Identification of a New Alcaligenes faecalis Strain MOR02 and Assessment of Its Toxicity and Pathogenicity to Insects

• Main Authors: Rosa Estela Quiroz-Castañeda, Ared Mendoza-Mejía, Verónica Obregón-Barboza, Fernando Martínez-Ocampo, Armando Hernández-Mendoza, Felipe Martínez-Garduño, Gabriel Guillén-Solís, Federico Sánchez-Rodríguez, Guadalupe Peña-Chora, Laura Ortíz-Hernández, Paul Gaytán-Colín, Edgar Dantán-González
• Format: Article
• Language: English
• Published: Hindawi Limited 2015-01-01
• Series: BioMed Research International
• Online Access: http://dx.doi.org/10.1155/2015/570243

We report the isolation of a bacterium from Galleria mellonella larva and its identification using genome sequencing and phylogenomic analysis. This bacterium was named Alcaligenes faecalis strain MOR02. Microscopic analyses revealed that the bacteria are located in the esophagus and intestine of the nematodes Steinernema feltiae, S. carpocapsae, and H. bacteriophora. Using G. mellonella larvae as a model, when the larvae were injected with 24,000 CFU in their hemocoel, more than 96% mortality was achieved after 24 h. Additionally, toxicity assays determined that 1 μg of supernatant extract from A. faecalis MOR02 killed more than 70% G. mellonella larvae 96 h after injection. A correlation of experimental data with sequence genome analyses was also performed. We discovered genes that encode proteins and enzymes that are related to pathogenicity, toxicity, and host/environment interactions that may be responsible for the observed phenotypic characteristics. Our data demonstrates that the bacteria are able to use different strategies to colonize nematodes and kill insects to their own benefit. However, there remains an extensive group of unidentified microorganisms that could be participating in the infection process. Additionally, a nematode-bacterium association could be established probably as a strategy of dispersion and colonization.