Abstract

Agrobacterium rhizogenes strains viz., 532, 2364 and A4 were used to induce hairy roots in Psoralea corylifolia. Strain A4 induced the maximum hairy roots in leaf explants with root induction frequency of 80%. Manual wounding of explant with the addition of 100 µM acetosyringone in the medium resulted in better induction of hairy roots. Transfer of Ri plasmid was confirmed by the detection of ags gene in transformed hairy roots. Among the different concentrations of hairy root suspension extract tested for antifungal activity, 2.0% concentration displayed 100% inhibition over mycelial growth and spore germination of Colletotrichum falcatum at in vitro conditions. In addition to that, the extracts were found to be highly compatible with beneficial microflora viz., Gluconacetobacter diazotrophicus (endophytic nitrogen fixer in sugarcane), Bacillus megaterium (phosphorous solublizer) and Pseudomonas fluorescens (biocontrol agent) under in vitro conditions. The hairy roots cultured in Erlenmeyer flasks at shaker recorded less multiplication rate due to turbulence of the medium, whereas the hairy roots multiplied in the newly designed airlift bioreactor exhibited 10 fold increases in growth when compared to hairy roots growth in Erlenmeyer flasks which was significantly higher.

Key words: Hairy roots, Psoralea corylifolia, red rot, sugarcane, Colletotrichum falcatum.