Biomaterial Database

Resistance of Trichoplusia ni to Bacillus thuringiensis toxin Cry1Ac is independent of alteration of the cadherin-like receptor for Cry toxins. 2012

Xin Zhang, and Kasorn Tiewsiri, and Wendy Kain, and Lihua Huang, and Ping Wang

Department of Entomology, Cornell University, New York State Agricultural Experiment Station, Geneva, New York, United States of America.

Alteration of binding sites for Bacillus thuringiensis (Bt) toxins in insect midgut is the major mechanism of high-level resistance to Bt toxins in insects. The midgut cadherin is known to be a major binding protein for Bt Cry1A toxins and linkage of Bt-resistance to cadherin gene mutations has been identified in lepidopterans. The resistance to Bt toxin Cry1Ac evolved in greenhouse populations of Trichoplusia ni has been identified to be associated with the down-regulation of an aminopeptidase N (APN1) gene by a trans-regulatory mechanism and the resistance gene has been mapped to the locus of an ABC transporter (ABCC2) gene. However, whether cadherin is also involved with Cry1Ac-resistance in T. ni requires to be understood. Here we report that the Cry1Ac-resistance in T. ni is independent of alteration of the cadherin. The T. ni cadherin cDNA was cloned and the cadherin sequence showed characteristic features known to cadherins from Lepidoptera. Various T. ni cadherin gene alleles were identified and genetic linkage analysis of the cadherin alleles with Cry1Ac-resistance showed no association of the cadherin gene with the Cry1Ac-resistance in T. ni. Analysis of cadherin transcripts showed no quantitative difference between the susceptible and Cry1Ac-resistant T. ni larvae. Quantitative proteomic analysis of midgut BBMV proteins by iTRAQ-2D-LC-MS/MS determined that there was no quantitative difference in cadherin content between the susceptible and the resistant larvae and the cadherin only accounted for 0.0014% (mol%) of the midgut BBMV proteins, which is 1/300 of APN1 in molar ratio. The cadherin from both the susceptible and resistant larvae showed as a 200-kDa Cry1Ac-binding protein by toxin overlay binding analysis, and nano-LC-MS/MS analysis of the 200-kDa cadherin determined that there is no quantitative difference between the susceptible and resistant larvae. Results from this study indicate that the Cry1Ac-resistance in T. ni is independent of cadherin alteration.

UI	MeSH Term	Description	Entries
D007305	Insecticide Resistance	The development by insects of resistance to insecticides.	Insecticide Resistances,Resistance, Insecticide,Resistances, Insecticide
D007306	Insecticides	Pesticides designed to control insects that are harmful to man. The insects may be directly harmful, as those acting as disease vectors, or indirectly harmful, as destroyers of crops, food products, or textile fabrics.	Insecticide
D007814	Larva	Wormlike or grublike stage, following the egg in the life cycle of insects, worms, and other metamorphosing animals.	Maggots,Tadpoles,Larvae,Maggot,Tadpole
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009036	Moths	Insects of the suborder Heterocera of the order LEPIDOPTERA.	Antheraea,Giant Silkmoths,Giant Silkworms,Silkmoths, Giant,Silkworms, Giant,Antheraeas,Giant Silkmoth,Giant Silkworm,Moth,Silkmoth, Giant,Silkworm, Giant
D010572	Pest Control, Biological	Use of naturally-occuring or genetically-engineered organisms to reduce or eliminate populations of pests.	Biological Pest Control,Biologic Pest Control,Pest Control, Biologic,Biologic Pest Controls,Biological Pest Controls,Pest Controls, Biologic,Pest Controls, Biological
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004731	Endotoxins	Toxins closely associated with the living cytoplasm or cell wall of certain microorganisms, which do not readily diffuse into the culture medium, but are released upon lysis of the cells.	Endotoxin
D006460	Hemolysin Proteins	Proteins from BACTERIA and FUNGI that are soluble enough to be secreted to target ERYTHROCYTES and insert into the membrane to form beta-barrel pores. Biosynthesis may be regulated by HEMOLYSIN FACTORS.	Hemolysin,Hemolysins,Hemalysins,Proteins, Hemolysin