AIMS Trichoderma harzianum strains T22 and T39 are two micro-organisms used as active agents in a variety of commercial biopesticides and biofertilizers and widely applied amongst field and greenhouse crops. The production, isolation, biological and chemical characterization of the main secondary metabolites produced by these strains are investigated. METHODS AND RESULTS Of the three major co...

ABSTRACT Fluorescent Pseudomonas spp. that produce 2,4-diacetylphloroglucinol (2,4-DAPG) have biocontrol activity against damping-off, root rot, and wilt diseases caused by soilborne fungal pathogens, and play a key role in the natural suppression of Gaeumannomyces graminis var. tritici, known as take-all decline. Diversity within phlD, an essential gene in the biosynthesis of 2,4-DAPG, was stu...

The ability of some soils to suppress plant disease has been well documented 1. An important example is the development of soils suppressive to Gaeumannomyces graminis var. tritici (Ggt), the causative agent of 'takeall' of wheat 2. Such natural examples of biological control have been attributed to the indigenous beneficial rhizosphere microflora (see Glossary), especially fluorescent pseudomo...

Pseudomonas fluorescens 2-79 and P. aureofaciens 30-84 produce the antibiotic phenazine-1-carboxylic acid and suppress take-all, an important root disease of wheat caused by Gaeumannomyces graminis var. tritici. To determine whether the antibiotic is produced in situ, wheat seeds were treated with strain 2-79 or 30-84 or with phenazine-nonproducing mutants or were left untreated and then were s...

Wheat production around the world is severely compromised by the occurrence of "take-all" disease, which is caused by the soil-borne pathogen Gaeumannomyces graminis var. tritici (Ggt). In this context, suppressive soils are those environments in which plants comparatively suffer less soil-borne pathogen diseases than expected, owing to native soil microorganism activities. In southern Chile, w...

The aim of this study was to inventory the types of plant growth-promoting rhizobacteria (PGPR) present in the rhizosphere of plants grown in soils contaminated with heavy metals, recalcitrant organics, petroleum sewage or salinity in China. We screened 1223 isolates for antifungal activity and about 24% inhibited Rhizoctonia solani or Sclerotinia sclerotiorum. Twenty-four strains inhibitory to...

Prevalent fungal pathogens of cereals in Lithuania belong to diverse systematic groups and this makes search for microbial biocontrol measures rather difficult. One of the options would be broad-spectrum biocontrol agents. In order to find these, 1037 seed-borne and 11 soil-borne rhizosphere pathogenic fungi were isolated and their systematic position determined. Fungi of genera Alternaria, Ulo...

Bacillus subtilis strain NCD-2 and Pseudomonas protegens FD6 produce a range of antimicrobial metabolites known to be effective against soil-borne plant pathogens. Quantitative qPCR assays were designed from sequence characterized amplified fragment length polymorphisms (AFLP) diagnostic for each inoculant genotype. The minimum detection thresholds (MDT) ranged between 5.2 × 103 (log 3.71) 1.5 ...