title: Characterization of Arabidopsis sterol glycosyltransferase TTG15/UGT80B1 role during freeze and heat stress.
abstract: Sterol glycosyltransferases regulate the properties of sterols by catalyzing the transfer of carbohydrate molecules to the sterol moiety for the synthesis of steryl glycosides and acyl steryl glycosides. We have analyzed the functional role of TTG15/UGT80B1 gene of Arabidopsis thaliana in freeze/thaw and heat shock stress using T-DNA insertional sgt knockout mutants. Quantitative study of spatial as well as temporal gene expression showed tissue-specific and dynamic expression patterns throughout the growth stages. Comparative responses of Col-0, TTG15/UGT80B1 knockout mutant and p35S:TTG15/UGT80B1 restored lines were analyzed under heat and freeze stress conditions. Heat tolerance was determined by survival of plants at 42°C for 3 h, MDA analysis and chlorophyll fluorescence image (CFI) analysis. Freezing tolerance was determined by survival of the plants at -1°C temperature in non-acclimatized (NA) and cold acclimatized (CA) conditions and also by CFI analysis, which revealed that, p35S:TTG15/UGT80B1 restored plants were more adapted to freeze stress than TTG15/UGT80B1 knockout mutant under CA condition. HPLC analysis of the plants showed reduced sterol glycoside in mutant seedlings as compared to other genotypes. Following CA condition, both β-sitosterol and sitosterol glycoside quantity was more in Col-0 and p35S:TTG15/UGT80B1 restored lines, whereas it was significantly less in TTG15/UGT80B1 knockout mutants. From these results, it may be concluded that due to low content of free sterols and sterol glycosides, the physiology of mutant plants was more affected during both, the chilling and heat stress.
authors.affiliation: a CSIR - National Botanical Research Institute ; Lucknow , India.
authors.forename: Manoj K
authors.initials: MK
authors.lastname: Mishra
authors.affiliation: a CSIR - National Botanical Research Institute ; Lucknow , India.
authors.forename: Gaurav
authors.initials: G
authors.lastname: Singh
authors.affiliation: a CSIR - National Botanical Research Institute ; Lucknow , India.
authors.forename: Shalini
authors.initials: S
authors.lastname: Tiwari
authors.affiliation: a CSIR - National Botanical Research Institute ; Lucknow , India.
authors.forename: Ruchi
authors.initials: R
authors.lastname: Singh
authors.affiliation: b Department of Botany ; Banaras Hindu University ; Varanasi , India.
authors.forename: Nishi
authors.initials: N
authors.lastname: Kumari
authors.affiliation: a CSIR - National Botanical Research Institute ; Lucknow , India.
authors.forename: Pratibha
authors.initials: P
authors.lastname: Misra
mesh_terms: D000064:Acclimatization; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D060146:Ecotype; D005453:Fluorescence; D005615:Freezing; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005964:Glucosyltransferases / Q000378:metabolism*; D006358:Hot Temperature; D015227:Lipid Peroxidation; D009154:Mutation; D010641:Phenotype; D011401:Promoter Regions, Genetic / Q000235:genetics; D012855:Sitosterols / Q000378:metabolism; D013312:Stress, Physiological; D013997:Time Factors
chemical_list: D029681:Arabidopsis Proteins; D012855:Sitosterols; C025473:gamma-sitosterol; D005964:Glucosyltransferases; C577617:UGT80B1 protein, Arabidopsis; C011015:lyoniside
keywords: Arabidopsis thaliana; chlorophyll fluorescence image; freeze stress; heat stress; sterol glycosyltransferases