GmFT4, a homolog of FLOWERING LOCUS T, is positively regulated by E1 and functions as a flowering repressor in soybean

PLoS One. 2014 Feb 19;9(2):e89030. doi: 10.1371/journal.pone.0089030. eCollection 2014.

Abstract

The major maturity gene E1 has the most prominent effect on flowering time and photoperiod sensitivity of soybean, but the pathway mediated by E1 is largely unknown. Here, we found the expression of GmFT4, a homolog of Flowering Locus T, was strongly up-regulated in transgenic soybean overexpressing E1, whereas expression of flowering activators, GmFT2a and GmFT5a, was suppressed. GmFT4 expression was strongly up-regulated by long days exhibiting a diurnal rhythm, but down-regulated by short days. Notably, the basal expression level of GmFT4 was elevated when transferred to continous light, whereas repressed when transferred to continuous dark. GmFT4 was primarily expressed in fully expanded leaves. Transcript abundance of GmFT4 was significantly correlated with that of functional E1, as well as flowering time phenotype in different cultivars. Overexpression of GmFT4 delayed the flowering time in transgenic Arabidopsis. Taken together, we propose that GmFT4 acts downstream of E1 and functions as a flowering repressor, and the balance of two antagonistic factors (GmFT4 vs GmFT2a/5a) determines the flowering time of soybean.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / genetics
  • Arabidopsis Proteins / genetics
  • Flowers / genetics*
  • Gene Expression Regulation, Plant
  • Molecular Sequence Data
  • Phylogeny
  • Plant Proteins / genetics*
  • Plants, Genetically Modified
  • Repressor Proteins / genetics*
  • Sequence Homology
  • Soybeans / genetics*
  • Transcription Factors / genetics*

Substances

  • Arabidopsis Proteins
  • FT protein, Arabidopsis
  • Plant Proteins
  • Repressor Proteins
  • Transcription Factors

Grant support

This work was supported by National Natural Science Foundation of China (31271742 and 31301338), Chinese Academy of Sciences (Hundred Talents Program, KZCX2-EW-303, XDA08010105), and Natural Science Foundation of Heilongjiang Province of China (ZD201120). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.