The sugarcane borer, Diatraea saccharalis （E）, is a major maize borer pest and a target of transgenic maize expressing Bacillus thuringiensis （Bt） proteins in South America and the mid-southern region of the Unite...The sugarcane borer, Diatraea saccharalis （E）, is a major maize borer pest and a target of transgenic maize expressing Bacillus thuringiensis （Bt） proteins in South America and the mid-southern region of the United States. Evolution of resistance in target pest populations is a great threat to the long-term efficacy of Bt crops. In this study, we compared the genetic basis of resistance to CrylAb protein in 3 resistant colonies of sugarcane borer established from field populations in Louisiana, USA. Responses of larvae to the CrylAb protein for the parental and 10 other cross colonies were assayed in a diet-incorporated bioassay. All 3 resistant colonies were highly resistant to the CrylAb protein with a resistance ratio of 〉 5 5 5.6 fold. No maternal effect or sex linkage was evident for the resistance in the 3 colonies; and the resistance was functionally nonrecessive at the CrylAb concentrations of 〈 3.16 μg/g, but it became recessive at 〉10μg/g. In an interstrain complementation test for allelism, the Fl progeny from crosses between any 2 of the 3 resistant colonies exhibited the similar resistance levels as their parental colonies, indicating that the 3 colonies most likely shared a locus of CrylAb resistance. Results generated from this study should provide useful information in developing effective strategies for managing Bt resistance in the insect.展开更多
文摘The sugarcane borer, Diatraea saccharalis （E）, is a major maize borer pest and a target of transgenic maize expressing Bacillus thuringiensis （Bt） proteins in South America and the mid-southern region of the United States. Evolution of resistance in target pest populations is a great threat to the long-term efficacy of Bt crops. In this study, we compared the genetic basis of resistance to CrylAb protein in 3 resistant colonies of sugarcane borer established from field populations in Louisiana, USA. Responses of larvae to the CrylAb protein for the parental and 10 other cross colonies were assayed in a diet-incorporated bioassay. All 3 resistant colonies were highly resistant to the CrylAb protein with a resistance ratio of 〉 5 5 5.6 fold. No maternal effect or sex linkage was evident for the resistance in the 3 colonies; and the resistance was functionally nonrecessive at the CrylAb concentrations of 〈 3.16 μg/g, but it became recessive at 〉10μg/g. In an interstrain complementation test for allelism, the Fl progeny from crosses between any 2 of the 3 resistant colonies exhibited the similar resistance levels as their parental colonies, indicating that the 3 colonies most likely shared a locus of CrylAb resistance. Results generated from this study should provide useful information in developing effective strategies for managing Bt resistance in the insect.
