Identification and bacterial characteristics of Xenorhabdus hominickii ANU101 from an entomopathogenic nematode, Steinernema monticolum

- Steinernema monticolum is isolated in Korea and its symbiotic bacterium is identified.
- Xenorhabdus hominickii is characterized in carbon utility, growth pattern, and pathogenic spectrum.
- Four plasmids of X. hominickii are sequenced and their 332 predicted genes are annotated.

An entomopathogenic nematode, Steinernema monticolum, was collected in Korea. Its identity was confirmed by morphological and molecular characters. Its symbiotic bacterium, Xenorhabdus hominickii ANU101, was isolated and assessed in terms of bacterial characteristics. Sixty-eight different carbon sources were utilized by X. hominickii ANU101 out of 95 different sources from a Biolog assay. Compared to other Xenorhabdus species, X. hominickii ANU101 was relatively susceptible to high temperatures and did not grow above 34 °C. Furthermore, its growth rate was much slower than other Xenorhabdus species. X. hominickii exhibited insecticidal activities against coleopteran, dipteran, and lepidopteran insect pests. The bacterial virulence was not correlated with its host nematode virulence with respect to relative insecticidal activity against target insects. X. hominickii ANU101 exhibited antibiotics tolerance. The bacterium possesses four different plasmids (Xh-P1 (104,132 bp), Xh-P2 (95,975 bp), Xh-P3 (88,536 bp), and Xh-P4 (11,403 bp)) and encodes 332 open reading frames. Subsequent predicted genes include toxin/antitoxins comprising a multidrug export ATP-binding/permease. This study reports bacterial characters of X. hominickii and its entomopathogenicity.

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