Expressional analysis of FT and CEN genes in a continuously flowering highbush blueberry 'Blue Muffin'
The production of blueberries (Vaccinium spp.) has increased rapidly because of their appealing taste and health benefits. Most blueberry cultivars bloom once a year; thus, their harvest period is limited. Therefore, there is a long off-season from autumn to spring when fresh blueberries are not available in the Japanese market. Blue Muffin, a high-bush blueberry cultivar, flowers continuously in the temperate zone. Although this unique trait might contribute to shorten the off-season, the phenology and its molecular regulation remains to be characterized. We cultivated Blue Muffin at two sites with different climates; Kyoto, Japan (temperate zone) and Taipei, Taiwan (subtropics), and compared phenological characters such as flowering, leaf shedding, and dormancy, for several seasons. In the temperate Kyoto climate, Blue Muffin started to bloom in early April, and also bloomed from July to December when it shed leaves after exposure to low temperatures. In the Taipei climate, on the other hand, Blue Muffin showed evergreen character and bloomed continuously on the current-season shoots after flushing through winter. These results suggested that Blue Muffin has a unique genetic mechanism for flower initiation that is less sensitive to a long photoperiod and high temperature, which usually stop flower initiation in blueberry. In Arabidopsis, the roles of flowering promoter FLOWERING LOCUS T (FT) and flowering repressors such as TERMINAL FLOWER1 (TFL1)/CENTRORADIALIS (CEN) have been well documented. In this study, seasonal expression changes of two important flowering-related genes, FT and CEN, were investigated by quantitative reverse transcripts polymerase chain reaction. The results showed that VcFT and VcCEN expression levels increased and decreased, respectively, earlier in Blue Muffin than in other normal-flowering highbush cultivars. The earlier seasonal changes of these two genes may contribute to continuous flowering of Blue Muffin.
Omori, M., Yamane, H., Li, K.-T., Matsuzaki, R., Ebihara, S., Li, T.-S. and Tao, R. (2020). Expressional analysis of FT and CEN genes in a continuously flowering highbush blueberry 'Blue Muffin'. Acta Hortic. 1280, 197-202
blueberry, CEN, flowering, FT, off-season fruit production, quantitative PCR