Applied and Environmental Microbiology (2000) 66, 3784-3789

Jian-Zhou Zhao, Hilda L. Collins, Juliet D. Tang, Jun Cao, Elizabeth D. Earle, Richard T. Roush, Salvador Herrero, Baltasar Escriche, Juan Ferré and Anthony M. Shelton (2000)
Development and characterization of diamondback moth resistance to transgenic broccoli expressing high levels of Cry1C
Applied and Environmental Microbiology 66 (9), 3784-3789
Abstract: A field-collected colony of the diamondback moth, Plutella xylostella, had 31-fold resistance to Cry1C protoxin of Bacillus thuringiensis. After 24 generations of selection with Cry1C protoxin and transgenic broccoli expressing a Cry1C protein, the resistance that developed was high enough that neonates of the resistant strain could complete their entire life cycle on transgenic broccoli expressing high levels of Cry1C. After 26 generations of selection, the resistance ratios of this strain to Cry1C protoxin were 12,400- and 63,100-fold, respectively, for the neonates and second instars by a leaf dip assay. The resistance remained stable until generation 38 (G38) under continuous selection but decreased to 235-fold at G38 when selection ceased at G28. The Cry1C resistance in this strain was seen to be inherited as an autosomal and incompletely recessive factor or factors when evaluated using a leaf dip assay and recessive when evaluated using Cry1C transgenic broccoli. Saturable binding of ¹²⁵I-Cry1C was found with brush border membrane vesicles (BBMV) from both susceptible and Cry1C-resistant strains. Significant differences in Cry1C binding to BBMV from the two strains were detected. BBMV from the resistant strain had about sevenfold-lower affinity for Cry1C and threefold-higher binding site concentration than BBMV from the susceptible strain. The overall Cry1C binding affinity was just 2.5-fold higher for BBMV from the susceptible strain than it was for BBMV from the resistant strain. These results suggest that reduced binding is not the major mechanism of resistance to Cry1C.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Full text of article
Database assignments for author(s): Baltasar Escriche, Juan Ferre, Anthony M. Shelton, Salvador Herrero, Juliet D. Tang

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
pesticide resistance of pest
Research topic(s) for beneficials or antagonists:
resistance/tolerance/defence of host

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Plutella xylostella	Cabbage (Brassica oleracea)
Bacillus thuringiensis genes in crops (entomopathogen)	Plutella xylostella	Cabbage (Brassica oleracea)
Bacillus thuringiensis Cry1C-toxin (entomopathogen)	Plutella xylostella	Cabbage (Brassica oleracea)