Assessing the Pathogenicity of Two Bacteria Isolated from the Entomopathogenic Nematode Heterorhabditis indica against Galleria mellonella and Some Pest Insects.

Rosalba Salgado-Morales,Kathia Vilchis-Martínez,Verónica Obregón-Barboza,Alfredo Jiménez-Pérez,Edgar Dantán-González,Fernando Martínez-Ocampo

doi:10.3390/insects10030083

Rosalba Salgado-Morales, Kathia Vilchis-Martínez + Show 4 more

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https://doi.org/10.3390/insects10030083

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Abstract

The entomopathogenic nematodes Heterorhabditis are parasites of insects and are associated with mutualist symbiosis enterobacteria of the genus Photorhabdus; these bacteria are lethal to their host insects. Heterorhabditis indica MOR03 was isolated from sugarcane soil in Morelos state, Mexico. The molecular identification of the nematode was confirmed using sequences of the ITS1-5.8S-ITS2 region and the D2/D3 expansion segment of the 28S rRNA gene. In addition, two bacteria HIM3 and NA04 strains were isolated from the entomopathogenic nematode. The genomes of both bacteria were sequenced and assembled de novo. Phylogenetic analysis was confirmed by concatenated gene sequence datasets as Photorhabdus luminescens HIM3 (16S rRNA, 23S rRNA, dnaN, gyrA, and gyrB genes) and Pseudomonas aeruginosa NA04 (16S rRNA, 23S rRNA and gyrB genes). H. indica MOR03 infects Galleria mellonella, Tenebrio molitor, Heliothis subflexa, and Diatraea magnifactella larvae with LC50 values of 1.4, 23.5, 13.7, and 21.7 IJs/cm2, respectively, at 48 h. These bacteria are pathogenic to various insects and have high injectable insecticide activity at 24 h.

Highlights

The entomopathogenic nematodes (Rhabditida: Heterorhabditidae and Steinernematidae) are parasites of insects that are associated in mutualist symbiosis with enterobacteria of the generaPhotorhabdus and Xenorhabdus [1,2]
The entomophatogenic nematode H. indica MOR03 was isolated from agricultural soil cultivated with entomophatogenic nematode H. indica MOR03 was isolated from agricultural soil cultivated with sugarcane in the town of Oacalco in Yautepec, Morelos, where the average temperature is around sugarcane in the town of Oacalco in Yautepec, Morelos, where the average temperature is around
This paper reports the isolation and molecular identification of the nematode H. indica MOR03 that has proven to be lethal for various insects

Summary

Introduction

The entomopathogenic nematodes (Rhabditida: Heterorhabditidae and Steinernematidae) are parasites of insects that are associated in mutualist symbiosis with enterobacteria of the genera. Photorhabdus and Xenorhabdus [1,2]. The entomopathogenic nematodes, unlike other parasites, cause the death of the host insect in a short time (within 24–48 h of infection), and this lethality is provided by associated bacteria [2]. The infective juvenile stage (IJ) is the only free life form of the entomopathogenic nematodes and functions as a vector carrying the symbiotic bacteria in the intestine to release them in the host insect’s hemolymph [3]. The life cycle of the nematode is completed inside the insect cadaver. The symbiotic bacteria of entomopathogenic nematodes (Photorhabdus and Xenorhabdus) are gammaproteobacteria, Gram-negative, and members of the family Enterobacteriaceae.

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