Use of the cryptogein gene to stimulate the accumulation of Bacopa saponins in transgenic Bacopa monnieri plants.
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 A(3), 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.                         Key message The cryptogein gene, which encodes a proteinaceous elicitor is associated with increase in secondary metabolite accumulation-either alone or in addition to the increases associated with transformation by A. rhizogenes.
Department of Botany, Centre of Advanced Study, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India.
Sukanya
S
Majumdar
Saraswati
S
Garai
Sumita
S
Jha
D060054:Agrobacterium / Q000235:genetics / Q000378:metabolism; D034681:Bacopa / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D054337:Cell Dedifferentiation; D002454:Cell Differentiation; D003470:Culture Media / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D006027:Glycosides / Q000096:biosynthesis*; D007612:Kanamycin / Q000494:pharmacology; D010838:Phytophthora / Q000737:chemistry; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D012503:Saponins / Q000096:biosynthesis*; D014170:Transformation, Genetic; D014315:Triterpenes
D003470:Culture Media; D005656:Fungal Proteins; D006027:Glycosides; D012503:Saponins; D014315:Triterpenes; C454645:bacopasaponin C; C411343:bacopasaponin F; C476480:bacopaside III; C061032:cryptogein protein, Phytophthora cryptogea; C087625:bacoside A3; D007612:Kanamycin; C442169:bacopaside II