Functional characterization of the MdMYB73L gene in drought and salt stress tolerance in apple

Drought and salt stresses impose serious effects on plant proliferation and development, with multiple categories of transcription factors (TFs) playing important regulatory effects in modulation stress reaction. In this study, the apple R2R3 MYB TF, MdMYB73L, was cloned and characterized its role in conferring abiotic stress tolerance. Firstly, expression assays demonstrated that the transcript levels of MdMYB TFs changed substantially under salt and drought stresses. Subsequently, MdMYB73L-overexpressing transgenic Arabidopsis, apple calli and tomato plants all showed increased sensitivity to salt and drought treatments, manifesting as short roots and severe growth inhibition compared to controls. These results demonstrate that MdMYB73L functions as a key negative regulator in the response to drought and salt stresses. Overall, these research not only demonstrate the specific function of a MYB TF in stress responses but also provide a crucial framework for elucidating the broader effects of the apple MYB family in abiotic stress tolerance.