Muhammad Zubair Khan has practical expertise in studying primary and secondary metabolites of plants especially of the medicinal plants from Himalayan region Northern to Pakistan. His analytical studies of Elaeagnus umbellata (Thunb.) fruit for its micronutrients have suggested the potential use of it in agricultural, pharmaceutical and the food industries. Based on the metabolic analysis, of the carotenoids, followed by cloning, Isolation and functional identification of carotenoids biosynthesis genes, he has reported a comprehensive carotenoids biosynthetic pathway in sweetpotato (Ipomoea batatas L.) for the first time. His research projects include the genetic, metabolic and pathway engineering of plants and microbes to synthesize nutritionally, medicinally and commercially high value bio-tech. products. His core area of research is synthesizing carotenoids and other isoprenoids which have economic impact in nutrition, pharmaceutical and other inter-related industries such as cosmetics, agriculture and aquaculture.Email: zubairgenes@gmail.com

Abstract: Introduction & Objective: Sweet potato (Ipomoea batatas L.) has not been fully evaluated for its primary and secondary metabolites in Pakistan. Although, it has seventh rank among the world food crop plants, no studies on local germplasm have been made regarding its variation and utilization in conventional and molecular plant breeding. Carotenoids, the visible colors of life are the 40-carbon isoprenoids synthesized naturally by fungi, bacteria, algae, cyanobacteria and lower and higher plants. They play numerous metabolically active roles in living organisms. Molecular mechanism of the carotenoides accumulation in sweet potato has not yet been fully studied.Method: Two sweet potato cultivars, WS and W71, were selected for carotenoid pigments extraction and analysis by HPLC-PDA-HRMS. Carotenoid composition in the leaves and tubers of sweet potato cultivars was calculated based on the HPLC chromatograms. 3′and 5′-RACE PCR were carried out to isolate full length cDNA sequences of carotenoids genes from s selected cultivars. Isolated carotenoids cyclase genes were simultaneously sequenced, functionally identified by E. coli heterologous gene complementation expression system and submitted to DDBJ and the GenBank respectively.rnrnResults: Carotenoids content and composition of sweet potato cultivar WS and W71 are shown in the table on right side. Tubers of cultivars, WS and W71 were found to contain unique carotenoids viz., β-carotene-5,8-epoxide, β-carotene-5,6,5′,8′-diepoxide and β-carotene-5,8,5′,8′-diepoxide Moreover, the WS and W71 tubers were found to contain ipomoeaxanthin A and β-cryptoxanthin-5′,6′-epoxide respectively.Conclusion: Based on the content and the composition of carotenoids analyzed a comprehensive carotenoids metabolic biosynthetic pathway was elucidated for the first time in sweet potato. These results will help in molecular cloning and elucidation of the carotenoids biosynthesis genes and their metabolic pathway engineering for enhanced production of novel carotenoids to be possibly used in agricultural, nutritional, pharmaceutical, and cosmetic industries.