title: Discovery of a novel insecticidal protein from Chromobacterium piscinae, with activity against Western Corn Rootworm, Diabrotica virgifera virgifera.
abstract: Western corn rootworm (WCR), Diabrotica virgifera virgifera, is one of the most significant pests of corn in the United States. Although transgenic solutions exist, increasing resistance concerns make the discovery of novel solutions essential. In order to find a novel protein with high activity and a new mode of action, a large microbial collection was surveyed for toxicity to WCR using in vitro bioassays. Cultures of strain ATX2024, identified as Chromobacterium piscinae, had very high activity against WCR larvae. The biological activity from the strain was purified using chromatographic techniques and fractions were tested against WCR larvae. Proteins in the final active fraction were identified by mass spectrometry and N-terminal sequencing and matched to the genome of ATX2024. A novel 58.9kDa protein, identified by this approach, was expressed in a recombinant expression system and found to have specific activity against WCR. Transgenic corn events containing this gene showed good protection against root damage by WCR, with average scores ranging between 0.01 and 0.04 on the Iowa State node injury scale. Sequence analysis did not reveal homology to any known insecticidal toxin, suggesting that this protein may act in a novel way to control WCR. The new WCR active protein is named GNIP1Aa, for Gram Negative Insecticidal Protein.
authors.affiliation: Bayer, Crop Science Division, Morrisville, NC, USA. Electronic address: kimberly.sampson@bayer.com.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Sampson
authors.affiliation: Bayer, Crop Science Division, Morrisville, NC, USA.
authors.forename: Jelena
authors.initials: J
authors.lastname: Zaitseva
authors.affiliation: Bayer, Crop Science Division, Morrisville, NC, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Stauffer
authors.affiliation: Bayer, Crop Science Division, Morrisville, NC, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Vande Berg
authors.affiliation: Bayer, Crop Science Division, Morrisville, NC, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Guo
authors.affiliation: Bayer, Crop Science Division, Morrisville, NC, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Tomso
authors.affiliation: Bayer, Crop Science Division, Morrisville, NC, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: McNulty
authors.affiliation: Bayer, Crop Science Division, Morrisville, NC, USA.
authors.forename: Nalini
authors.initials: N
authors.lastname: Desai
authors.affiliation: Bayer, Crop Science Division, Morrisville, NC, USA.
authors.forename: Deepa
authors.initials: D
authors.lastname: Balasubramanian
mesh_terms: D000818:Animals; D002861:Chromobacterium / Q000235:genetics / Q000378:metabolism; D001517:Coleoptera; D004731:Endotoxins / Q000235:genetics / Q000633:toxicity*; D007306:Insecticides / Q000378:metabolism / Q000494:pharmacology*; D013058:Mass Spectrometry; D010572:Pest Control, Biological / Q000379:methods*; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction; D003313:Zea mays
chemical_list: D004731:Endotoxins; D007306:Insecticides
keywords: Chromobacterium piscinae; Diabrotica virgifera; Insecticidal protein toxin; Western corn rootworm