Quantification of Bt Proteins Expression Throughout a Growing Season Among Different Plant Structures and Their Efficacy of Control Towards the Cotton Bollworm Helicoverpa zea (Boddie)

Cotton bollworm (CBW) Helicoverpa zea (Boddie) is a major target pest of genetically engineered crops that express Bacillus thuringiensis (Bt). Field evolved resistance of CBW has been documented to several Bt crops including Bt cotton. (Tabashnik et al. 2009, Tabashnik and Carrière 2010, Zhang et al. 2012). To sustain the susceptibility of CBW towards Bt crops high-dose strategies have been implemented to ensure CBW larvae are ingesting lethal doses of Bt high enough to kill ³95% of heterozygous individuals possessing a major resistant allele can be killed (Huang et al. 2011). Several factors contribute to the decline of expression of the Bt in transgenic plants (Dong and Li 2007). It has been documented that not only is expression controlled by the transgene expression and differs from variety to variety, but under stressful conditions concentration levels could become very difficult to predict, and levels of expression could decline (Trtikova et al. 2015). The goal of this project is to experimentally quantify the levels of expression within different plant and fruiting structures of Bt cotton grown under two different production environments, and to provide the evidence of the susceptibility of resistant and heterozygote populations on the different levels of expression. This data will give insight to 1.) how much expression changes throughout a season, 2.) does expression statistically differ among different plant parts, 3.) under environmentally induced stress, such as water deficit, does expression significantly change.