Abstract
We developed phytohormone-induced and Agrobacterium-induced root culture systems using a model legume, Lotus japonicus. Root segments of aseptic seedlings were inoculated in B5 medium supplemented with 0.1 mg/l indole-3-butyric acid. A number of adventitious roots were elongated, and the fresh weight was increased more than 20 times in three weeks. The condensed tannin content in the roots cultured in B5 medium was 0.4-0.5 mg/g fw and was tripled if roots were cultured in a modified B5 medium containing both 1/10 levels of nitrogen and phosphate. On the other hand, we optimized the protocol for hairy root induction with A. rhizogenes infection. In order to modify the isoflavonoid content, we produced hairy roots transformed with a cDNA encoding a dehydratase involved in isoflavone biosynthesis in soybean. The flavonoid composition in the transgenic hairy roots will be reported.
