Sugarcane Borer (Lepidoptera: Crambidae) Resistance to Transgenic Bacillus thuringiensis Maize

Huang, Fangneng; Leonard, B. R.; Andow, David A.

doi:10.1093/jee/100.1.164

Cited by 50 publications

(98 citation statements)

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“…In addition, a known Cry1Ab-resistant strain (Cry1Ab-RR-2004) of D. saccharalis was also included in the bioassays in this study to serve as a positive control. Cry1Ab-RR-2004 was established from a field collection in 2004, which has been well documented to be highly resistant to both Cry1Ab-maize plants and purified Cry1Ab protein (Huang et al, 2007a(Huang et al, , 2007bWu et al, 2007;Ghimire et al, 2011;Wangila et al, 2012). Individuals of the seven resistant strains were backcrossed 2-3 times with individuals from the Cry1Ab-SS strain and re-selected for Bt resistance using leaf tissue from Cry1Ab expressing maize plants during the F 2 generations of the backcross.…”

Section: Sources Of Cry1ab-susceptible and -Resistant Strains Of D Smentioning

confidence: 99%

Susceptibility of Cry1Ab maize-resistant and -susceptible strains of sugarcane borer (Lepidoptera: Crambidae) to four individual Cry proteins

Zhang

Huang

Leonard

et al. 2013

Journal of Invertebrate Pathology

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a b s t r a c tSugarcane borer, Diatraea saccharalis (F.), is a major target of Bt maize in South America and many areas of the US mid-south region. Six laboratory strains of D. saccharalis were established from six single-pair F 2 families possessing major resistance alleles to Cry1Ab maize hybrids. Susceptibility of the six strains was evaluated on diet treated with each of four purified trypsin-activated Bt proteins, Cry1Ab, Cry1Aa, Cry1Ac and Cry1F. Bt susceptibility of the six strains was compared with that of known Cry1Ab-susceptible and -resistant strains of D. saccharalis. At least two of the six strains demonstrated a similar level (>526-fold) of resistance to Cry1Ab as shown in the known Cry1Ab-resistant strain, while resistance levels were relatively lower for other strains (116-to 129-fold). All the six strains were highly cross-resistant to Cry1Aa (71-to 292-fold) and Cry1Ac (30-to 248-fold), but only with a low level to Cry1F (<7-fold). Larval growth of all six strains was also inhibited on Bt-treated diet, but, except for Cry1F, the growth inhibition of the six strains was considerably less than that of the Cry1Ab-susceptible larvae. The results provide clear evidence that the observed resistance to Cry1Ab maize in the six strains is a result of resistance to the Cry1Ab protein in the plants. The low level of cross-resistance between Cry1A and Cry1F suggests that pyramiding these two types of Bt proteins into a plant could be a good strategy for managing D. saccharalis.

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Section: Sources Of Cry1ab-susceptible and -Resistant Strains Of D Smentioning

confidence: 99%

Susceptibility of Cry1Ab maize-resistant and -susceptible strains of sugarcane borer (Lepidoptera: Crambidae) to four individual Cry proteins

Zhang

Huang

Leonard

et al. 2013

Journal of Invertebrate Pathology

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“…44 Bt-RR larvae completed development on commercial Cry1Ab corn hybrids. 44 Before the current study, the Bt-RR strain was backcrossed three times with the Bt-SS strain and reselected for resistance with Cry1Ab corn leaf tissue in the F2 generation after each backcross. 45 GYBT was derived from GY by 28 generations of selection with larvae exposed by diet surface overlay to activated Cry1Ac toxin.…”

Section: Saccharalismentioning

confidence: 99%

“…A Bt-resistant strain (Bt-RR) was developed from a single isoline family using an F2 screen. 44 Bt-RR larvae completed development on commercial Cry1Ab corn hybrids. 44 Before the current study, the Bt-RR strain was backcrossed three times with the Bt-SS strain and reselected for resistance with Cry1Ab corn leaf tissue in the F2 generation after each backcross.…”

