Effect of Temperature Stress on the Althaea officinalis’s “Hairy” Roots Carrying the Human Interferon α2b Gene

“Hairy” roots obtained through genetic transformation of plants by Agrobacterium rhizogenes , a soil phytopathogen, are valuable producers of important secondary metabolites possessing medicinal properties as well as a useful model system for studying plant responses to impacts of unfriendly environmental conditions. This study compares a postponed response of Althaea officinalis L. “hairy” roots to the impacts of short-term cold- and high-temperature stress factors. The results obtained by the study have shown that “hairy” roots from different A. officinalis lines (individual transformational events) are characterized by different sensitivity to short-term temperature stress impacts, regardless of the transformation vectors or the presence of the human interferon( ifn )-α 2b gene. High temperature caused a significant level of growth inhibition in roots of all lines, except those with the highest flavonoid content under the control conditions. On the other hand, a short-term cultivation of “hairy” roots at a low temperature did not cause growth suppression. In parallel with growth inhibition caused by a temperature increase, the activation of flavonoid synthesis, which was probably a response of plants to high temperature as a stress factor, was observed. The study has shown a strong ( R 2 = 0.78) linear dependence between the antioxidant activity of extracts from “hairy” roots and their flavonoid content. Thus, it is obvious that flavonoids participate in the process of response and adaptation of roots to impacts of high-temperature stress.