Impingement of miRNAs During Biotic and Abiotic Stress on Metabolic Pathways of Rice

_{Rice, consumed by half of the world's population, is under constant threat of several biotic and abiotic stresses. To assist the rice biotechnologist, to improve the quality and quantity of rice, there is a need to unravel the regulation of rice cellular physiology under normal versus stress condition.}

_{Here we showed how stress (like drought, salt, ABA, H2O2) induced miRNAs, collected from literatures, are involved in the regulation of rice metabolism. The metabolic pathways were taken from RiceCyc database. We identified the enzymes and hence the metabolic processes targeted by one or many miRNAs. A miRNA–miRNA coregulatory network was also generated where miRNAs are nodes and an edge exists between two miRNAs if their targets share a common pathway and are significantly enriched in that pathway. In depth study of pathways targeted by miRNAs expressed at different stress conditions revealed some potential target enzymes and hence, pathways. Some of them are sulfur metabolism, amino acid and starch biosynthesis, etc. While some pathways are co-regulated by a set of miRNAs, some miRNAs regulate different enzymes of single pathway. We have also constructed a genome scale miRNA-miRNA co-targeting and co-functional network and thereby identified some modules relating rice cellular physiology. A web-based tool (C2 analyzer), developed by us, was used in this analysis and would be helpful for others.}

_{The results might provide a platform for testing the hypothetical role of co-targeting associations in rice post-transcriptional control. By manipulating the expression of these regulatory RNAs, stress tolerant rice plant could be designed.}

_{Grant: UGC(RFSMS), Govt. of India.}