Sucrose Promotes Strawberry Fruit Ripening by Stimulation of Abscisic Acid Biosynthesis

The interaction of sugar with ABA plays an important role in many aspects of plant growth and development. Although glucose is reported to act as a signal molecular to promote abscisic acid (ABA) biosynthesis, whether sucrose can also serve as a signal molecule involved in ABA biosynthesis is yet unclear. Here, we showed that soluble sugars, especially sucrose, could accelerate strawberry fruit ripening both In vivo and In vitro. Based on analyses of ABA levels and transcripts of both 9-cisepoxycarotenoid dioxygenase 1 (FaNCED1) and ABA glucosidase 1 (FaBG1) genes in developmental strawberry fruit, we found that ABA accumulation was mainly attributed to the FaNCED1 transcripts. A fruit-tissue sucrose-incubation test indicated that sucrose could promote both FaNCED1 and FaBG1 transcripts evidenced by real-time PCR and SqRT-PCR. In conclusion, the main results gained from the present study suggested that sucrose might serve as a signal molecule to promote the mRNA expression levels of FaNCED1 and plays an important role in ABA accumulation and strawberry fruit ripening.