UDP-Glucose: A Potential Signaling Molecule in Plants?

Abstract

This perspective paper focuses on the most recent results suggesting a potential role for UDP-Glucose as a signaling molecule in plants. In animals, UDP-Glucose is well-established as an extracellular signaling molecule that is sensed by G-protein coupled receptors, activating several downstream defense mechanisms. Recent studies have shown that abnormal growth occurred in both vegetative and reproductive tissue of plants with reduced UDP-Glucose levels, and this could be rescued by exogenous UDP-Glucose. In plants with increased biomass accumulation, the genes involved in UDP-Glucose production were up-regulated. However, excessive endogenous accumulation of UDP-Glucose induced programmed cell death (PCD), and this could also be obtained by exogenous UDP-Glucose application. Plants with decreased UDP-glucose were insensitive to pathogen induced PCD. We speculate that UDP-Glucose acts as an extracellular signaling molecule in plants, and that it may be perceived as a damage-associated molecular pattern.

Mechanisms underlying the enhanced biomass and abiotic stress tolerance phenotype of an Arabidopsis MIOX over‐expresser

“…Enhanced production of glucose leads to manipulation of root architecture for maximum development through interactions with auxin metabolism genes (Li et al, 2007;Moore et al, 2003;Peng et al, 2018). Furthermore, increased concentration of UDP-glucose leads to accumulation of higher biomass in plants and helps in vegetative phase change by repressing the miR156A/miR156C (Christopher, Rensburg, & Ende, 2017;Yang, Xu, Koo, He, & Poethig, 2013).…”

Sugar Signaling During Fruit Ripening

“…Additionally, as sucrose, a known signaling molecule in plant, is rapidly split into glucose, UDPG, and fructose, a potential role of these breakdown products in sugar signaling cannot be ruled out ( Hummel et al., 2009 ). Furthermore, the lack of identified sucrose receptor might imply a signaling function of its breakdown products ( Janse van Rensburg and Van den Ende, 2018 ). However, as UDPG is directly related to the concentration of sucrose, and therefore, to the accumulation of glucose, fructose, and trehalose-6-phosphate, it cannot be ruled out that UDPG can cause an imbalance in the levels of other metabolites involved in signaling instead of being a signaling sugar itself.…”

“…Deeper studies on the possible signaling role of UDPG seems nevertheless necessary, as UDPG function in plant growth and development is well described, and a recent study suggests that UDPG enhances biomass accumulation in sugarcane because of its rapid conversion to sucrose ( Wai et al., 2017 ). UDPG pyrophosphorylase, an enzyme involved in UDPG formation and which is differentially expressed under stress conditions ( Ciereszko et al., 2001 ; Meng et al., 2007 ), has been shown to be a regulator of programmed cell death ( Janse van Rensburg and Van den Ende, 2018 ; Xiao et al., 2018 ). A very recent study has suggested that UDPG might have an important role in the induction of reactive oxygen species generation and lesion mimics in rice ( Xiao et al., 2018 ), nevertheless, further studies are required to understand this process and the possible role of UDPG or any other UDP-sugar in plant signaling and fruit ripening.…”

Can early peroxidase quantification detect graft-compatible in anonaceous rootstocks?

“…However, Baron et al (2016) cultivated atemoya scion graft onto biribá rootstock at 60 and 90 days after grafting, that UGP gene expression was similar to that graft-compatible, for example, atemoya graft onto araticum-de-terra-fria and araticum-mirim rootstock. This gene encoded UDP-glucose pyrophosphorylase (UGPase) protein plays an important role in many physiological processes, including carbohydrate metabolism, sucrose and cellulose formation in cell walls (Lerouxel et al, 2006;Janse Van Rensenburg et al, 2018). Despite its important regulatory role, little is known about the expression of this gene associated with graftcompatible (Pina and Errea, 2008).…”