Binding and toxicity of Bacillus thuringiensis Protein Cry1C to susceptible and resistant diamondback moth (lepidoptera: plutellidae)

Yong Biao Liu, Bruce E Tabashnik, Luke Masson, Baltasar Escriche, Juan Ferré

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

We studied mechanisms of resistance to Bacillus thuringiensis insecticidal crystal protein Cry1C in the diamondback moth, Plutella xylostella (L.). Binding assays with midgut brush border membrane vesicles prepared from whole larvae showed no significant difference between resistant and susceptible strains in binding of radioactively-labeled Cry1C. These results indicate that reduced binding of Cry1C to midgut membrane target sites did not cause resistance to Cry1C. Thus, the mechanism of resistance to Cry1C differs from that observed in several previously reported cases of resistance to Cry1A toxins in diamondback moth. We tested Cry1C toxin and Cry1C crystalline protoxin against resistant and susceptible larvae using leaf disk bioassays. After adjusting for the size difference between Cry1C toxin and protoxin, we found that with resistant larvae, toxin was significantly more toxic than protoxin. In contrast, with susceptible larvae, no significant difference in toxicity occurred between Cry1C toxin and protoxin. The resistance ratios for Cry1C were 19 for toxin and 48 for protoxin. These results suggest that reduced conversion of Cry1C protoxin to toxin is a minor mechanism of resistance to Cry1C. Because neither reduced binding nor reduced conversion of protoxin to toxin appear to be major mechanisms, one or more other mechanisms are important in diamondback moth resistance to Cry1C.

Original languageEnglish (US)
Pages (from-to)1-6
Number of pages6
JournalJournal of Economic Entomology
Volume93
Issue number1
StatePublished - 2000

Fingerprint

Plutellidae
Plutella xylostella
Bacillus thuringiensis
moth
toxin
toxins
Lepidoptera
toxicity
protein
proteins
resistance mechanisms
larva
larvae
midgut
membrane
brush border membrane vesicles
crystal proteins
insecticidal proteins
vesicle
bioassay

Keywords

  • Bacillus thuringiensis
  • Binding
  • Cry1C
  • Mechanism
  • Plutella xylostella
  • Resistance

ASJC Scopus subject areas

  • Insect Science
  • Ecology

Cite this

Binding and toxicity of Bacillus thuringiensis Protein Cry1C to susceptible and resistant diamondback moth (lepidoptera : plutellidae). / Liu, Yong Biao; Tabashnik, Bruce E; Masson, Luke; Escriche, Baltasar; Ferré, Juan.

In: Journal of Economic Entomology, Vol. 93, No. 1, 2000, p. 1-6.

Research output: Contribution to journalArticle

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