Safety Assessment Of Bt Protein Expressed By Transgenic Rice On The Wolf Spiders (Pardosa Pseudoannulata)

To clearly show the effects of the Bt protein expressed by transgenic rice on the natural enemies of pests in the field, this thesis utilized the CrylAb/CrylAc transgenic rice Shanyou 63 (referred to as Bt rice) and the common Shanyou 63 which was its control varieties as the materials, which are primary producers on the food chain; The larve of rice case worm(Cnaphalocrocis medinalis) was used as primary consumer and the wolf spider(Pardosa pseudoannulata) which was the dominant species in the field as secondary consumer. We researched the transfer law of Bt protein in different trophic levels on the food chain and the impacts of Bt protein on the different developmental times of wolf spider. The results as follows:1. Bt protein transfer primary producer to its consumer on the predatory food chain.The larvae of rice case worm, which were naturally grown in the common rice plants for 3-4 phases, were kept respectively in the Bt rice and its control rice plants. After several free feeding hours, as 12h,24h, 36h,48h,60h, respectively. Bt protein content measured in the larvae of rice case worm, which showed as follows:As the feeding time went on, the Bt content in the rice case worm increased gradually, which reached its maximum content at 2.84±0.08ng/head after 36h of feeding, then it tended to decrease but maintained its quantities at 1.77±0.34 ng/head, while no Bt protein detected in the control group. Bt content of wolf spiders were quantified, this spiders were preying on the rice case worm that fed 24h Bt rice, for 2d,4d,6d,8d, 10d, respectively (the control group of spiders preyed on the larvae of rice case worm which are fed by the conventional rice for 24 hours). The results as follows:As the quantity of its prayed insects increased, the Bt content in the spiders gradually increased and reached its maximum at 4.65±0.54ng/head. Since then, Bt content in the spiders did not keep on increasing as rice case worm contue preyed, and no Bt protein were detected in the control group. Therefore, Bt protein expressed by transgenic rice could passed through the rice case worm to the wolf spiders on the predatory food chain with the occurrence of bioaccumulation, and this bioaccumulation maintained a certain extent.2. Wolf spiders intake Bt protein affect the activity of its protective enzymes (SOD,POD and CAT)The larvae of rice case worm, which fed on transgenic Cry1Ab/Cry1Ac rice plant during 24 hours, were hunted by the wolf spider (pardosa pseudoannulata) for 3,6,9, and 12 days respectively. Effects of transgenic Bt rice on the activities of the 3 protective enzymes in the spider's body, namely, SOD, POD, and CAT, have been investigated through enzyme activity measurement. Experimental results demonstrate that the SOD activity increase as time goes by, and reaching maximum on the 9th day. It was also, however, showed that the SOD activities of the treatment group are restrained during the whole experiment, leading to its activities much lowering than that of the control. For the management group, the activities of POD and CAT also enhanced with the extension of feeding duration. Though the activities of POD and CAT of the management group was remarkably lower (p<0.05) than that of the control group during the experiment initial phase (for the first 6 days), it surpassed the control group in terms of activities of POD and CAT on the 9th day. So the Bt protein expressed by transgenic rice transferred to the third trophic level on food chain, while these protein affect wolf spiders at a certain extent.3. Wolf spiders intake Bt protein affect its reproduction, development, life-span and mature spiders weightIn order to appraise Bt protein expressed by transgenic rice affect the third trophic level creature on the food chain, the natural enemy wolf spider, which dominate paddy field, was used in this experiment (28±0.5℃, R.H=80%, L:D=12h:12h). We used the larve of rice case worm fed with transgenic rice for 24h as prey for wolf spider (the wolf spiders of control group preyed that larve fed with conventional rice) and observed the developmental parameters of spiders. The results showed that significantly higher development and lower mature spiders weight were observed in the wolf spiders fed on Bt rice compared with control treatment (p<0.01); longer spiders life-span than that of management group (p<0.05) though the spiders molting, the amount of spawned egg and hatchability is no significant difference (p>0.05). These results demonstrate the Bt protein expressed by transgenic rice transfer to the third trophic level on food chain, while these protein affect wolf spiders develop at a certain extent.4. Wolf spiders intake Bt protein affect the Bases sequence of its mitochondrial DNA-12S rRNA geneTo explore the long-term ecological effects of the Bt protein expressed by the transgenic rice, to the natural enemies from the molecular level, used the third domain of wolf spider's mt DNA-12S rRNA gene as its target area, studies this area's Bases composition and sequence. We made that third domain sequence determination of the 5th generation sexually mature spiders, which was sustainably affected by the Bt protein expressed by the transgenic rice. Result has shown that 302 bases, which are rich in A, T, were detected in this domain. It was also shown that no conversion, transversions and other changes were occurred in this domain after a comparison is made between the treated group and the control group. The above results indicate that Bt protein expressed by transgenic rice did not lead to the changes of bases sequence of the third domain, which belongs to the mitochondrial DNA-12S rRNA gene of the wolf spider, in these treatment time.On the basis of the above, although Bt protein expressed by transgenic rice can transfer to the third trophic level creature, this protein has no evidently advers impacts on wolf spiders for the short-term or long-term ecological effects. So we can say Bt rice relativistic make no impression on the health of spiders. But we should make further investigate to evaluate this Bt rice affect advanced animal or not.