title: Molecular Regulation of Temperature-Dependent Floral Induction inTulipa gesneriana.
abstract: The vegetative-to-reproductive phase change in tulip (Tulipa gesneriana) is promoted by increasing temperatures during spring. The warm winters of recent years interfere with this process and are calling for new adapted cultivars. A better understanding of the underlying molecular mechanisms would be of help, but unlike the model plant Arabidopsis (Arabidopsis thaliana), very little is known about floral induction in tulip. To shed light on the gene regulatory network controlling flowering in tulip, RNA sequencing was performed on meristem-enriched tissue collected under two contrasting temperature conditions, low and high. The start of reproductive development correlated with rounding of the shoot apical meristem and induction ofTGSQAexpression, a tulip gene with a high similarity to ArabidopsisAPETALA1Gene Ontology enrichment analysis of differentially expressed genes showed the overrepresentation of genes potentially involved in floral induction, bulb maturation, and dormancy establishment. Expression analysis revealed thatTERMINAL FLOWER1(TgTFL1) andSUPPRESSOR OF OVEREXPRESSION OF CONSTANS1-like1(TgSOC1-like1) might be repressors, whereasTgSOC1-like2likely is an activator, of flowering. Subsequently, the flowering time-associated expression of eight potential flowering time genes was confirmed in three tulip cultivars grown in the field. Additionally, heterologous functional analyses in Arabidopsis resulted in flowering time phenotypes in line withTgTFL1being a floral repressor andTgSOC1-like2being a floral activator in tulip. Taken together, we have shown that long before morphological changes occur in the shoot apical meristem, the expression of floral repressors in tulip is suppressed by increased ambient temperatures, leading either directly or indirectly to the activation of potential flowering activators shortly before the commencement of the phase change.
authors.affiliation: Wageningen Seed Laboratory, Laboratory of Plant Physiology, Wageningen University and Research, 6708PB Wageningen, The Netherlands.
authors.forename: Hendrika A C F
authors.initials: HA
authors.lastname: Leeggangers
authors.affiliation: Wageningen Seed Laboratory, Laboratory of Plant Physiology, Wageningen University and Research, 6708PB Wageningen, The Netherlands.
authors.forename: Harm
authors.identifier: 0000-0002-9167-4945
authors.initials: H
authors.lastname: Nijveen
authors.affiliation: Wageningen Seed Laboratory, Laboratory of Plant Physiology, Wageningen University and Research, 6708PB Wageningen, The Netherlands.
authors.forename: Judit Nadal
authors.initials: JN
authors.lastname: Bigas
authors.affiliation: Wageningen Seed Laboratory, Laboratory of Plant Physiology, Wageningen University and Research, 6708PB Wageningen, The Netherlands.
authors.forename: Henk W M
authors.identifier: 0000-0002-6743-583X
authors.initials: HW
authors.lastname: Hilhorst
authors.affiliation: Wageningen Seed Laboratory, Laboratory of Plant Physiology, Wageningen University and Research, 6708PB Wageningen, The Netherlands richard.immink@wur.nl.
authors.forename: Richard G H
authors.identifier: 0000-0002-0182-4138
authors.initials: RG
authors.lastname: Immink
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D000595:Amino Acid Sequence; D035264:Flowers / Q000235:genetics* / Q000502:physiology; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant; D063990:Gene Ontology; D053263:Gene Regulatory Networks; D017343:Genes, Plant / Q000235:genetics; D018519:Meristem / Q000235:genetics / Q000502:physiology; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D012098:Reproduction / Q000235:genetics / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012621:Seasons; D017423:Sequence Analysis, RNA / Q000379:methods; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D013997:Time Factors; D031447:Tulipa / Q000235:genetics* / Q000502:physiology
chemical_list: D010940:Plant Proteins