Isolation of Bacillus thuringiensis strains from Saudi Arabia soil and study of their potential efficiency against the lepidopteran pest Ephestia kuehniella
1 Department of Biology, Faculty of Science and Arts at Khulis, University of Jeddah, Jeddah, Saudi Arabia.
2 Laboratory of Biopesticides, Centre of Biotechnology of Sfax, Sfax, Tunisia.
3 Higher Institute of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
¥ These authors contributed equally to this work
Research Article
World Journal of Advanced Research and Reviews, 2021, 12(02), 238–245
Article DOI: 10.30574/wjarr.2021.12.2.0568
Publication history:
Received on 06 October 2021; revised on 07 November 2021; accepted on 09 November 2021
Abstract:
Insect pests represent a major threat to food crops and human health, and therefore have to be combated in several ways, including chemical methods. However, researchers demonstrated that these molecules are dangerous for the farmers, consumers and the environment in general. For this reason, scientists permanently searched environment friendly alternatives such as the use of the bacterium Bacillus thuringiensis classified as one of the best insect pathogens. This microorganism is known by its ability to produce two types of insecticidal proteins, Vegetative insecticidal proteins (Vip) and delta-endotoxins produced during vegetative and sporulation stages of growth, respectively.
In the present study, 15 B. thuringiensis strains were isolated from soil collected from different regions in Saudi Arabia (Al Baha, Jeddah, Khulis and Yanbu). B. thuringiensis isolates were then classified according to the shape of their parasporal crystals identified under microscope and proteins content of these crystals. Delta-endotoxins efficiency of the different isolates was investigated and promising strains were identified as very active. After 5 days-treatment, B. thuringiensis isolates 14 and 7 killed Ephestia kuehniella larvae with low LC50 of about 59.18 and 65.67 mg/cm2, respectively.
The results described in the present study proved that the new B. thuringiensis isolates could be of a great interest in the control of lepidopteran pests by using their delta-endotoxins in bioinsecticide formulations.
Keywords:
Bacillus thuringiensis; Delta-endotoxins; Biocontrol; Ephestia kuehniella
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