Temporal transcriptional networks coordinate ABA-GA-JA crosstalk during cold-induced modulation of seed dormancy and germination in wheat (Triticum aestivum L.).
Using a combination of genome-wide transcriptome, targeted hormonome and pharmacological approaches, this study showed that temporally resolved transcriptional regulatory networks integrating hormonal crosstalk underlie cold-induced modulation of seed dormancy and germination in wheat. Gene homoeologues (GHs) differentially expressed between cold-treated and untreated dormant seeds imbibed at optimal temperature (OT, 22°C) as well as between the same seed samples imbibed in cold and at OT represent distinct biological processes (BPs), indicating the role of coordinated activation/repression specific BPs in cold-mediated alteration of dormancy and germination. Our analyses highlighted that jasmonate (JA)-gibberellin (GA) synergism and JA-abscisic acid (ABA) or GA-ABA antagonism play roles in regulating dormancy release during imbibition of cold-treated dormant seeds at OT. The repression of germination in dormant seeds imbibed in cold compared to those imbibed at OT is associated with synergistic repression of seed sensitivity to JA and GA and activation of its sensitivity to ABA. Specific members of TaWRKY, TabHLH, TaMYB, TaNAC, TaERF, TaARF and TabZIP transcription factor families establish the transcriptional network involving specific GA, ABA and JA metabolism and signaling GHs and thereby the ABA-GA-JA crosstalk that enhance dormancy release during imbibition at OT after cold treatment and inhibition of germination during cold treatment.