Characterization of the UDP-glycosyltransferase UGT72 Family in Poplar and Identification of Genes Involved in the Glycosylation of Monolignols

Abstract

Monolignols are the building blocks for lignin polymerization in the apoplastic domain. Monolignol biosynthesis, transport, storage, glycosylation, and deglycosylation are the main biological processes partaking in their homeostasis. In Arabidopsis thaliana, members of the uridine diphosphate-dependent glucosyltransferases UGT72E and UGT72B subfamilies have been demonstrated to glycosylate monolignols. Here, the poplar UGT72 family, which is clustered into four groups, was characterized: Group 1 UGT72AZ1 and UGT72AZ2, homologs of Arabidopsis UGT72E1-3, as well as group 4 UGT72B37 and UGT72B39, homologs of Arabidopsis UGT72B1-3, glycosylate monolignols. In addition, promoter-GUS analyses indicated that poplar UGT72 members are expressed within vascular tissues. At the subcellular level, poplar UGT72s belonging to group 1 and group 4 were found to be associated with the nucleus and the endoplasmic reticulum. However, UGT72A2, belonging to group 2, was localized in bodies associated with chloroplasts, as well as possibly in chloroplasts. These results show a partial conservation of substrate recognition between Arabidopsis and poplar homologs, as well as divergent functions between different groups of the UGT72 family, for which the substrates remain unknown.

Active Transport of Lignin Precursors into Membrane Vesicles from Lignifying Tissues of Bamboo

“…The overexpression of a glycosyltransferase involved in monolignol glucoside biosynthesis in A. thaliana resulted in ectopic lignification [39]. However, the overexpression of the UDP-glycosyltransferase involved in monolignol glycosylation in poplar did not affect lignification [40]. Although the roles of monolignol glucosides in lignification are obscure, the present study, in addition to previous studies [16,20,21], clearly shows that the transport activities of coniferin and p-glucocoumaryl alcohol are highly conserved in lignifying tissues, implying the importance of the transport of monolignol glucosides in lignification.…”

Leaf necrosis resulting from downregulation of poplar glycosyltransferaseUGT72A2

“…sequence of interest was PCR-amplified (the sequence of all primers used in this study is provided in Table S1) and inserted in the destination vector pK7GWIWG2D(II) (Karimi et al 2002) using the Gateway technology. Full length cDNA sequence of UGT72A2 was cloned into pK7WG2D to produce overexpressing lines as described previously (Speeckaert et al 2020).…”

“…Recombinant protein production, purification and enzymatic activities were essentially performed as previously described (Speeckaert et al 2020). Briefly, full-length coding sequence of UGT72A2 (GenBank MT181026) cloned into pGEX-4T-1 (GE HealthCare) was transferred into E. coli BL21(DE3)pLysS strain (Novagen).…”

“…response to fungal pathogen (Veljanovski and Constabel 2013) and more recently in monolignol glucosylation (Speeckaert et al 2020). More widely, a number of plant UGTs partake in redox homeostasis under various (a)biotic stresses, such as cold temperature, exposure to oxidising agents, salt or high osmotic condition and bacterial infection (reviewed in Behr et al 2020).…”

Enhanced Heterologous Production of Glycosyltransferase UGT76G1 by Co-Expression of Endogenous prpD and malK in Escherichia coli and Its Transglycosylation Application in Production of Rebaudioside

“…To date, substantial efforts have been made to reveal glucosylation enzymes and successfully excavated more and more uridine diphosphate (UDP)-dependent glucosyltransferases (UGTs) [11][12][13][14]. The UGTs with high regioselectivity and substrate specificity have attracted remarkable attention due to their great potential application in biotechnology [15][16][17].…”