The JatrophaFT ortholog is a systemic signal regulating growth and flowering time

Abstract

Background: Jatropha curcas is being promoted as a new bioenergy crop in tropical and subtropical regions due to its high amount of seed oil and its potential capacity to grow on marginal land for biofuel production. However, the productivity of the plant is constrained by the unfavorable flowering time and inflorescence architecture, which render harvesting of seeds time-consuming and labor-intensive. These flowering-related traits have limited further widespread cultivation of Jatropha.Results: We identified a Jatropha curcas homolog of Flowering locus T (JcFT) and demonstrated its function by genetic complementation of the Arabidopsis ft mutant. The JcFT expression level was found to be remarkably correlated with leaf age. Overexpression of JcFT in Jatropha reduced flowering time and altered plant architecture by producing more branches. Grafting experiments suggested that the earlyflowering and alteration of plant architecture traits were graft-transmissible. We also showed that the FT-overexpressing transgenic Jatropha can be used as a root stock for grafting of scions derived from other Jatropha. Conclusion:We generated early flowering transgenic Jatropha plants that accumulate higher levels of the florigen FT. Not only early flowering but also plant growth was affected in JcFT overexpression lines. More seeds can be produced in a shorter time frame by shortening the flowering time in Jatropha, suggesting the possibility to increase seed yield by manipulating the flowering time.

An ortholog of LEAFY in Jatropha curcas regulates flowering time and floral organ development

“…Therefore, the JcLFY -overexpression transgenic lines used in this work showed a slightly early flowering, but weaker phenotype than plants overexpressing the Arabidopsis LFY gene in Arabidopsis 27 and citrus31. The early flowering phenotype of JcLFY transgenic Jatropha was also weaker than observed in studies of transgenic Jatropha plants overexpressing the florigen gene JcFT 4142, in which flower buds initiated directly from transformed callus 7 weeks after in vitro culture47. However, the JcLFY co-suppressed transgenic Jatropha plants did not exhibit late flowering (Fig.…”

“…The existence of a lengthy juvenile phase in woody species is a limiting factor for their genetic improvement, and this prevents the full domestication of many economically important woody species. Currently, only Jatropha FLOWERING LOCUS T ( JcFT )4142, and JcAP1 43 have been functionally analyzed in Jatropha . However, cloning and molecular characterization of JcLFY has not yet been reported.…”

FT and florigen long-distance flowering control in plants

“…[55 ]. Expression of Jatropha JcFT under the control of the relatively weak synthetic G10-90 promoter reduced flowering time from 8 months to 1-2 months and induced early flowering in non-transgenic scions (Figure 3).…”

Unisexual flower initiation in the monoeciousQuercus suberL., a molecular approach

“…Whichever mechanism is used to respond to different photoperiods, the main output of the interaction between the circadian clock and the light cues is the regulation of a CONSTANS -like factor that tightly control the expression of a FT- like gene, whose gene product is commonly known as the florigen (reviewed in Golembeski et al ., 2014; Song et al ., 2015). The ectopic expression or down-regulation of FT -like genes in a broad range of plant species have demonstrated that FT -like genes act as universal promoters of flowering (Endo et al 2005, Böhlenius et al 2006, Hsu et al 2006, 2011, Tränkner et al 2010, Fu et al 2014, Ye et al 2014, Freiman et al 2015, Klocko et al 2016).…”