Conference summary

Abstract

Progress on the research and development of insect-resistant transgenic rice, especially expressing insecticidal proteins from Bacillus thuringiensis (Bt), in China has been rapid in recent years. A number of insect-resistant transgenic rice lines/varieties have passed restricted and enlarged field testing, and several have been approved for productive testing since 2002 in China, although none was approved for commercial use until 2006. Extensive laboratory and field trials have been conducted for evaluation of the efficiency of transgenic rice on target lepidoteran pests and potential ecological risks on non-target arthropods. The efficacy of a number of transgenic rice lines currently tested in China was excellent for control of the major target insect pests, the rice stem borers (Chilo suppressalis, Scirpophaga incertulas, Sesamia inferens) and leaffolder (Cnaphalocrocis medinalis), and was better than most insecticides extensively used by millions of farmers at present in China. No significantly negative or unintended effects of transgenic rice on non-target arthropods were found compared with non-transgenic rice. In contrast, most of the current insecticides used for the control of rice stem borers and leaffolders proved harmful to natural enemies, and some insecticides may directly induce resurgence of rice planthoppers. Studies for developing a proactive insect resistance management of transgenic rice in the future are discussed to ensure the sustainable use of transgenic rice.

Analysis of Cry1Ab toxin bioaccumulation in a food chain of Bt rice, an herbivore and a predator

“…Movement patterns and impacts on non-target organisms of Bt toxins through tritrophic interactions have been reported in some previous studies (reviewed by Romeis et al 2006 andChen et al 2006). However, the ecological impact of Bt toxin movement has not always been clearly evaluated.…”

“…Bt rice field trials were first conducted in China in 1998 and large field trials of several Bt rice lines have continued in China (Chen et al 2006;Wang and Johnston 2007). Field trials have confirmed that Bt rice effectively controls stem borers and leaffolders (Chen et al 2006). In a study in farmers' fields in China, a Bt rice line resulted in yield increases of 6-9%, and 80% reduction in insecticide use, in comparison to conventional varieties (Huang et al 2005).…”

“…To date, many studies have evaluated the impact of Bt toxins through tritrophic interactions (reviewed by Romeis et al 2006 andChen et al 2006), however bioaccumulation of Bt toxins at different trophic levels has not been investigated. Moreover, the ecological impact of the possible biotransfer and bioaccumulation of Bt toxins expressed in Bt rice through tritrophic interactions has not been explored.…”

“…Since 1993, numerous genotypes of GM rice with insecticidal Bt gene(s) (referred as Bt rice hereafter) have been developed that confer strong resistance against rice stem borers and leaffolders (reviewed by High et al 2004;Chen et al 2006;Wang and Johnston 2007). Bt rice field trials were first conducted in China in 1998 and large field trials of several Bt rice lines have continued in China (Chen et al 2006;Wang and Johnston 2007).…”

Development of Bt Rice and Bt Maize in China and Their Efficacy in Target Pest Control

“…In the development of Bt rice lines, China made great efforts for independent innovation, and also took an active part in international cooperation. For example, KMD was developed by Zhejiang University in collaboration with the University of Ottawa, and Huahui 1 and Bt Shanyou 63 were developed by Huazhong Agricultural University in collaboration with the International Rice Research Institute [16]. Agrobacterium - and gene gun-mediated transformations are commonly used for Bt rice development, and the promoters used for driving the expression of Bt genes include ubiquitin , rice rbcS (small subunit of ribulose-1, 5-bisphosphate carboxylase/oxygenase) promoter, and Actin1 (Table 1).…”