Wheat gibberellin oxidase genes and their functions in regulating tillering

PeerJ. 2023 Sep 1:11:e15924. doi: 10.7717/peerj.15924. eCollection 2023.

Abstract

Multiple genetic factors control tillering, a key agronomy trait for wheat (Triticum aestivum L.) yield. Previously, we reported a dwarf-monoculm mutant (dmc) derived from wheat cultivar Guomai 301, and found that the contents of gibberellic acid 3 (GA3) in the tiller primordia of dmc were significantly higher. Transcriptome analysis indicated that some wheat gibberellin oxidase (TaGAox) genes TaGA20ox-A2, TaGA20ox-B2, TaGA3ox-A2, TaGA20ox-A4, TaGA2ox-A10 and TaGA2ox-B10 were differentially expressed in dmc. Therefore, this study systematically analyzed the roles of gibberellin oxidase genes during wheat tillering. A total of 63 TaGAox genes were identified by whole genome analysis. The TaGAoxs were clustered to four subfamilies, GA20oxs, GA2oxs, GA3oxs and GA7oxs, including seven subgroups based on their protein structures. The promoter regions of TaGAox genes contain a large number of cis-acting elements closely related to hormone, plant growth and development, light, and abiotic stress responses. Segmental duplication events played a major role in TaGAoxs expansion. Compared to Arabidopsis, the gene collinearity degrees of the GAoxs were significantly higher among wheat, rice and maize. TaGAox genes showed tissue-specific expression patterns. The expressions of TaGAox genes (TaGA20ox-B2, TaGA7ox-A1, TaGA2ox10 and TaGA3ox-A2) were significantly affected by exogenous GA3 applications, which also significantly promoted tillering of Guomai 301, but didn't promote dmc. TaGA7ox-A1 overexpression transgenic wheat lines were obtained by Agrobacterium mediated transformation. Genomic PCR and first-generation sequencing demonstrated that the gene was integrated into the wheat genome. Association analysis of TaGA7ox-A1 expression level and tiller number per plant demonstrated that the tillering capacities of some TaGA7ox-A1 transgenic lines were increased. These data demonstrated that some TaGAoxs as well as GA signaling were involved in regulating wheat tillering, but the GA signaling pathway was disturbed in dmc. This study provided valuable clues for functional characterization of GAox genes in wheat.

Keywords: Expression profiles; Gene transformation; Gibberellin (GA); Gibberellin oxidase (GAox); Tillering; Wheat (Triticum aestivum L.).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agriculture
  • Agrobacterium / genetics
  • Amino Acid Motifs / genetics
  • Arabidopsis
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant / drug effects
  • Gibberellins / pharmacology
  • Mixed Function Oxygenases* / genetics
  • Mixed Function Oxygenases* / metabolism
  • Oxidoreductases* / genetics
  • Oxidoreductases* / metabolism
  • Phylogeny
  • Plant Growth Regulators / pharmacology
  • Plant Proteins* / genetics
  • Plant Proteins* / metabolism
  • Promoter Regions, Genetic / genetics
  • Triticum* / classification
  • Triticum* / enzymology
  • Triticum* / genetics

Substances

  • Gibberellins
  • Oxidoreductases
  • Mixed Function Oxygenases
  • Plant Proteins
  • gibberellic acid
  • Plant Growth Regulators

Grants and funding

This study was supported by the National Natural Science foundation of China (NSFC, 32171972), and the Internal Foundation of National Key Laboratory of Crop Science on Wheat and Maize (SKL2022ZZ06). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.