Planta (2005), in press.
The Agrobacterium rhizogenes rolC-gene induced somatic embryogenesis and shoot organogenesis in Panax ginseng transformed calluses
Gorpenchenko 1 T.Y.,
Kiselev 1 K.V.,
Bulgakov 1 V.P., Tchernoded 1
G.K., Bragina 2
E., Khodakovskaya 1 M.V., Koren
1 O.G., Batygina
2 T.B., Zhuravlev 1 Yu.N.
1- Institute of Biology and Soil Sciences, Far East Division, Russian Academy of Sciences, pr. Stoletiya Vladivostoka 159, Vladivostok, 690022 Russia; fax: 7 (4232) 31-0193; e-mail: bulgakov@ibss.dvo.ru 2- Komarov Botanical Institute of Russian Academy of Sciences, 2 Prof. Popov Street, St.-Petersburg, 197376, Russia
Abstract
Expression of the Agrobacterium rhizogenes rolC gene in Panax ginseng
callus cells results in formation of tumors that are capable to form roots.
The selection of the tumor clusters, which did not develop roots, yielded the
embryogenic 2c3 callus line. The ability to form somatic embryos is independent
of external growth factors. Such developmental shift is of particular interest
because this is the first indication of the rolC-embryogenic effect and,
to our knowledge, the first indication that a single gene of non-plant origin
can induce somatic embryogenesis in plants. The DNA sequence analysis showed
that the somatic-to-embryonic transition was not due to a mutation of the rolC
gene inserted. Although the 2c3 somatic embryos developed through a typical
embryogenesis process, they terminated prematurely and repeatedly formed adventitious
shoot meristems and embryo-like structures. A part of the shoots and somatic
embryos formed enlarged and fasciated meristems. The observed developmental
abnormalities are similar to those that have been previously described for Arabidopsis
embryogenic calluses where the WUSCHEL gene was continuously overexpressed.