Integrative analysis of transcriptome and metabolome revealed the mechanisms by which flavonoids and phytohormones regulated the adaptation of alfalfa roots to NaCl stress

Abstract

IntroductionSalinity critically affects the growth and development of alfalfa (Medicago sativa), making it necessary to understand the molecular mechanism of alfalfa’s adaptation to salt stress.MethodsIn this study, alfalfa roots were subjected to salt stress and transcriptomics and metabolomics analyses were performed.ResultsThe results showed that flavonoid synthesis, hormone synthesis, and transduction pathways may be involved in the alfalfa salt stress adaptation reaction, and that they are related. Combined analysis of differential genes and differential metabolites found that dihydroquercetin and beta-ring hydroxylase (LUT5), ABA responsive element binding factor 2 (ABF2), protein phosphatase PP2C (PP2C) and abscisic acid (ABA) receptor PYL2 (PYL), luteolinidin was significantly correlated with PP2C and phytochrome-interacting factor 4 (PIF4) and (+)-7-isomethyl jasmonate were significantly correlated with flavonol synthase (FLS) gene. (+)-7-isomethyl jasmonate and homoeriodictyol chalcone were significantly correlated with peroxidase (POD). POD was significantly up-regulated under NaCl stress for 6 and 24 h. Moreover, flavonoids, gibberellin (GA), jasmonic acid (JA) and ABA were suggested to play an important role in alfalfa’s response to salt stress. Further, GA,ABA, and JA may be involved in the regulation of flavonoids to improve alfalfa’s salt tolerance, and JA may be a key signal to promote the synthesis of flavonoids. DiscussionThis study revealed the possible molecular mechanism of alfalfa adaptation to salt stress, and identified a number of salt-tolerance candidate genes from the synthesis and signal transduction pathways of flavonoids and plant hormones, providing new insights into the regulatory network of alfalfa response to salt stress.

Metabolomics reveal root differential metabolites of different root-type alfalfa under drought stress

“…Phytohormone content in plants is significantly altered by drought stress due to its impact on phytohormone metabolism ( Ghafari et al., 2020 ; Talaat, 2023 ). The PST pathway responds simultaneously to water deficit stress in three alfalfa varieties, and there is a close correlation between hormone synthesis and metabolic pathways ( Wang et al., 2023b ). The trend of IAA and GA 4 is contrary to the enrichment tendency shown by the metabolites of SA and jasmonic acid (JA) in the PST pathway.…”

Exogenous Calcium Alleviates Oxidative Stress Caused by Salt Stress in Peanut Seedling Roots by Regulating the Antioxidant Enzyme System and Flavonoid Biosynthesis

“…The absorbance values of the samples were measured at 240 nm, and catalase (CAT) activity was calculated by converting the rate of catalase consumption per unit time. Malondialdehyde (MDA) content was determined based on the content of thiobarbituric acid reactive substances (TBARSs) in root samples (nmol/g; extinction coefficient; 155 mMcm −1 ; [33]). The contents of H 2 O 2 , O 2− , and soluble sugars in the root system were determined according to Wang et al [33].…”

“…Malondialdehyde (MDA) content was determined based on the content of thiobarbituric acid reactive substances (TBARSs) in root samples (nmol/g; extinction coefficient; 155 mMcm −1 ; [33]). The contents of H 2 O 2 , O 2− , and soluble sugars in the root system were determined according to Wang et al [33]. Root vigor was determined by the tetrazolium (2,3,5-triphenyl tetrazolium chloride, TTC) reduction method [34].…”

Transcriptomic Analysis of Melatonin-Mediated Salt Stress Response in Germinating Alfalfa

“…Consequently, this will enhance the scale and level of the forage industry and play a vital role in promoting the development of circular ecological agriculture centered around forage and animal husbandry [12][13][14]. Existing research has elucidated the mechanisms underlying salt-alkali tolerance in alfalfa, focusing on areas such as seed germination, plant growth and development, physiological and biochemical reactions, and molecular biology [15]. Osmotic regulation, ion balance and repair, reactive oxygen species (ROS) production, and their effects on downstream molecular targets are among the key processes investigated in the literature [2,16,17].…”