Pest Management Science (2014) 70, 1588-1594

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Litao Guo, Wen Xie, Shaoli Wang, Qingjun Wu, Rumei Li, Nina Yang, Xin Yang, Huipeng Pan and Youjun Zhang (2014)
Detoxification enzymes of Bemisia tabaci B and Q: biochemical characteristics and gene expression profiles
Pest Management Science 70 (10), 1588-1594
The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most invasive and destructive pests of field crops worldwide. The sibling species B and Q are the two most damaging members of the B. tabaci species complex. That Q is more resistant than B to many insecticides has been well documented. Over the last decade, Q has gradually displaced B and has become the dominant form of B. tabaci in field agricultural systems in most parts of China. To help understand the differences in insecticide resistance, the activities and gene expression profiles of detoxification enzymes in B. tabaci B and Q were investigated.
The activity of P450 towards 7-ethoxycoumarin was significantly higher (1.46-fold higher) in Q than in B. The expression of 43 of 65 P450 genes was higher (>1-fold) in Q than in B, and expression for eight P450 genes was more than 50-fold greater in Q than in B. The increased expression of selected P450 genes in Q relative to B was confirmed with two other B strains and two other Q strains. On the other hand, carboxylesterase (CarE) activity was significantly lower (0.71-fold lower) in Q than in B; the Km value of CarE was significantly lower in B than in Q, but the opposite was true for the Vmax value of CarE. Glutathione S-transferase activity and values of Km and Vmax did not differ between B and Q.
Enhanced metabolic detoxification of insecticides by P450s may be an important reason why B. tabaci Q is more resistant than B. tabaci B to insecticides.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Shaoli Wang, Qing Jun Wu

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Bemisia tabaci biotype MEAM1
Bemisia tabaci biotype MED