Bacterial Vegetative Insecticidal Proteins (Vip) from Entomopathogenic Bacteria

Abstract

SUMMARYEntomopathogenic bacteria produce insecticidal proteins that accumulate in inclusion bodies or parasporal crystals (such as the Cry and Cyt proteins) as well as insecticidal proteins that are secreted into the culture medium. Among the latter are the Vip proteins, which are divided into four families according to their amino acid identity. The Vip1 and Vip2 proteins act as binary toxins and are toxic to some members of the Coleoptera and Hemiptera. The Vip1 component is thought to bind to receptors in the membrane of the insect midgut, and the Vip2 component enters the cell, where it displays its ADP-ribosyltransferase activity against actin, preventing microfilament formation. Vip3 has no sequence similarity to Vip1 or Vip2 and is toxic to a wide variety of members of the Lepidoptera. Its mode of action has been shown to resemble that of the Cry proteins in terms of proteolytic activation, binding to the midgut epithelial membrane, and pore formation, although Vip3A proteins do not share binding sites with Cry proteins. The latter property makes them good candidates to be combined with Cry proteins in transgenic plants (Bacillus thuringiensis-treated crops [Bt crops]) to prevent or delay insect resistance and to broaden the insecticidal spectrum. There are commercially grown varieties of Bt cotton and Bt maize that express the Vip3Aa protein in combination with Cry proteins. For the most recently reported Vip4 family, no target insects have been found yet.

Bringing New Plant Varieties to Market: Plant Breeding and Selection Practices Advance Beneficial Characteristics while Minimizing Unintended Changes

“…In recent years, the trend is to include multiple genes of interest within a single DNA construct (Weber et al, 2012;NAS, 2016). For example, for effective insect control, different mechanisms of action can be identified by a combination of competitive binding experiments and testing new control agents against insects resistant to other insecticides (Pardo-López et al, 2013;Ladics et al, 2015aLadics et al, , 2015bChakroun et al, 2016;Jerga A et al, 2016;Jurat-Fuentes and Crickmore, 2017;Moar et al, 2017). Typically, dozens of versions of an expression cassette are tested in plants, both in greenhouse and confined field trials, to determine which best optimizes the gene expression needed to ensure commercial viability and reproducible efficacy of the trait.…”

Genetically engineered (modified) crops (Bacillus thuringiensis crops) and the world controversy on their safety

“…The first consists of a binary system composed of two proteins: Vip 1 and Vip 2, which are 100 kDa and 52 kDa in size, respectively. These proteins are highly toxic to certain coleopteran species (Chakroun et al 2016). The second class is of a 88.5 kDa protein (Vip 3) and active against a wide range of lepidopteran insects (Chakroun et al 2016).…”

“…These proteins are highly toxic to certain coleopteran species (Chakroun et al 2016). The second class is of a 88.5 kDa protein (Vip 3) and active against a wide range of lepidopteran insects (Chakroun et al 2016). These two classes of proteins do not display sequence homology with Cry or Cyt proteins (Chakroun et al 2016).…”

“…The second class is of a 88.5 kDa protein (Vip 3) and active against a wide range of lepidopteran insects (Chakroun et al 2016). These two classes of proteins do not display sequence homology with Cry or Cyt proteins (Chakroun et al 2016). There are, to date, about 82 identified Vip genes.…”

Interaction between toxin crystals and vegetative insecticidal proteins of Bacillus thuringiensis in lepidopteran larvae

“…In vegetative stage of growth other toxins are produced, named vegetative insecticidal proteins (Vips). Vip1 and Vip2 proteins act as binary toxins and show activity against Coleoptera, whereas Vip3 are active against Lepidoptera (Chakroun et al 2016).…”