BACKGROUND: Bollgard(®) cotton, expressing Cry1Ac insecticidal protein, was approved for commercial planting in India in 2002, and by 2009 constituted 87% of the Indian crop, reducing losses from lepidopteran pests, including pink bollworm (PBW), Pectinophora gossypiella. Inadequate control of PBW in fields of single-gene Bollgard cotton was reported in 2009; surveys revealed heavy infestations of PBW in Bollgard, restricted to Gujarat state, but not elsewhere in India. RESULTS: Bioassays of PBW strains from Bollgard bolls showed that, while susceptible PBW could not complete development to third and later instar at 10.0 µg Cry1Ac mL(-1) , 66.1% of larvae from Gujarat Bollgard strains could. A field-resistant strain, further selected in the laboratory, had susceptibility to Cry1Ac reduced by >2000-fold. Resistance to Cry1Ac did not confer cross-resistance to the Cry2Ab2 protein. In 2010, Bollgard fields in Gujarat continued to be infested with PBW, and many Bollgard fields in the adjoining states of Maharashtra and Madhya Pradesh showed high-level infestation by PBW. CONCLUSION: Inadequate planting of refuges for PBW is the likely explanation for the field resistance to Bt cotton observed in Gujarat. These findings underscore the higher vulnerability of single-gene Bt products relative to dual-gene products expressing Cry1Ac and Cry2Ab2, and the increased risk of resistance evolution with low refuge compliance.
BACKGROUND: Bollgard(®) cotton, expressing Cry1Ac insecticidal protein, was approved for commercial planting in India in 2002, and by 2009 constituted 87% of the Indian crop, reducing losses from lepidopteran pests, including pink bollworm (PBW), Pectinophora gossypiella. Inadequate control of PBW in fields of single-gene Bollgard cotton was reported in 2009; surveys revealed heavy infestations of PBW in Bollgard, restricted to Gujarat state, but not elsewhere in India. RESULTS: Bioassays of PBW strains from Bollgard bolls showed that, while susceptible PBW could not complete development to third and later instar at 10.0 µg Cry1Ac mL(-1) , 66.1% of larvae from Gujarat Bollgard strains could. A field-resistant strain, further selected in the laboratory, had susceptibility to Cry1Ac reduced by >2000-fold. Resistance to Cry1Ac did not confer cross-resistance to the Cry2Ab2 protein. In 2010, Bollgard fields in Gujarat continued to be infested with PBW, and many Bollgard fields in the adjoining states of Maharashtra and Madhya Pradesh showed high-level infestation by PBW. CONCLUSION: Inadequate planting of refuges for PBW is the likely explanation for the field resistance to Bt cotton observed in Gujarat. These findings underscore the higher vulnerability of single-gene Bt products relative to dual-gene products expressing Cry1Ac and Cry2Ab2, and the increased risk of resistance evolution with low refuge compliance.
Authors: Renato J Horikoshi; Oderlei Bernardi; Daniela N Godoy; Altair A Semeão; Alan Willse; Gustavo O Corazza; Elderson Ruthes; Davi de S Fernandes; Daniel R Sosa-Gómez; Adeney de F Bueno; Celso Omoto; Geraldo U Berger; Alberto S Corrêa; Samuel Martinelli; Patrick M Dourado; Graham Head Journal: Sci Rep Date: 2021-10-29 Impact factor: 4.379
Authors: Erica E Tassone; Gina Zastrow-Hayes; John Mathis; Mark E Nelson; Gusui Wu; J Lindsey Flexner; Yves Carrière; Bruce E Tabashnik; Jeffrey A Fabrick Journal: Gigascience Date: 2016-06-22 Impact factor: 6.524
Authors: Jeffrey A Fabrick; Gopalan C Unnithan; Alex J Yelich; Ben DeGain; Luke Masson; Jie Zhang; Yves Carrière; Bruce E Tabashnik Journal: Sci Rep Date: 2015-11-12 Impact factor: 4.379
Authors: Lolita G Mathew; Jeyakumar Ponnuraj; Bheemanna Mallappa; Lingutla R Chowdary; Jianwei Zhang; Wee Tek Tay; Thomas K Walsh; Karl H J Gordon; David G Heckel; Sharon Downes; Yves Carrière; Xianchun Li; Bruce E Tabashnik; Jeffrey A Fabrick Journal: Sci Rep Date: 2018-09-10 Impact factor: 4.379
Authors: V Chinna Babu Naik; Pratik P Pusadkar; Sandesh T Waghmare; Raghavendra K P; Sandhya Kranthi; Sujit Kumbhare; V S Nagrare; Rishi Kumar; Tenguri Prabhulinga; Nandini Gokte-Narkhedkar; V N Waghmare Journal: Sci Rep Date: 2020-03-16 Impact factor: 4.996