Evolution of the PEBP Gene Family in Plants: Functional Diversification in Seed Plant Evolution    

Abstract

The phosphatidyl ethanolamine-binding protein (PEBP) gene family is present in all eukaryote kingdoms, with three subfamilies identified in angiosperms (FLOWERING LOCUS T [FT], MOTHER OF FT AND TFL1 [MFT], and TERMINAL FLOWER1 [TFL1] like). In angiosperms, PEBP genes have been shown to function both as promoters and suppressors of flowering and to control plant architecture. In this study, we focus on previously uncharacterized PEBP genes from gymnosperms. Extensive database searches suggest that gymnosperms possess only two types of PEBP genes, MFT-like and a group that occupies an intermediate phylogenetic position between the FT-like and TFL1-like (FT/TFL1-like). Overexpression of Picea abies PEBP genes in Arabidopsis (Arabidopsis thaliana) suggests that the FT/TFL1-like genes (PaFTL1 and PaFTL2) code for proteins with a TFL1-like function. However, PaFTL1 and PaFTL2 also show highly divergent expression patterns. While the expression of PaFTL2 is correlated with annual growth rhythm and mainly confined to needles and vegetative and reproductive buds, the expression of PaFTL1 is largely restricted to microsporophylls of male cones. The P. abies MFT-like genes (PaMFT1 and PaMFT2) show a predominant expression during embryo development, a pattern that is also found for many MFT-like genes from angiosperms. P. abies PEBP gene expression is primarily detected in tissues undergoing physiological changes related to growth arrest and dormancy. A first duplication event resulting in two families of plant PEBP genes (MFTlike and FT/TFL1-like) seems to coincide with the evolution of seed plants, in which independent control of bud and seed dormancy was required, and the second duplication resulting in the FT-like and TFL1-like clades probably coincided with the evolution of angiosperms.

Mutation inTERMINAL FLOWER1Reverses the Photoperiodic Requirement for Flowering in the Wild StrawberryFragaria vesca

“…Natural variation in TFL1 homologs has been important for the domestication and crop improvement of several annual crops (Turnbull, 2011), and our study shows the importance of TFL1 in the perennial context. As TFL1 homologs exist in all angiosperms (Karlgren et al, 2011) and their function as floral repressors is conserved between plant families (Shannon and Meeks-Wagner, 1991;Foucher et al, 2003;Kotoda et al, 2006;Mohamed et al, 2010;Imamura et al, 2011), our findings are of general significance for understanding the regulation of flowering-and perennial-specific traits in a wide range of economically important crops.…”

The Norway spruce genome sequence and conifer genome evolution

“…It has been suggested that gymnosperms lack orthologues of FT genes, instead containing a group of FT/TFL1-like genes that probably act as flowering repressors 36,37 . We identified four putative FT/TFL1-like genes in the P.abies 1.0 genome that have not been previously described and confirmed that the genome does indeed lack FT-like genes (Supplementary Information 5.1).…”

Transcriptome Profiling of Tiller Buds Provides New Insights into PhyB Regulation of Tillering and Indeterminate Growth in Sorghum

“…Expression of TFL1 (SbCN2) was approximately 30-fold higher in buds of phyB-1 plants at 6 DAP and approximately 80-fold higher by 8 DAP. TFL1 is a member of the phosphatidyl ethanolamine-binding protein gene family, and members of this family in Arabidopsis include FLOWERING LOCUS T (FT), MOTHER OF FT AND TFL1 (MFT), and CENTRORADIALIS homolog (ATC), genes that activate flowering (Karlgren et al, 2011). TFL1-like genes encode proteins that are expressed in meristems and bind to leaf-derived FT to prevent FT-induced flowering (Lifschitz et al, 2014).…”