ZmHDT103 Negatively Regulates Drought Stress Tolerance in Maize Seedlings

Drought stress presents a significant threat to the growth and development of maize. It is important to study the genes and mechanisms that contribute to drought tolerance. In this study, we identified ZmHDT103 (that encodes a histone deacetylase) by conducting a homologous sequence comparison and found that the expression of ZmHDT103 in maize seedlings is responsive to treatment with polyethylene glycol (PEG). We utilized CRISPR/Cas9 gene editing technology to generate three distinct knockout lines and obtained the ChinaMU mutant of the ZmHDT103 gene. Under drought conditions, the seedlings of ZmHDT103 mutants exhibited significantly lower water loss rate (WLR), relative electrolytic leakage (REL), hydrogen peroxide (H2O2) level, and malonaldehyde (MDA) level than those of their wild-type (WT) counterparts. Additionally, the seedlings of ZmHDT103 mutants exhibited significantly higher levels of abscisic acid (ABA), relative water content (RWC), peroxidase (POD), and proline (Pro) than those of the WT control. These findings indicate that ZmHDT103 acts as a negative regulator of drought tolerance in maize.