Comprehensive Analysis of Miscanthus NF-YA Genes Reveals Potential Involvement in Drought Stress Adaptation

<i>Miscanthus</i>, a perennial grass, is renowned for its remarkable tolerance to abiotic stress. Excessive levels of drought severely impair plant growth and yield. Plant nuclear factor Y (NF-Y) transcription factors (TFs) play pivotal roles in regulating responses to drought stress in species such as <i>Arabidopsis</i> and maize. However, their functional roles in conferring drought tolerance in <i>Miscanthus</i> remain largely unexplored. This study's genome-wide analysis and gene expression profiling of <i>Miscanthus</i> under dehydration/osmotic stress identified a transcription factors gene, <i>MsNF-YA4</i>, which was significantly upregulated under dehydration/osmotic stress. <i>MsNF-YA4</i> overexpression in <i>Arabidopsis</i> significantly enhanced drought tolerance, leading to increased transcription of stress- and antioxidant enzyme-related genes. Compared with the wild type (WT), the transgenic lines exhibited markedly higher relative water content (RWC), chlorophyll content, proline level, and antioxidant enzyme activity. Furthermore, the MsNF-YA4/MsNF-YB3/MsNF-YC2 improved the transactivation of the <i>Miscanthus P5CS1</i>, <i>SOD</i> (Cu/Zn) and <i>CAT1</i> promoters in the transient system. These results offer fresh perspectives on the role of <i>Miscanthus</i> NF-YAs in drought tolerance and offer promising genetic resources for developing drought-tolerant crops through breeding programs.