The R2R3-MYB transcription factor MdMYB62 negatively regulates the drought and salt tolerance in apple

Abstract

Drought and salt stresses represent significant environmental constraints that severely impair global plant growth and development. While numerous transcription factors regulating drought and salt stress responses have been identified across plant species, their functional mechanisms remain incompletely understood. In this study, we characterized MdMYB62, a MYB transcription factor from apple (Malus domestica), and elucidated its functional role under abiotic stress conditions. Quantitative reverse transcription PCR (qRT-PCR) analysis revealed that MdMYB62 expression was significantly modulated under both drought and salt stress conditions. Functional analyses revealed that overexpression of MdMYB62 in apple calli led to increased sensitivity to drought and salt stress.Consistent with these findings, ectopic expression of MdMYB62 in Arabidopsis resulted in reduced tolerance to these stress, which was associated with elevated accumulation of reactive oxygen species (ROS). These results collectively establish MdMYB62 as a negative regulator of plant stress responses and provide new insights into the molecular mechanisms underlying plant adaptation to abiotic stress.