The transcription factor StTINY3 enhances cold-induced sweetening resistance by coordinating starch resynthesis and sucrose hydrolysis in potato. (2nd May 2022)

• Record Type: Journal Article
• Authors: Shi, Weiling; Ma, Qiuqin; Yin, Wang; Liu, Tiantian; Song, Yuhao; Chen, Yuanya; Song, Linjin; Sun, Hui; Hu, Shuting; Liu, Tengfei; Jiang, Rui; Lv, Dianqiu; Song, Botao; Wang, Jichun; Liu, Xun
• Editors: Beckles, Diane
• Is Part Of: Journal of experimental botany. Volume 73:Number 14(2022)
• Page Start: 4968
• Page End: 4980
• Publication Date: 2022-05-02
• Subjects: Cold-induced sweetening resistance -- potato -- StAGPaseL3 -- StInvInh2 -- StTINY3 -- transcriptional regulation; Botany -- Periodicals; Botany, Experimental -- Periodicals; Plant physiology -- Periodicals; 580
• DOI: 10.1093/jxb/erac171
• Languages: English
• ISSNs: 0022-0957

Abstract

Abstract : StTINY3 positively regulates StInvInh2 to inhibit the sucrose hydrolysis pathway and StAGPaseL3, StG6PT2, and StPGM1 to promote increases in flux through the starch resynthesis pathway. Abstract: The accumulation of reducing sugars in cold-stored tubers, known as cold-induced sweetening (CIS), negatively affects potato processing quality. The starch to sugar interconversion pathways that are altered in cold-stored CIS tubers have been elucidated, but the mechanism that regulates them remains largely unknown. This study identified a CBF/DREB transcription factor (StTINY3) that enhances CIS resistance by both activating starch biosynthesis and repressing the hydrolysis of sucrose to reducing sugars in detached cold-stored tubers. Silencing StTINY3 in a CIS-resistant genotype decreased CIS resistance, while overexpressing StTINY3 in a CIS-sensitive genotype increased CIS resistance, and altering StTINY3 expression was associated with expression changes in starch resynthesis-related genes. We showed first that overexpressing StTINY3 inhibited sucrose hydrolysis by enhancing expression of the invertase inhibitor gene StInvInh2, and second that StTINY3 promoted starch resynthesis by up-regulating a large subunit of the ADP-glucose pyrophosphorylase gene StAGPaseL3, and the glucose-6-phosphate transporter gene StG6PT2 . Using electrophoretic mobility shift assays, we revealed that StTINY3 is a nuclear-localized transcriptional activator that directly binds to the dehydration-responsive element/CRT cis -element in the promoters of StInvInh2 and StAGPaseL3 . Taken together, these findings established that StTINY3 influences CIS resistance in cold-stored tubers by coordinately modulating the starch to sugar interconversion pathways and is a good target for improving potato processing quality.