The genus Phytopythium (Peronosporales) has been described, but a complete circumscription has not yet been presented. In the present paper we provide molecular-based evidence that members of Pythium clade K as described by Lévesque & de Cock (2004) belong to Phytopythium. Maximum likelihood and Bayesian phylogenetic analysis of the nuclear ribosomal DNA (LSU and SSU) and mitochondrial DNA cyto...

A new species of Pythium isolated from wheat and apple roots in eastern Washington is described. Pythium abappressorium sp. nov. is characterized by abundant appressoria. Plerotic oospores and sporangia are formed from the appressoria and remnants of the appressoria remain attached to the base of sporangia at maturity. Smaller appressorial swellings, reminiscent of hyphal swellings, are also fo...

The phylogeny of 116 species and varieties of Pythium was studied using parsimony and phenetic analysis of the ITS region of the nuclear ribosomal DNA. The D1, D2 and D3 regions of the adjacent large subunit nuclear ribosomal DNA of half the Pythium strains were also sequenced and gave a phylogeny congruent with the ITS data. All the 40 presently available ex-type strains were included in this ...

Stand problems consistently cause significant production losses and management problems in Arkansas rice fields. Previous research, funded by the Rice Research and Promotion Board, identified the role of environmental factors and soilborne plant pathogens in limiting rice stand establishment, and had the goal of determining the conditions where soilborne pathogens, especially Pythium species, p...

The influences of Gaeumannomyces graminis var. tritici (which causes take-all of wheat), Rhizoctonia solani AG-8 (which causes rhizoctonia root rot of wheat), Pythium irregulare, P. aristosporum, and P. ultimum var. sporangiiferum (which cause pythium root rot of wheat) on the population dynamics of Pseudomonas fluorescens 2-79 and Q72a-80 (bicontrol strains active against take-all and pythium ...

Three new species of Pythium, namely, P. oopapillum, P. emineosum and P. camurandrum are presented in this paper based on morphological descriptions and molecular phylogenetic characterisation. These new species were isolated from various ecological regions in Canada. They have unique morphological features in the genus Pythium, and form distinct clades in maximum parsimony analyses, which are ...

ABSTRACT Previously, the zoosporicidal activity and control of Pythium root rot of flower bulbs by Pseudomonas fluorescens SS101 was attributed, in part, to the production of the cyclic lipopeptide surfactant massetolide A. The capacity of strain SS101 and its surfactant-deficient massA mutant 10.24 to suppress populations and root infection by complex Pythium spp. communities resident in orcha...

Two independent experiments were conducted to investigate the influence of rhizosphere bacteria on the growth of Anthoxanthum odoratum and Panicum sphaerocarpon. We tested whether host-specific populations of Bacillus mycoides affected the growth of their Anthoxanthum and Panicum hosts and whether host-specific differences in Bacillus populations modified the strong detrimental effect of the ro...

Plants can influence the soil they grow in, and via these changes in the soil they can positively or negatively influence other plants that grow later in this soil, a phenomenon called plant-soil feedback. A fascinating possibility is then to apply positive plant-soil feedback effects in sustainable agriculture to promote plant growth and resistance to pathogens. We grew the cut flower chrysant...

Pythium species are the most common seedling disease pathogens isolated from rice in producers’ fields in Arkansas. These studies examined the value of Pythium resistance in breeding lines with cold tolerance in early-season planting environments. These lines show promise for reliable stand establishment in Arkansas. The breeding line RU0701124 had more plants/acre and greater relative root wei...