Ppmar1 and Ppmar2: the first two complete and intact full-length mariner-like elements isolated in Phyllostachys edulis

Abstract We report the isolation of two full-length mariner-like elements (MLEs) from a bamboo species (Phyllostachys edulis) by chromosome walking using a modified magnetic enrichment procedure. Ppmar1 is 3472 base pairs (bp) in length with 28-bp perfect inverted terminal repeats (ITRs) and a 1986-bp open reading frame (ORF) encoding transposase, whereas Ppmar2 is 2679 bp in length with the 27-bp perfect ITRs and the 1877-bp ORF encoding transposase. Ppmar1 and Ppmar2 share the typical ITR consensus sequences of plant MLEs (5′-CTC CCT CCR T-3′, where R is A or G) and the typical TA/AT target site duplications. Phylogenetic analysis demonstrated that Ppmar1 belongs to clade A2 and Ppmar2 to clade C of plant MLE subfamilies. The two transposases encoded contain intact DNA-binding motifs and a DD39D catalytic domain and many residues previously shown to be critical for transposase activity are conserved in Ppmar1 and Ppmar2. All the above results imply that both transposons are likely to be naturally active. Cloning of two full-length mariner-like elements would provide a foundation for the investigation of transpositional activity of moso bamboo MLE.