Cryptogein is a proteinaceous elicitor secreted by Phytophthora cryptogea that can induce resistance to P. parasitica in tobacco plants. On the basis of previous computer modelling experiments, by site-directed mutagenesis a series of cryptogein variants was prepared with altered abilities to bind sterols, phospholipids or both. The sterol binding and phospholipid transfer activities correspond...

We observed the biphasic production of ethylene and reactive oxygen species (ROS) in susceptible tobacco (Nicotiana tabacum 'Wisconsin 38') plants after shoot inoculation with Phytophthora parasitica var nicotianae. The initial transient increase in ROS and ethylene at 1 and 3 h (phase I), respectively, was followed by a second massive increase at 48 and 72 h (phase II), respectively, after pat...

Phytopathogenic oomycetes cause some of the most devastating diseases affecting agricultural crops. Hyaloperonospora parasitica is a native oomycete pathogen of Arabidopsis and is related to other oomycete phytopathogens that include several species of Phytophthora, including the causal agent of potato late blight. Recently, four oomycete effector genes have been isolated, and several oomycete ...

The effects of differing cytokinin and auxin concentrations on resistance of tobacco (Nicotiana tabacum L.) tissue cultures to race 0 of Phytophthora parasitica var. nicotianae were examined. With 1 micromolar kinetin and either 11.5 micromolar indoleacetic acid or 1 micromolar 2,4-dichlorophen-oxyacetic acid, tissues from resistant cultivars exhibited a "hypersensitive" reaction to zoospores o...

We have investigated nuclear changes induced in tomato (Lycopersicon esculentum) plant roots by two different pathogens, a phytoplasma of the stolbur group and the soil-borne fungus Phytophthora nicotianae var. parasitica, using light and electron microscopy as well as flow cytometry. Our results show that both pathogens strongly influenced nuclear structure, causing pyknosis and chromatolysis,...

In vivo expression technology (IVET) was employed to study colonization of Phytophthora parasitica by a biological control bacterium, Pseudomonas putida 06909, based on a new selection marker. The pyrB gene, which encodes aspartate transcarbamoylase, an enzyme used for pyrimidine biosynthesis, was cloned from P. putida 06909. A pyrB-disrupted mutant did not grow in pyrimidine-deficient media un...

The oomycete class includes pathogens of animals and plants which are responsible for some of the most significant global losses in agriculture and aquaculture. There is a need to replace traditional chemical means of controlling oomycete growth with more targeted approaches, and the inhibition of sterol synthesis is one promising area. To better direct these efforts, we have studied sterol acq...

The author investigated aquatic fungi developing on the seeds of some plants in various types of water bodies of Podlasie Province. The bait method was used to isolate the fungi. Seventy-four aquatic fungal species were found on seeds of three species of plants: Cannabis sativa hemp-seeds 59, Fagopyrum esculentum buckwheat-seeds 55 and on Vicia sativa vetch-seeds 44 in water of four various bod...