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confidence: 99%

Efficacy of genetically modified Bt toxins against insects with different genetic mechanisms of resistance

et al. 2011

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Transgenic crops that produce Bacillus thuringiensis (Bt) toxins are grown widely for pest control, 1 but insect adaptation can reduce their efficacy. [2][3][4][5][6] The genetically modified Bt toxins Cry1AbMod and Cry1AcMod were designed to counter insect resistance to native Bt toxins Cry1Ab and Cry1Ac. 7 Previous results suggested that the modified toxins would be effective only if resistance was linked T A B A S H N I K E T A L ., N A T U R E B I O T E C H N O L O G Y 2 9 : 1 2 ( D E C E M B E R 2 0 1 1 )2 with mutations in genes encoding toxin-binding cadherin proteins. 7 Here we report evidence from five major crop pests refuting this hypothesis. Relative to native toxins, the potency of modified toxins was >350-fold higher against resistant strains of Plutella xylostella and Ostrinia nubilalis in which resistance was not linked with cadherin mutations. Conversely, the modified toxins provided little or no advantage against some resistant strains of three other pests with altered cadherin. Independent of the presence of cadherin mutations, the relative potency of the modified toxins was generally higher against the most resistant strains.The toxins produced by Bt kill some major insect pests but cause little or no harm to people and most other organisms. 8 Bt toxins have been used in sprays for decades and in transgenic plants since 1996 (ref. 6). Transgenic corn and cotton producing Bt toxins were planted on >58 million hectares worldwide in 2010 (ref. 1). The primary threat to the longterm efficacy of Bt toxins is the evolution of resistance by pests. [2][3][4][5][6] Many insects have been selected for resistance to Bt toxins in the laboratory, and some populations of at least eight crop pests have evolved resistance to Bt toxins outside of the laboratory, including two species resistant to Bt sprays and at least six species resistant to Bt crops. [2][3][4][5][6][9][10][11][12][13] The most widely used Bt toxins are crystalline proteins in the Cry1A family, particularly Cry1Ab in transgenic Bt corn and Cry1Ac in transgenic Bt cotton, which kill some lepidopteran larvae. 3 Cry1A toxins bind to the extracellular domains of cadherin, aminopeptidase, and alkaline phosphatase in larval midgut membranes. 14,15 Disruption of Bt toxin binding to midgut receptors is the most common general mechanism of insect resistance. 9 Mutations in the genes encoding midgut cadherins that bind Cry1Ac are linked with resistance in at least three lepidopteran pests of cotton, [16][17][18] but such cadherin mutations are not the primary cause of many other cases of field-and laboratory-selected resistance. 9,19,20 Although some aspects of the mode of action of Bt toxins remain unresolved, extensive evidence shows that after Cry1A protoxins are ingested by larvae, they are solubilized in the gut and cleaved by mid-gut proteases such as trypsin to yield activated 60-kD monomeric toxins that bind with membrane-associated receptors. 14,15 The signaling model suggests that after protease-activated monomeric toxins bind to ca...

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“…The Cry1Ab-SS strain is susceptible to purified Cry1Aa, Cry1Ab, Cry1Ac, Cry1A.105, and Cry2Ab2 proteins (Huang et al, 2007b;Wu et al, 2009), as well as to Bt corn leaf tissue expressing Cry1Ab, Cry1A.105, and Cry2Ab2 . The Cry1Ab-resistant strain was obtained from a single two-parent family developed through an F2 screen in 2004 (Huang et al, 2007a). The resistant strain can survive and complete its entire larval development (from neonate to pupa) on commercial Cry1Ab corn plants in the greenhouse (Huang et al, 2007a).…”

Section: Insect Sourcesmentioning

confidence: 99%

Larval survival and plant injury of Cry1Ab-susceptible, -resistant, and -heterozygous genotypes of the sugarcane borer on transgenic corn containing single or pyramided Bt genes

et al. 2012

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Sugarcane Borer (Lepidoptera: Crambidae) Resistance to Transgenic Bacillus thuringiensis Maize

Cited by 50 publications

References 0 publications

Susceptibility of Cry1Ab maize-resistant and -susceptible strains of sugarcane borer (Lepidoptera: Crambidae) to four individual Cry proteins

Susceptibility of Cry1Ab maize-resistant and -susceptible strains of sugarcane borer (Lepidoptera: Crambidae) to four individual Cry proteins

Efficacy of genetically modified Bt toxins against insects with different genetic mechanisms of resistance

Larval survival and plant injury of Cry1Ab-susceptible, -resistant, and -heterozygous genotypes of the sugarcane borer on transgenic corn containing single or pyramided Bt genes

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