Browsing by Author "Buragohain, Alak Kumar"

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Comparative analysis of phytochemicals and nutrient availability in two contrasting cultivars of sweet potato (Ipomoea batatas L.)
(Elsevier B.V., 2014) Shekhar, Shubhendu; Mishra, Divya; Buragohain, Alak Kumar; Chakraborty, Subhra; Chakraborty, Niranjan
Sweet potato ranks as the world's seventh most important food crop, and has major contribution to energy and phytochemical source of nutrition. To unravel the molecular basis for differential nutrient availability, and to exploit the natural genetic variation(s) of sweet potato, a series of physiochemical and proteomics experiment was conducted using two contrasting cultivars, an orange-fleshed sweet potato (OFSP) and a white-fleshed sweet potato (WFSP). Phytochemical screening revealed high percentage of carbohydrate, reducing sugar and phenolics in WFSP, whereas OFSP showed increased levels of total protein, flavonoids, anthocyanins, and carotenoids. The rate of starch and cellulose degradation was found to be less in OFSP during storage, indicating tight regulation of gene(s) responsible for starch-degradation. Comparative proteomics displayed a cultivar-dependent expression of proteins along with evolutionarily conserved proteins. These results suggest that cultivar-specific expression of proteins and/or their interacting partners might play a crucial role for nutrient acquisition in sweet potato.
Comparison of proteomic and metabolomic profiles of two contrasting ecotypes of sweetpotato (Ipomoea batata L)
(Elsevier B.V., 2016) Shekhar, Shubhendu; Mishra, Divya; Gayali, Saurabh; Buragohain, Alak Kumar; Chakraborty, Subhra; Chakraborty, Niranjan
Sweetpotato has long been acknowledged as a significant contributor of global caloric needs, which continues to be of remarkable economic value. It is an important staple and emergency food in many countries and its annual world production hovers to about 130 million tons. The tubers act as sink and compete for the available photoassimilates eventually leading to the acquisition of nutrients and phytochemicals. Differential display of genes or gene-products, and metabolites causes differences in nutritive value of closely related ecotypes. To better understand the molecular basis for differential nutrient availability and phytochemicals, and exploit the natural genetic variation(s), we aimed at developing proteometabolic profiles of two contrasting ecotypes of sweetpotato. Proteomic analyses led to the identification of 1541 and 1201 proteins in orange fleshed and white fleshed sweetpotato ecotypes, respectively, presumably associated with binding, followed by catalytic, transferase, hydrolase, kinase and transporter activities. Furthermore, metabolome profiling revealed 148 and 126 metabolites in cv. OFSP and WFSP, respectively. This study would provide a basis for future comparative proteometabolomic efforts for sweetpotato, in particular and tuber crops in general. The results would expand our understanding of the proteome as well as metabolome and give new insights into how ecotype-specific traits are developed.
Ectopic expression of amaranth seed storage albumin modulates photoassimilate transport and nutrient acquisition in sweetpotato
(Nature Publishing Group, 2016) Shekhar, Shubhendu; Agrawal, Lalit; Mishra, Divya; Buragohain, Alak Kumar; Unnikrishnan, Mullath; Mohan, Chokkappan; Chakraborty, Subhra; Chakraborty, Niranjan
Storage proteins in plants, because of high nutrient value, have been a subject of intensive investigation. These proteins are synthesized de novo in the cytoplasm and transported to the storage organelles where they serve as reservoir of energy and supplement of nitrogen during rapid growth and development. Sweetpotato is the seventh most important food crop worldwide, and has a significant contribution to the source of nutrition, albeit with low protein content. To determine the behaviour of seed storage proteins in non-native system, a seed albumin, AmA1, was overexpressed in sweetpotato with an additional aim of improving nutritional quality of tuber proteins. Introduction of AmA1 imparted an increase in protein and amino acid contents as well as the phytophenols. The proteometabolomics analysis revealed a rebalancing of the proteome, with no significant effects on the global metabolome profile of the transgenic tubers. Additionally, the slower degradation of starch and cellulose in transgenic tubers, led to increased post-harvest durability. Present study provides a new insight into the role of a seed storage protein in the modulation of photoassimilate movement and nutrient acquisition.