An NAC transcription factor gene from Malus baccata, MbNAC29, increases cold and high salinity tolerance in Arabidopsis

Abstract

NAC (no apical meristem [NAM], Arabidopsis thaliana transcription activation factor [ATAF1/2], and cup-shaped cotyledon [CUC2]) TFs are involved in stress responses in plants. However, their roles in abiotic stresses are still not well known in Malus plants. In the present study, MbNAC29 from Malus baccata was identified and characterized. Quantitative real-time PCR analysis revealed that the expression of MbNAC29 was induced by cold, high salinity, drought, and heat. The open reading frame (ORF) of MbNAC29 is 1122 bp, encodes 373 amino acids. Subcellular localization showed that the MbNAC29-GFP (green fluorescent protein) fusion protein was localized in the nucleus. Furthermore, MbNAC29 was highly expressed in new leaf and mature leaf. When MbNAC29 was introduced into Arabidopsis, it improved cold and high salinity tolerance in transgenic plants under low-temperature stress (− 4°C) and salt stress (200 mM NaCl). When MbNAC29 was introduced into Arabidopsis, it increased the survival rate of transgenic lines than wild type (WT) under cold and high-salinity stresses. In addition, overexpression of MbNAC29 in transgenic Arabidopsis increased the contents of chlorophyll and proline and the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), while decreased the content of malondialdehyde (MDA). Therefore, these results suggest that MbNAC29 probably plays an important role in response to cold and salt stresses in Arabidopsis by enhancing scavenging capability of reactive oxygen species (ROS).