Possesses 5'->3' exoribonuclease activity. Acts as an endogenous post-transcriptional gene silencing (PTGS) suppressor. Degrades miRNA target cleavage products that lack a 5'-cap structure. Antagonizes the negative feedback regulation on EIN3 by promoting EBF1 and EBF2 mRNA decay, which consequently allows the accumulation of EIN3 protein to trigger the ethylene response. Expressed in roots, leaves, stems and flowers. Not induced by ethylene. Plants are viable with no apparent deleterious phenotype. Belongs to the 5'-3' exonuclease family. XRN2/RAT1 subfamily.