Sucrose functions as a signal involved in the regulation of strawberry fruit development and ripening

Abstract

Summary Fleshy fruits are classically divided into climacteric and nonclimacteric types. It has long been thought that the ripening of climacteric and nonclimacteric fruits is regulated by ethylene and abscisic acid (ABA), respectively. Here, we report that sucrose functions as a signal in the ripening of strawberry (Fragaria × ananassa), a nonclimacteric fruit. Pharmacological experiments, as well as gain‐ and loss‐of‐function studies, were performed to demonstrate the critical role of sucrose in the regulation of fruit ripening. Fruit growth and development were closely correlated with a change in sucrose content. Exogenous sucrose and its nonmetabolizable analog, turanose, induced ABA accumulation in fruit and accelerated dramatically fruit ripening. A set of sucrose transporters, FaSUT1–7, was identified and characterized, among which FaSUT1 was found to be a major component responsible for sucrose accumulation during fruit development. RNA interference‐induced silencing of FaSUT1 led to a decrease in both sucrose and ABA content, and arrested fruit ripening. By contrast, overexpression of FaSUT1 led to an increase in both sucrose and ABA content, and accelerated fruit ripening. In conclusion, this study demonstrates that sucrose is an important signal in the regulation of strawberry fruit ripening.

Increased Sucrose Accumulation Regulates Iron-Deficiency Responses by Promoting Auxin Signaling in Arabidopsis Plants

“…However, recently, several studies showed that Suc also functions as a signaling molecule involved in regulation of various physiological processes in plants such as root growth, fruit development and ripening, and hypocotyl elongation (Kircher and Schopfer, 2012;Lilley et al, 2012;Jia et al, 2013;Ruan, 2014). In this study, we found that Fe deficiency-induced root FCR activity and expression of FRO2 and IRT1 were significantly further up-regulated by exogenous Suc ( Fig.…”

SUCROSE NONFERMENTING1-RELATED PROTEIN KINASE2.6, an Ortholog of OPEN STOMATA1, Is a Negative Regulator of Strawberry Fruit Development and Ripening

“…2) suggests that FaSnRK2.6 is an important regulator of strawberry fruit development and ripening. To test this possibility, we performed loss-and gain-of-function experiments using transient overexpression (OE) and RNA interference (RNAi) techniques (Jia et al, 2013b). As shown in Figure 4A, FaSnRK2.6-OE resulted in a more than 4-fold increase in the level of FaSnRK2.6 transcript, whereas FaSnRK2.6-RNAi resulted in a dramatic decrease in FaSnRK2.6 transcript level.…”

“…Expression of FaSnRK2.6 in Response to Internal Signals As ABA and Suc have been identified as internal signals that control strawberry fruit development and ripening (Jia et al, , 2013b, we examined the expression of FaSnRK2.6 in response to ABA and Suc stimuli in fruits. As shown in Figure 3A, the level of FaSnRK2.6 expression declined upon ABA treatment in a concentrationdependent manner.…”

“…The cDNA was cloned into the HindIII and BamHI restriction sites of the plant expression vector pBI121, generating the proFaSnRK2.6-GUS construct. The constructs were introduced into A. tumefaciens strain AGL0, and the A. tumefaciens was infiltrated into fruits at 18 DPA (Jia et al, 2013b). After 6 d, the fruits were treated with GUS solution (Gallagher, 1992).…”

“…When the culture reached an optical density at 600 nm of approximately 0.1, A. tumefaciens cells were harvested and resuspended in infection buffer (10 mM MgCl 2 , 10 mM MES, pH 5.6, and 200 mM acetosyringone) and shaken for 2 h at room temperature before being used for infiltration. For transfection, attached fruits with basically identical sizes and shapes at 18 DPA were selected, and the A. tumefaciens suspension was evenly injected into the fruits with a syringe until the whole fruit became hygrophanous (Jia et al, 2013b). The transfections were carried out in different batches according to different experimental aims, and in each batch, 40 fruits were injected, with 20 fruits being transformed with FaSnRK2.6-RNAi or FaSnRK2.6-OE and the other 20 used as the control (i.e.…”