Cotton bollworm is a major crop pest that feeds on over 300 hosts from 68
plant families. Due to its reported resistance to most insecticides,
determining its mechanism of detoxifying these phytochemicals and
insecticides is important in managing this pest.
Researcher Yidong Wu from Nanjing Agricultural University in China and
colleagues used CRISPR-Cas9 to knockout a cluster of nine P450 genes in
cotton bollworm through embryo microinjection. The knockout strain was
subjected to different phytochemicals and synthetic insecticides, including
xanthotoxin, gossypol acetate, 2-tridecanone, coumarin, nicotine,
esfenvalerate, indoxacarb, emamectin benzoate, and chlorantraniliprole. Gene
expression was also determined using qRT PCR. Results showed significantly
reduced survival rate of the pests with the knockout when subjected to
phytochemicals and insecticides. CRISPR-Cas9 proved to be an effective
approach to identifying genes involved in insecticide resistance in pests
like cotton bollworm.