Genetic transformation of an elite Indian genotype of cotton (Gossypium hirsutum L.) for insect resistance.

摘要

Agrobacterium-mediated genetic transformation of an elite Indian genotype (Bikaneri Nerma) of cotton (Gossypium hirsutum L.) was achieved using shoot apical meristems isolated from seedlings as explants and a synthetic gene encoding Cry1Ac delta -endotoxin of Bacillus thuringiensis. Regeneration of shoots was carried out in selection medium containing kanamycin (100 mg/l) after co-cultivation of the explants with Agrobacterium tumefaciens (strain EHA 105). Rooting was accomplished on a medium containing naphthaleneacetic acid and kanamycin. Progeny obtained by selfing T< sub>0 plants was grown in the greenhouse and screened for the presence of neomycin phosphotransferase (nptII), and cry1Ac genes by polymerase chain reaction (PCR) and Southern hybridization. Expression of Cry1Ac in the leaves of the transgenic plants was detected by Xpress strips and quantified by Quan-T ELISA kits (DesiGen). Insect bioassays were performed with the larvae of cotton bollworm (Helicoverpa armigera). Field tests of the most promising lines (T< sub>2 and T< sub>3 generations) were performed under contained conditions. Results of the field tests showed considerable potential of the transgenic cotton for resistance against cotton bollworm.