0000000000087830
AUTHOR
Axel Gruppe
Mode of action of Bacillus thuringiensis PS86Q3 strain in hymenopteran forest pests
The mode of action of Cry toxins has been described principally in lepidopteran insects as a multistep process. In this work we describe the mode of action of a Cry toxin active in the common pine sawfly Diprion pini (Hymenoptera, Diprionidae), considered a major forest pest in Europe. Strain PS86Q3 contains a long bipyramidal crystal composed of five major proteins. The N-terminal sequence shows that the 155 kDa protein corresponds to Cry5B toxin and the other proteins belong to the Cry5A subgroup. PCR analysis indicates the presence of cry5Ac and cry5Ba genes, suggesting that Cry5A protein should be Cry5Ac. Activation of protoxins with trypsin or with midgut content from D. pini and Cepha…
Hymenopteran specificity of Bacillus thuringiensis strain PS86Q3
Abstract The biological activity of Bacillus thuringiensis (Bt) strain PS86Q3 against five Hymenopteran species was determined by means of bioassays adapted to each species. Four species of sawfly that are important pests of conifers (Diprion pini, Gilpinia hercyniae and Pristiphora abietina) or ornamental plants (Arge rosae), as well as the non-target honeybee, Apis mellifera, were studied. Two out of the four sawfly species tested were found to be sensitive to PS86Q3 crystals or spore/crystal suspensions. A sporulated culture of this strain was moderately active on D. pini, and a complete bioassay with solubilized crystals was performed to estimate the LC50 of 4.9 mg/ml. Pristiphora abiet…
Biodiversity and ecosystem services in forest - the ‘BioHolz’ project
Whenever a tree dies, it makes room for millions of organisms contributing to the crucial ecosystem process of decomposition. The diversity of saproxylic organisms, which are depending in at least some stage of their life on decaying wood, comprises about one third of all forest species. Forest management in Europe of the last centuries changed forest structures and in particular reduced the amount of available dead wood, which is mirrored by the current extinction risk of saproxylic species1. However, society expects a forest to be a multi-functional ecosystem, which provides, among others, timber, recreation and biodiversity conservation. In the trans-disciplinary project ‘BioHolz’, we tr…