Investigating the regulatory roles of the microRNAs and the Argonaute 1-enriched small RNAs in plant metabolism

The biological roles of small RNAs (sRNAs) in metabolic processes are emerging. However, a systemic study is needed to investigate the wide-spread involvement of the sRNAs in plant metabolism. By using the metabolism-related transcripts retrieved from the public database Plant Metabolic Network, and the publicly available sRNA high-throughput sequencing data, large-scale target identification was performed for microRNAs (miRNAs) and Argonaute 1 (AGO1)-enriched sRNAs in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa). Based on the publicly available degradome sequencing data, 200 miRNA/sRNA-target pairs involving 19 miRNAs, 111 AGO1-enriched sRNAs and 58 target transcripts in Arabidopsis, and 151 pairs involving 62 miRNAs, 33 AGO1-enriched sRNAs and 69 target transcripts in rice were identified. After considering protein-protein interactions for the above identified target genes, a total of 251 pairs involving 21 miRNAs, 120 AGO1-enriched sRNAs and 75 target transcripts exist within the regulatory network of Arabidopsis, and 168 pairs involving 64 miRNAs, 38 AGO1-enriched sRNAs and 80 target transcripts exist in rice. Based on GO (Gene Ontology) term enrichment analysis, the targets within the networks of both plants are enriched in “metabolic process” and “catalytic activity”, pointing to the high relevance of the established networks to metabolism. Several functionally conserved subnetworks were identified between the two plant species. Our study provides a basis for studies on metabolism-related sRNAs in plants.