ZmYABBY8</i> as a hub gene that was significantly induced under drought stress, as validated by RT-qPCR. Furthermore, its promoter region was found to be enriched with conserved stress-responsive cis-elements, including ABRE and DRE. Subcellular localization further confirmed that <i>ZmYABBY8</i> is localized to the nucleus. In summary, the maize YABBY gene family is evolutionarily conserved yet functionally diversified, with <i>ZmYABBY8</i> acting as a potential hub linking development and stress responses, making it a promising candidate for improving stress tolerance in maize.