Simplified Transposon Display (STD): a New Procedure for Isolation of a Gene Tagged by a Transposable Element Belonging to the Tpn1 Family in the Japanese Morning Glory.

Transposable elements are regarded as a powerful mutagen and as an effective tool to isolate genes tagged by transposon insertions. In the Japanese morning glory, a number of spontaneous mutants related to the colors and shapes of the flowers have been isolated. The plant contains around 500-1000 copies of an En/Spm-related element Tpn1 and its relatives, which act as major spontaneous mutagens. We have developed a new protocol for identifying genes tagged by insertion of Tpn1-related elements. The procedure, named simplified transposon display (STD), is simple and requires neither biotinylated oligonucleotides nor streptavidin-capturing which are essential in other transposon display methods published recently. Here we describe the details of STD used for identification of the Purple(Pr) gene that encodes a vacuolar Na+/H+ exchanger for increasing vacuolar pH responsible for blue flower coloration.