Abstract
Potato tuber dormancy is critical for the post-harvest quality. Snakin/Gibberellic Acid Stimulated in Arabidopsis (GASA) family genes are involved in the plants’ defense against pathogens and in growth and development, but the effect of Snakin-2 (SN2) on tuber dormancy and sprouting is largely unknown. In this study, a transgenic approach was applied to manipulate the expression level of SN2 in tubers, and it demonstrated that StSN2 significantly controlled tuber sprouting, and silencing StSN2 resulted in a release of dormancy and overexpressing tubers showed a longer dormant period than that of the control. Further analyses revealed that the decrease expression level accelerated skin cracking and water loss. Metabolite analyses revealed that StSN2 significantly down-regulated the accumulation of lignin precursors in the periderm, and the change of lignin content was documented, a finding which was consistent with the precursors’ level. Subsequently, proteomics found that cinnamyl alcohol dehydrogenase (CAD), caffeic acid O-methyltransferase (COMT) and peroxidase (Prx), the key proteins for lignin synthesis, were significantly up-regulated in silencing lines, and gene expression and enzyme activity analyses also supported this effect. Interestingly, we found that StSN2 physically interacts with three peroxidases catalyzing the oxidation and polymerization of lignin. In addition, SN2 altered the hydrogen peroxide (H2O2) content and the activities of superoxide dismutase (SOD) and catalase (CAT). These results suggest that StSN2 negatively regulates lignin biosynthesis and H2O2 accumulation, and ultimately inhibits the sprouting of potato tubers.
Highlights
Potato (Solanum tuberosum L.) is the third most important food and vegetable crop in the world, with wide adaptability, high yield and rich nutrition [1]
The potato industry is facing a serious problem regarding the inappropriate transition from dormancy to sprouting, which leads to the decline of tuber quality and marketability, and seriously affects the production, consumption and sales [1,2,3]
OE27 and OE27 vs. WT), and the results indicated that 15 differentially expressed proteins (DEPs) between RNAi line 7 creased by ~5 to 10-fold inwere the enriched periderm of silencing linesbiosynthesis”, compared with that of the wild- and and WT
Summary
Potato (Solanum tuberosum L.) is the third most important food and vegetable crop in the world, with wide adaptability, high yield and rich nutrition [1]. To reveal the mechanism of tuber dormancy release is a very important issue in potato production, storage and processing. Tuber dormancy release is a complex process that is known to involve several physiological and biochemical changes, mainly including hormonal signaling, carbohydrate metabolism and oxidation-reduction [4,6,7,8]. Hormonal regulation and carbohydrate metabolism are thought to be the important factors controlling the dormancy release process in potato [4]. The complex polyphenolic (lignin-like) and polyaliphatic in the phellem cell wall affected the tuber cortex and resulted in the change of dehydration and respiration [10]. SN2 promoted the accumulation of lignin precursors and induced lignin-related protein expression in the tuber periderm.
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