CHARACTERIZATION OF SOLUBLEAND MEMBRANE-BOUNDALKALINE PHOSPHATASE INNilaparvata lugens AND THEIRPOTENTIAL RELATION TODEVELOPMENT AND INSECTICIDERESISTANCE

摘要

Two forms (soluble and membrane-bound) of alkaline phosphatases(ALPs) were found in the brown planthopper, Nilaparvata lugens.In order to further study ALPs in N. lugens, two putative ALP genes(Nl-ALP1 and Nl-ALP2) were identi?ed in this pest. Both Nl-ALP1and Nl-ALP2 show approximately the same degree of sequence identity(40–50%) to other insect soluble and membrane-bound forms of ALP.Correlation of ALP activity and mRNA levels at different developmentalstages, or following application of 20-hydroxyecdysone (20E) and insecticide fenvalerate, suggests that Nl-ALP1 and Nl-ALP2 mightencode a soluble (sALP) and a membrane-bound ALP (mALP),respectively. Nl-ALP1-speci?c antibody Nl1-I detected only a speci?c bandin soluble protein preparations and Nl-ALP2 speci?c antibody Nl2-I onlydetected a speci?c band in insoluble protein preparations, which providedconclusive linkages between Nl-ALP1 and a sALP and between Nl-ALP2and a m ALP. Then, Nl-ALP1 was denoted as Nl-sALP for a sALP andNl-ALP2 was denoted as Nl-mALP for a mALP. Only sALP activity andNl-sALP mRNA level were induced by 20E and fenvalerate, which wascon?rmed by the density of speci?c band detected by Nl1-I in Sus strainwith or without fenvalerate treatment. Additionally, the sALP activity, aswell as Nl-sALP mRNA level, was signi?cantly higher in a fenvalerateresistant population, compared with Sus strain. These results indicate thatthe sALP is more responsive to chemical stimulus, such as hormone andinsecticide, and might play dual roles in development and insecticidetolerance.