Hydrogen cyanamide induces grape bud endodormancy release through carbohydrate metabolism and plant hormone signaling

Abstract

BackgroundGrape buds exhibit non-uniform, or delayed, break in early spring in subtropical regions because the accumulation of chilling is insufficient. Hydrogen cyanamide (H2CN2, HC) can partially replace chilling to effectively promote bud sprouting and is used widely in warm winter areas. However, the exact underlying mechanism of grape bud release from endodormancy induced by HC remains elusive.ResultsIn this study, the transcriptome of grape winter buds under in vitro conditions following HC and water treatment (control) was analyzed using RNA-seq technology. A total of 6772 differentially expressed genes (DEGs) were identified. Furthermore, the gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that starch and sucrose metabolism and plant hormone signaling transduction were most enriched out of the 50 total pathways. HC treatment induced the upregulated expression of sucrose synthase (SUS), sucrose phosphate synthase (SPS), α-amylase (AM), and β-amylase (BM) and downregulated expression of sucrose invertase (INV), hexokinase (HK), fructokinase (FK), soluble starch synthase (SS), and granule-bound starch synthase (GBSS). Hence, the starch concentration in the HC-treated group was significantly lower than that in control, whereas soluble sugar content in the HC-treated group increased quickly and was higher than that in control between 0 and 8 d. The concentration of indoleacetic acid (IAA) and zeatin (ZT) increased, whereas that of abscisic acid (ABA) and gibberellin (GA) decreased in HC treated group, which coincided with the expression level of genes involved in above hormone signals. The content of hydrogen peroxide (H2O2) and enzyme activity of superoxide dismutase (SOD) and peroxidase (POD) were increased in grape buds with HC treatment, whereas catalase (CAT) activity was decreased. HC treatment increased the expression of POD, SOD, primary amine oxidase (PAO), polyamine oxidase (PAOX), and glutathione peroxidase (GSH-Px).ConclusionBased on these results, it is possible to propose a mechanistic model that underlies the regulation of endodormancy release in grapevine buds by exogenous HC application.

Ethephon-Mediated Bloom Delay in Peach Is Associated With Alterations in Reactive Oxygen Species, Antioxidants, and Carbohydrate Metabolism During Dormancy

“…Interestingly, Kuroda et al, 2005 found that an exogenous application of H 2 O 2 (2.5%) to the endodormant buds of Japanese pear increased bud break, but it required a higher concentration of H 2 O 2 (10%) to attain a similar bud break rate when the application was made during ecodormancy. Treatments with hydrogen cyanamide (HC), a dormancy-breaking agent, were also found to substitute chilling requirements in grapevine and Japanese pear by inducing H 2 O 2 accumulation in the buds ( Kuroda and Sugiura, 2002 ; Liang et al, 2019 ). In both species, the accumulation profile of H 2 O 2 during endodormancy was similar to what we observed in the present study ( Figure 2B ), where H 2 O 2 reaches its peak at endodormancy release and declines during ecodormancy ( Kuroda and Sugiura, 2002 ; Pérez et al, 2021 ).…”

Changes in Reactive Oxygen Species, Antioxidants and Carbohydrate Metabolism in Relation to Dormancy Transition and Bud Break in Apple (Malus × domestica Borkh) Cultivars

“…Similarly, in barley seeds, NADPH oxidase induces ABA catabolism and α-amylase activity, which are prerequisite for seed germination [35]. Along the same vein, exogenous application of HC which is widely reported to induce H 2 O 2 production, decreases endogenous ABA levels in grape [45,46] and sweet cherry [47] by promoting ABA degradation and inhibiting ABA synthesis. In walnut, redox interaction rather than sugar metabolism was found to govern bud dormancy release [18].…”

A candidate gene identified in converting platycoside E to platycodin D from Platycodon grandiflorus by transcriptome and main metabolites analysis

“…In addition, through the catalysis of nucleotide-diphospho-sugar (NDP-sugar) interconversion enzymes (NSEs), many other NDP sugars were produced from UDP-Glc and GDP-Man 28 . Another way is that sucrose invertase (INV) and hexokinase (HK) catalyze the production of D-Glucose-6P from sucrose 29 . Subsequently, D-Glucose-6P is converted into UDP-Gal, UDP-GalA, UDP-Rha and other polysaccharide precursors under the catalysis of enzymes such as Phosphoglucomutase (PGM), UTP-glucose-1-phosphate Uridylyltransferase (UGP2), and UDP-apiose/xylose synthase (AXS) et al 30 .…”