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Assessment of vase quality and transcriptional regulation of sucrose transporter and invertase genes in cut peony (Paeonia lactiflora ‘Yang Fei Chu Yu’) treated by exogenous sucrose

Xue, Jingqi, Tang, Ye, Wang, Shunli, Yang, Ruowen, Xue, Yuqian, Wu, Chaohai, Zhang, Xiuxin
Postharvest biology and technology 2018 v.143 pp. 92-101
Paeonia lactiflora, beta-fructofuranosidase, corolla, databases, fructose, gene expression, genes, glucose, osmotic pressure, quantitative polymerase chain reaction, reverse transcriptase polymerase chain reaction, sucrose, transcription (genetics), vacuoles, vase life, water uptake
Cut peonies (Paeonia lactiflora Pall.) have become increasingly popular worldwide in recent years. However, the limited vase life and often poor vase quality have negatively affected the commercial development of this ornamental flower. In this study, 20 g L−1 sucrose was added to the vase solution of cut peony (‘Yang Fei Chu Yu’) to better understand the effect of sucrose on the vase quality. The results showed that sucrose treatment increased the number of days during which the flowers were fully opened by approximately 1.3 d, whereas treatment effects on the opening process were limited. Sucrose treatment delayed the decrease in flower fresh weight and sucrose concentration of the petals, while increasing glucose and fructose concentrations. Two sucrose transporter (SUT) genes, PlSUT1 and PlSUT2, and five invertase (INV) genes, PlCWIN1, PlVIN1, PlCIN1, PlCIN2 and PlCIN3, were isolated from a peony transcriptional database. Gene expression by RT-qPCR showed that both PlSUT2 and PlSUT4 were induced by sucrose treatment, indicating their putative role in transporting sucrose from the vase solution to the flowers. Among the five INVs, the expression of PlCWIN1 was greater in sucrose-treated flowers than in the controls from day 3 to the end of the vase period, indicating its possible role in increasing the number of days when the flowers were fully opened. The expression of PlVIN1 decreased in control flowers, but was delayed by sucrose treatment, especially on day 3. Since PlVIN1 was predicted to be located in the vacuole, it is highly possible that the expression of PlVIN1 helped to increase the vacuolar osmotic potential through the accumulation of glucose and fructose, thereby increasing water uptake for maintenance of flowers at the fully opened stage. Among the three PlCINs, the expression of PlCIN2 was much higher in sucrose-treated than in the control flowers throughout the vase period, indicating its major role in improving vase quality through sucrose treatment. Our study indicates that both SUTs and INVs are involved in maintaining the vase quality of cut peony flowers.