Effects Of Insect-resistant Transgenic Rice On Some Biological Parameters Of Non-target Pest Nilaparvata Lugens (Stal)

Rice is the main source of food that consumed by more than half of the population in the world. With the development of modern biotechnology, transgenic rice is applied to control diseases, insect pests and weeds. However, genetically modified crop is a double-edged sward, which may bring some potential risks along with the economical and ecological benefits. And the risks such as potential effects on non-target organisms and gene flow hinder the commercialization process. So four kinds of transgenic insect-resistant and herbicide-resistant rices were used to assess the effects on some biological parameters of non-target pest Nilapan’ata lugens (Stal)(Homoptera:Delphacidae) in the laboratory.1Effects of transgenic Bt rice on the main components of honeydew excreted by brown planthopper (BPH)We analyzed the contents such as sucrose, glucose, fructose, maltose and free amino acids in honeydew excreted by brown planthoppers that feeding on different non-Bt rice lines (XS134, WYJ7, XS11) and the corresponding Bt rice lines (S, G8-7, KMD1, KMD2). The results showed that the contents of glucose, fructose and maltose in honeydew excreted by brown planthoppers feeding on Bt rice S were significantly lower compared with XS134, but the content of sucrose had no significant difference. There were no significant differences in four kinds of sugars in honeydew excreted by brown planthoppers feeding on WYJ7and G8-7. No significant differences in the contents of sugars were obsevered except fructose among XS11and Bt rice KMD1and KMD2.We detected18kinds of free amino acids in all samples. As to Bt rice S, the content of His in honeydew was significantly higher than XS134. The contents of Glu and Ala in honeydew increased significantly on KMD2compared with its parent XS11and another Bt rice KMD1. Meanwhile the contents of Asp, Val and Phe on KMD2were significantly higher than XS11. However, we found no significant differences in the contents of free amino acids between WYJ7and G8-7.2Effects of transgenic Bt rice on the relative expression level of four genes related to ovarian development of BPHThe results of real-time PCR showed that the expression level of mag continued increasing in8days after eclosion of BPH. The expression level of mag in BPH feeding on Bt rice KMD1was significantly higher than that feeding on KMD1on the2nd,3rd and4th day, and was also significantly higher compared with its parent XS11on the2nd day. There were no significant differences in the expressions level of mag in brown planthoppers’ovaries between WYJ7and G8-7.During8days the expression level of exu increased at the beginning, and then dropped down. The expression level of exu in BPH feeding on KMD1reached a peak on the5th day and was significantly higher than that feeding on XS11and KMD2. The expression level of this gene in brown planthoppers feeding on the other rice lines reached peaks on the6th day. There is a significant increase of the expression level of brown planthopper feeding on WYJ7compared with G8-7on the6th,7th and8th day. However, we found no differences on the other5days.As to vg and vasa, the expressions of these two genes increased at first and decreased subsequently. No differences in the expressions of the two genes were observed between each Bt rice line and its corresponding non-Bt rice line.3Effects of transgenic Bt rice on juvenile hormone III titer in brown planthopperWe studied the changes of JH III titers in different developmental stages of brown planthoppers feeding on Bt and non-Bt rice by HPLC. The results showed that JH III existed in all detected samples. The concentration continued to decrease from the3rd instar to5th instar nymphs. However, the concentration of JH III increased in24h after eclosion. Furthermore, we found no significant differences between Bt and non-Bt rice.