Agrobacterium-mediated transformation of lavandin (Lavandula x intermedia Emeric ex Loiseleur)

Lavandin (Lavandula x Emeric ex Loiseleur) is an aromatic plant, the essent ial oil of which is widely used in the perfume, cosmetic, flavouring and ph armaceutical industries. The qualitative or quantitative modification of it s terpenes-containing essential oil by genetic engineering could have impor tant scientific and commercial applications. In this study, we report the f irst Agrobacterium tumefaciens-mediated gene transfer into lavandin. The tr ansformation protocol was optimized by lengthening precultivation and cocul tivation periods and by testing five different bacterial strains. We obtain ed transformed callus lines at a frequency of 40-70 with strains AGL1/GI, E HA105/GI and C58/GI. Transgenic shoots were regenerated from these kanamyci n resistant calli and rooted on selective medium with 150 mg l(-1) kanamyci n. The final percentage of transgenic plants obtained varied from 3 to 9, a ccording to the strain used, within 6 months of culture. The presence of th e introduced beta-glucuronidase and neomycin phosphotransferase II genes wa s shown both by PCR and Southern blot analysis. Transgene expression was in vestigated using histoenzymatic beta-glucuronidase assays, leaf callus assa ys and RT-PCR. Results showed that both beta-glucuronidase and neomycin pho sphotransferase II genes were expressed at a high level in at least 41 of t he transgenic plants regenerated. This efficient transformation strategy co uld be used to modify some genetic traits of lavandin (flower colour, patho gens resistance) and to study the biosynthesis of the major monoterpene com ponents of its essential oil (linalool, linalyl acetate, camphor and 1,8-ci neole).