OBJECTIVE:  The field degradation dynamics of Cry1Ab insecticidal protein in transgenic Bacillus thuringiensis corn in the root debris and rhizosphere soil of corn of events MON810 and Bt11 at harvest stage were investigated and compared.
METHOD:  The levels of Cry1Ab protein expression in root debris and rhizosphere soil of the two transgenic Bt corns of events MON810 and Bt11were quantified by using enzyme-linked immunosorbent essay(ELISA).
RESULT:  It was showed that the Cry1Ab toxin in Bt corn root debris and rhizosphere soil were gradually degraded.The content of Cry1Ab insecticidal protein in corn root debris of MON810 was higher than that of Bt11,the degradation speed was slower compared with that of Bt11.The Cry1Ab insecticidal protein in root debris could not degrade completely in 8 months after harvest.No Cry1Ab insecticidal protein was detected in root debris of Bt11 in 7 months after harvest.Degradation of Cry1Ab insecticidal protein in rhizosphere soil of event MON810 was slower than that of event Bt11,no Cry1Ab insecticidal protein was detected in the rhizosphere soil of events MON810 and Bt11 in 8 months and 7 months after harvest,respectively.
CONCLUSION:  The Cry1Ab insecticidal protein could not degrade completely,and some residues still remain in root debris and rhizosphere soil of events MON810 and Bt11 in the emerging stage of the spring crops in following year in field where the MON810 and Bt11 were planted.