Effect of hygromycin on peanut germination and its application in Agrobacterium-mediated genetic transformation

To overcome the laborious screening tasks in in planta transformation, Agrobacterium infected seed parts mainly embryonated cotyledons and embryos can be passed through the selection of antibiotics for a very short duration for successful identification of transformants. Hygromycin B more toxic than the existing antibiotics and has been used as a selective agent in many crop plants. With the increase in hygromycin concentrations, a decline in the survival frequency of explants was observed. The threshold concentration of hygromycin for the selection of transformants was optimized using embryonated cotyledon and embryo on MS media containing different concentrations of hygromycin. It was observed that 20 mg/l hygromycin was threshold concentration for the selection of embryonated cotyledons and 15 mg/l for embryos. These concentrations suppress the growth of peanut plants. Therefore, hygromycin at 20 mg/l for embryonated cotyledons and embryos at 15 mg/l could screen hygromycin-tolerant transgenic peanuts.