The Effect Of ABRE BINDING FACTOR 4-Mediated FYVE1 On Salt Stress Tolerance In Arabidopsis

FYVE1 encodes a protein that is localized to the peripheral membrane of late endosomal compartments,and is involved in the regulation of multivesicular/prevacuolar compartment protein sorting.It was found that FYVE1 attenuates ABA signaling through degrading ABA receptors PYR1 and PYL4 by ESCRT pathway,and also interacts with transcription factors ABF4 and ABI5 to transcriptionally inhibit ABA signaling pathway by reducing their binding to the cis-regulatory sequences of their downstream genes in Arabidopsis thaliana.However,the mechanisms underlying the transcriptional regulation of FYVE1 and its biological function in salt stress are largely unknown.In this paper,the research results are as follows:(1)Analysis of FYVE1 gene expression showed that the expression of FYVE1 gene was significantly induced under salt stress,indicating that FYVE1 may play a role in salt stress.(2)Using the method of loss/gain-of-function of gene,we found that fyve1 knockdown mutants showed tolerance to salt stress,while the over expression plant FYVE1-OE showed sensitivity to salt stress,suggesting that FYVE1 could negatively regulate salt stress tolerance in Arabisopsis.(3)By detecting the expression of related genes in fyve1 mutant and FYVE1-overexpression plants,we found that expression of many genes related to ABA signaling pathway had significant changes in both plants,suggesting that FYVE1-mediated salt stress tolerance was related to ABA signaling pathway.(4)Further studies showed that ABF4 could bind to the promoter of FYVE1 gene and activate its expression.(5)In addition,it was proved that FYVE1 could interact with all ABA PYR/PYLs receptors and promote their degradation by yeast two hybrid and Bi FC methods.Therefore,these results showed that FYVE1 negatively modulates salt stress tolerance in Arabidopsis via a negative feedback loop.