Binding of Bacillus thuringiensis Cry1A toxins to brush border membrane vesicles of midgut from Cry1Ac susceptible and resistant Plutella xylostella.
Plutella xylostella strain resistant (PXR) to Bacillus thuringiensis Cry1Ac toxin was not killed at even more than 1000 microg Cry1Ac/g diet but killed by Cry1Ab at 0.5 microg/g diet. In contrast, susceptible strain (PXS) was killed by Cry1Ac at 1 microg/g diet. Cy3-labeld Cry1A(s) binding to brush border membrane vesicles (BBMV) prepared from both strains were analyzed with direct binding assay. The Kd value of Cry1Aa to both BBMV was almost identical: 213.2 and 205.8 nM, and 263.5 and 265.0 nM for Cry1Ac. The highest Kd values were in Cry1Ab which showed most effective insecticidal activity in PXS and PXR, 2126 and 2463 nM, respectively. These results clearly showed that the BBMV from PXR and PXS could equally bind to Cry1Ac. The binding between BBMV and Cy3-labeled Cry1Ac was inhibited only by anti-175 kDa cadherin-like protein (CadLP) and -252 kDa protein antisera, but not by anti-120 kDa aminopeptidase. This supports that resistance in PXR resulted from the abortion of pore formation after the binding of Cry1Ac to the BBMV. And furthermore, the importance of 175K CadLP and P252 proteins in those bindings was suggested. We briefly discuss possible mechanisms of the resistance.
Higuchi
Masahiro
M
Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan.
Haginoya
Kohsuke
K
Yamazaki
Takanori
T
Miyamoto
Kazuhisa
K
Katagiri
Takahiro
T
Tomimoto
Kazuya
K
Shitomi
Yasuyuki
Y
Hayakawa
Tohru
T
Sato
Ryoichi
R
Hori
Hidetaka
H
D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000378:metabolism* / Q000494:pharmacology*; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism; D004064:Digestive System / Q000378:metabolism* / Q000648:ultrastructure; D004305:Dose-Response Relationship, Drug; D004731:Endotoxins / Q000378:metabolism* / Q000494:pharmacology*; D006460:Hemolysin Proteins / Q000378:metabolism* / Q000494:pharmacology*; D007305:Insecticide Resistance; D008871:Microvilli / Q000378:metabolism; D009036:Moths / Q000033:anatomy & histology / Q000187:drug effects; D011485:Protein Binding; D022161:Transport Vesicles / Q000378:metabolism
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis