The Agrobacterium rhizogenes rolC-gene-induced somatic embryogenesis and shoot organogenesis in Panax ginseng transformed calluses

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 non-root forming tumor clusters yielded the embryogenic 2c3 callus line, which formed somatic embryos and shoots independently of external growth factors. 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. This is the first indication of the rolC gene embryogenic effect and, to our knowledge, the first indication that a single gene of non-plant origin can induce somatic embryogenesis in plants.

Recent Advances in the Understanding of Agrobacterium rhizogenes-Derived Genes and Their Effects on Stress Resistance and Plant Metabolism

“…The main effect is that rolC-transformed cells demonstrate a high viability during long-term cultivation [9,11,29,54]. For example, rolC-transformed roots of Panax ginseng, established almost 20 years ago, continue to grow well up to the present day.…”

“…In contrast, normal in vitro cultivated roots of this plant demonstrate less viability during a long-term cultivation. RolC-low expressing P. ginseng calli (2c2 line) is characterized by a remarkably stable and vigorous pattern of growth over a long period (over 12 years) without any selection [29]. Callus cultures of rolC-transformed cells of R. cordifolia possess a remarkably stable and vigorous growth during a 12-year period of cultivation [54].…”

Molecular characterization of ginseng farnesyl diphosphate synthase gene and its up-regulation by methyl jasmonate

“…RNA (1 μg) was utilized as a template. For normalization, actin gene was employed as an external standard, as described by Gorpenchenko et al (2006). RT-PCR conditions for both actin gene and PgFPS were as follows: one cycle at 45 °C for 45 min, and then 30 cycles at 95 °C for 1 min, 56 °C for 1 min, 72 °C for 1 min; and a final 5-min extension at 72 °C.…”

Structure-Function Analysis of Transformation Events

“…The transformed cells are successfully induced and form an embryo-like structure. However, without reaching the torpedo stage, the structures revert to embryogenesis, now secondary, and the cycle is repeated over many passages (Gorpenchenko et al, 2006). We understand the results of this experiment as follows.…”