Expression profiling of ABA and GA signaling cascades regulating bud dormancy in grape

Abstract Dormancy is an essential stage of development in perennial plants that allows them to tolerate against unfavorable climatic conditions. Based on RNA-seq analysis, we compared the level of transcripts related to Gibberellins (GA) and Abscisic acid (ABA) at three different dormancy stages, i.e. summer buds (C1), para -dormancy (C2), and endo -dormancy (C3). Our results revealed a prominent up-regulation of GA and ABA signaling transcripts at different dormancy stages. Most of the transcripts related to protein phosphatase 2C (PP2C) showed down-regulatory behavior during C2 vs C3. In C1 vs C3, three transcripts related to PYR/PYLs were up-regulated while in C2 vs C3, only one had expressed the low transcript level. Four (SnRK2) related transcripts had exhibited down-regulation in case of C2 vs C3. Six transcripts encoding DELLA proteins in GA signaling pathway showed down-regulation in C1 vs C3 while ten transcripts were up-regulated in case of C2 vs C3. Nine transcripts encoding GID2 proteins were up-regulated in C1 vs C3 whereas six transcripts were down-regulated in C1 vs C3, respectively. The lower ABA content was observed at C3 stage as compared to other two stages whereas GA3 content was higher at C3 stage than C2 stage. The expression profiles depicted that the transcripts related to ABA and GA signaling were involved in dormancy mechanism. Based on these results we can speculate that ABA and GA pathways act as regulatory switches to regulate grape bud dormancy.