An NAC transcription factor gene fromMalus baccata,MbNAC29, increases cold and high salinity tolerance inArabidopsis

NAC (no apical meristem [NAM],Arabidopsis thalianatranscription 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 inMalusplants. In the present study,MbNAC29fromMalus baccatawas identified and characterized. Quantitative real-time PCR analysis revealed that the expression ofMbNAC29was induced by cold, high salinity, drought, and heat. The open reading frame (ORF) ofMbNAC29is 1122 bp, encodes 373 amino acids. Subcellular localization showed that the MbNAC29-GFP (green fluorescent protein) fusion protein was localized in the nucleus. Furthermore,MbNAC29was highly expressed in new leaf and mature leaf. WhenMbNAC29was introduced intoArabidopsis, it improved cold and high salinity tolerance in transgenic plants under low-temperature stress (- 4 degrees C) and salt stress (200 mM NaCl). WhenMbNAC29was introduced intoArabidopsis, it increased the survival rate of transgenic lines than wild type (WT) under cold and high-salinity stresses. In addition, overexpression ofMbNAC29in transgenicArabidopsisincreased 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 thatMbNAC29probably plays an important role in response to cold and salt stresses inArabidopsisby enhancing scavenging capability of reactive oxygen species (ROS).