Use of the cryptogein gene to stimulate the accumulation of bacopa saponins in transgenic Bacopa monnieri plants

摘要

Genetic transformation of the Indian medicinal plant, Bacopa monnieri, using a gene encoding cryptogein, a proteinaceous elicitor, via Ri and Ti plasmids, were established and induced bioproduction of bacopa saponins in crypt-transgenic plants were obtained. Transformed roots obtained with A. rhizogenes strain LBA 9402 crypt on selection medium containing kanamycin (100 mg l−1) dedifferentiated forming callus and redifferentiated to roots which, spontaneously showed shoot bud induction. Ri crypt-transformed plants thus obtained showed integration and expression of rol genes as well as crypt gene. Ti crypt-transformed B. monnieri plants were established following transformation with disarmed A. tumefaciens strain harboring crypt. Transgenic plants showed significant enhancement in growth and bacopa saponin content. Bacopasaponin D (1.4–1.69 %) was maximally enhanced in transgenic plants containing crypt. In comparison to Ri-transformed plants, Ri crypt-transformed plants showed significantly (p ≤ 0.05) enhanced accumulation of bacoside A3, bacopasaponin D, bacopaside II, bacopaside III and bacopaside V. Produced transgenic lines can be used for further research on elicitation in crypt-transgenic plants as well as for large scale production of saponins.