Induction and characterization of callus from Psammosilene tunicoides hairy roots

Zong-shen Zhang, Nan-nan Qiu,

Abstract

In our previous study, we reported the success of inducing hairy roots from the P. tunicoides leaves by infection of Agrobacterium rhizogenes ACCC10060. In this paper, we further reported the induction of callus from the induced hairy roots of P. tunicoides. Results showed that 6-BA and 2,4-D improved the dedifferentiation of hairy roots by inhibition of its growth, while NAA and KT both had no detectable effect on this aspect. Rational combination of 6-BA and 2,4-D therefore led to successful dedifferentiation of the induced hairy roots into callus. Agropine analyses demonstrated that hairy root-derived callus still remained the ability of agropine biosynthesis, which suggested that the callus didn’t lose its transformed Ri genes after dedifferentiation. More important, the content of total saponins within hairy root-derived callus appeared indistinguishable from that of the parental hairy roots, and four times higher than that of normal callus (induced from normal explants, such as leaves, root tips, flowers etc.), indicating the strong ability of synthesizing secondary metabolites within hairy root-derived callus. Taken together, these results suggested that the large scale culture of hairy root-derived callus would be an efficient alternative to the field cultivation or wildlife resources of P. tunicoides for the production of useful natural compounds.