The Plant Hormone Abscisic Acid Regulates The Defense Response Mediated By Jasmonic Acid

Plants live in continually changing environments that are often unfavorable for growth and development.These adverse environmental conditions include biotic stress,such as pathogen infection and herbivore attack,and abiotic stress,such as drought,excess of salt,extreme climates and others.How plants sense stress signals and adapt to adverse environments are fundamental biological questions.So far,it has been reported that plant hormone jasmonate mediates defense responses against biotic stress by degrading JAZ proteins and releasing downstream transcription factors MYC2 and EIN3.Abscisic acid activates responses against abiotic stress by derepressing SnRK2 s and phosphorylation of many effectors.Although there has been plenty of researches explaining different responses against biotic and abiotic stress.Most functions directly triggered by responses of jasmonic acid or abscisic acid have been illuminated.Yet it's still unclear that how plant achieve trade-offs from limited resources when faced with multiple stresses.Our research aimed to research the crosstalk between jasmonate and abscisic acid for this exact reason.In this study,we found that JAZ1 physically interacted with PYL4,ABI1,OST1,etc.which are belong to central signaling module of ABA signaling pathway.Exogenous ABA treatment accelerated JA-mediated upregulation of JAZ1 expression and degradation of JAZ1 protein.ABA signal may promote JA transduction.Result of JA marker genes expression showed that MYC2-induced genes VSP1 and VSP2,which are responded to wounding,have more fold change after ABA and JA treatment than JA treatment,demonstrating that defenses to insects and wounding controlled by MYC2 are enhanced by ABA signal.Taken together,this work uncovers a potential mechanism by which exogenous ABA signal affects JA-mediated defenses against biotic stress,through protein-protein interactions and regulation the protein stability of JAZs.