Genome-wide analysis of the family 1 glycosyltransferases in cotton.

Family 1 GT, designated as UGT, is the largest and most functionally important multigene family in the plant kingdom. In this study, we carried out a genome-wide identification, analysis, and comparison of 142, 146, and 196 putative UGTs from Gossypium raimondii, Gossypium arboreum, and Gossypium hirsutum, respectively. All members present the 44 amino-acid conserved consensus sequence termed the plant secondary product glycosyltransferase motif. According to the phylogenetic relationship among the cotton UGT proteins and those from other species, GrUGTs and GaUGTs could be classified into 16 major phylogenetic groups (A-P), whereas GhUGTs are classified into 15 major phylogenetic groups with a lack of group C. All cotton UGTs are dispersed throughout the chromosomes and are displayed in clusters with the same open reading frame orientation. The expansion of them appears to result from genome duplication and rearrangement. Two conserved introns, A and B, are detected in most of the intron-containing-UGTs in G. raimondii and G. arboreum, whereas only intron A is detected in the intron-containing-UGTs in G. hirsutum. Furthermore, expression patterns of the UGT genes in G. hirsutum wild type and its near isogenic fuzzless-lintless mutant at the stage of fiber initiation were analyzed using the RNA-seq data. Overall, this study not only deepens our understanding of the structure, phylogeny, evolution, and expression of cotton UGT genes, but also provides a solid foundation for further cloning and functional studies of the UGT family genes.

Genome-Wide Identification and Characterisation of Cytokinin-O-Glucosyltransferase (CGT) Genes of Rice Specific to Potential Pathogens.

Cytokinin glucosyltransferases (CGTs) are key enzymes of plants for regulating the level and function of cytokinins. In a genomic identification of rice CGTs, 41 genes with the plant secondary product glycosyltransferases (PSPG) motif of 44-amino-acid consensus sequence characteristic of plant uridine diphosphate (UDP)-glycosyltransferases (UGTs) were identified. In-silico physicochemical characterisation revealed that, though the CGTs belong to the same subfamily, they display varying molecular weights, ranging from 19.6 kDa to 59.7 kDa. The proteins were primarily acidic (87.8%) and hydrophilic (58.6%) and were observed to be distributed in the plastids (16), plasma membrane (13), mitochondria (5), and cytosol (4). Phylogenetic analysis of the CGTs revealed that their evolutionary relatedness ranged from 70-100%, and they aligned themselves into two major clusters. In a comprehensive analysis of the available transcriptomics data of rice samples representing different growth stages only the CGT, Os04g25440.1 was significantly expressed at the vegetative stage, whereas 16 other genes were highly expressed only at the reproductive growth stage. On the contrary, six genes, LOC_Os07g30610.1, LOC_Os04g25440.1, LOC_Os07g30620.1, LOC_Os04g25490.1, LOC_Os04g37820.1, and LOC_Os04g25800.1, were significantly upregulated in rice plants inoculated with Rhizoctonia solani (RS), Xoo (Xanthomonas oryzae pv. oryzae) and Mor (Magnaporthe oryzae). In a qRT-PCR analysis of rice sheath tissue susceptible to Rhizoctonia solani, Mor, and Xoo pathogens, compared to the sterile distilled water control, at 24 h post-infection only two genes displayed significant upregulation in response to all the three pathogens: LOC_Os07g30620.1 and LOC_Os04g25820.1. On the other hand, the expression of genes LOC_Os07g30610.1, LOC_Os04g25440, LOC_Os04g25490, and LOC_Os04g25800 were observed to be pathogen-specific. These genes were identified as the candidate-responsive CGT genes and could serve as potential susceptibility genes for facilitating pathogen infection.

Controlled underdilation using novel VIATORR® controlled expansion stents improves survival after transjugular intrahepatic portosystemic shunt implantation.

