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An α‐amylase is a novel receptor for Bacillus thuringiensis ssp. israelensis Cry4Ba and Cry11Aa toxins in the malaria vector mosquito Anopheles albimanus ( Diptera : Culicidae )
Author(s) -
FernandezLuna Maria Teresa,
LanzMendoza Humberto,
Gill Sarjeet S.,
Bravo Alejandra,
Soberon Mario,
MirandaRios Juan
Publication year - 2010
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2009.02117.x
Subject(s) - anopheles albimanus , biology , bacillus thuringiensis , vector (molecular biology) , malaria , anopheles , microbiology and biotechnology , recombinant dna , genetics , gene , bacteria , immunology
Summary Bacillus thuringiensis ssp. israelensis ( Bti ) produces four Cry toxins (Cry4Aa, Cry4Ba, Cry10Aa and Cry11Aa), and two Cyt proteins (Cyt1Aa and Cyt2Ba), toxic to mosquito‐larvae of the genus Aedes , Anopheles and Culex , important human disease vectors that transmit dengue virus, malaria and filarial parasites respectively. Previous work showed that Bti is highly toxic to Anopheles albimanus , the main vector for transmission of malaria in Mexico. In this work, we analysed the toxicity of isolated Cry proteins of Bti and identified an An. albimanus midgut protein as a putative Cry4Ba and Cry11Aa receptor molecule. Biossays showed that Cry4Ba and Cry11Aa of Bti are toxic to An. albimanus larvae. Ligand blot assays indicated that a 70 kDa glycosylphosphatidylinositol‐anchored protein present in midgut brush border membrane vesicles of An. albimanus interacts with Cry4Ba and Cry11Aa toxins. This protein was identified as an α‐amylase by mass spectrometry and enzymatic activity assays. The cDNA that codes for the α‐amylase was cloned by means of 5′‐ and 3′‐RACE experiments. Recombinant α‐amylase expressed in Escherichia coli specifically binds Cry4Ba and Cry11Aa toxins.