scholarly journals Role of Armillaria species on tree dying in Turkey oak and Hungarian oak forest in Lipovica

2006 ◽  
pp. 151-158
Author(s):  
Nenad Keca ◽  
Dragan Karadzic

The species and population structure of Armillaria species were studied in Turkey oak and Hungarian oak forest. Two species were observed, Armillaria gallica and A. mellea. Armillaria mellea was found on only one tree, and A. gallica was found on seven trees. Four gewets of A. gallica were observed of which two were represented only by one isolate each, while two covered the area of 5 and 9 areas respectively.

1991 ◽  
Vol 69 (12) ◽  
pp. 2732-2739 ◽  
Author(s):  
Kjell Wahlström ◽  
Jan-Olof Karlsson ◽  
Ottmar Holdenrieder ◽  
Jan Stenlid

Pectinolytic activities in Armillaria ostoyae, Armillaria mellea, Armillaria gallica, Armillaria borealis, and Armillaria cepistipes were assessed by measuring the ability of fungal strains to reduce the viscosity of their pectic growth media. Isozyme patterns of pectin esterases and polygalacturonases were determined directly from the culture filtrate. A total of 94 strains, representing isolations from various parts of Europe, were analyzed for their isozyme patterns. Armillaria mellea and A. borealis caused a 50% reduction in viscosity within 7 and 9 days, respectively. Growth medium from the other species were slower to reach the 50% level, i.e., means were 13 days for A. ostoyae and 17 days for A. cepistipes and A. gallica. All species produced more isozymes on spruce wood than on citrus pectin medium, and pectic isozyme patterns differed between media. The pectic isozyme pattern for A. mellea differed distinctly from those of the other four species by having two bands of polygalacturonase not found in the others. The pectic isozyme patterns of the other four species were separated using multivariate analysis. The value of such analyses for use in distinguishing between European Armillaria species is discussed, as is the relation between enzyme activity and fungal pathogenicity. Key words: root rot, diagnostic tests, Agaricales, polygalacturonase, pectin esterase.


2011 ◽  
Vol 12 (2) ◽  
pp. 227-233 ◽  
Author(s):  
G. Koncz ◽  
P. Török ◽  
M. Papp ◽  
G. Matus ◽  
B. Tóthmérész

2018 ◽  
Vol 56 (9) ◽  
Author(s):  
Tessa E. LeCuyer ◽  
Barbara A. Byrne ◽  
Joshua B. Daniels ◽  
Dubraska V. Diaz-Campos ◽  
G. Kenitra Hammac ◽  
...  

ABSTRACTEscherichia coliis the most common cause of human and canine urinary tract infection (UTI). Clonal groups, often with high levels of antimicrobial resistance, are a major component of theE. colipopulation that causes human UTI. While little is known about the population structure ofE. colithat causes UTI in dogs, there is evidence that dogs and humans can share fecal strains ofE. coliand that human-associated strains can cause disease in dogs. In order to better characterize theE. colistrains that cause canine UTI, we analyzed 295E. coliisolates obtained from canine urine samples from five veterinary diagnostic laboratories and analyzed their multilocus sequence types, phenotypic and genotypic antimicrobial resistance profiles, and virulence-associated gene repertoires. Sequence type 372 (ST372), an infrequent human pathogen, was the predominant sequence type in dogs at all locations. Extended-spectrum β-lactamase-producing isolates withblaCTX-Mgenes were uncommon in canine isolates but when present were often associated with sequence types that have been described in human infections. This provides support for occasional cross-host-species sharing of strains that cause extraintestinal disease and highlights the importance of understanding the role of companion animals in the overall transmission patterns of extraintestinal pathogenicE. coli.


1990 ◽  
Vol 20 (1) ◽  
pp. 43-47 ◽  
Author(s):  
M. Sabourin ◽  
M. Dessureault ◽  
J. A. Bérubé

Biological species of the Armillaria complex present in declining sugar maple stands in southeastern Quebec were identified by pairing monosporous isolates with known tester strains. Armillariaostoyae (I), A. gemina (II), A. calvescens (III), and A. sinapina (V) were collected. Armillariacalvescens was the most frequent species and was found in almost all the stands sampled. The presence of various Armillaria species was not correlated with either the severity of decline of the stands or the health of the hosts with which they were associated, suggesting that none of the species present in sugar maple stands is particularly responsible for their decline. However, the role of A. calvescens and the factors that favor its development warrant further investigations because this species appears to be found almost exclusively on maple trees.


2010 ◽  
Vol 100 (7) ◽  
pp. 708-718 ◽  
Author(s):  
Kendra Baumgartner ◽  
Renaud Travadon ◽  
Johann Bruhn ◽  
Sarah E. Bergemann

Armillaria mellea infects hundreds of plant species in natural and managed ecosystems throughout the Northern hemisphere. Previously reported nuclear genetic divergence between eastern and western U.S. isolates is consistent with the disjunct range of A. mellea in North America, which is restricted mainly to both coasts of the United States. We investigated patterns of population structure and genetic diversity of the eastern (northern and southern Appalachians, Ozarks, and western Great Lakes) and western (Berkeley, Los Angeles, St. Helena, and San Jose, CA) regions of the United States. In total, 156 diploid isolates were genotyped using 12 microsatellite loci. Absence of genetic differentiation within either eastern subpopulations (θST = –0.002, P = 0.5 ) or western subpopulations (θST = 0.004, P = 0.3 ) suggests that spore dispersal within each region is sufficient to prevent geographic differentiation. In contrast to the western United States, our finding of more than one genetic cluster of isolates within the eastern United States (K = 3), revealed by Bayesian assignment of multilocus genotypes in STRUCTURE and confirmed by genetic multivariate analyses, suggests that eastern subpopulations are derived from multiple founder sources. The existence of amplifiable and nonamplifiable loci and contrasting patterns of genetic diversity between the two regions demonstrate that there are two geographically isolated, divergent genetic pools of A. mellea in the United States.


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