The effects of exotoxin (Thuringiensin) from Bacillus thuringiensis on Meloidogyne incognita and Caenorhabditis elegans

Abstract

A partially purified preparation as well as two formulations of exotoxin from Bacillus thuringiens& (thuringiensin) were evaluated for nematicidal activity. The methods used in our evaluations included direct contact nematicidal assays, hatching tests, infection tests in seed pouches using the cucumber/ root-knot nematode (Meloidogyne incognita) system, and greenhouse test using the root-knot nematode. While contact nematicidal activity was not observed against juveniles of M. incognita, 100% mortality occurred when the free-living nematode, Caenorhabdit& elegans, was used as the test organism. Nematode infection evaluations in the seed pouch assay showed reduced root galling at relatively high concentrations (>10 mg kg i). Greenhouse assays indicated significant reduction in the soil population. However, the degree of control in relation to the amount of material applied, as measured by the gall numbers, larvae from soil/roots, and plant growth parameters, was not considered adequate. Data on the plant response in relation to treatment with different formulations of the toxin are presented.

Evaluation of Organic Matter, Bio-inoculants and Inorganic Fertilizers on Growth and Yield Attributes of Tomato with Respect to the Management of Plant-Parasitic Nematodes

“…Biological nitrogen fixers are known to exert indirect effects on soil microbiological activities which in turn help the plant to grow better , besides direct effects on nitrogen fixation and phosphorus mobilization (Rana and Chandel, 2003). They also produced hormones, vitamins and other growth factors for plant growth and development, besides suppression of the growth of phytopathogens (Widham et al, 1989;Devidas and Rehberger, 1992;Verma et al, 2000). The bio-fertilizers like Azospirillum and Azotobacter associated with the rhizosphere of many crop plants, harvest atmospheric nitrogen, which in due course is made available to the plants or released in soil thus increasing soil fertility.…”

Killing of Caenorhabditis elegans by Pseudomonas aeruginosa used to model mammalian bacterial pathogenesis

“…In this paper, we describe the development of a pathogenesis model that involves the killing of the soil nematode C. elegans by the P. aeruginosa strain PA14. Hitherto, except for reports that Bacillus megaterium kills C. elegans (18) and that beta exotoxin from Bacillus thuringiensis exhibits contact nematicide activity against all stages of C. elegans (19), to the best of our knowledge, no pathogenic interaction between C. elegans and a bacterium has been described in the literature.…”

Insecticidal Activity and HPLC Correlation of Thuringiensin from Fermentation and Two-phase Aqueous Separation Processes

“…4 Field-trial results with DiBeta, a thuringiensin-based development candidate from Abbott Laboratories, has demonstrated efficacious control of several species of mites, resistant Colorado potato beetles, and lygus bugs. Scaled-up runs of the carbon-limited fermentation showed very consistent and reproducible process translation from the 55-litre scale to the 24 000-litre scale and even up to the 80 000-litre scale.…”