Pyrus betulaefolia ERF3 interacts with HsfC1a to coordinately regulate aquaporin PIP1;4 and NCED4 for drought tolerance.

Environmental disasters like drought reduce agricultural output and plant growth. Redox management significantly affects plant stress responses. An earlier study found that PbPIP1;4 transports H2O2 and promotes H2O2 downstream cascade signaling to restore redox equilibrium. However, this regulatory mechanism requires additional investigation. In this search, the AP2 domain-containing transcription factor was isolated by screening Y1H from the wild pear (Pyrus betulaefolia) cDNA library, named PbERF3. The overexpression of PbERF3 in pear callus and Arabidopsis enhanced plant resistance to drought and re-established redox balance. The transcripts of the NCEDs gene were upregulated under drought stress. The drought stress-related abscisic acid (ABA) signaling pathway modulates PbERF3. PbERF3 silencing lowered drought tolerance. Furthermore, yeast 2-hybrid, luciferase, bimolecular fluorescence complementation, and co-immunoprecipitation assays verified that PbERF3 physically interacted with PbHsfC1a. The PbERF3-PbHsfC1a heterodimer coordinately bound to PbPIP1;4 and PbNCED4 promoter, therefore activating both the H2O2 and the ABA signaling pathway. This work revealed a novel PbERF3-PbHsfC1a-PbNCED4-PbPIP1;4 regulatory module, in which PbERF3 interacts with PbHsfC1a to trigger the expression of target genes. This module establishes an interaction between the H2O2 signaling component PbPIP1;4 and the ABA pathways component PbNCED4, enabling a response to drought.