3'-to-5' exoribonuclease (RNase) specifically targeting single-stranded RNAs (PubMed:28463111). Triggers miRNA accumulation in RNA-induced silencing complex (RISC), composed of miRNAs and AGO proteins, by degrading uridylated cleavage fragments (PubMed:28463111). Required during plant growth and development (By similarity). Exonucleolytic cleavage in the 3'- to 5'-direction to yield nucleoside 5'-phosphates. Homohexamer with DnaQ-like exonuclease fold in a ring-shaped structure with a central cavity (PubMed:28463111, PubMed:23616405, PubMed:17850744). Component of AGO1 and AGO10-centered RNA-induced silencing complexes (RISC) (PubMed:28463111). Interacts with and acts as a cofactor of AGO1 and AGO10 (PubMed:28463111). Restricted to shoot and root apical meristems, trichomes, and vascular veins. Little effect on miRNAs levels (PubMed:28463111). Plants lacking both RICE1 and RICE2 have reduced miRNAs levels and lower miRNA retained by AGO1, thus leading to the up-regulation of targeted mRNA transcripts (PubMed:28463111). Belongs to the RICE family.