PEBP Genes Research Articles

Three FLOWERING LOCUS T-like genes function as potential florigens and mediate photoperiod response in sorghum.

Sorghum is a typical short-day (SD) plant and its use in grain or biomass production in temperate regions depends on its flowering time control, but the underlying molecular mechanism of floral transition in sorghum is poorly understood. Here we characterized sorghum FLOWERING LOCUS T (SbFT) genes to establish a molecular road map for mechanistic understanding. Out of 19 PEBP genes, SbFT1, SbFT8 and SbFT10 were identified as potential candidates for encoding florigens using multiple approaches. Phylogenetic analysis revealed that SbFT1 clusters with the rice Hd3a subclade, while SbFT8 and SbFT10 cluster with the maize ZCN8 subclade. These three genes are expressed in the leaf at the floral transition initiation stage, expressed early in grain sorghum genotypes but late in sweet and forage sorghum genotypes, induced by SD treatment in photoperiod-sensitive genotypes, cooperatively repressed by the classical sorghum maturity loci, interact with sorghum 14-3-3 proteins and activate flowering in transgenic Arabidopsis plants, suggesting florigenic potential in sorghum. SD induction of these three genes in sensitive genotypes is fully reversed by 1 wk of long-day treatment, and yet, some aspects of the SD treatment may still make a small contribution to flowering in long days, indicating a complex photoperiod response mediated by SbFT genes.

Cloning and Expression Analysis of GbMFT1 Gene in Gossypium barbadense L．

Angiosperm genes sharing a conserved phosphatidylethanolamine-binding(PEBP) domain have been shown to be involved in the control of flowering time.The family is divided into three subfamilies,FT-like,TFL1-like and MFT-like.Evolution analysis showed that MOTHER OF FT AND TFL1(MFT) is the ancestral form of all PEBP genes in plant;however the exact fuction of MFT is still unknown.One MFT-like homolog,designated GbMFT1,was isolated from Gossypium barbadense L.cv.Xinhai 14 using RT-PCR and RACE methods.The open reading frame of GbMFT1 is 528 bp in length,which encodes a putative protein of 175 amino acids.GbMFT1 gene has a PEBP conserved motif.In consistency with almost all MFT-like proteins,GbMFT1 has a conserved proline residue near the C-terminus.Phylogenetic analysis revealed that GbMFT1 has high sequence similarities with VvMFT and SP2G and they belong to the same clade.The result of qRT-PCR assay indicated that GbMFT1 expressed in different tissues of cotton,with a maximum expression in petal,and in different developmental stages of fibre,especially in two-day ovule and nine-day fibre.Semiquantitative RT-PCR assay indicated that GbMFT1 had a high level of transcription at the beginning of seed germination.Exogenous abscisic acid(ABA) of different concentrations resulted in no significant change in GbMFT1 expression in germinating seeds,indicating that the expression of this gene is not regulated by ABA.

Phylogenomic Analysis of the PEBP Gene Family in Cereals

The TFL1 and FT genes, which are key genes in the control of flowering time in Arabidopsis thaliana, belong to a small multigene family characterized by a specific phosphatidylethanolamine-binding protein domain, termed the PEBP gene family. Several PEBP genes are found in dicots and monocots, and act on the control of flowering time. We investigated the evolution of the PEBP gene family in cereals. First, taking advantage of the complete rice genome sequence and EST databases, we found 19 PEBP genes in this species, 6 of which were not previously described. Ten genes correspond to five pairs of paralogs mapped on known duplicated regions of the rice genome. Phylogenetic analysis of Arabidopsis and rice genes indicates that the PEBP gene family consists of three main homology classes (the so-called TFL1-LIKE, MFT-LIKE, and FT-LIKE subfamilies), in which gene duplication and/or loss occurred independently in Arabidopsis and rice. Second, phylogenetic analyses of genomic and EST sequences from five cereal species indicate that the three subfamilies of PEBP genes have been conserved in cereals. The tree structure suggests that the ancestral grass genome had at least two MFT-like genes, two TFL1-like genes, and eight FT-like genes. A phylogenomic approach leads to some hypotheses about conservation of gene function within the subfamilies.