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 H 2 O 2 and promotes H 2 O 2 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 H 2 O 2 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 H 2 O 2 signaling component PbPIP1;4 and the ABA pathways component PbNCED4 , enabling a response to drought.