Highly pathogenicBacillus thuringiensissubsp.tenebrionisfrom European shot‐hole borer,Xyleborus dispar(Coleoptera: Scolytidae)

Abstract

The entomopathogenic bacterium Bacillus thuringiensis is the most widely used biopesticide. In this study, to find and identify the more toxic B. thuringiensis strains against coleopteran pests, we isolated a B. thuringiensis strain (Xd3) from European shot-hole borer, Xyleborus dispar (Coleoptera: Scolytidae), a higly damaging pest of hazelnut. Based on various morphological, physiological, biochemical, and molecular characteristics, the bacterial isolate was identified as B. thuringiensis subsp. tenebrionis (morrisoni) serovar H8a8b. This isolate was compared with the reference strains by scanning electron microscopy, SDS-PAGE analysis, cry gene content, and insecticidal activity. Isolate Xd3 forms a flat-square inclusion containing a protein component of c. 70 kDa. PCR analysis showed that the Xd3 has a cry gene, cry3. Toxicity tests were performed against coleopteran species. One hundred percent mortality was observed against larvae of Agelastica alni (Coleoptera: Chrysomelidae). The others were 90% for Amphimallon solstitiale

Isolation, characterization and virulence of bacteria from Ostrinia nubilalis (Lepidoptera: Pyralidae)

“…This isolate has been also previously shown that it has a good insecticidal activity (100%) against Agelastica alni (L.), Amphimallon solstitiale (L.), Leptinotarsa decemlineata (Say.) and Melolontha melolontha (L.) (Sezen et al 2008). These results mean that B. thuringiensis subsp.…”

Isolation and identification of bacteria from Thaumetopoea pityocampa Den. and Schiff. (Lep., Thaumetopoeidae) and determination of their biocontrol potential

“…B. thuringiensis is the most widely used microbial control agent and has a high insecticidal activity on the species of Lepidoptera, Diptera and Coleoptera. B. thuringiensis has been isolated from several insects such as Balaninus nucum (Sezen and Demirbag 1999), Melolontha melolontha (Sezen et al 2001;Kurt et al 2005), Hyphantria cunea (Yaman et al 2002), Euproctis chrysorrhoea , Dendroctonus micans (Yilmaz et al 2006), Xyleborus dispar (Sezen et al 2008), Tenebrio molitor (Krieg et al 1983), Ephestia kuhniella (Kurstak 1962), Lygus lineolaris (Cote et al 1992), Bombyx mori (Ishikawa et al 1964), Agrotis segetum (Lipa and Wiland 1972), Cydia pomonella (Konecka et al 2007), Malacosoma neustria (Katı et al 2005) and T. pityocampa (Rausell et al 1999). Tp6 and Tp14 isolates share 99% 16S rRNA gene sequence homology and significantly common features with Bacillus thuringiensis.…”

Multiple cry Genes in Bacillus thuringiensis Strain BTG Suggest a Broad-Spectrum Insecticidal Activity

“…Crystals are synthesized after the second stage of sporulation and accumulate in the cell, where they can represent up to 30% of the dry weight of sporulated cells [ 18 ]. The shapes of the parasporal crystals can be bipyramidal, pyramidal, cubic, flat rhombic, spherical, or rectangular [ 19 , 20 , 21 , 22 ] and may include one or more endotoxins, with a molecular weight between 60 kDa and 140 kDa [ 13 ].…”