Characterization of transgenic rice expressing fusion protein Cry1Ab/Vip3A for insect resistance

Chao Xu,Jianhua Gao,Haiyan Lin,Chaoyang Lin,Zhicheng Shen,Jiahui Cheng

doi:10.1038/s41598-018-34104-4

Abstract

Management of resistance development of insect pests is of great importance for continued utilization of Bt crop. The high-dose/refuge and pyramid (gene stacking) strategy are commonly employed to delay the evolution of insect resistance. Due to the anticipated difficulty for deployment of mandatory refuge for transgenic crops in China, where the size of farmer is quite small, stacking of genes with different modes of action is a more feasible strategy. Here we report the development of transgenic rice expressing a fusion protein of Cry1Ab and Vip3A toxin. Analysis of trypsin proteolysis suggested that the fusion protein is equivalent to the combination of Cry1Ab and Vip3A protein. The transgenic plants expressing the fusion protein were found to be highly resistant to two major rice pests, Asiatic rice borer Chilo suppressalis (Lepidoptera: Crambidae) and rice leaf folder Cnaphalocrocis medinalis (Lepidoptera: Crambidae), while their agronomic performances showed no significant difference compared to the non-transgenic recipient rice. Therefore, the transgenic rice may be utilized for rice pest control in China.

Highlights

Bacillus thuringiensis (Bt) was a ubiquitous gram-positive and sporulating bacterium that produces various insecticidal proteins
A commercial trypsin and the insect midgut juice was prepared to investigate if C1V3 protein retained these trypsin-resistant cores, and Western blot analysis was performed with Cry1Ab and Vip3A polyclonal antiserum respectively (Fig. 2)
We found that C1V3 protein did generate a ~60-kDa Cry1Ab and a ~65-kDa Vip3A trypsin-resistant core, exactly same as individual Cry1Ab and Vip3A were digested by trypsin and insect midgut juice (Fig. 2)

Summary

Introduction

Bacillus thuringiensis (Bt) was a ubiquitous gram-positive and sporulating bacterium that produces various insecticidal proteins. Cotton bollworm (Helicoverpa armigera) and pink bollworm (Pectinophora gossypiella) evolved resistance on transgenic cotton expressing Cry1Ac in China during the last 10 years[18,19,20] These lessons asked for improved strategy for insect resistance management. The transgenic line KMD1 expressing a synthetic cry1Ab gene was highly resistant to eight lepidopteran rice pest species[25]. Another case was Bt shanyou-63 containing a chimeric cry1Ab/cry1Ac gene, which showed high protection against rice leaffolder and yellow stem borer[26]. We reported the development of a transgenic rice line expressing a fusion protein of Cry1Ab and Vip3A. The transgenic line A1L3 could be a good candidate for rice pest control in China

Methods

Results

Conclusion