A novel binary pesticidal protein from Chryseobacterium arthrosphaerae controls western corn rootworm by a different mode of action to existing commercial pesticidal proteins

Abstract

The western corn rootworm (WCR) Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) remains one of the economically most important pests of maize (Zea mays) due to its adaptive capabilities to pest management options. This includes the ability to develop resistance to some of the commercial pesticidal proteins originating from different strains of Bacillus thuringiensis. Although urgently needed, the discovery of new, environmentally safe agents with new modes of action is a challenge. In this study we report the discovery of a new family of binary pesticidal proteins isolated from several Chryseobacterium species. These novel binary proteins, referred to as GDI0005A and GDI0006A, produced as recombinant proteins, prevent growth and increase mortality of WCR larvae, as does the bacteria. These effects were found both in susceptible and resistant WCR colonies to Cry3Bb1 and Cry34Ab1/Cry35Ab1 (reassigned Gpp34Ab1/Tpp35Ab1). This suggests GDI0005A and GDI0006A may not share the same binding sites as those commercially deployed proteins and thereby possess a new mode of action. This paves the way towards the development of novel biological or biotechnological management solutions urgently needed against rootworms.

Changes in Hemolymph Microbiota of Chinese Mitten Crab (Eriocheir sinensis) in Response to Aeromonas hydrophila or Staphylococcus aureus Infection

“…The genus Candidatus Hepatoplasma was reported to involve the response of E. sinensis to heat stress [15]. The members of the genus Chryseobacterium were shown to implicate fatal nosocomial infections in humans and have antimicrobial activity in maize (Zea mays) against western corn rootworm larva [48,49]. Collectively, our findings indicate that the structure of the microbial community in E. sinensis exhibited distinct successional trajectories following infections.…”

Diabrotica v. virgifera Seems Not Affected by Entomotoxic Protease Inhibitors from Higher Fungi

“…Biopesticides based on single active ingredients such as entomotoxic proteins may be the more promising approach. However, finding such novel active ingredients has proven difficult, despite high-throughput screenings by industry [44].…”

“…Families according to Merops classification (https://www.ebi.ac.uk/merops/, accessed on 10 May 2022) [33]. To assess the effects of fungal protease inhibitors on larvae of D. v. virgifera, bioassays based on artificial diet were performed under controlled, semi-sterile conditions according to the methods of [17,44]. Each bioassay consisted of 6 to 7 transparent polystyrene 96-well plates (BioLite 96 well multidish, Thermo Scientific, Waltham, MA, USA).…”

A universal artificial diet for corn rootworm (Diabrotica spp.) larval biopesticide assays

“…The diet assays for corn rootworm ( Diabrotica spp.) larvae typically run up to 10 days ( 15 , 20 , 22 ). Larval molting was recorded daily during the assays, while larval fresh weight and survival were determined at the end of the assays.…”

“…Diet assays, whereby insecticidal toxins are typically overlaid onto an artificial diet for evaluating their efficacy on insects, and on-plant assays allow determining the susceptibility of corn rootworms to target compounds and entomopathogenic agents. These tools are crucial for the resistance monitoring programs as well as research discovery programs of new insecticidal toxins and other control agents (e.g., entomopathogenic nematodes) to manage the insect pests of maize ( 15 – 22 ).…”