Surge in insect resistance to transgenic crops and prospects for sustainability

Abstract

Transgenic crops have revolutionized insect pest control, but their effectiveness has been reduced by evolution of resistance in pests. We analyzed global monitoring data reported during the first two decades of transgenic crops, with each case representing the responses of one pest species in one country to one insecticidal protein from Bacillus thuringiensis (Bt). The cases of pest resistance to Bt crystalline (Cry) proteins produced by transgenic crops increased from 3 in 2005 to 16 in 2016. By contrast, in 17 other cases there was no decrease in pest susceptibility to Bt crops, including the recently introduced transgenic corn that produces a Bt vegetative insecticidal protein (Vip). Recessive inheritance of pest resistance has favored sustained susceptibility, but even when inheritance is not recessive, abundant refuges of non-Bt host plants have substantially delayed resistance. These insights may inform resistance management strategies to increase the durability of current and future transgenic crops.

Tying pest insects in knots: the deployment of spider‐venom‐derived knottins as bioinsecticides

“…The introduction in 1996 of transgenic crops expressing Bt toxins revolutionized insect pest control by dramatically reducing insecticide use, improving crop yields, and sparing beneficial insects . However, a recent surge in insect resistance to Bt crops has accelerated interest in the development of alternative insecticidal toxin transgenes.…”

“…The introduction in 1996 of transgenic crops expressing Bt toxins revolutionized insect pest control by dramatically reducing insecticide use, improving crop yields, and sparing beneficial insects . However, a recent surge in insect resistance to Bt crops has accelerated interest in the development of alternative insecticidal toxin transgenes. Because knottins are genetically encoded mini‐proteins with oral insecticidal activity, knottin transgenes have the potential to serve as standalone insect‐resistance traits in transgenic crops or to be used for trait stacking with transgenes encoding other insecticidal toxins such as Bt endotoxins or other knottins with different molecular targets.…”

Decreased Cry1Ac activation by midgut proteases associated with Cry1Ac resistance in Helicoverpa zea

“…Transgenic corn and cotton that produce insecticidal proteins from Bacillus thuringiensis (Bt) have been useful in managing this polyphagous pest . However, Bt crops producing crystalline (Cry) proteins do not meet the high‐dose requirement against this pest, and this has favored the evolution of resistance . Practical resistance, defined as field‐evolved resistance that has practical consequences for pest control, to the Cry toxins used in Bt corn and Bt cotton has been documented for some populations of H. zea …”

Transgenic microRNA‐14 rice shows high resistance to rice stem borer

“…Transgenic Bt rice showed high resistance to early‐instar larvae of RSB (90%–100% mortality; Liu et al ., ), however, the mortalities significantly decreased when feeding it to higher instar larvae (Hu et al ., ). At present, only a limited number of insecticidal genes have been identified at present (Tabashnik and Carriere, ). Here, we demonstrated that an insect‐specific miRNA, miR‐14 , can be used for producing transgenic insect‐resistant rice.…”