Induction of hairy roots and plant regeneration from the medicinal plant Pogostemon Cablin

An efficient transformation system for the medicinal and aromatic plant, Pogostemon cablin Benth was developed by using Agrobacterium rhizogenes ATCC15834 and C58C1. Hairy roots formed directly from the cut edges of leaf explants after infection for 2 days. The highest frequency of leaf explant transformation by A. rhizogenes ATCC15834 and C58C1 were 83.3% and 80.5% after pre culture about 2 days and infection by the bacterium containing 15 mg l^-1 acetosyringone about 25 min. The PCR amplification showed that rolB genes of Ri plasmid of A. rhizogenes were integrated and expressed into the genome of transformed hairy roots. The optimum medium for callus induction of hairy roots consisted of 2.0 mg l^-1 benzyladenine (BA) and 0.1 mg l^-1 a-naphthaleneacetic acid (NAA); while optimum medium for adventitious shoot regeneration from these cultures consisted of 0.1 mg l^-1 BA and 0.1 mg l^-1 NAA. Adventitious shoots could be rooted on 1/2MS. PCR analysis confirmed that rol genes of TL-DNA of Ri plasmid was integrated with at least three copies into the genome of hairy roots-regenerated P. cablin plants. The results presented provide a possibility for breeding of a new cultivar of P. cablin.