Molecular characterization and RNA interference of three midgut aminopeptidase N isozymes from Bacillus thuringiensis-susceptible and -resistant strains of sugarcane borer, Diatraea saccharalis

Yang, Yunlong; Zhu, Yu Cheng; Ottea, James A.; Husseneder, Claudia; Leonard, B. R.; Abel, Craig A.; Huang, Fangneng

doi:10.1016/j.ibmb.2010.05.006

Cited by 64 publications

(64 citation statements)

References 71 publications

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“…A similar 210 kDa binding protein was observed in the D. saccharalis for both Cry1Ab and Cry1F ligand blots and may represent a cadherin-like receptor as described by Yang et al (2011). However, there was no evidence of binding to putative amino peptidase-N isoforms, which had previously been reported to confer Cry1Ab resistance in this species (Yang et al, 2010). No evidence of cross-reactivity with the cadherin and aminopeptidase antsera was detected, thus further confirming that both O. furnacalis and O. nubilalis are closely related and distinct from D. saccharalis.…”

Section: Discussionsupporting

confidence: 71%

Comparative binding of Cry1Ab and Cry1F Bacillus thuringiensis toxins to brush border membrane proteins from Ostrinia nubilalis, Ostrinia furnacalis and Diatraea saccharalis (Lepidoptera: Crambidae) midgut tissue

Tan

Cayabyab

Alcantara

et al. 2013

Journal of Invertebrate Pathology

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Section: Discussionsupporting

confidence: 71%

Comparative binding of Cry1Ab and Cry1F Bacillus thuringiensis toxins to brush border membrane proteins from Ostrinia nubilalis, Ostrinia furnacalis and Diatraea saccharalis (Lepidoptera: Crambidae) midgut tissue

Tan

Cayabyab

Alcantara

et al. 2013

Journal of Invertebrate Pathology

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“…With alteration of APNs as the molecular basis for Cry1Ac resistance, the greenhouse-evolved T. ni not only is highly resistant to Cry1Ac on an artificial diet, but also is highly resistant to Cry1Ac plants (16). Interestingly, different alleles and differing transcript levels of APN genes have been reported in laboratory-selected Cry1A toxin-resistant strains of several lepidopterans (27,28). However, genetic linkages between the different APN alleles or differential transcript levels and the resistance in these insects have not been established to confirm the correlation with resistance.…”

Section: Discussionmentioning

confidence: 99%

Differential alteration of two aminopeptidases N associated with resistance to Bacillus thuringiensis toxin Cry1Ac in cabbage looper

Tiewsiri

Wang

2011

Proc. Natl. Acad. Sci. U.S.A.

175

152

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The soil bacterium Bacillus thuringiensis (Bt) is the most successfully used biopesticide in agriculture, and its insecticidal protein genes are the primary transgenes used for insect control in transgenic crops. However, evolution of insect resistance to Bt toxins threatens the long-term future of Bt applications. To date, cases of resistance to Bt toxins have been reported in agricultural situations in six insect species, but the molecular basis for these cases of resistance remains unclear. Here we report that the resistance to the Bt toxin Cry1Ac in the cabbage looper, Trichoplusia ni, evolved in greenhouses, is associated with differential alteration of two midgut aminopeptidases N, APN1 and APN6, conferred by a trans-regulatory mechanism. Biochemical, proteomic, and molecular analyses showed that in the Cry1Ac-resistant T. ni, APN1 was significantly down-regulated, whereas APN6 was significantly up-regulated. The Cry1Ac resistance was correlated with downregulation of APN1 but not with the up-regulation of APN6. The concurrent up-regulation of APN6 and down-regulation of APN1 might play a role in compensating for the loss of APN1 to minimize the fitness costs of the resistance. Along with identifying reduced expression of APN1 as the molecular basis of Bt resistance selected in an agricultural setting, our findings demonstrate the importance of APN1 to the mode of action of Bt toxin Cry1Ac.

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“…26 In the Bt-RR strain of D. saccharalis, the resistance is associated with reduced expression of three aminopeptidase N genes and cadherin, but not with mutations in the genes encoding these proteins. 28,29 In addition, previous work showed the efficacy of the modified toxins against a greenhouse-selected resistant strain of T. ni. 10 Recent results indicate that this resistance is associated with reduced transcription of an aminopeptidase (APN1) and is linked with an ABC transporter gene, but not with genes encoding either cadherin or APN1 (refs.…”

Section: 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 Lmentioning

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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Molecular characterization and RNA interference of three midgut aminopeptidase N isozymes from Bacillus thuringiensis-susceptible and -resistant strains of sugarcane borer, Diatraea saccharalis

Cited by 64 publications

References 71 publications

Comparative binding of Cry1Ab and Cry1F Bacillus thuringiensis toxins to brush border membrane proteins from Ostrinia nubilalis, Ostrinia furnacalis and Diatraea saccharalis (Lepidoptera: Crambidae) midgut tissue

Comparative binding of Cry1Ab and Cry1F Bacillus thuringiensis toxins to brush border membrane proteins from Ostrinia nubilalis, Ostrinia furnacalis and Diatraea saccharalis (Lepidoptera: Crambidae) midgut tissue

Differential alteration of two aminopeptidases N associated with resistance to Bacillus thuringiensis toxin Cry1Ac in cabbage looper

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

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