Hydrogen Peroxide Increases during Endodormancy and Decreases during Budbreak in Grapevine (Vitis vinifera L.) Buds.

Francisco Javier Pérez,Sebastián Rubio,Ximena Noriega

doi:10.3390/antiox10060873

Abstract

Changes in the level of hydrogen peroxide (H2O2) is a good indicator to monitor fluctuations in cellular metabolism and in the stress responses. In this study, the changes in H2O2 content during bud endodormancy (ED) and budbreak were analysed in grapevine (Vitis vinifera L.). The results showed a gradual increase in the H2O2 content during the development of bud ED, which was mainly due to an increase in the activity of peroxidases (PODs). The maximum H2O2 content reached in the grapevine buds coincided with the maximum depth of bud ED. In contrast, during budbreak, the H2O2 content decreased. As the plant hormones cytokinin (CK) and auxin play an important role in budbreak and growth resumption in grapevine, the effect of exogenous applications of H2O2 on the expression of genes involved in CK and auxin metabolism was analysed. The results showed that H2O2 represses the expression of the CK biosynthesis genes VvIPT3a and VvLOG1 and induces the expression of the CK-inactivating gene VvCKX3, thus reducing potentially the CK content in the grapevine bud. On the other hand, H2O2 induced the expression of the auxin biosynthesis genes VvAMI1 and VvYUC3 and of the auxin transporter gene VvPIN3, thus increasing potentially the auxin content and auxin transport in grapevine buds. In general, the results suggest that H2O2 in grapevine buds is associated with the depth of ED and negatively regulates its budbreak.

Highlights

The buds of the grapevine (Vitis vinifera L.), similar to the buds of other deciduous fruit trees enter a state of winter recess or endodormancy (ED) to survive winter conditions.In the grapevine bud, ED is induced by the shortening of the photoperiod [1,2,3] and is regulated by endogenous factors that inhibit its growth and development [4]
The results showed that the maximum Peroxidase class III (POD) activity coincided with the maximum H2 O2 content, suggesting that the POD activity may be at least partially responsible for the increases in the H2 O2 content in grapevine buds
The results showed that when the data were adapted to the conditions of the Southern Hemisphere (Figure 2b), only the expression profile of VvPOD38 was with similar genes from Arabidopsis [20]

Summary

Introduction

The buds of the grapevine (Vitis vinifera L.), similar to the buds of other deciduous fruit trees enter a state of winter recess or endodormancy (ED) to survive winter conditions.In the grapevine bud, ED is induced by the shortening of the photoperiod [1,2,3] and is regulated by endogenous factors that inhibit its growth and development [4]. The plant hormone abscisic acid (ABA) accumulates in the buds of grapevines throughout ED [5,6]. Hydrogen peroxide (H2 O2 ), which is continuously generated from various sources during normal metabolism and is a signalling molecule that mediates responses to biotic and abiotic stresses [10], accumulates in the buds of grapevine during ED [11,12,13]. The plant antioxidant system removes H2 O2 efficiently, and the oxidative effects of many stimuli could be mediated via a reduction in the activities of antioxidant enzymes, rather than by increased H2 O2 generation [10]. Hypoxia, as well as mitochondrial respiration inhibitors, such as potassium cyanide (KCN) and sodium nitroprusside (SNP), increase H2 O2 levels [15]. Seven VvRBOH genes have been identified and characterised [17], and three of them are expressed in the buds [18]

Methods

Results

Conclusion