A novel Miscanthus NAC transcription factor MlNAC10 enhances drought and salinity tolerance in transgenic Arabidopsis.

Abstract

NAC (NAM, ATAF1/2 and CUC2) proteins are key regulators of various plant stress tolerances. However, knowledge of NAC genes remains largely unknown in Miscanthus. Here, we characterized a novel NAC gene MlNAC10 from M. lutarioriparius than plays a role in abiotic stress tolerance. MlNAC10 encodes a nuclear-localized protein with a C-terminal transactivation domain, and has a specific binding affinity to the NAC recognition sequence (NACRS). Ectopic expression of MlNAC10 in Arabidopsis led to increased sensitivity to abscisic acid (ABA) at early seedling growth stages. In addition, the proline content was significantly increased and the reactive oxygen species (ROS) scavenging capability was significantly enhanced in MlNAC10 overexpression lines under ABA treatment. Moreover, the drought and salt stress tolerance was significantly improved in MlNAC10 overexpression lines. Consistently, the activities of three antioxidant enzymes, namely catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), were dramatically stimulated in the overexpression lines compared to the wild type (WT). Correspondingly, the accumulation of ROS was dramatically decreased and malondialdehyde (MDA) was accumulated at a much lower level in the transgenic lines. Meanwhile, the expression of six abiotic stress-related genes was dramatically stimulated in the overexpression lines in comparison to the WT. Together, our results demonstrated that MlNAC10 acts as an important regulator of drought and salinity stress tolerance by stimulating antioxidant enzymes and alleviating ROS damage via the ABA signaling pathway.