Physiological, biochemical and molecular characterizaiton of nitrate transport during n uptake and remobilization in sugarcane (Saccharum spp.)

Abstract

The increasing yield of modern agriculture, together with increase demand for renewable sources of energy have led to the indiscriminate use of nitrogen fertilizers with a negative impact in the environment. Therefore, it becomes evident the requirement to improve the application and use efficiency of N fertilizers by crops in Brazil. Sugarcane presents a great importance in Brazil for the economic contribution and cultivated area. Compared to other crop plants, the nitrate use efficiency of sugarcane as the inorganic source of N is low, with unknown physiological and genetics causes for this reduced efficiency. This project aims to characterize the nitrate uptake process by sugarcane roots, as well as the process regulation in relation to the plant N status and to the inorganic sources of N(ammonium and nitrate) and characterize the transport and remmobilization of nitrate and N derived from nitrate in shoots by uptake kinetic studies and 15N redistribution, global metabolic profile and N metabolism key enzyme activities in sugarcane. Characterization of transcriptional profile of genes from the NRT/PRT (NITRATE TRANSPORTERS/ PEPTIDE TRANSPORTERS) family, encoding membrane transporters in plants will be related with data from nitrate uptake and transport and metabolic profile in sugarcane, enabling to infer about nitrate metabolism in sugarcane, and helping to elucidate the adaptive process according to the N availability in the soil. (AU)