Selection and characterisation of an HD1‐like Bacillus thuringiensis isolate with a high insecticidal activity against Spodoptera littoralis (Lepidoptera: Noctuidae). Issue 8 (22nd October 2013)

• Record Type: Journal Article
• Authors: Azzouz, Hichem; Kebaili‐Ghribi, Jihene; ben Farhat‐Touzri, Dalel; Daoud, Fatma; Fakhfakh, Ines; Tounsi, Slim; Jaoua, Samir
• Is Part Of: Pest management science. Volume 70:Issue 8(2014:Aug.)
• Page Start: 1192
• Page End: 1201
• Publication Date: 2013-10-22
• Subjects: Pests -- Control -- Periodicals; Pesticides -- Periodicals; 632.9
• DOI: 10.1002/ps.3661
• Languages: English
• ISSNs: 1526-498X

Abstract

<abstract abstract-type="main" id="ps3661-abs-0001"> <title>Abstract</title> <sec id="ps3661-sec-0001" sec-type="section"> <title>BACKGROUND</title> <p id="ps3661-para-0001"> <bold> <italic>Spodoptera littoralis</italic> (Boisduval) larvae are known by their susceptibility to <italic>Bacillus thuringiensis</italic> subsp. <italic>aizawai</italic> strains. In order to prevent the appearance of <italic>B. thuringiensis</italic> (<italic>Bt</italic>) resistance and to develop economical <italic>Bt</italic>‐based biopesticides, the selection and the characterisation of a <italic>B. thuringiensis</italic> isolate toxic against <italic>S. littoralis</italic> larvae and overproducing <italic>δ</italic>‐endotoxins were investigated</bold>.</p> </sec> <sec id="ps3661-sec-0002" sec-type="section"> <title>RESULTS</title> <p id="ps3661-para-0002"> <bold>Among 124 Tunisian <italic>B. thuringiensis</italic> isolates assessed against <italic>S. littoralis</italic> larvae, four isolates showed toxicity similar to and higher than the toxicity of the <italic>aizawai</italic> strain HD133 and the <italic>kurstaki</italic> strain HD1 respectively. The plasmid pattern of the selected isolates was similar to that of HD1. Polymerase chain reaction (PCR) analysis using specific primers revealed that these isolates present different gene contents. The only detected gene encoding <italic>Spodoptera</italic>‐specific toxin was <italic>cry9</italic>. The selected isolates were found to produce bipyramidal and cubic crystals. The assessment of <italic>δ</italic>‐endotoxin production by these isolates showed that BUPM28 produced 43.71 and 80.81% more <italic>δ</italic>‐endotoxin than HD1 and HD133 respectively. The application of osmotic or heat shock stress on the BUPM28 isolate made it possible to enhance <italic>δ</italic>‐endotoxin production by 22 and 23% respectively</bold>.</p> </sec> <sec id="ps3661-sec-0003" sec-type="section"> <title>CONCLUSION</title> <p id="ps3661-para-0003"> <bold>On the basis of its potent insecticidal activity and its high level of <italic>δ</italic>‐endotoxin production, the BUPM28 isolate can be considered to be an effective alternative for the control of <italic>S. littoralis</italic>. © 2013 Society of Chemical Industry</bold> </p> </sec> </abstract>