Safety Assessments Of Transgenic Indica Rice On The Non-Target White-Backed Planthopper, Sogatella Furcifera (Homoptera: Delphacidae)

Biosafety of transgenic crops has been becoming a focus in the world. Concerns on the biosafety of transgenic rice are necessary, because rice is one of major foods of human. Biosafety assessments should be systematically and scientifically conducted before the commercialization of transgenic rice. So, a series of laboratory experiments were carried out, in order to systematically evaluate the biosafety effects of the transgenic indica rice (B1 and B6) with cry1Ab gene on their non-target white-backed planthopper, Sogatellafurcifera.1 Effects of transgenic indica rice expressing a gene of crylAb on the feeding behavior of a non-target pest, Sogatellafurcifera (Homoptera: Delphacidae)The feeding behavior of the white-backed planthopper (WHP), Sogatellafurcifera (Horvath), on two homogenous genotypes of transgenic indica rice (B1 and B6) were investigated as compared with that on their non-transgenic parental cultivar (Jiaozao 935). Under the selection condition of host plants, there were no significant differences in loading percentage between the Bt rice and the control in different time treatments except 2 h after inoculation. There were no significant difference in the probing wound numbers by WHP on the rice plant between the transgenic Bt rice (B1 and B6) and the non-transgenic control (Jiazao935) under either selection or non-selection condition. Honeydew weights secreted by WHP after feeding on the Bt rice for 48 hours were significantly less than those on the non-transgenic control (Jiazao935).2 Effects of transgenic indica rice expressing a gene of crylAb on the growth and development as well as reproduction of a nontarget pest, Sogatella furcifera (Homoptera: Delphacidae)The growth and development, oviposition behavior and fecundity of the white-backed planthopper, Sogatella furcifera (Horvath), on two homogenous genotypes of transgenic indica rice, Bl and B6 expressing a synthetic gene of crylAb from Bacillus thuringiensis, were investigated as compared with those on their non-transgenic parental cultivar (Jiaozao 935). Both total duration of female and male nymph were significantly elongated on these two transgenic genotypes tested by comparison with Jiaozao 935. The duration was increased by 1.3 and 1.5 days for female and male nymphs fed on B1, respectively, and by 2.0 and 1.4 days for female and male nymphs fed on B6. Theoviposition behavior recorded using an electronic monitoring system showed that no marked differences in the oviposition frequency, the duration per oviposition and total oviposition time were found between two transgenic genotypes tested and the control. Under the selection conditions of host plants, the planthopper female adults seemingly preferred to lay eggs into Bl plants, on which the number of oviposition scar and egg masse as well as total number of eggs were considerably or numerically more than those on the control. In contrast, they apparently abstained from laying eggs into B6 plants, on which the number of egg mass, egg mass size and total number of eggs were significantly or numerically less than those on the control. However, the female adults did not show any preference for laying eggs between two transgenic genotypes tested and the control under no selection conditions of host plants. In this case, no obvious differences in the number of egg mass, egg mass size and total number of eggs were found among these three genotypes tested. As to egg hatching ratio, Bl and B6 did not show any marked adverse effect on it by comparison with the control under either the selection conditions of host plants or not.. 3 The physical and biochemical basis of effects of the transgenic indica riceexpressing a gene of crylAb on the non-target pest, Sogatella furcifera (Homoptera :Delphacidae)The physical and biochemical basis of effects of the transgenic indica rice, B1 and B6 expressing a synthetic gene of crylAb on the non-target pest, Sogatella furcifera were investigated by analyzing the silica bodies and the concents of free amino acids in the leaf sheath. The results were showed as follows: (1) The amount of silica bodies in leaf sheath of Bl was highest and significant different with that in leaf sheath of the control, Jiazao935. The amount of silica bodies in leaf sheath of B6 was higher than that in leaf sheath of the control, but not statistical difference. (2) The contents of Asp -. Gnu Asn, Ser, Gin, His, Val, Ile> Phe> Lys, Pro and the total in the sheath between B1 and B6 were significantly different and also significantly different with those in the control respectively. The contents of Thr, Trp and Leu in the leaf sheath of Bl were significantly different with those in B6 and the control, but those were not statistical difference between B6 and the control. The contents of Gly, Arg, Ala, Tyr in B6 were significantly different with those in Bl and the control though those were not statistical difference between Bl and the control.