Comparative Study on Reagents Involved in Grape Bud Break and Their Effects on Different Metabolites and Related Gene Expression during Winter (original) (raw)
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Proceedings of the 2nd World Congress on New Technologies, 2016
Hydrogen cyanamide (HC) and pruning have frequently been used to break dormancy in grapevine floral buds. This study aimed to address the effects of these treatments on accumulation of ROS and alteration in expression of ROS-related genes in the dormancy breaking buds of grapevine in the summer in sub/tropical. Four treatments were compared, namely: Pruning (P), hydrogen cyanamide (HC), Pruning and hydrogen cyanamide (PHC) and Control (water) and 8 days after treatment the bud break rates were 33%, 53%, 95%, and 0%, respectively. Clearly, HC is effective in stimulating grapevine bud break and pruning further enhanced its potency. In situ detection of various Reactive oxygen species (ROS) and Nitric oxide (NO) in longitudinal bud sections after 12 h of treatments showed that high levels of ROS and NO accumulate in the buds treated with PHC, compared with HC or P only. The amounts of ROS and NO accumulated were closely correlated with the rates of bud break among the treatments. Microarray analysis was conducted with the dormancy breaking buds after 24 h of treatments. Gene ontology (GO) analysis indicated that alteration in expression of ROS related genes is the major factor responsible for bud break. PHC treatment gave rise to dynamic changes in highly up-/down-regulation of antioxidant activity at 24 h post-treatment. Twelve genes were identified as key genes involved in dormancy bud break in the early response. The time course of expression of these genes (examined by qRT-PCR) showed different expression during the 48 h treatment. It is concluded that accumulation of ROS at the early stage is important for dormant bud break, and that the microarray analysis of differentially expressed genes among the treatments allowed the construction of the model pathway related to ROS metabolisms during dormant bud breaking.
BMC Plant Biology, 2016
Background: Hydrogen cyanamide (HC) and pruning (P) have frequently been used to break dormancy in grapevine floral buds. However, the exact underlying mechanism remains elusive. This study aimed to address the early mode of action of these treatments on accumulation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and expression of related genes in the dormancy breaking buds of grapevine in the summer. Results: The budbreak rates induced by pruning (P), hydrogen cyanamide (HC), pruning plus hydrogen cyanamide (PHC) and water (control) after 8 days were 33, 53, 95, and 0 %, respectively. Clearly, HC was more effective in stimulating grapevine budbreak and P further enhanced its potency. In situ staining of longitudinal bud sections after 12 h of treatments detected high levels of ROS and nitric oxide (NO) accumulated in the buds treated with PHC, compared with HC or P alone. The amounts of ROS and NO accumulated were highly correlated with the rates of budbreak among these treatments, highlighting the importance of a rapid, transient accumulation of sublethal levels of ROS and RNS in dormancy breaking. Microarray analysis revealed specific alterations in gene expression in dormancy breaking buds induced by P, HC and PHC after 24 h of treatment. Relative to control, PHC altered the expression of the largest number of genes, while P affected the expression of the least number of genes. PHC also exerted a greater intensity in transcriptional activation of these genes. Gene ontology (GO) analysis suggests that alteration in expression of ROS related genes is the major factor responsible for budbreak. qRT-PCR analysis revealed the transient expression dynamics of 12 specific genes related to ROS generation and scavenge during the 48 h treatment with PHC. Conclusion: Our results suggest that rapid accumulation of ROS and NO at early stage is important for dormancy release in grapevine in the summer, and the identification of the commonly expressed specific genes among the treatments allowed the construction of the signal transduction pathway related to ROS/RNS metabolism during dormancy release. The rapid accumulation of a sublethal level of ROS/RNS subsequently induces cell wall loosening and expansion for bud sprouting.
