Proteins from the FLOWERING LOCUS T-like subclade of the PEBP family act antagonistically to regulate floral initiation in tobacco.
Flowering is an important agronomic trait that often depends on the integration of photoperiod, vernalization, gibberellin and/or autonomous signaling pathways by regulatory proteins such as FLOWERING LOCUS T (FT), a member of the phosphatidylethanolamine-binding protein (PEBP) family. Six PEBP family proteins control flowering in the model plant Arabidopsis thaliana, and their regulatory functions are well established, but variation in the number and structural diversity of PEBPs in different species means their precise functions must be determined on a case-by-case basis. We isolated four novel FT-like genes from Nicotiana tabacum (tobacco), and determined their expression profiles in wild-type plants and their overexpression phenotypes in transgenic plants. We found that all four genes were expressed in leaves under short-day conditions, and at least NtFT3 expression was restricted to phloem companion cells. We also found that the NtFT1, NtFT2 and NtFT3 proteins are floral inhibitors (atypical for FT-like proteins), whereas only NtFT4 is a floral inducer. We were unable to detect the expression of these genes under long-day conditions, suggesting that all four tobacco FT-like proteins may control flowering in response to short days. Phylogenetic analysis of PEBP family proteins and their functions in different solanaceous species confirmed that gene duplication and divergence within the FT-like clade has led to the evolution of antagonistic regulators that may help to fine-tune floral initiation in response to environmental cues.
Fraunhofer Institut für Molekularbiologie und Angewandte Ökologie, Hindenburgplatz 55, 48143 Münster, GermanyWestfälische Wilhelms-Universität Münster, Institut für Biologie und Biotechnologie der Pflanzen, Hindenburgplatz 55, 48143 Münster, GermanyFraunhofer Institut für Molekularbiologie und Angewandte Ökologie, Forckenbeckstraße 6, 52074 Aachen, GermanyDepartment of Biological Sciences, University of Warwick, Coventry CV4 7AL, UK.
Lena
L
Harig
Farina A
FA
Beinecke
Jan
J
Oltmanns
Jost
J
Muth
Oliver
O
Müller
Boris
B
Rüping
Richard M
RM
Twyman
Rainer
R
Fischer
Dirk
D
Prüfer
Gundula A
GA
Noll
D001483:Base Sequence; D035264:Flowers / Q000235:genetics / Q000254:growth & development* / Q000502:physiology / Q000528:radiation effects; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000378:metabolism; D008027:Light; D008969:Molecular Sequence Data; D010641:Phenotype; D052585:Phloem / Q000235:genetics / Q000254:growth & development / Q000502:physiology / Q000528:radiation effects; D049488:Phosphatidylethanolamine Binding Protein / Q000235:genetics / Q000378:metabolism*; D017440:Photoperiod; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000502:physiology / Q000528:radiation effects; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D013997:Time Factors; D014026:Nicotiana / Q000235:genetics / Q000254:growth & development* / Q000502:physiology / Q000528:radiation effects
D005875:Gibberellins; D049488:Phosphatidylethanolamine Binding Protein; D010937:Plant Growth Regulators; D010940:Plant Proteins