AtERF60, negatively regulates ABR1 to modulate basal resistance response in Arabidopsis

Abstract

APETALA2 (AP2)/ERF family transcription factors (TFs) contribute an important function against various external cues. Our study reports AtERF60, an AP2/ERF TF, which plays a key role in regulating the ABR1 gene, leading to an altered basal resistance response in Arabidopsis. AtERF60 is induced in response to drought, salt, abscisic acid (ABA), salicylic acid (SA), and bacterial pathogen PstDC3000 infection. AtERF60 interacts with DEHYDRATION RESPONSE ELEMENTS and GCC box, indicating its ability to regulate multiple responses. The overexpressing lines of AtERF60 demonstrated increased resistance to PstDC3000 infection, whereas erf60 mutant lines showed increased susceptibility. Complementation of the erf60 mutant background exhibits no significant difference towards PstDC3000 infection compared with the WT Col-0. Microarray and qRT-PCR analysis of overexpression and mutant lines indicated that AtERF60 regulates stress-inducible genes. The induction of these differentially expressed transcripts was significantly increased in erf60 mutant lines, whereas it was reversed in wild-type lines when AtERF60 was complemented. ABR1 was one of the differentially expressed transcripts, and we discovered that AtERF60 interacts with the DRE cis-elements in the ABR1 promoter. Further, qRT-PCR expression analysis after infection with PstDC3000 in AtERF60-OX, erf60 and its complementation background suggest that the mutation in AtERF60 upregulates ABR1 activity, leading to the enhanced susceptibility towards PstDC3000. Conversely, AtERF60 overexpression suppresses ABR1 activity, strengthening the basal resistance responses of Arabidopsis.