Transposition of the retrotransposon MAGGY in heterologous species of filamentous fungi

MAGGY is a gypsy like LTR retrotransposon isolated from the blast fungus Py ricularia grisea (teleomorph, magnaporthe grisea). We examined transpositio n of MAGGY in three P. grisea isolates (wheat, finger millet, and crabgrass pathogen), which did not originally possess a MAGGY element, and in two he terologous species of filamentous fungi, Colletotrichum lagenarium and P. z ingiberi. Genomic Southern analysis of MAGGY transformants suggested that t ransposition of MAGGY occurred in all filamentous fungi tested. In contrast , no transposition was observed in any transformants with a modified MAGGY containing a 513-bp deletion in the reverse transcriptase domain. When a MA GGY derivative carrying an artificial intron was introduced into the wheat isolate of P. grisea and C. lagenarium, loss of the intron was observed. Th ese results showed that MAGGY can undergo autonomous RNA-mediated transposi tion in heterologous filamentous fungi. The frequency of transposition diff ered among fungal species. MAGGY transposed actively in the wheat isolate o f P. grisea and P. zingiberi, but transposition in C. lagenarium appeared t o be rare. This is the first report that demonstrates active transposition of a fungal transposable element in heterologous hosts. Possible usage of M AGGY as a genetic tagging tool in filamentous fungi is discussed.