Modeling And Validation Of ABA-dependent And ABA-independent Drought-resistant Gene Interaction Network In Arabidopsis Thaliana

Drought is one of the most severe abiotic factors restricting plant growth and yield.Numerous genes functioning in drought resistance are regulated by abscisic acid(ABA)-dependent and ABA-independent pathways.Despite the importance of crosstalk between the two pathways,knowledge of how they regulate each other in response to drought stress has been limited until recently.Therefore,we integrated transcriptome sequencing and network analyses to explore interplays between ABA-dependent and ABA-independent pathways responding to drought stress in Arabidopsis thaliana.Through RNA sequencing,we identified 1,612 genes that were significantly differentially expressed under drought stress.Among these differentially expressed genes(DEGs),211 ABA-dependent genes were responsive to both drought stress and ABA treatment,whereas 1,118 ABA-independent genes were specifically responsive to drought stress but not to ABA.RTFQ PCR was used to verify the gene expression level of 11 DEGs,and the results showed that generally the gene expression in RNA-seq analysis is consistent with that in RTFQ PCR analysis.Functional analysis showed that ABA-dependent DEGs were significantly enriched in expected biological processes in response to water deprivation and ABA stimulus,while ABA-independent DEGs were preferentially enriched in response to jasmonic acid(JA),salicylic acid(SA)and gibberellin(GA)stimuli.We found significantly enriched interactions between ABA-dependent and ABA-independent pathways with 32 ABA-dependent and 62 ABA-independent genes acting as core interacting components by combining network analyses.Among these putative relationships,a link between ABA and JA signaling mediated through a direct interaction of the ABA responsive elements-binding factor ABF3 with the basic helix-loop-helix transcription factor MYC2 was validated by yeast two-hybrid and bimolecular fluorescence complementation(BiFC)assays.Our study provides a reference to discover novel interactions of ABA and other hormone signals in response to drought stress.