Abstract
Model legume Lotus japonicus has been used for symbiotic nitrogen fixation (SNF) study. Lotus has LORE1, endogenous active Ty3-gypsy retrotransposon, and attempt to establish gene tagging system using LORE1 is undergoing. Here, we report the identification of another active retrotoransposon, LORE2 (Lotus Retrotransposon 2).
Responsible genes of two independent SNF mutants, isolated from Ac/Ds tagging population, were found to be interrupted by endogenous Ty3-gypsy retrotransposons. They were very similar to each other and designated as LORE2. Number of cognate LORE2 copies in Gifu was estimated as around twenty.
LORE2 transcripts were detected in all tissues investigated, however, up-regulation of transcription in calli, well-known phenomenon for other active retrotransposons in plant, was not seen for LORE2. It was assumed that LORE2 transposition in the two SNF mutants had happened in intact plant during sequence of screening for SNF mutants from the population.
