Transposition of the bamboo Mariner-like element Ppmar1 in yeast

The moso bamboo genome contains the two structurally intact and thus potentially functional mariner like elements Ppmarl and Ppmarl. Both elements contain perfect terminal inverted repeats (TIRs) and a full-length intact transposase gene. Here we investigated whether Ppmarl is functional in yeast (Saccharomyces cerevisiae). We have designed a two-component system consisting of a transposase expression cassette and a non-autonomous transposon on two separate plasmids. We demonstrate that the Ppmarl transposase Pptpasel catalyses excision of the non-autonomous Ppmarl NA element from the plasmid and reintegration at TA dinucleotide sequences in the yeast chromosomes. In addition, we generated 14 hyperactive Ppmarl transposase variants by systematic single amino acid substitutions. The most active transposase variant, S171A, induces 10-fold more frequent Ppmarl NA excisions in yeast than the wild type transposase. The Ppmarl transposon is a promising tool for insertion mutagenesis in moso bamboo and may be used in other plants as an alternative to the established transposon tagging systems. (C) 2017 Elsevier Inc. All rights reserved.