title: Ectopic overexpression of WsSGTL1, a sterol glucosyltransferase gene in Withania somnifera, promotes growth, enhances glycowithanolide and provides tolerance to abiotic and biotic stresses.
abstract: Overexpression of sterol glycosyltransferase (SGTL1) gene of Withania somnifera showing its involvement in glycosylation of withanolide that leads to enhanced growth and tolerance to biotic and abiotic stresses. Withania somnifera is widely used in Ayurvedic medicines for over 3000 years due to its therapeutic properties. It contains a variety of glycosylated steroids called withanosides that possess neuroregenerative, adaptogenic, anticonvulsant, immunomodulatory and antioxidant activities. The WsSGTL1 gene specific for 3β-hydroxy position has a catalytic specificity to glycosylate withanolide and sterols. Glycosylation not only stabilizes the products but also alters their physiological activities and governs intracellular distribution. To understand the functional significance and potential of WsSGTL1 gene, transgenics of W. somnifera were generated using Agrobacterium tumefaciens-mediated transformation. Stable integration and overexpression of WsSGTL1 gene were confirmed by Southern blot analysis followed by quantitative real-time PCR. The WsGTL1 transgenic plants displayed number of alterations at phenotypic and metabolic level in comparison to wild-type plants which include: (1) early and enhanced growth with leaf expansion and increase in number of stomata; (2) increased production of glycowithanolide (majorly withanoside V) and campesterol, stigmasterol and sitosterol in glycosylated forms with reduced accumulation of withanolides (withaferin A, withanolide A and withanone); (3) tolerance towards biotic stress (100 % mortality of Spodoptera litura), improved survival capacity under abiotic stress (cold stress) and; (4) enhanced recovery capacity after cold stress, as indicated by better photosynthesis performance, chlorophyll, anthocyanin content and better quenching regulation of PSI and PSII. Our data demonstrate overexpression of WsSGTL1 gene which is responsible for increase in glycosylated withanolide and sterols, and confers better growth and tolerance to both biotic and abiotic stresses.
authors.affiliation: Tissue Culture and Plant Transformation Laboratory, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India.|Department of Bioscience, Integral University, Lucknow, India.
authors.forename: Syed
authors.initials: S
authors.lastname: Saema
authors.affiliation: Department of Biotechnology, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India.
authors.forename: Laiq Ur
authors.initials: LU
authors.lastname: Rahman
authors.affiliation: Tissue Culture and Plant Transformation Laboratory, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India.
authors.forename: Ruchi
authors.initials: R
authors.lastname: Singh
authors.affiliation: Tissue Culture and Plant Transformation Laboratory, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Niranjan
authors.affiliation: Department of Bioscience, Integral University, Lucknow, India.
authors.forename: Iffat Zareen
authors.initials: IZ
authors.lastname: Ahmad
authors.affiliation: Tissue Culture and Plant Transformation Laboratory, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India. pratibhaflora@gmail.com.
authors.forename: Pratibha
authors.identifier: http://orcid.org/0000-0003-1718-6238
authors.initials: P
authors.lastname: Misra
mesh_terms: D000818:Animals; D000872:Anthocyanins / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005960:Glucosides / Q000378:metabolism; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D045331:Photosystem I Protein Complex / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000378:metabolism; D010840:Phytosterols / Q000378:metabolism*; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D018411:Spodoptera / Q000502:physiology; D013312:Stress, Physiological; D014315:Triterpenes / Q000378:metabolism; D032341:Withania / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D054358:Withanolides / Q000378:metabolism*
chemical_list: C433551:3-rhamnopyranosyl(1-4)-glucopyranosyl-12-diacetoxy-20-hydroxywitha-5,24-dienolide; D000872:Anthocyanins; D005960:Glucosides; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D010840:Phytosterols; D010940:Plant Proteins; D014315:Triterpenes; D054358:Withanolides; D002734:Chlorophyll; D005964:Glucosyltransferases; C560597:withanone; C009684:withaferin A
keywords: Abiotic and biotic stress tolerance; Glycosylation; Growth; Transgenic Withania somnifera; Withanolides; WsSGTL1