BACKGROUND & AIMS: Smaller 8-mm diameter transjugular intrahepatic portosystemic shunts (TIPS) appear to be more beneficial than larger 10-mm TIPS stent-grafts, but lack the ability for secondary dilation in cases of clinical ineffectiveness. Underdilated VIATORR® TIPS stent grafts (VTS) expand passively, whereas novel VIATORR Controlled Expansion (VCX) stent grafts do not. This study evaluated the impact on survival of underdilated VCX compared with VTS in patients with decompensated cirrhosis. METHODS: This was a prospective case-control study including patients with cirrhosis receiving TIPS using 10-mm VCX underdilated to 8 mm. Patients with cirrhosis receiving 10-mm VTS underdilated to 8 mm were matched for age, sex, indication for TIPS, and liver function. RESULTS: A total of 114 patients (47 VCX, 47 VTS, and 20 fully dilated VCX/VTS) were included. After TIPS implantation, underdilated VCX diameter was 8.0 (7.8-9.2) mm at a median time of 359 (87-450) days, compared with VTS at 9.9 (9.7-10.0) mm (p <0.001). The portosystemic pressure gradient immediately after TIPS procedure and after 7 days did not change significantly in VCX [mean 9.4 (± 0.8) vs. 10.4 (± 0.7) mmHg, p = 0.115). Hospital readmission rates for hepatic encephalopathy were 23% (n = 11) vs 51% (n = 24) for VCX and VTS (p <0.001), respectively. Patients with VCX had significantly lower rates of large-volume paracentesis (n = 5 [11%] vs. n = 10 [21%], p = 0.017) and heart failure (n = 1 [2%] vs. n = 7 [15%], p = 0.015). One-year mortality for underdilated VCX and VTS was 15% (n = 7) and 30% (n = 14) and, for fully dilated VCX/VTS, was 45% (n = 9) (log-rank p = 0.008), respectively. CONCLUSIONS: This study demonstrated that VCX stent grafts underdilated to 8 mm do not passively expand to nominal diameter and suggests reduced hospital readmissions because of hepatic encephalopathy, uncontrolled ascites, and heart failure, and improved 1-year survival compared with underdilated VTS. LAY SUMMARY: Transjugular intrahepatic portosystemic shunt (TIPS) improves survival in selected patients with liver cirrhosis and acute variceal bleeding or refractory ascites. Smaller 8-mm diameter TIPS stent grafts appear to improve patient outcome compared with larger 10-mm diameter stent grafts. Novel VIATORR® Controlled Expansion (VCX) stent grafts facilitate safe and stable underdilation to 8 mm of large 10-mm diameter stent grafts with improved patient outcome (survival, hepatic encephalopathy, ascites and heart failure) compared with legacy VIATORR TIPS stent graft (VTS). Thus, the use of underdilated VCX could preserve heart function. CLINICAL TRIALS REGISTRATION: The study is registered at Clinicaltrials.govNCT03628807.

Isolation and characterization of a novel glucosyltransferase involved in production of emodin-6-O-glucoside and rhaponticin in Rheum palmatum.

Anthraquinones are widely distributed in various organisms and known as bioactive ingredients. Some of the anthraquinones accumulate as glycosides in higher plants. Plant secondary product glycosyltransferases (PSPGs) are the well-characterized enzymes producing plant secondary metabolite glycosides. However, PSPGs involved in the formation of anthraquinone glycosides remains unclear. The rhizome of Rheum palmatum contains anthraquinones as laxative agents, some of which are accumulated as glucosides. We isolated a glucosyltransferase, R. palmatum UDP-glycosyltransferase (RpUGT) 1 from the rhizome of R. palmatum, and characterized functionally. RpUGT1 glucosylated emodin yielding emodin-6-O-glucoside, and it also glucosylated rhapontigenin, a compound belonging to stilbenes, yielding rhaponticin. The expression patterns of RpUGT1 and the accumulation of the metabolites revealed that RpUGT1 contributes to the production of these glucosides in R. palmatum. These results may provide important information for the substrate recognition of the PSPGs for anthraquinones and stilbenes.

The enzymatic biosynthesis of acylated steroidal glycosides and their cytotoxic activity.

Herein we describe the discovery and functional characterization of a steroidal glycosyltransferase (SGT) from Ornithogalum saundersiae and a steroidal glycoside acyltransferase (SGA) from Escherichia coli and their application in the biosynthesis of acylated steroidal glycosides (ASGs). Initially, an SGT gene, designated as OsSGT1, was isolated from O. saundersiae. OsSGT1-containing cell free extract was then used as the biocatalyst to react with 49 structurally diverse drug-like compounds. The recombinant OsSGT1 was shown to be active against both 3ß- and 17ß-hydroxyl steroids. Unexpectedly, in an effort to identify OsSGT1, we found the bacteria lacA gene in lac operon actually encoded an SGA, specifically catalyzing the acetylations of sugar moieties of steroid 17ß-glucosides. Finally, a novel enzymatic two-step synthesis of two ASGs, acetylated testosterone-17-O-ß-glucosides (AT-17ß-Gs) and acetylated estradiol-17-O-ß-glucosides (AE-17ß-Gs), from the abundantly available free steroids using OsSGT1 and EcSGA1 as the biocatalysts was developed. The two-step process is characterized by EcSGA1-catalyzed regioselective acylations of all hydroxyl groups on the sugar unit of unprotected steroidal glycosides (SGs) in the late stage, thereby significantly streamlining the synthetic route towards ASGs and thus forming four monoacylates. The improved cytotoxic activities of 3'-acetylated testosterone17-O-ß-glucoside towards seven human tumor cell lines were thus observable.