Plant Growth Regulation, 2009
Sodium azide (NaN3), a well-known inhibitor of mitochondrial respiration, stimulated bud-dormancy release in grapevines similar to hydrogen cyanamide (HC), while HC, a well-known dormancy release agent, inhibited the O2 uptake in isolated grape bud mitochondria similarly to NaN3. Additionally, both chemicals induced transcript expression of the antioxidative enzyme glutathione reductase and glucose-6-phosphate-dehydrogenase (G6PD), therefore upregulated the ascorbate-glutathione cycle (AGC) and the pentose phosphate pathway, respectively. As a result of AGC activation, the ratio of reduced to oxidized glutathione (GSH/GSSG) increased. Both stimuli also upregulated the transcription of 1,3-β-d-glucanase, a key enzyme in dormancy release. Together, these data support mechanistic connection between impaired Mit function and dormancy release, and suggests that as a consequence of O2 deprivation, increases in glycolysis and in ethanolic fermentation could be responsible for activation of downstream stages in the dormancy release mechanisms.
H 2 O 2 is involved in the dormancy-breaking effect of hydrogen cyanamide in grapevine buds
Plant Growth Regulation, 2008
Hydrogen cyanamide (HC) is widely used to induce the breakage of endodormancy (ED) in grape and other deciduous fruit crop, though its mechanism of action is poorly understood. Applications of HC to grapevine buds produce oxidative stress and transient respiratory disturbances which are related to the breakage of ED. Moreover, since the expression and activity of catalase (Cat) is inhibited by HC, enhancements in the levels of H2O2 have also been associated to the breakage of ED in grapevine buds. Here, we reported that increases in H2O2 level in HC-treated grapevine buds are due to the inhibition of Cat activity and enhancement of the respiratory activity of buds. In addition, exogenous applications of H2O2 partially reproduced the inducing effect of HC in the breakage of ED, thus providing further support for the hypothesis that H2O2 mediates the effects of HC. On the other hand, Mit isolated from both control and HC-treated buds respired equally well when NADH was used as a respiratory substrate, but when succinate was used as an electron donor Mit respiration was non-detected, suggesting that the stimulatory effect of HC on bud respiration is related to metabolic alterations leading to increase of the concentration of NADH rather than to changes in Mit functionality.
Journal of experimental botany, 2015
In warm-winter regions, induction of dormancy release by hydrogen cyanamide (HC) is mandatory for commercial table grape production. Induction of respiratory stress by HC leads to dormancy release via an uncharacterized biochemical cascade that could reveal the mechanism underlying this phenomenon. Previous studies proposed a central role for abscisic acid (ABA) in the repression of bud meristem activity, and suggested its removal as a critical step in the HC-induced cascade. In the current study, support for these assumptions was sought. The data show that ABA indeed inhibits dormancy release in grape (Vitis vinifera) buds and attenuates the advancing effect of HC. However, HC-dependent recovery was detected, and was affected by dormancy status. HC reduced VvXERICO and VvNCED transcript levels and induced levels of VvABA8'OH homologues. Regulation of these central players in ABA metabolism correlated with decreased ABA and increased ABA catabolite levels in HC-treated buds. Int...
Short growing season is one of the main obstacles to the commercial production of grapes in regions experiencing cold/semi-cold climates. This is known to impact the quality and quantity of production. Consequently, this study was conducted to evaluate the effects of foliar application of hydrogen cyanamide (Dormex) solution (0, 1%) as a rest-break agent and its physiological and biochemical mechanisms, on 10-year-old Askari grape (Vitis vinifera 'Askari') trees, in a completely randomized block design in a factorial combination with three replications. The results showed that catalase activity was lower in the samples treated with hydrogen cyanamide solution (1%) compared to the untreated buds during the second, third, and fourth sampling dates, and hydrogen peroxide accumulated in the buds during the same period. Putrescine concentration was increased more than 6 folds in hydrogen cyanamide treated (1%) samples during the bud dormancy release period compared to the first s...
