Comparative transcriptome analysis of flower bud transition and functional characterization of EjAGL17 involved in regulating floral initiation in loquat

PLoS One. 2020 Oct 8;15(10):e0239382. doi: 10.1371/journal.pone.0239382. eCollection 2020.

Abstract

Floral initiation plays a critical role for reproductive success in plants, especially fruit trees. However, little information is known on the mechanism of the initiation in loquat (Eriobotrya japonica Lindl.). Here, we used transcriptomic, expression and functional analysis to investigate the candidate genes in floral initiation in loquat. Comparative transcriptome analysis showed differentially expressed genes (DEGs) were mainly enriched in the metabolic pathways of plant hormone signal transduction. The DEGs were mainly involved in the gibberellin, auxin, cytokinin, abscisic acid, salicylic acid and ethylene signaling pathways. Meanwhile, some transcription factors, including MADS-box (MCM1, AGAMOUS, DEFICIENS and SRF), MYB (Myeloblastosis), TCP (TEOSINTE BRANCHED 1, CYCLOIDEA and PCF1), WOX (WUSCHEL-related homeobox) and WRKY (WRKY DNA-binding protein), were significantly differentially expressed. Among these key DEGs, we confirmed that an AGL17 ortholog EjAGL17 was significantly upregulated at the flower bud transition stage. Phylogenetic tree analysis revealed that EjAGL17 was grouped into an AGL17 clade of MADS-box transcription factors. Protein sequence alignment showed that EjAGL17 included a distinctive C-terminal domain. Subcellular localization of EjAGL17 was found only in the nucleus. Expression levels of EjAGL17 reached the highest at the development stage of flower bud transition. Moreover, ectopic expression of EjAGL17 in Arabidopsis significantly exhibited early flowering. Our study provides abundant resources of candidate genes for studying the mechanisms underlying the floral initiation in loquat and other Rosaceae species.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Eriobotrya / cytology
  • Eriobotrya / genetics*
  • Eriobotrya / growth & development*
  • Eriobotrya / metabolism
  • Flowers / genetics*
  • Flowers / growth & development*
  • Gene Expression Profiling*
  • Phylogeny
  • Plant Growth Regulators / metabolism
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Protein Transport
  • Signal Transduction

Substances

  • Plant Growth Regulators
  • Plant Proteins

Grants and funding

This work was funded by Natural Science Foundation of China (No. 31701876) to D.W., National Key R&D Program of China (2019YFD1000902) to Q.H., Fundamental Research Funds for the Central Universities (XDJK2019AA001 and XDJK2020B058). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.