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Molecular identification and genetic diversity among Photorhabdus and Xenorhabdus isolates

Reda E A Moghaieb1,2, Abdelhadi A Abdelhadi1, Hanan A El-Sadawy3

  • 1Department of Genetics and Genetic Engineering Research Center (GERC), Faculty of Agriculture Cairo University, Giza, 12613, Egypt.

3 Biotech
|April 10, 2017
PubMed

Insights

Molecular markers revealed genetic diversity among Photorhabdus and Xenorhabdus bacteria isolated from greater wax moth larvae. These genotype-specific markers can aid in developing future insect biological control programs.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Entomology

Background:

  • Greater wax moth larvae (Galleria mellonella) are hosts for entomopathogenic nematodes.
  • Nematode infection can lead to bacterial proliferation within the insect hemocoel.
  • Photorhabdus and Xenorhabdus are symbiotic bacteria commonly found with entomopathogenic nematodes.

Purpose of the Study:

  • To identify and characterize bacterial strains isolated from infected Galleria mellonella larvae.
  • To assess the genetic diversity among Photorhabdus and Xenorhabdus strains using molecular markers.
  • To determine the utility of these markers for distinguishing bacterial strains for potential use in insect biological control.

Main Methods:

  • Bacterial isolation from the hemocoel of infected Galleria mellonella larvae.
  • Identification of bacterial isolates using 16S rDNA sequence analysis.
  • Application of three molecular markers: Random Amplified Polymorphic DNA (RAPD), Inter-Simple Sequence Repeat (ISSR), and Simple Repetitive Amplicon (SRAP) analysis.
  • Cluster analysis to infer phylogenetic relationships.

Main Results:

  • Five bacterial strains were identified as Photorhabdus luminescens (three strains) and Xenorhabdus (two strains).
  • RAPD, ISSR, and SRAP analyses revealed significant genetic polymorphism percentages among the Photorhabdus (70.1–75.6%) and Xenorhabdus (54.5–75.2%) strains.
  • Cluster analysis successfully grouped the Photorhabdus strains together and the Xenorhabdus strains together, reflecting their phylogenetic relationships.
  • Genotype-specific markers were identified, capable of distinguishing between the tested bacterial strains.

Conclusions:

  • The study successfully identified and differentiated Photorhabdus and Xenorhabdus bacterial strains from Galleria mellonella.
  • Molecular markers (RAPD, ISSR, SRAP) are effective tools for assessing genetic diversity and establishing phylogenetic relationships among these bacteria.
  • The identified genotype-specific markers hold potential for application in developing future insect biological control strategies utilizing these bacterial strains.
Keywords:
16S rDNAGenetic diversityMolecular markersPhotorhabdusXenorhabdus

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