Transcriptomic and metabolomic analyses reveal that ABA increases the salt tolerance of rice significantly correlated with jasmonic acid biosynthesis and flavonoid biosynthesis.

Abscisic acid (ABA) has been shown to mitigate the deleterious effects of abiotic stresses and to regulate plant growth and development. Salinity is one of the important abiotic stresses affecting plant cell metabolism and physiology, which causes serious damages to crops. In this study, we investigated the protective role of exogenous ABA on leaves in response to salinity stress using rice seedlings (two leaf-one heart) subjected to three treatments: ZCK (control), ZS (50 mM NaCl), and ZSA (5 mg L ABA + 50 mM NaCl). We carried out transcriptomic and metabolomic analyses to identify the molecular mechanisms by which ABA protects plants against salt stress. Results showed that 1159 differentially expressed genes (DEGs) (916 up-regulated, 243 down-regulated) and 63 differentially accumulated metabolites (DAMs) (42 up-regulated, 21 down-regulated) were identified between the ZS and ZSA treatments, respectively. In addition, ABA pretreatment regulated the expression pattern of genes responsible for oxidation redox, starch and sucrose metabolism, and phenylpropanoid biosynthesis. The combined transcriptomic and metabolomic analysis revealed that 16 DEGs and 2 DAMs were involved in Flavonoid biosynthesis and 8 DEGs and 2 DAMs were involved alpha-Linolenic acid metabolism which are responsible for salinity stress tolerance through induced by exogenous ABA. Overall, ABA could enhance rice leaves growth and development mainly by regulating flavonoid biosynthesis and linoleic acid metabolism pathway.