Abstract
LORE1 (Lotus Retrotransposon 1) is a Ty3-gypsy retrotranposon family in Lotus japoncius, of which transpositional activity has been indirectly demonstrated by the identifications of the three symbiotic (sym) mutants of which responsible genes were inactivated by LORE1 insertions (Madsen, et al. 2005). This time we report the direct demonstration of transpositional activity of LORE1.
The three sym mutants were isolated from same Ac transposon tagging population, established by introducing maize transposon Ac to L. japonicus accession Gifu by tissue culture mediated transformation procedure (Thykjaer, et al. 1995). Therefore, we inferred that the activation of LORE1 is related to in vitro tissue culture process. Our investigations revealed that LORE1 activation can be triggered via tissue culture process, however the transpositions occur in regenerated intact plants, not during tissue culture. Furthermore, LORE1 was shown to transpose in gametophytic manner. Those data proved the feasibility of establishing gene tagging population of L. japonicus using LORE1.
