There is increasing evidence that microbial volatiles (VOCs) play an important role in natural suppression of soil-borne diseases, but little is known on the factors that influence production of suppressing VOCs. In the current study we examined whether a stress-induced change in soil microbial community composition would affect the production by soils of VOCs suppressing the plant-pathogenic o...

The aim of this research was to isolate and characterize bacteria from spores of arbuscular mycorrhizal fungi (AMF). We designated these bacteria 'probable endobacteria' (PE). Three bacterial strains were isolated from approximately 500 spores of Gigaspora margarita (Becker and Hall) using a hypodermic needle (diameter, 200 μm). The bacteria were identified by morphological methods and on the b...

Leaf composts were studied for their suppressive effects on Pythium ultimum sporangium germination, cottonseed colonization, and the severity of Pythium damping-off of cotton. A focus of the work was to assess the role of fatty-acid-metabolizing microbial communities in disease suppression. Suppressiveness was expressed within the first few hours of seed germination as revealed by reduced P. ul...

The bacterium Pseudomonas aureofaciens 63-28 is antagonistic to several plant pathogenic fungi, including Pythium spp. The bacterium produced at least four antifungal metabolites active against Pythium ultimum and Phytophthora cryptogea when tested in culture for antifungal activity. Two of these compounds were identified as the novel butyrolactones (Z)-4-hydroxy-4-methyl-2-(1-hexenyl)-2-buteno...

A new species Pythium canariense (CI-07), isolated from soil samples taken in the San Nicolas region of the Canary islands (Gran Canaria, Spain), is being described here. This species is characterised by its spherical to pyriform, intercalary to catenulate sporangia, smooth-walled terminal oogonia supplied with monoclinous and diclinous antheridia which at times are branched and wrap around the...

Crude aqueous and methanolic extracts of 97 plant species belonging to 35 families collected from the west of Iran were screened for antifungal activity against economically important phytopathogenic fungi, Pythium aphanidermatum. Bioassay of the extracts was conducted by paper disc diffusion method on agar plate cultures with four replications. Seventeen of 97 (17.5%) plant species showed inhi...

many fungi cause sugar beet root rot during various stages of the plant growth. among them rhizoctonia spp. induce crown rot, dry rot and violet root rot on sugar beet (whitney and duffos,1986). root rot caused by phytophthora drechsleri has been observed in fields with excessive moisture (habibi,1975). pythium aphanidermatum has been recognized as one of the causal agents of sugar beet, dampin...