Assessment of hairy roots induction in Echium khuzistanicum by different strains of Agrobacterium rhizogenes

In this study for the first time, different strains of Agrobacterium rhizogenes, co-cultivation times, and concentrations of acetosyringon in leaf explants of Echium khuzistanicum were examined to produce hairy roots.

The leaves of 21-day-old plant, different concentrations of acetosyringone (0,100,200 µM) and 3 strains of Agrobacterium (A4, ATCC15834 and 11325) were used for hairy root induction. In each explant, surficial wounds were created by a syringe contaminated with the bacterium and put for 10 minutes in bacterial suspension. After infection, the explants were transferred in the ½ MS solid medium supplemented with ascorbic acid (100 mg/L) to a light free growth chamber with 25 ° C temperature for 48 or 72 hours. PCR technique was used to confirm transformation by gene amplification with the rolBprimers. HPLC analysis was conducted on a high performance liquid chromatography system for shikonin measurement.  

The results of this study showed that, the first hairy roots emerged from wounded places after 14-21 days. The presence of A. rhizogenes T-DNA in the hairy root genome was confirmed by PCR using specific primers for rolB gene. Strain ATCC15834 had the highest rate of hairy root induction at 100 and 200 µM concentrations of acetosyringone indicating that the phenolic compound, acetosyringone, was effective in increasing hairy root induction. Generally, High concentrations of acetosyringone and more co-cultivation time together resulted in a significant increase in the hairy root induction in three strains of Agrobacterium rhizogenesis. Line 1 of hairy root produced 254.4±0.56 µg/g FW of shikonin.  

For the first time the results of this research showed that transformation and hairy root induction in E.khuzistanicum is possible by Agrobacterium rhizogenes and it can be used in the gene transfer and hairy root culture in order to shikonin production.