Plant and Soil

, Volume 256, Issue 1, pp 161–168

Evaluation of Bacillus thuringiensis bioinsecticidal protein effects on soil microorganisms

Authors

  • L.H.P.L. Ferreira
    • Centro de Ciências Biológicas, Departamento de Biologia Geral, Programa de Mestrado em Genética e MelhoramentoUniversidade Estadual de Londrina
  • J.C. Molina
    • Centro de Ciências Biológicas, Departamento de Microbiologia, Laboratório de Ecologia MicrobianaUniversidade Estadual de Londrina
  • C. Brasil
    • Centro de Ciências Biológicas, Departamento de Microbiologia, Laboratório de Ecologia MicrobianaUniversidade Estadual de Londrina
    • Centro de Ciências Biológicas, Departamento de Microbiologia, Laboratório de Ecologia MicrobianaUniversidade Estadual de Londrina
Article

DOI: 10.1023/A:1026256700237

Cite this article as:
Ferreira, L., Molina, J., Brasil, C. et al. Plant and Soil (2003) 256: 161. doi:10.1023/A:1026256700237

Abstract

The effect of B. thuringiensis and its crystal protein on plant growth and on functional groups of microorganisms is not well understood. Soybean (Glycine max) var. Br 322 was grown in non-sterile soil infested with three B. thuringiensis (Bt) inocula: insecticidal crystal protein producer (Cry+), a mutant non-producer (Cry−), or insecticidal crystal protein (ICP), at a rate of 107 cells g−1 dry soil or 1.25 mg of protein g−1 dry soil. Non-inoculated plants were maintained as control. Measurements were carried out on soil samples before sowing (time zero) and after sowing and inoculation (5, 15, 25, 35 and 45 d) on samples of rhizosphere soil. The effect of spore and crystal protein produced by B. thuringiensis on the populations of functional groups of microorganisms (bacteria including actinomycetes and fungi) involved in the biogeochemical cycling of carbon (cellulolytic, amylolytic and proteolytic), phosphorus (arbuscular mycorrhizal fungi), and nitrogen (number of nodules and proteolytic) were evaluated. Population sizes of culturable heterotrophic bacteria and saprophytic fungi were also evaluated. No difference was found in heterotrophic bacterial populations inoculated with B. thuringiensis. Difference was observed in functional groups of C-cycling microorganisms. Nodule formation and plant growth were increased by Cry+ strain and ICP when compared with uninoculated plants. Crystal protein did not show any effect on arbuscular mycorrhiza (AM) colonization. However, a deleterious effect was observed with Cry+ and Cry− strains that inhibited colonization of AM fungi when compared with uninoculated plants.

arbuscular mycorrhizaBacillus thuringiensisbiocontrolfunctional groupsmicrobial populationrhizosphere
Download to read the full article text

Copyright information

© Kluwer Academic Publishers 2003