Identification of midgut membrane proteins from different instars of Helicoverpa armigera (Lepidoptera: Noctuidae) that bind to Cry1Ac toxin

Author(s)

Sena Da Silva, Igor Henrique ^[1] ; Gomez, Isabel ^[2] ; Sanchez, Jorge ^[2] ; Martinez de Castro, Diana L. ^[2] ; Valicente, Fernando Hercos ^[3] ; Soberon, Mario ^[2] ; Polanczyk, Ricardo Antonio ^[1] ; Bravo, Alejandra ^[2]

Affiliation

^[1] Univ Estadual Paulista, Fac Ciencias Agr & Vet, Dept Fitossanidade, Jaboticabal, SP - Brazil

^[2] Univ Nacl Autonoma Mexico, Inst Biotecnol, Cuernavaca, Morelos - Mexico

^[3] Embrapa Milho & Sorgo, Sete Lagoas, MG - Brazil

• Document type: Journal article
• Source: PLoS One; v. 13, n. 12 DEC 6 2018.
• Web of Science Citations: 2

Abstract

Helicoverpa armigera is a polyphagous pest sensitive to Cry1Ac protein from Bacillus thuringiensis (Bt). The susceptibility of the different larval instars of H. armigera to Cry1Ac protoxin showed a significant 45-fold reduction in late instars compared to early instars. A possible hypothesis is that gut surface proteins that bind to Cry1Ac differ in both instars, although higher Cry toxin degradation in late instars could also explain the observed differences in susceptibility. Here we compared the Cry1Ac-binding proteins from second and fifth instars by pull-down assays and liquid chromatography coupled to mass spectrometry analysis (LC-MS/MS). The data show differential protein interaction patterns of Cry1Ac in the two instars analyzed. Alkaline phosphatase, and other membrane proteins, such as prohibitin and an anion selective channel protein were identified only in the second instar, suggesting that these proteins may be involved in the higher toxicity of Cry1Ac in early instars of H. armigera. Eleven Cry1Ac binindg proteins were identified exclusively in late instar larvae, like different proteases such as trypsin-like protease, azurocidin-like proteinase, and carboxypeptidase. Different aminopeptidase N isofroms were identified in both instar larvae. We compared the Cry1Ac protoxin degradation using midgut juice from late and early instars, showing that the midgut juice from late instars is more efficient to degrade Cry1Ac protoxin than that of early instars, suggesting that increased proteolytic activity on the toxin could also explain the low Cry1Ac toxicity in late instars. (AU)

• FAPESP's process: 15/24330-5 - Interação da toxina Cry1Ac de Bacillus thurigiensis às microvilosidades apicais das células colunares (BBMVs) do intestino médio de diferentes ínstares larvais de Helicoverpa armigera (Lepidoptera: Noctuidae)
• Grantee: Igor Henrique Sena da Silva
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 16/21464-3 - Bacillus thuringiensis Cry1Ac interactions to brush border emebrane vesicles (BBMV) in the midgut of different larval instars of Helicoverpa armigera (Lepidoptera: Noctuidae)
• Grantee: Igor Henrique Sena da Silva
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree