0000000000183698
AUTHOR
Yudong Quan
showing 9 related works from this author
Insecticidal Activity and Synergistic Combinations of Ten Different Bt Toxins against Mythimna separata (Walker)
2018
The oriental armyworm (OAW), Mythimna separata (Walker), is a destructive pest of agricultural crops in Asia and Australia. Commercialized Bt crops have performed very well against their target pests
Studies on the insecticidal mechanism of Bacillus thuringiensis Vip3A and Cry proteins
2022
El control de plagas y patógenos ha tenido un efecto importante en la mejora del rendimiento de los sistemas agrícolas a nivel mundial. Diferentes tipos de insecticidas químicos se han usado extensivamente durante mucho tiempo para el control de plagas de insectos. Debido a la aparición de resistencias, problemas de contaminación de aguas y problemas de salud humana causados por dichos insecticidas de síntesis, la agricultura moderna necesita una estrategia de gestión integrada de plagas más saludable, respetuosa con el medio ambiente y sostenible. El uso de Bacillus thuringiensis (Bt) y sus proteínas insecticidas para el control de plagas es una de las estrategias biotecnológicas más impor…
Critical Domains in the Specific Binding of Radiolabeled Vip3Af Insecticidal Protein to Brush Border Membrane Vesicles from Spodoptera spp. and Cultu…
2021
Vegetative insecticidal proteins (Vip3) from Bacillus thuringiensis have been used, in combination with Cry proteins, to better control insect pests and as a strategy to delay the evolution of resistance to Cry proteins in Bt crops (crops protected from insect attack by the expression of proteins from B. thuringiensis). In this study, we have set up the conditions to analyze the specific binding of 125I-Vip3Af to Spodoptera frugiperda and Spodoptera exigua brush border membrane vesicles (BBMV). Heterologous competition binding experiments revealed that Vip3Aa shares the same binding sites with Vip3Af, but Vip3Ca does not recognize all of them. As expected, Cry1Ac and Cry1F did not compete f…
Artefactual band patterns by SDS-PAGE of the Vip3Af protein in the presence of proteases mask the extremely high stability of this protein.
2018
Abstract Vip3 proteins are secretable proteins from Bacillus thuringiensis with important characteristics for the microbiological control of agricultural pests. The exact details of their mode of action are yet to be disclosed and the crystallographic structure is still unknown. Vip3 proteins are expressed as protoxins that have to be activated by the insect gut proteases. A previous study on the peptidase processing of Vip3Aa revealed that the protoxin produced artefactual band patterns by SDS-PAGE due to the differential stability of this protein and the peptidases to SDS and heating (Bel et al., 2017 Toxins 9:131). To determine whether this phenomenon also applies to other Vip3A proteins…
Structural Domains of the Bacillus thuringiensis Vip3Af Protein Unraveled by Tryptic Digestion of Alanine Mutants
2019
Vip3 proteins are increasingly used in insect control in transgenic crops. To shed light on the structure of these proteins, we used the approach of the trypsin fragmentation of mutants altering the conformation of the Vip3Af protein. From an alanine scanning of Vip3Af, we selected mutants with an altered proteolytic pattern. Based on protease digestion patterns, their effect on oligomer formation, and theoretical cleavage sites, we generated a map of the Vip3Af protein with five domains which match some of the domains proposed independently by two in silico models. Domain I ranges amino acids (aa) 12&ndash
The Rapid Evolution of Resistance to Vip3Aa Insecticidal Protein in Mythimna separata (Walker) Is Not Related to Altered Binding to Midgut Receptors
2021
Laboratory selection for resistance of field populations is a well-known and useful tool to understand the potential of insect populations to evolve resistance to insecticides. It provides us with estimates of the frequency of resistance alleles and allows us to study the mechanisms by which insects developed resistance to shed light on the mode of action and optimize resistance management strategies. Here, a field population of Mythimna separata was subjected to laboratory selection with either Vip3Aa, Cry1Ab, or Cry1F insecticidal proteins from Bacillus thuringiensis. The population rapidly evolved resistance to Vip3Aa reaching, after eight generations, a level of >3061-fold resistance…
Analysis of cross-resistance to Vip3 proteins in eight insect colonies, from four insect species, selected for resistance to Bacillus thuringiensis i…
2018
Abstract Bacillus thuringiensis Vip3 proteins are synthesized and secreted during the vegetative growth phase. They are activated by gut proteases, recognize and bind to midgut receptors, form pores and lyse cells. We tested the susceptibility to Vip3Aa and Vip3Ca of Cry1A-, Cry2A-, Dipel- and Vip3-resistant insect colonies from different species to determine whether resistance to other insecticidal proteins confers cross-resistance to Vip3 proteins. As expected, the colonies resistant to Cry1A proteins, Dipel (Helicoverpa armigera, Trichoplusia ni, Ostrinia furnacalis and Plodia interpunctella) or Cry2Ab (H. armigera and T. ni) were not cross-resistant to Vip3 proteins. In contrast, H. arm…
Effect of substitutions of key residues on the stability and the insecticidal activity of Vip3Af from Bacillus thuringiensis
2021
Modern agriculture demands for more sustainable agrochemicals to reduce the environmental and health impact. The whole process of the discovery and development of new active substances or control agents is sorely slow and expensive. Vegetative insecticidal proteins (Vip3) from Bacillus thuringiensis are specific toxins against caterpillars with a potential capacity to broaden the range of target pests. Site-directed mutagenesis is one of the most approaches used to test hypotheses on the role of different amino acids on the structure and function of proteins. To gain a better understanding of the role of key amino acid residues of Vip3A proteins, we have generated 12 mutants of the Vip3Af1 …
Structural Domains of the <em>Bacillus thuringiensis</em> Vip3Af Protein Unraveled by Tryptic Digestion of Alanine Mutants
2019
Vip3 proteins are increasingly used in insect control in transgenic crops. To shed light on the structure of these proteins, we used the approach of trypsin fragmentation of mutants altering the conformation of the Vip3Af protein. From an alanine scanning on Vip3Af, we selected mutants with an altered proteolytic pattern. Based on the protease digestion patterns, their effect on oligomer formation, and theoretical cleavage sites, we generated a map of the Vip3Af protein with five domains, which match some of the domains proposed independently by two in silico models. Domain I ranges from aa12-198, domain II from aa199-313, domain III from aa314-526, domain IV from aa527-668 and domain V fro…