Taxonomic revision of the complex.

and the related fungi were separated into three biological species by morphological and physiological characteristics, as well as DNA sequences and mating reactions. We propose that the complex should be divided into three species (, and ) and two varieties ( var. and var.

Multimycotoxin and fungal analysis of maize grains from south and southwestern Ethiopia.

The natural occurrence of fungi, mycotoxins and fungal metabolites was investigated in 100 samples of maize grains collected from south and southwestern Ethiopia in 2015. The maize samples were contaminated by Fusarium, Aspergillus and Penicillium species. Using liquid chromatography tandem mass spectrometry 127 secondary metabolites were analysed.

Global transcriptome changes in perennial ryegrass during early infection by pink snow mould.

Lack of resistance to pink snow mould (Microdochium nivale) is a major constraint for adaptation of perennial ryegrass (Lolium perenne L.) to continental regions with long-lasting snow cover at higher latitudes. Almost all investigations of genetic variation in resistance have been performed using cold acclimated plants.

Profile and Morphology of Fungal Aerosols Characterized by Field Emission Scanning Electron Microscopy (FESEM).

Fungal aerosols consist of spores and fragments with diverse array of morphologies; however, the size, shape, and origin of the constituents require further characterization. In this study, we characterize the profile of aerosols generated from , and grown for 8 weeks on gypsum boards. Fungal particles were aerosolized at 12 and 20 L min using the Fungal Spore Source Strength Tester (FSSST) and the Stami particle generator (SPG).

Effects of Development of Ontogenic Resistance in Strawberry Leaves Upon Pre- and Postgermination Growth and Sporulation of Podosphaera aphanis.

The temporal distribution and magnitude of ontogenic resistance in strawberry leaves to Podosphaera aphanis has recently been quantified. However, the degree to which the pathogen is inhibited at sequential stages of conidial germination, hyphal growth, haustoria formation, latent period, colony expansion, and sporulation on the adaxial and abaxial leaf surfaces of various strawberry cultivars remains unclear. Five developmental stages of strawberry leaves ranging from newly emerged and folded leaves to fully expanded and dark-green leaves were inoculated with conidia of P.

Indirect Immunodetection of Fungal Fragments by Field Emission Scanning Electron Microscopy.

Submicronic fungal fragments have been observed in in vitro aerosolization experiments. The occurrence of these particles has therefore been suggested to contribute to respiratory health problems observed in mold-contaminated indoor environments. However, the role of submicronic fragments in exacerbating adverse health effects has remained unclear due to limitations associated with detection methods.

Submicronic fungal bioaerosols: high-resolution microscopic characterization and quantification.

Submicronic particles released from fungal cultures have been suggested to be additional sources of personal exposure in mold-contaminated buildings. In vitro generation of these particles has been studied with particle counters, eventually supplemented by autofluorescence, that recognize fragments by size and discriminate biotic from abiotic particles. However, the fungal origin of submicronic particles remains unclear.

Overwintering of herbaceous plants in a changing climate. Still more questions than answers.

The increase in surface temperature of the Earth indicates a lower risk of exposure for temperate grassland and crop to extremely low temperatures. However, the risk of low winter survival rate, especially in higher latitudes may not be smaller, due to complex interactions among different environmental factors. For example, the frequency, degree and length of extreme winter warming events, leading to snowmelt during winter increased, affecting the risks of anoxia, ice encasement and freezing of plants not covered with snow.

Inhibition of fungal plant pathogens by synergistic action of chito-oligosaccharides and commercially available fungicides.

Chitosan is a linear heteropolymer consisting of β 1,4-linked N-acetyl-D-glucosamine (GlcNAc) and D-glucosamine (GlcN). We have compared the antifungal activity of chitosan with DPn (average degree of polymerization) 206 and FA (fraction of acetylation) 0.15 and of enzymatically produced chito-oligosaccharides (CHOS) of different DPn alone and in combination with commercially available synthetic fungicides, against Botrytis cinerea, the causative agent of gray mold in numerous fruit and vegetable crops.

Ontogenic resistance of leaves and fruit, and how leaf folding influences the distribution of powdery mildew on strawberry plants colonized by Podosphaera aphanis.

Ontogenic or age-related resistance has been noted in many pathosystems but is less often quantified or expressed in a manner that allows the concept to be applied in disease management programs. Preliminary studies indicated that leaves and fruit of three strawberry cultivars rapidly acquired ontogenic resistance to the powdery mildew pathogen, Podosphaera aphanis. In the present study, we quantify the development of ontogenic resistance in controlled inoculations of 10 strawberry cultivars using diverse isolates of P.

Temperature regulates the initiation of chasmothecia in powdery mildew of strawberry.

The formation of chasmothecia by the strawberry powdery mildew pathogen (Podosphaera aphanis) is widespread but often sporadic throughout the range of strawberry cultivation. In some production regions, notably in warmer climates, chasmothecia are reportedly rare. We confirmed that the pathogen is heterothallic, and that initiation of chasmothecia is not only dependent upon the presence of isolates of both mating types but also largely suppressed at temperatures >13°C.

