Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

The effect of host plant species on the detoxifying enzymes of the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae).

Abstract

Diaphorina citri Kuwayama (Hemiptera: Liviidae) is a phytophagous insect and the vector of the bacterium 'Candidatus' Liberibacter asiaticus. This is the likely causal pathogen of huanglongbing, which results in decline and possible death of citrus trees. It has been shown that host plants can affect the detoxification enzyme profile of arthropods. Here, we examined the effect of rearing D. citri on various host plant species with respect to activity of general esterases (ESTs), glutathione S-transferases (GST), and cytochrome P450 monooxygenases (P450s). These enzymes were selected because they are known to metabolize a wide diversity of insecticides and are known to directly contribute to resistance in D. citri. We reared D. citri on Citrus sinensis L., Bergera koenigii L. and Murraya paniculata (L.) Jacq. (Sapindales: Rutaceae). Following 12 generations of rearing, the activities of EST, GST, and P450 enzymes were compared between the colonies raised on the different host plants. The GST activity level was significantly higher in D. citri reared on M. paniculata than in those reared on C. sinensis. The P450 expression level was significantly higher in D. citri reared on M. paniculata than in those reared on either B. koenigii or C. sinensis. There was no significant difference in EST activity between treatments. These results suggest that host plant allelochemicals may alter the detoxification enzyme system in D. citri. However, these changes did not correlate with changes in mortality of D. citri when treated with fenpropathrin.