Interaction between MdZAT10a-like and MdbHLH100 negatively regulates salt tolerance in apple (Malus domestica Borkh.)

Salinity is a harmful environmental factor that inhibits plant growth, and reduces the yield and quality of crops, including apple (Malus ×domestica Borkh.). In this study, we treated tissue-cultured wild-type apple ‘Royal Gala’ seedlings with different concentrations of NaCl. A zinc finger of Arabidopsis thaliana (ZAT) transcription factor, designated MdZAT10a-like, was screened by qRT-PCR analysis and shown to be significantly responsive to salt stress. Overexpression of MdZAT10a-like in apple callus reduced the expression of MdNHX1 and thereby enhanced the sensitivity of callus to salt stress. Yeast two-hybrid screening showed that MdbHLH100 was capable of interacting with MdZAT10a-like. The MdZAT10a-like–MdbHLH100 protein complex significantly inhibited the expression of the downstream gene MdNHX1. The present functional analyses of MdZAT10a-like provide valuable insights into the regulatory network of salt tolerance in apple.