Response of different Agrobacterium rhizogenes strains for in vitro hairy root induction and accumulation of rosmarinic acid production in Agastache rugosa

Abstract

In this study a total of seven different Agrobacterium rhizogenes strains were evaluated for their ability to transform the plant Agastache rugosa and to produce the secondary metabolite rosmarinic acid. All the strains of A. rhizogenes i.e., 13333, 15834, A4, LBA9402, R1000, R1200 and R1601 strains tested here in this study, were able to induce hairy root formation in leaf tissue explants. The strain A4had the highest rate of infection (94.1±8.3%) and the strain R1000 had the lowest rate (88.6±6.9%). The highest frequency of hairy roots per explant (13.6±1.4) was found for strain R1601 and the tallest root length (20.4±1.7 mm) was found for strain 13333. We also evaluated dry weight and level of rosmarinic acid in the hairy roots and found that the highest growth (310.1±14.6 mg/flask) was occurred after infection with strain R1200, while the highest production of rosmarinic acid (68.2±3.8 mg/g dry weight) was noted using strain 13333. Our study showed that A. rhizogenes strain 13333 was the most effective of the 7 tested strains for production of transformed root cultures as well as rosmarinic acid in the hairy roots.