A novel family of cyclic oligopeptides derived from ribosomal peptide synthesis of an in planta-induced gene, gigA, in Epichloë endophytes of grasses.

•A group of cyclic peptides (epichloëcyclins) are the product of a single gene, gigA.•gigA encodes a small secreted protein containing an imperfect 27 amino acid repeat.•Epichloëcyclins vary due to both sequence and repeat number within the gigA gene.•Epichloëcyclins are synthesised by a ribosomal peptide synthetic (RiPS) pathway.