Pythium polare, a new heterothallic oomycete causing brown discolouration of Sanionia uncinata in the Arctic and Antarctic.

Pythium polare sp. nov. is a new heterothallic oomycete species isolated from fresh water and moss from various locations in both the Arctic and Antarctic.

Characterization of field isolates of Trichoderma antagonistic against Rhizoctonia solani.

The aim of the present study was to characterize sixteen isolates of Trichoderma originating from a field of sugar beet where disease patches caused by Rhizoctonia solani were observed. Use of both molecular and morphological characteristics gave consistent identification of the isolates. Production of water-soluble and volatile inhibitors, mycoparasitism and induced systemic resistance in plant host were investigated using in vitro and in vivo tests in both sterilized and natural soils.

Antagonism of Nutrient-Activated Conidia of Trichoderma harzianum (atroviride) P1 Against Botrytis cinerea.

ABSTRACT The effect of preliminary nutrient activation on the ability of conidia of the antagonist Trichoderma harzianum (atroviride) P1 to suppress Botrytis cinerea was investigated in laboratory, greenhouse, and field trials. Preliminary nutrient activation at 21 degrees C accelerated subsequent germination of the antagonist at temperatures from 9 to 21 degrees C; at >/=18 degrees C, the germination time of preactivated T. harzianum P1 conidia did not differ significantly from that of B.

Genetic variation between Phytophthora cactorum isolates differing in their ability to cause crown rot in strawberry.

Analysis of 44 isolates of Phytophthora cactorum, isolated from strawberry and other hosts, by AFLP showed that the crown rot pathotype is different from leather rot isolates and from P. cactorum isolated from other hosts. 16 of 23 crown rot isolates, including isolates from Europe, Japan, Australia, and New Zealand, were identical in an analysis based on 96 polymorphic bands from seven primer combinations.

Induced Resistance as a Possible Means to Control Diseases of Strawberry Caused by Phytophthora spp.

Two putative elicitors of disease resistance (acibenzolar-S-methyl and chitosan) were tested for their effect on crown rot (Phytophthora cactorum) in strawberry. The effect of both compounds was enhanced when the time between treatment and inoculation was prolonged from 2 to 20 days. There were no significant differences between treatments when the concentration of acibenzolar-S-methyl was increased from 10 to 1,000 μg a.

Chilling resistances of isolates of Pythium ultimum var. ultimum from the Arctic and Temperate Zones.

Chilling resistances in moss pathogenic fungi, Pythium ultimum var. ultimum, from Longyearbyen, Svalbard (78 degree N, 15 degree E), located in the Arctic Zone and in the same isolates from Temperate Zone, were determined. Both strains had similar optimum growth temperatures.

First Report of Colletotrichum acutatum in Strawberry in Norway.

Anthracnose caused by Colletotrichum acutatum J. H. Simmonds was detected in strawberry (Fragaria × ananassa Duch.

Isolation and characterization of a cDNA from Trichoderma harzianum P1 encoding a 14-3-3 protein homolog.

A full-length cDNA close, Th1433, (GenBank accession No. U24158), was isolated and characterized from the filamentous fungus, Trichoderma harzianum. The deduced amino acid (aa) sequence showed an acidic 30-kDa protein homologous to the 14-3-3 proteins, a family of putative kinase regulators originally characterized in mammalian brain tissue.

Isolation and sequence of an endochitinase-encoding gene from a cDNA library of Trichoderma harzianum.

There are no reports of gene sequences coding for extracellular chitinolytic enzymes from filamentous fungi, even though these enzymes are considered critical to the biological control of plant pathogenic fungi. The purpose of this paper was to report the isolation of a gene (ThEn-42) encoding endochitinase (Ech) from Trichoderma harzianum strain P1, describe its sequence, and to determine whether it was related to genes coding for enzymes with similar functions from prokaryotic or other eukaryotic sources. A clone containing a 1096-bp foreign cDNA fragment was isolated from thalli grown under induced conditions.

Nucleotide sequence of an endo-beta-1,4-glucanase gene from Bacillus subtilis CK-2.

The gene encoding endo-beta-1,4-glucanase in Bacillus subtilis CK-2 was cloned into Escherichia coli DH5 alpha, and the nucleotide sequence determined. The 1500 bp gene encodes a protein of 499 amino-acid residues with a calculated molecular mass of 55,261, and is equipped with a typical B. subtilis signal peptide.

Characterization of production and enzyme properties of an endo-beta-1,4- glucanase from Bacillus subtilis CK-2 isolated from compost soil.

Bacillus subtilis CK-2, isolated from garden organic waste compost, was found to have high hydrolytic activity against carboxymethylcellulose (CMC) due to the secretion of an endo-beta-1,4- glucanase. Enzyme production was related to the sporulation process, and was regulated by the concentration of readily metabolizable carbohydrate in growth medium. Enzyme production did not require CMC or other cellulose containing materials.

Carbohydrate content and glycosidase activities following cold hardening in two grass species.

The freezing resistance of the grass species Phleum pratense L. (timothy) and Phalaris arundinaces L. increases significantly after cold hardening.