You Want it Sweeter: How Glycosylation Affects Plant Response to Oxidative Stress

Abstract

Oxidative stress is a cellular threat which puts at risk the productivity of most of crops valorized by humankind in terms of food, feed, biomaterial, or bioenergy. It is therefore of crucial importance to understand the mechanisms by which plants mitigate the deleterious effects of oxidizing agents. Glycosylation of antioxidant molecules and phytohormones modifies their chemical properties as well as their cellular and histological repartition. This review emphasizes the mechanisms and the outcomes of this conjugation reaction on plant ability to face growing conditions favoring oxidative stress, in mirror with the activity of deglycosylating enzymes. Pioneer evidence bridging flavonoid, glycosylation, and redox homeostasis paved the way for numerous functional analyses of UDP-glycosyltransferases (UGTs), such as the identification of their substrates and their role to circumvent oxidative stress resulting from various environmental challenges. (De)glycosylation appears as a simple chemical reaction regulating the biosynthesis and/or the activity of a myriad of specialized metabolites partaking in response to pathogen and abiotic stresses. This outcome underlies the possibility to valorize UGTs potential to upgrade plant adaptation and fitness in a rising context of suboptimal growing conditions subsequent to climate change.

Potential Mitigation of Smoke Taint in Wines by Post-Harvest Ozone Treatment of Grapes

“…Plant tissue responds rapidly to O 3 and within ~2 h of exposure, ozonation induces the formation and accumulation of different reactive oxygen species (ROS), mainly hydrogen peroxide, in the cell wall and plasma membrane [ 49 ]. When ROS production exceeds the capacity of scavenging systems to maintain the optimal redox status, oxidative stress occurs [ 50 , 51 ]. The oxidative stress induced by O 3 exposure can stimulate cellular defense mechanisms, including biosynthesis of antioxidants such as glutathione, ascorbate and polyphenols [ 52 , 53 , 54 , 55 ].…”

“…Glycosylation (and deglycosylation) of antioxidants and phytohormones plays an important role in plant defense mechanisms [ 57 ]. Oxidative stress induces UGT activity, which can in turn increase glycosylation processes [ 51 ], and this might explain the observed increase in VP glycosides following 3 ppm O 3 treatment of smoke-affected grapes (at t = 6). Glycosylation of smoke-derived VPs likely reflects a detoxification strategy, i.e., glycosylation allows compartmentalization and stable storage of small and toxic/reactive molecules, such as VPs, by lessening their volatility through derivatization [ 15 ].…”

Sweet Modifications Modulate Plant Development

“…Glycosylation of plant hormones exerts also a plethora of other functions for plant development and dealing with biotic and abiotic stress. For an overview of glycosylated small molecules, we refer to Behr et al [ 279 ].…”

Ozone and Bioactive Compounds in Grapes and Wine

“…As such, the UGTs plays a key role not only in plant defence mechanisms [ 69 ], but also in the formation of glycosylated volatiles. Therefore, the induced oxidative stress stimulating UGTs activity can, in turn, increase glycosylated volatiles [ 70 ], also known as aromatic precursors.…”