Knockout of the OsNAC113 Transcription Factor Causes High Salt Resistance in Rice

The plant NAC (NAM, ATAF1/2, and CUC2) transcription factor family plays an important regulatory role in stress response. In this study, we analyzed the rice transcription factor OsNAC113 and elucidated its tissue-specific characteristics and stress response regulatory mechanisms. qRT-PCR results showed that under laboratory-simulated drought, high salt, temperature stress, and hormone treatments, such as abscisic acid (ABA) and gibberellic acid (GA₃), the expression level of OsNAC113 significantly changed, indicating that OsNAC113 responds to various stress conditions. Targeted creation of the rice (Oryza sativa L. spp. japonica) OsNAC113 (LOC_os08g10080.1) mutant based on the CRISPR-Cas9 genome editing strategy revealed its response to salt stress (200 mM). The growth status and survival rate of the mutant under high-salt stress were significantly higher than those of the wild type. Testing showed that the mutant exhibited increased relative water, chlorophyll, and soluble sugar contents under salt stress than the wild type. The malondialdehyde content in the mutant was lower, and the activities of superoxide dismutase, peroxidase, and catalase were higher than those in the wild type, indicating that the mutant with functional loss caused by knocking out OsNAC113 had a significantly enhanced tolerance to salt treatment. Using RNA-seq to detect genome-wide changes in OsNAC113 mutant materials under stress, KEGG annotation showed that knocking out OsNAC113 resulted in regulatory changes in "plant hormone signaling pathway" and "MAPK signaling pathway," and GO and KEGG annotations showed significant changes in "amino acid transport and metabolism," "carbohydrate transport and metabolism," "lipid transport and metabolism," and "replication, recombination, and repair." OsNAC113 may be involved in the response to salt stress by regulating these signaling pathways. Using comparative metabolomic analysis, we further elucidated the function of OsNAC113 in physiological metabolic pathways. The knockout of OsNAC113 resulted in changes in various important metabolic pathways in plants, including flavonoid biosynthesis and ABC transporters. Therefore, it is suggested that OsNAC113 is involved in these metabolic processes and affects their regulation in high-salt environments. These results provide a theoretical foundation and reliable material for the molecular breeding of rice.