Phytochemistry, 2017
Plants are able to synthesize a large number of organic compounds. Among them, primary metabolites are known to participate in plant growth and development, whereas secondary metabolites are mostly involved in defense and other facultative processes. In grapevine, one of the major fruit crops in the world, secondary metabolites, mainly polyphenols, are of great interest for the wine industry. Even though there is an extensive literature on the content and profile of those compounds in berries, scarce or no information is available regarding polyphenols in other organs. In addition, little is known about the effect of plant growth regulators (PGRs), ABA and GA 3 (extensively used in table grapes) on the synthesis of primary and secondary metabolites in wine grapes. In table grapes, cultural practices include the use of GA 3 sprays shortly before veraison, to increase berry and bunch size, and sugar content in fruits. Meanwhile, ABA applications to the berries on pre-veraison improve the skin coloring and sugar accumulation, anticipating the onset of veraison. Accordingly, the aim of this study was to assess and characterize primary and secondary metabolites in leaves, berries and roots of grapevine plants cv. Malbec at veraison, and changes in compositions after ABA and GA 3 aerial sprayings. Metabolic profiling was conducted using GC-MS, GC-FID and HPLC-MWD. A large set of metabolites was identified: sugars, alditols, organic acids, amino acids, polyphenols (flavonoids and non-flavonoids) and terpenes (mono-, sesqui-, di-and triterpenes). The obtained results showed that ABA applications elicited synthesis of mono-and sesquiterpenes in all assessed tissues, as well as L-proline, acidic amino acids and anthocyanins in leaves. Additionally, applications with GA 3 elicited synthesis of L-proline in berries, and mono-and sesquiterpenes in all the tissues. However, treatment with GA 3 seemed to block polyphenol synthesis, mainly in berries. In conclusion, ABA and GA 3 applications to grapevine plants cv. Malbec influenced the synthesis of primary and secondary metabolites known to be essential for coping with biotic and abiotic stresses.
Plant Physiology and Biochemistry, 2016
ABA has been proposed as the main signal triggering the onset of the ripening process in grapes, and modulating the secondary metabolism in grape berry skins. To determine the effect of ABA on secondary metabolism in berries, clusters of Carm en ere were sprayed with 0 mLL À1 ABA; 50 mLL À1 ABA and 100 mLL À1 ABA during pre-v eraison, and the gene expression of the transcription factors and enzymes of the phenylpropanoid pathway were assessed from v eraison to 70 days after v eraison (DAV). Additionally, flavonols, tannins and anthocyanins were assessed from v eraison until harvest (110 DAV). ABA accelerated sugar and anthocyanin accumulation at v eraison. The grape transcript abundance of VvDFR, VvANS, VvUFGT and VvMybA1, all peaking around v eraison mimicked the concentration of ABA throughout the season. The highest anthocyanin concentration occurred 35 DAV for all treatments, but higher pigment concentrations were observed in ABA-treated berries at v eraison and from 60 to 70 DAV to harvest. VvPAL was also increased by treatment at the higher concentration of ABA from v eraison to 40 DAV. Regarding flavanol synthesis, VvLAR2 and VvMyb4A decreased from v eraison until 40 DAV and then increased again until 70 DAV. Compared to the control, both ABA treatments resulted in a less-than-proportional reduction of the expression of both genes compared to the control and, after 40 DAV, in a more-thanproportional increase compared to the control, suggesting a long-term effect of the pre-v eraison ABA spray on the berries. A concomitant increase in flavanols was observed in berries after 40 DAV, and this occurred at a higher extent in berries treated with the highest ABA concentration.
Abscisic acid catabolism enhances dormancy release of grapevine buds
Plant, cell & environment, 2018
The molecular mechanism regulating dormancy release in grapevine buds is as yet unclear. It was formerly proposed that dormancy is maintained by abscisic acid (ABA)-mediated repression of bud-meristem activity and that removal of this repression triggers dormancy release. It was also proposed that such removal of repression may be achieved via natural or artificial up-regulation of VvA8H-CYP707A4, which encodes ABA 8'-hydroxylase, and is the most highly expressed paralog in grapevine buds. The current study further examines these assumptions, and its experiments reveal that (a) hypoxia and ethylene, stimuli of bud dormancy release, enhance expression of VvA8H-CYP707A4 within grape buds, (b) the VvA8H-CYP707A4 protein accumulates during the natural transition to the dormancy release stage, and (c) transgenic vines overexpressing VvA8H-CYP707A4 exhibit increased ABA catabolism and significant enhancement of bud break in controlled and natural environments and longer basal summer l...