Agrobacterium-Mediated Transformation of Jojoba [Simmondsia chinensis (Link.) Schneider]

抄録

Jojoba is an important oil crop that produces unique wax ester in seeds. Genetic transformation of jojoba, however, has not been reported yet. In this study, we used nodal segments as explants for transformation of jojoba by an Agrobacterium strain harbouring a plasmid containing the GUS gene with an intron, as well as the hygromycin resistance gene. Multiple shoots were regenerated from axillary buds of the nodal segments that were infected by the Agrobacterium strain. GUS activity was detected by histochemical assay in nodal segments as well as in the regenerated shoots that suggests jojoba cells were stably transformed and regenerated. Sonication and shaking treatments of the explants did not significantly affect on the transformation efficiency, but rather negatively affected on shoot regeneration. To obtain the effective hygromycin concentration for the selection of transgenic shoots, we examined hygromycin sensitivity of non-transgenic shoots on jojoba explants, and found that none of the shoots survived on the medium with 30 mg L^-1 of hygromycin. Regenerated shoots of Agrobacterium-treated explants were then selected on the same medium, and hygromycin-resistant shoots were observed with frequencies of 3.3 - 16.4 %. We also detected expression of the GUS gene in the hygromycin-resistant shoots by RT-PCR and GUS staining. This study is the first report of the successful introduction and expression of a foreign gene into jojoba, and will lead to generation of transgenic jojoba plants useful for the tropical and subtropical agriculture.