Phylogeny and Molecular Study of Some Entomopathogenic Rhizobacteria Isolated from Two Regions in Algeria

Oulebsir-Mohandkaci Hakima,Khemili-Talbi Souad,Mohammedi Arezki,Hadjouti Ryma,Halouane Fatma,Benzina Farida

doi:10.3844/ajbsp.2019.55.61

Abstract

The use of bacteria in the control of insect pests is a form of biological control whose practice is still not widespread. It is in this context that the present work falls. It concerns the isolation, characterization and identification of local bacterial strains for the purpose of their use in the control of certain pests. Indeed, 20 bacteria were isolated from soil cultivated in the region of Boumerdes (center of Algeria) with a total of 21 bacterial strains isolated from Adrar region (Desert Algerian). After carrying out the efficacy tests against 2 insect pests; Migratory locust (Locusta migratoria) and wax moth (Galleria mellonella), 8 potentially interesting strains were identified based on their genetic traits. Molecular characterization of these strains was performed by isolation of DNA, PCR and sequencing of the 16S rRNA gene, followed by phylogenetic analysis. The rDNA16S sequences of the 8 strains named B1, B2, B3, B4, B5, B6, H1 and H2 were recorded in the EMBL/EBI database and their phylogenetic analysis revealed that they belong to the genera Bacillus, Pseudomonas, Enterobacter and Delftia with a very high percentage of similarity with Bacillus thuringiensis strains (NR_043403) (99%) for isolate B1, Bacillus weihenstephanensis (NR_024697) (99%) for isolate B2, Pseudomonas fragi (JCM5420) (99%) for isolates B3 and B4, Bacillus thuringiensis (CMBLBT-5) (99%) for isolate B4, Enterobacter ludwigii (EN-119) for B5, Bacillus thuringiensis (4916) (99%) for isolate H1 and Delftia lacustris (R-54734) (100%) for isolate H2.

Highlights

Due to the use of a large amount of chemical products, continuous loss of soil fertility puts pressure on farmers toward more crop production in a sustainable manner
Multiple species of entomopathogenic bacteria may be isolated from this part of soil, they are the enemies of pest-insects, whose utility in agroecosystems has been studied since decades
Ordinary nutrient agar (GN) medium, pH 7.2 was used for isolation bacterial strains. 0.1 mL of 10-1 to 105 dilutions was seeded on the surface of isolation medium

Summary

Introduction

Due to the use of a large amount of chemical products, continuous loss of soil fertility puts pressure on farmers toward more crop production in a sustainable manner. It requires adapting an eco-friendly, sustainable and cost-effective approach for agricultural practices without arising environmental issues (Singh et al, 2019). Multiple species of entomopathogenic bacteria may be isolated from this part of soil, they are the enemies of pest-insects, whose utility in agroecosystems has been studied since decades These entomopathogens spend significant time period in soil, either as saprotrophs, resting spores or dormant endospores (OulebsirMohandkaci et al, 2016; Sharma et al, 2019)

Methods

Results

Conclusion