Abstract
Lygus species of plant-feeding insects have emerged as economically important pests of cotton in the United States. These species are not controlled by commercial Bacillus thuringiensis (Bt) cotton varieties resulting in economic losses and increased application of insecticide. Previously, a Bt crystal protein (Cry51Aa2) was reported with insecticidal activity against Lygus spp. However, transgenic cotton plants expressing this protein did not exhibit effective protection from Lygus feeding damage. Here we employ various optimization strategies, informed in part by protein crystallography and modelling, to identify limited amino-acid substitutions in Cry51Aa2 that increase insecticidal activity towards Lygus spp. by >200-fold. Transgenic cotton expressing the variant protein, Cry51Aa2.834_16, reduce populations of Lygus spp. up to 30-fold in whole-plant caged field trials. One transgenic event, designated MON88702, has been selected for further development of cotton varieties that could potentially reduce or eliminate insecticide application for control of Lygus and the associated environmental impacts.
Highlights
Lygus species of plant-feeding insects have emerged as economically important pests of cotton in the United States
These species are not controlled by commercial Bacillus thuringiensis (Bt) cotton varieties resulting in economic losses and increased application of insecticide
Protein accumulation did not change over time except for Crystal proteins from Bt belonging to the insecticidal threedomain Cry toxin family have long been the subject of both protein improvement efforts and structure–function studies[16,17,18,19]
Summary
These species are not controlled by commercial Bacillus thuringiensis (Bt) cotton varieties resulting in economic losses and increased application of insecticide. Other benefits include area-wide suppression of lepidopteran pest species in other crops[2] and a resurgence in beneficial insects for improved integrated pest management[3] In this low spray environment conferred using Bt crops, some pests such as plant bugs have emerged as important economic pests of cotton in many countries[4,5]. We report modifications made to Cry51Aa2 to increase its specific activity towards Lygus spp. and the subsequent identification of the transgenic event GH_A710504 designated MON88702 that has been advanced for development of commercial cotton varieties for Lygus control
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
