Maize transcriptomic repertoires respond to gibberellin stimulation

Abstract

Phytohormone gibberellin (GA) serves as hub modulator of diverse biological events. Understanding the transcriptomic features of GA-mediated processes has scientific significance. The transcriptomic landscapes of cereal crops upon GA stimulation remains largely unknown. Herein, to reveal the transcriptomic changes in cereal crop maize under GA treatment, we first selected normal height and GA-sensitive maize dwarf plants from advanced backcross population for GA treatment. RNA-seq analysis discovered multiple protein-coding transcripts that were differentially expressed in GA-treated samples compared to distilled water-treated ones. Some differentially expressed transcripts, namely GA-responsive transcripts in this study, encoded the components of GA pathway, including CPS, KS, and KO enzymes for GA biosynthesis, GA2ox enzymes for GA degradation, DELLA repressors and GID1 receptor for GA signaling. A total of 214 shared GA-responsive transcripts were identified both in GA3-treated normal height and GA-sensitive dwarf samples. Shared GA-responsive transcripts were involved in GA signaling, auxin biosynthesis, ethylene response, the composition and structure of cell wall, chlorophyll biogenesis, and sugar homeostasis. In addition, the convergence and divergence in expression of shared GA-responsive transcripts were observed in GA3-treated normal height and GA-sensitive dwarf plants. Interaction network modeling indicated that some shared GA-responsive transcripts tended to be co-regulated, which increases the complexity of GA-triggered regulation at transcriptomic layer. Results presented here will extend our knowledge of GA-mediated regulatory cascade, and enhance our ability to apply hormone GA knowledge in agricultural practice.