Open AccessDominant resistance to B t cotton and minor cross‐resistance to B t toxin C ry2Ab in cotton bollworm from C hina
Author(s) -
Jin Lin,
Wei Yiyun,
Zhang Lei,
Yang Yihua,
Tabashnik Bruce E.,
Wu Yidong
Publication year - 2013
Publication title -
evolutionary applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.776
H-Index - 68
ISSN - 1752-4571
DOI - 10.1111/eva.12099
Subject(s) - biology , toxin , trichoplusia , cross resistance , bollworm , strain (injury) , bacillus thuringiensis , microbiology and biotechnology , pest analysis , botany , noctuidae , bacteria , genetics , larva , anatomy
Abstract Evolution of resistance by insect pests threatens the long‐term benefits of transgenic crops that produce insecticidal proteins from B acillus thuringiensis ( B t). Previous work has detected increases in the frequency of resistance to B t toxin C ry1Ac in populations of cotton bollworm, H elicoverpa armigera , from northern C hina where B t cotton producing C ry1 A c has been grown extensively for more than a decade. Confirming that trend, we report evidence from 2011 showing that the percentage of individuals resistant to a diagnostic concentration of C ry1 A c was significantly higher in two populations from different provinces of northern China (1.4% and 2.3%) compared with previously tested susceptible field populations (0%). We isolated two resistant strains: one from each of the two field‐selected populations. Relative to a susceptible strain, the two strains had 460‐ and 1200‐fold resistance to C ry1 A c, respectively. Both strains had dominant resistance to a diagnostic concentration of C ry1 A c in diet and to B t cotton leaves containing C ry1 A c. Both strains had low, but significant cross‐resistance to C ry2 A b (4.2‐ and 5.9‐fold), which is used widely as the second toxin in two‐toxin B t cotton. Compared with resistance in other strains of H . armigera , the resistance in the two strains characterized here may be especially difficult to suppress.