ICAR-Indian Institute of Sugarcane Research, India
Amaresh Chandra has completed his PhD from Jawaharlal Nehru University, New Delhi, India and Postdoctoral studies from CSIRO, Australia and USDA-ARS, USA. He is the Head of Plant Physiology and Biochemistry Department at Indian Institute of Sugarcane Research, Lucknow, a premier institute of Indian Council of Agricultural Research (ICAR), Ministry of Agriculture and Farmers Welfare, Government of India. He has published more than 100 papers in reputed journals and has been serving as associate editor of Acta Physiologiae Plantarum and consulting editor of SugarTech.
Sugarcane is a sucrose accumulating crop plant accounting for >70% of the world’s sugar supply. Even though it has been reported to have a bio-physiological limit to store up to 62% of dry weight and 25% of fresh weight of culm as sucrose, most commercial cultivars presently yield less sucrose, offering considerable scope to improve culm sucrose content. Uniquely, this crop possesses working source-sink systems, wherein the leaves constitute the ‘source’, while the growing stalk/culm also the major sucrose storage tissue, serves as ‘sink’ and tandem signaling between these tissues ultimately controls plant growth and sucrose accumulation. Sucrose synthesis/accumulation in sugarcane involves the complex interaction of many genes and regulatory sequences that control biochemical events in both source and sink tissues; some pivotal genes exhibited differential expression in both spatial and temporal manners. Expression of these genes was suppressed by enzyme inhibitors such as manganese chloride (Mn++), which led to decline in sucrose accumulation. Perturbation of source-sink communication achieved by application of GA3, resulted in improved sink strength and consequent redistribution of photosynthates. In comparison to control, the GA3 applied canes showed a prominent increase in internode length, brix%, pol% and a comparable decrease in reducing sugars due to increase in sink potential which lost effect over the period of three months after GA3 application. Differential gene expression patterns as observed with GA3 applications influence the source-sink communication exhibiting increased sink strength to retain more sucrose in culm tissues.