Genome Wide Analysis of Family-1 UDP Glycosyltransferases in Populus trichocarpa Specifies Abiotic Stress Responsive Glycosylation Mechanisms

Abstract

Populus trichocarpa (Black cottonwood) is a dominant timber-yielding tree that has become a notable model plant for genome-level insights in forest trees. The efficient transport and solubility of various glycoside-associated compounds is linked to Family-1 UDP-glycosyltransferase (EC 2.4.1.x; UGTs) enzymes. These glycosyltransferase enzymes play a vital role in diverse plant functions, such as regulation of hormonal homeostasis, growth and development (seed, flower, fiber, root, etc.), xenobiotic detoxification, stress response (salt, drought, and oxidative), and biosynthesis of secondary metabolites. Here, we report a genome-wide analysis of the P. trichocarpa genome that identified 191 putative UGTs distributed across all chromosomes (with the exception of chromosome 20) based on 44 conserved plant secondary product glycosyltransferase (PSPG) motif amino acid sequences. Phylogenetic analysis of the 191 Populus UGTs together with 22 referenced UGTs from Arabidopsis and maize clustered the putative UGTs into 16 major groups (A–P). Whole-genome duplication events were the dominant pattern of duplication among UGTs in Populus. A well-conserved intron insertion was detected in most intron-containing UGTs across eight examined eudicots, including Populus. Most of the UGT genes were found preferentially expressed in leaf and root tissues in general. The regulation of putative UGT expression in response to drought, salt and heat stress was observed based on microarray and available RNA sequencing datasets. Up- and down-regulated UGT expression models were designed, based on transcripts per kilobase million values, confirmed their maximally varied expression under drought, salt and heat stresses. Co-expression networking of putative UGTs indicated their maximum co-expression with cytochrome P450 genes involved in triterpenoid biosynthesis. Our results provide an important resource for the identification of functional UGT genes to manipulate abiotic stress responsive glycosylation in Populus.

The transcriptional regulation of a putative hemicellulose gene, PtrPARVUS2 in poplar

“…According to previous research, genes in clades I and III are associated with two different environmental stresses. Potri.015G027700, classified in clade I, has been significantly downregulated under heat shock in poplar 92 and Potri.006G022500 and Potri.017G052400 from clade III are activated under drought stress 91 , 93 , 94 . Understanding the regulation of UGTs in different plant species can provide valuable insights into the variability of cell wall structures and properties.…”

“…The substrate specificity of UGTs determines the precise glycosylation patterns of hemicelluloses within SCW. In poplar, 191 putative UGTs have been identified 91 , but their regulatory mechanisms have not been elucidated yet. The eight putative UGTs regulated by all six TFs can be grouped into three clades using promoter phylogenetic analysis (Supplemental Fig.…”

Functional Identification of HhUGT74AG11—A Key Glycosyltransferase Involved in Biosynthesis of Oleanane-Type Saponins in Hedera helix

“…Plant glycosyltransferases belong to a large enzyme family with varied functions. Taking into account the variety of sequences and functions, phylogenetic trees are usually constructed to compare gene family members and determine similarities and differences [28]. Cluster analysis (Figure 5) indicates that, in the evolution of higher plants, branches A, D, E, and L appear to have experienced greater expansion compared with other branches, aligning with the more prominent branches observed in the evolutionary tree [29].…”

Genome-Wide Association Analysis for Resistance to Coniothyrium glycines Causing Red Leaf Blotch Disease in Soybean

“…In soybean, the flooding stress is controlled by enolase with the contribution of other proteins [ 62 ]. UDP-glucosyl transferase 89B1 plays a vital role in diverse plant functions, and its response to drought, salt, and heat stress in Populus trichocarpa (Black cottonwood) has been revealed [ 63 ]. The potential role of the EF-hand calcium-binding protein family in the implementation of resistance to environmental and nutritional stress in soybean was described [ 64 ].…”