Search

Plants are the important sources of drugs. Secondary metabolites are responsible for therapeutic propertiesin plants. Three compounds including (-)-hyoscyamine, its racemate atropine, and scopolamine (hyoscine) are the most famous tropane alkaloids in the Solanaceae familly. Nowadays, attempts to developthese alkaloids in biotechnological procedures which are principally based on the hairy root cultures using Agrobacterium rhizogenes. In the present study, we showed the percent of induced hairy roots percent in the leaf and root explants of four plants from the Solanaceae family (Atropa belladonna L., Hyoscyamus niger L., Datura stramonium L. and Datura metel L.), that infected with the six strains of Agrobacterium rhizogenes (A4, A7, Ar15834, Ar9534, Ar9402, and Ar318). Hairy roots were appeared from the leaf and roots explants on ½MS medium culture. The presence of T-DNA in the supposedly transformal lines was shown by PCR. The highest transformation yield of 93% was accomplished using leaf explants of D. metel infected by AR15834 and A4 strains. One fastest growing clone of transforming D. metel roots line (induced by AR15834)was selected and the biomass of hairy and natural roots were measured and compared after 0, 2, 4, 6, 8 and 10 days. The results showed that, the fresh and dry weight of hairy roots was 4.44 and 4.92 times higher than the weights of non-transformed roots respectively after 8- 10 days. These roots are hormone-autotrophic and have the great lateral branches. Therefore, the hairy roots of D. metel and D. stramonium can be used to increase tropane alkaloids production yield in the pharmaceutical industry.

Artemisinin and its derivatives are still one of the most effective drugs for the treatment of malaria. Artemisia pallens commonly known as Dhavanam, is an aromatic herb belonging to the family Asteraceae. Increasing the artemisinin content of A. pallens by genetic engineering would improve the availability of this much needed drug. In the present study, Agrobacterium rhizogenes (strain NCIM 5140) mediated genetic transformation of Artemisia pallens were carried out for hairy root induction. The effect of different media (Half MS, MS, MS along with BAP 0.5 mg/l and MS along with Kinetin 0.5 mg/l) and type of explants (leaf and stem) on hairy root induction and culture were also studied. Maximum transformation efficiency (70.0 %) was observed in case of stem explants when it was co-cultivated with Agrobacterium rhizogenes and kept on half strength MS media. Artesunate is a derivative of artemisinin, was quantified using HPLC from dried aerial extract and hairy roots. The content of artesunate in hairy roots was increased up to twofold as compared to aerial part of Artemisia pallens. The maximum amount of artesunate found in hairy roots was 5.62 ± 0.16 μg/g of dry weight. Apart from artesunate the other phytochemicals like alkaloids, polyphenols, and flavonoids are important because they impart the medicinal properties in this plant. Therefore, we have also quantified total alkaloids, flavonoids and polyphenolic content in the aerial part of the plants. The total alkaloids and flavonoids content were found 1.72 ± 0.00 mg/g dry weight in aqueous extract and 3.8 ± 0.00 mg/g in methanolic extract in terms of colchicine and rutin equivalents, respectively. Similarly, total phenolic content is 3.70 ± 0.01 mg/g in ethanolic extract in terms of tannic acid equivalent. [ABSTRACT FROM AUTHOR]

Hairy roots, a plant disease caused by Agrobacterium rhizogenes, show distinctive features such as high growth rate, unlimited branching, and biochemical and genetic stability. Hairy roots resemble normal roots in terms of differentiated morphology and biosynthetic machinery, producing similar secondary metabolites compared to wild-type roots. As a result, hairy roots have been a topic of intense research for the past three decades, fueling innumerable attempts to develop in vitro hairy root cultures for a large number of plants for the commercial-scale production of secondary metabolites. The same characteristics have now led to further applications, such as using hairy root cultures as experimental systems for secondary metabolic pathway elucidation studies. Although the trend is relatively new, it has already gained momentum. This review summarizes these developments. The following discussion focuses on the rationale and advantages of using hairy root cultures for secondary metabolic pathway elucidation studies, the methods used, and the results that have been obtained so far. [ABSTRACT FROM AUTHOR]