The Ethylene effect on metabolic and proteomic profiles in Papaya.

Abstract

The ripening consists of a set of biochemical and physiological changes that occur in the final stage of development of fruit, making it attractive and edible to the consume. The climateric fruits like papaya have high rates of CO2 and auto-catalytic synthesis of the ethylene at the beginning of ripening. Ethylene is responsible for several changes in fruit development and ripening: among then changes in activities and protein-related-expression of enzymes. Studies with transgenic fruits have shown the change of the expression of numerous genes in response to the hormone ethylene, many of these genes related directly to the quality of fruits. Studies are showed, that some physicochemical changes, and even the expression of some genes in fruit, are differently affected by the level and/or ethylene perception during ripening because some events are more or less ethylene-dependent. Recently, studies with papaya have shown significant differences in transcriptome profile, even after a small treatment with exogenous ethylene, revealing valuable aspects of regulation of this hormone at the beginning of the apaya ripening. However, the determination of metabolites levels is a fundamental complement in determination of gene function, because the levels of metabolites represent an integrative information of cellular function, molecular level in response to genetic or changing environmental. Thus, the understanding of some processes, such as the ripening of fruit, has been possible due to the union of complementary techniques such as genomics Proteome and Metabolome. Recent studies of proteome of mature papaya pulp compared to green stage revealed expressive increase of protein synthesis related to ripening. The comparison of fruit treated with exogenous ethylene in a much smaller range of time, compared to control fruit, would reveal the individual action of ethylene in the context of ripening. The metabolic profile has been shown to be an important tool for the understanding of metabolic changes in large-scale fruit ripening and its correlations between the different metabolic pathways. There are no studies in papaya fruit focusing the metabolic profile in relation to ripening, nor about the effect of the ethylene hormone on the beginning of fruit ripening. In addition, there are no comparative studies between the metabolic profile and proteomic profile during the early ripening events. Thus, treatment with ethylene exogenous in a short period of time would be a way to induce controlled changes and a way to verified the directly action of the hormone on metabolic and proteomic profile of papaya. Thus, the overall objective of this project is to verify the changes in the metabolic and proteomic profiles associated with ethylene treatment, to better understand the ethylene effects in climacteric stage of papaya ripening. The this project proposes the treatment with exogenous ethylene in papaya for a short treatment time, followed by analysis and detection of metabolic and proteomic profile, and the analysis and processing of data, with the aid of bioinformatics tools for classification and correlation of metabolic and proteins groups to better understand the points of metabolic regulation affected by the action of ethylene in relation to the ripening process of fruit.