Molecular Regulation of Temperature-Dependent Floral Induction in Tulipa gesneriana

Abstract

The vegetative-to-reproductive phase change in tulip () 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 (), 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 of expression, a tulip gene with a high similarity to Arabidopsis Gene 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 that () and () might be repressors, whereas likely 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 with being a floral repressor and being 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.

Crosstalk in the darkness: bulb vernalization activates meristem transition via circadian rhythm and photoperiodic pathway

“…Similar results were obtained for the evergreen orchardgrass, where vernalization and photoperiod genes were involved and co-expressed during meristem transition [20]. Leeggangers et al [46] reported that GO terms of photomorphogenesis, photoperiodism, response to light stimulus, and circadian rhythm were upregulated in dormant tulip bulbs during floral induction by high summer temperatures. They offered the explanation that the aboveground drying leaves may receive light or photoperiodic signals.…”

LCM‐seq reveals the crucial role of LsSOC1 in heat‐promoted bolting of lettuce (Lactuca sativa L.)

“…Similarly to LsSOC1, DOSOC1 advances flowering in Dendrobium . Nevertheless, two SOC1like genes with opposing functions were identified in Tulipa gesneriana; TgSOC1L1 is a flowering repressor and TgSOC1L2 is a flowering inducer (Leeggangers et al, 2017). Under short days, FvSOC1 overexpression inhibits flower bud formation.…”

CYCLIC NUCLEOTIDE-GATED ION CHANNELs 14 and 16 Promote Tolerance to Heat and Chilling in Rice

“…Plant growth and development is highly regulated by environmental factors including temperature. Extreme temperatures cause an array of biochemical, physiological, and morphological changes in plants and often negatively impact plant productivity (Hatfield and Prueger, 2015;Liu et al, 2016;Leeggangers et al, 2017). Developing plant varieties that are tolerant to high and low temperatures is a challenge for researchers in plant biology and agriculture (Atkinson and Porter, 1996).…”