The interaction between Trichoderma harzianum and the soilborne plant pathogen Pythium ultimum was studied by electron microscopy and further investigated by gold cytochemistry. Early contact between the two fungi was accompanied by the abnormal deposition of a cellulose-enriched material at sites of potential antagonist penetration. The antagonist displayed the ability to penetrate this barrie...

Sixteen streams in middle and eastern Tennessee were surveyed for the sudden oak-death pathogen Phytophthora ramorum 2010-2012. Surveys were conducted in the spring and fall using healthy Rhododendron leaves, and a total of 354 oomycete isolates were recovered. Sequence analysis of the ITS region provisionally identified 151 Phytophthora, 200 Pythium, two Halophytophthora and one Phytopythium. ...

A new species of Pythium collected from grapevine roots (Vitis vinifera) in South Africa and roots of common beet (Beta vulgaris) in Majorca, Spain, is described. The phylogenetic position of the new species was investigated by multigene sequence analyses of the internal transcribed spacers (ITS1 and ITS2) of the rDNA region, as well as three other nuclear and three mitochondrial coding genes. ...

BACKGROUND Replant disease often occurs when certain crops are "replanted" in a soil that had previously supported the same or similar plant species. This disease typically leads to reductions in plant growth, crop yields, and production duration, and its etiology remains ill-defined. The objective of this study was to identify microorganisms associated with peach replant disease symptoms at a ...

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...

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...

The plant growth-promoting rhizobacterium Pseudomonas aeruginosa 7NSK2 produces three siderophores when iron is limited: the yellow-green fluorescent pyoverdin, the salicylate derivative pyochelin, and salicylic acid. This Pseudomonas strain was shown to be an efficient antagonist of Pythium-induced damping-off. The role of pyoverdin and pyochelin in the suppression of Pythium splendens was inv...

BACKGROUND Pythium insidiosum keratitis is a rare but sight-threatening disease with a high morbidity rate. It can be misdiagnosed as fungal keratitis in clinic settings. We report a case of severe Pythium insidiosum keratitis in a Chinese child, treated with combined approaches. CASE REPORT A 7-year-old boy from Hainan province in the south of China developed a suppurative corneal ulcer after ...

This work highlights the ability of various cyanobacterial extracts from Anabaena spp., Tolypothrix Nostoc or Trichormus, among others genera, to control incidence damping-off caused by Pythium ultimum in cucumber seedlings. Protocols applied aimed at preliminary characterization collection were very useful for predicting their phytotoxic, phytostimulating and biopesticidal capacity. First, phy...

Trichoderma spp. are fungi that occur worldwide. Recent studies show that they are not only parasites of fungal plant pathogens but also can produce antibiotics. In addition, certain strains can induce systemic and localized resistance to several plant pathogens. Moreover, some strains may enhance plant growth and development. The potential of Trichoderma species used as biological agents of pl...