Insecticidal toxin in root exudates from Bt corn
Authors: Saxena, D., Flores, S., Stotzky, G.
Journal, Volume, Year: Nature, volume 402:480, 1999
Seeds of Bt (NK4640Bt) and isogenic corn were germinated on agar. Seedlings were placed on plastic screening suspended over Hoagland�s solution. Soil free medium was removed and analyzed after 7, 15 and 25 days of growth at which time it was replaced with fresh solution. Cry1Ab protein was found after 7 and 15 days in the exudates from Bt corn and exhibited insecticidal activity. Cry1Ab protein was not detected after 25 days, when the medium was no longer sterile. Supernatants of rhizosphere soil of seedlings transplanted in sterile or non-sterile soil was analyzed using immunological and larvicidal assays. These tests were positive for Bt corn and negative for non-Bt corn after 25 days of growth.
This is the first article that suggests Bt protein is released from the roots of Bt corn. Because this is a short article, details are lacking. See Saxena and Stotzky (2000) for more details.