A label-free proteomic approach differentiates between conventional and organic rice

Rice is a major cereal in the food industry. In this study, a quantitative label-free proteomic characterization of the organic rice proteome was performed; the proteome was compared to its conventional counterparts. As a result, a total of 114 proteins were significantly changed between the organic and conventional rice samples. Among them, 56 proteins were regarded as upregulated proteins and 58 were downregulated proteins in organic cultivated samples. Molecular function and bioinformatics analyses indicated that changes in the biosynthesis of secondary metabolites, metabolic pathways, and microbial metabolism in diverse environments contributed to the differences. These results were confirmed through the identification of 20 significantly changed metabolites. Specifically, these proteins mainly corresponded to carbohydrate metabolism, ribosome biogenesis, and the stress response. This in-depth study of proteins in rice extracts has implicated the role of those metabolic cycles involved in planting patterns, and represents a starting point in the selection of key proteins for rice authentication in the food industry.