Browsing by Subject "FT"

Strawberries are perennial, flowering plants of genus Fragaria, in the family Rosaceae. Woodland Strawberry (wild F.vesca) is the most widely distributed natural species in the northern hemisphere and a new promising model plant for the study of flowering in perennial plants. Classified as a seasonal flowering short day (SD) plant, wild F.vesca initiates flowering in the autumn, flowers in spring and forms fruits in summer followed by a vegetative growth phase until the next autumn. The perpetual flowering genotype Hawaii-4 flowers continuously throughout the season. Flowering is regulated by ambient signals such as photoperiod and temperature. The photoperiod x temperature interaction was found to play a vital role in flowering initiation in Fragaria. SD F.vesca can behave as a day-neutral, short day plant or non-flowering plant depending on different ambient temperature. Flower initiation takes place regardless of photoperiod when F.vesca is put at 9°C, but only flower under SD at 15°C and no flowering is observed when the ambient temperature is higher than 21°C. The experiment was designed to observe flower induction and explore the role of few flowering genes in the temperature regulation of flowering at long day (LD) condition. The expression of key flowering genes FT, SOC1 and TFL1 were analyzed in wild F.vesca and transgenic lines in F.vesca background. The results showed low temperature (11°C) promotes flowering in SD F.vesca. FT was down-regulated by 11°C and negatively correlated with flowering in F.vesca, in contrast to findings in other SD plants. SOC1 may act downstream of FT, it represses flowering in SD F.vesc and may affect vegetative growth by interacting with GA pathway. Although FT functions as an integrator gene in flowering, there may be an FT-independent pathway in SD F.vesca. SOC1 integrates signals from different pathways; it might be the candidate gene mediating signals from the thermosensary pathway. TFL1, identified as SEASONAL FLOWERING LOCUS (SFL) in SD F.vesca, represses flowering and is regulated by temperature.