Seasonal Expression of Bt Proteins in Transgenic Rice Lines and the Resistance Against Asiatic Rice Borer Chilo suppressalis (Walker)

• Published in: Environmental entomology 2011-10, Vol.40 (5), p.1323-1330
• Main Authors: Zhang, Yongjun, Li, Yunhe, Zhang, Ying, Chen, Yang, Wu, Kongming, Peng, Yufa, Guo, Yuyuan
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Animals; Bacillus thuringiensis; bacterial proteins; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bioassays; Biological and medical sciences; Borers; Bt protein expression; Chilo suppressalis; control efficacy; correlation; CRY protein; Cry1Ac toxin; Data processing; Decision making; developmental stages; ELISA; Endotoxins - genetics; Endotoxins - metabolism; Enzyme-Linked Immunosorbent Assay; Fundamental and applied biological sciences. Psychology; Fusion protein; gene fusion; genes; Genetic engineering applications; Genetics and breeding of economic plants; Growing season; Growth stage; Hemolysin Proteins - genetics; Hemolysin Proteins - metabolism; Host-Parasite Interactions; Immunoassays; isogenic lines; Leaves; Moths - physiology; Oryza; Oryza - genetics; Oryza - metabolism; Oryza - parasitology; Oryza sativa; Pest control; Pest Control, Biological; Pest resistance; Pests; Plant breeding: fundamental aspects and methodology; plant tissues; Plants, Genetically Modified - metabolism; Plants, Genetically Modified - parasitology; protein synthesis; Proteins; resistance management; rice; Seasonal variations; Stems; Sulfur dioxide; surveys; transgenic plants; TRANSGENIC PLANTS & INSECTS; transgenic rice
• ISSN: 0046-225X; 1938-2936
• DOI: 10.1603/EN11035

Laboratory bioassays and field surveys were carried out to compare the resistance of three transgenic rice (Oryza sativa L.) lines including Bt-DL expressing a single gene cry1Ab, Bt-KF6 expressing stacked genes cry1Ab and CpTI genes and Bt-SY63 expressing a fusion gene cry1Ab/cry1Ac, respectively, to an important rice pest Chilo suppressalis (Walker). In addition, enzyme-linked immunosorbent assays (ELISA) were conducted to monitor the Bt protein expressions in rice leaves and stems at different rice growth stages. Results showed that all the transgenic rice lines exhibited significantly high resistance to the pest compared with their corresponding nontransformed isolines. Among the transgenic rice lines, Bt-SY63 and Bt-KF6 had higher resistance to C.suppressalis at early growth stage, but lower resistance at late stages, while the pest resistance of Bt-DL was relatively stable throughout the growing season. The results were consistent with ELISA results showing that Bt protein levels in Bt-SY63 or Bt-KF6 leaves decreased in late growth stages, but were relatively stable in Bt-DL at all growth stages. This demonstrates that the resistance to a pest by Bt plants is positively correlated with Cry protein expression levels in plant tissues. Compared with Bt-SY63 and Bt-KF6, the Bt protein expression levels were significantly lower in Bt-DL, while its resistance to C. suppressalis was the highest. This may suggest that C.suppressalis is more susceptible to Cry1Ab than to Cry1Ac. The data from the current study are valuable for decision-making for commercial use of Bt rice lines and development of appropriate pest control and resistance management strategies for the transgenic rice lines.