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Salt stress is a major environmental factor limiting plant growth and productivity.We recently discovered an important new salt tolerance pathway,where the cell wall leucine-rich repeat extensins LRX3/4/5,the RAPID ALKALINIZATION FACTOR(RALF)peptides RALF22/23 and receptor-like kinase FERONIA(FER)function as a module to simultaneously regulate plant growth and salt stress tolerance.However,the intracellular signaling pathways that are regulated by the extracellular LRX3/4/5-RALF22/23-FER module to coordinate growth,cell wall integrity and salt stress responses are still unknown.Here,we report that the LRX3/4/5-RALF22/23-FER module negatively regulates the levels of jasmonic acid(JA),salicylic acid(SA)and abscisic acid(ABA).Blocking JA pathway rescues the dwarf phenotype of the lrx345 and fer-4 mutants,while disruption of ABA biosynthesis suppresses the salt-hypersensitivity of these mutants.Many salt stress-responsive genes display abnormal expression patterns in the lrx345 and fer-4 mutants,as well as in the wild type plants treated with epigallocatechin gallate(EGCG),an inhibitor of pectin methylesterases,suggesting cell wall integrity as a critical factor that determines the expression pattern of stress-responsive genes.Production of reactive oxygen species(ROS)is constitutively increased in the lrx345 and fer-4 mutants,and inhibition of ROS accumulation suppresses the salt-hypersensitivity of these mutants.Together,our work provides strong evidence that the LRX3/4/5-RALF22/23-FER module controls plant growth and salt stress responses by regulating hormonal homeostasis and ROS accumulation.