Glucosinolates and their breakdown products are well-known for their cancer-chemoprotective functions and biocidal activities against pathogens and generalist herbivores. Insecticides are commonly used in the production of pak choi (Brassica rapa L. ssp. chinensis var. communis [N. Tsen & S.H. Lee] Hanelt). We studied the effects of four commonly used insecticides, namely, β-cypermethrin, acephate, pymetrozine, and imidacloprid, on glucosinolate metabolism in pak choi. All insecticides significantly increased both the transcription of glucosinolate biosynthetic genes and the aliphatic and total glucosinolate accumulations in pak choi. β-Cypermethrin and acephate caused gradual and continuous up-regulation of gene expression from 0.5 to 24 h after treatment, whereas pymetrozine and imidacloprid did so more rapidly, reaching a peak at 1 h and returning to normal at 3 h. Our findings indicate that the four insecticides affect glucosinolate metabolism in pak choi plants to various degrees and suggest that glucosinolates may be involved in plant insecticide metabolism.
Keywords: acephate; glucosinolate; imidacloprid; insecticide; pak choi; pymetrozine; β-cypermethrin.