ABSTRACT: To understand how CTS-12 the ABA-dependent multi-levels of regulation, the integration of transcriptomic and metabolomic profiling using the two-way orthogonal projections to latent structures (O2PLS) and OPLS discriminant analysis (OPLS-DA) modeling was performed to investigate the mechanisms underlying chilling tolerance. Our results revealed that metabolic flux shifts, including the activation of stachyose biosynthesis, amino acid metabolism pathways, phenylpropanoid/flavonoid biosynthesis, and ABA biosynthesis, and inhibition of glycolysis, occurred under chilling treatment, and in the recovery period, the differentially expressed genes/metabolites (DEGs/DEMs) that mapped to glutamate-related pathways, β-alanine biosynthesis and degradation, and serotonin biosynthesis pathways were differentiated between 9311 and DC90. Particularly, the differential alterations of the DEMs/DEGs, including galactinol, β-alanine, glutamate, naringenin, serotonin, abscisic acid (ABA), and LOC_Os03g44380 (OsNCED3), might be involved in the chilling stress phenotype variation of 9311 and DC90. The involvement of ABA pathway was validated by CRISPR/Cas9-edited of discriminatory DEGs OsNCED3 which impaired chilling tolerance of japonica rice. In addition, chilling tolerance of rice was associated with the balance of water uptake and loss that was modulated by stomatal movement under chilling stress. Therefore, we speculated that the CTS-12-mediated ABA signaling pathway leads to transcriptional regulation of chilling-responsive genes and, in turn, triggers metabolic shifts to coordinately regulate the stomatal movement of guard cells. The results of this study improve our understanding of the multilevel regulation of wild rice in response to chilling stress.
