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...

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...

Pythium insidiosum is a unique oomycete that can infect humans and animals. Patients with a P. insidiosum infection (pythiosis) have high rates of morbidity and mortality. The pathogen resists conventional antifungal drugs. Information on the biology and pathogenesis of P. insidiosum is limited. Many pathogens secrete proteins, known as effectors, which can affect the host response and promote ...

Calibrachoa (Calibrachoa  hybrida) is a popular annual ornamental that was introduced in the late 1990s by the greenhouse ornamental industry. Little is published about its interaction with pathogens commonly associated with greenhouse production. We report here for the first time the response of Calibrachoa to infection by pathogens that may be introduced in greenhouse production cycles throu...

Lecithin washed with NaCl solution was stimulatory to oospore formation of Phytophthora boehmeriae, P. sojae, P. cactorum, and Pythium aphanidermatum. Commercial glycerides of palmitic acid with 99% purity were found to contain a substance inhibitory to oospore formation. Purification with florisil column chromatography was more effective in removing the inhibitory substance than thin-layer chr...