scholarly journals The occurrence of endophytic fungus Phomopsis oblonga on elms in the area of southern Bohemia

2012 ◽  
Vol 52 (No. 11) ◽  
pp. 531-535 ◽  
Author(s):  
M. Dvořák ◽  
D. Palovčíková ◽  
L. Jankovský
Keyword(s):  
Endophytic Fungus ◽  
Health Condition ◽  
Dutch Elm Disease ◽  
Mixed Forests ◽  
Ophiostoma Ulmi

The health condition of the population of elms in the region of southern Bohemiawas studied from the viewpoint of their decline, the occurrence of Dutch Elm Disease (DED) and the presence of other diseases. Of the total number of 105 elms in total 33 of them were without any symptoms of the disease or other damage. Elms regenerated quite spontaneously in the neighbourhood of mother trees and their increasing population in mixed forests is hopeful. According to macroscopic symptoms, DED was identified in 10 trees but the presence of pathogens Ophiostoma ulmi and Ophiostoma novo-ulmi was not identified in isolations. A possible reason of this observation is overgrowing the colonies by the Phomopsis oblonga mycelium. This fungus was identified in most isolations. Thus, its role requires further research.

Analytical electrofocusing and two-dimensional electrophoresis of proteins extracted from the mycelia of aggressive and nonaggressive strains of Ophiostoma ulmi

1986 ◽  
Vol 64 (9) ◽  
pp. 2073-2081 ◽  
Author(s):  
Robert S. Jeng
Keyword(s):  
Dutch Elm Disease ◽  
Two Dimensional ◽  
Polyacrylamide Gels ◽  
Ophiostoma Ulmi ◽  
Two Dimensional Electrophoresis ◽  
Coomassie Blue ◽  
Isoelectric Points ◽  
Additional Protein ◽  
Dimensional Electrophoresis ◽  
Electrophoresis Of Proteins

Soluble mycelial proteins from Ophiostoma ulmi (Buism.) Nannf., the causal agent of Dutch elm disease, were separated by analytical electrofocusing and two-dimensional electrophoresis in polyacrylamide gels. Results showed the aggressive and nonaggressive strains of this pathogen each had about 60 Coomassie blue stained bands having isoelectric points from 3 to 7. Both strains of this fungus had their own characteristic electrofocusing patterns. Nonaggressive isolate S116, for example, lacked two protein bands, one near the anode and one near the cathode, but it had five additional protein bands distributed from pH 4 to 6. Two-dimensional electrophoresis of total soluble proteins depicted that there were 36 proteins found to be specific for the nonaggressive isolate S116 and 12 proteins for the aggressive isolate RR2.

scholarly journals Contribution to identify the causal gents of Dutch elm disease in the Czech Republic

2008 ◽  
Vol 43 (No. 4) ◽  
pp. 142-145 ◽  
Author(s):  
M. Dvořák ◽  
M. Tomšovský ◽  
L. Jankovský ◽  
D. Novotný
Keyword(s):  
Czech Republic ◽  
North America ◽  
Molecular Biology ◽  
The Other ◽  
Dutch Elm Disease ◽  
The Czech Republic ◽  
Ophiostoma Ulmi ◽  
Other Hand ◽  
Subspecies Level ◽  
First Time

This study provides new data on Dutch elm disease in the Czech Republic. <I>Ophiostoma novo-ulmi</I> is reported for the first time in the area of the Czech Republic, as well as both subspecies ssp. <I>novo-ulmi</I> (indigenous in the area of the Ukraine and Moldavia), and ssp. <I>Americana</I> indigenous in North America. The majority of the recorded strains belonged to <I>O. n.-u.</I> ssp. <I>novo-ulmi</I>, while <I>O. n.-u.</I> ssp. <I>Americana</I> and hybrids of these two subspecies were found less frequently. On the other hand, <I>Ophiostoma ulmi</I> was not found at all in the investigated samples. Identification on the subspecies level was performed by methods of molecular biology, i.e. PCR and RFLP of gene regions<I> cu</I> and <I>col1</I>.

Phaeotheca dimorphospora sp.nov.: description et caractéristiques culturales

1994 ◽  
Vol 72 (6) ◽  
pp. 808-817 ◽  
Author(s):  
Pierre DesRochers ◽  
G. B. Ouellette
Keyword(s):  
Growth Rate ◽  
Growth Temperature ◽  
Type Species ◽  
Optimal Growth ◽  
Outer Wall ◽  
Dutch Elm Disease ◽  
Optimal Growth Temperature ◽  
Ophiostoma Ulmi ◽  
Mother Cells

An unknown fungus isolated from an elm branch and inhibitory against Ophiostoma ulmi in vitro is described as Phaeotheca dimorphospora sp.nov. This dematiaceous deuteromycete propagates by endoconidia released after exfoliation of chlamydospore outer wall, as in mother cells of the type species Phaeotheca fissurella. However, P. dimorphospora differs from the type species by producing hyaline secondary ameroconidia between the endoconidial masses. Other ameroconidia, similar to the secondary ameroconidia, are produced through the chlamydospore outer wall. The optimal growth temperature of P. dimorphospora is 23 °C, whereas it is 15.5 °C for the type species. On media containing a high dextrose concentration (30 g ∙ L−1), colonies of P. dimorphospora are gray and crustose and grow slowly, at least initially. Conversely, on media with a low dextrose concentration (5 or 10 g ∙ L−1) colonies have a faster growth rate and appear whitish or ivory and fluffy. Key words: Phaeotheca dimorphospora, diagnosis, inhibition, Ophiostoma ulmi, Dutch elm disease.

Barrier Zone Formation as a Resistance Mechanism of Elms to Dutch Elm Disease

IAWA Journal ◽  
1985 ◽  
Vol 6 (1) ◽  
pp. 71-77 ◽  
Author(s):  
K.J.M. Bonsen ◽  
R.J. Scheffer ◽  
D.M. Elgersma
Keyword(s):  
Time Course ◽  
Resistance Mechanism ◽  
Dutch Elm Disease ◽  
Host Responses ◽  
Moderate Degree ◽  
Zone Formation ◽  
Ophiostoma Ulmi ◽  
Time Course Study ◽  
High Degree ◽  
Barrier Zone

Host responses of elms susceptible and resistant to Dutch elm disease were histologically examined. In a time course study the susceptible elm clone Ulmus × hollandica 'Belgica' and U. × hollandica '390', a clone which shows a high degree of resistance to non-aggressive isolates and a moderate degree of resistance to aggressive isolates of Ophiostoma ulmi, were inoculated in twig or trunk with either an aggressive or a non-aggressive isolate of O. ulmi. For purposes of comparison, the susceptible elm U. americana and the more resistant clones U. × hollandica 'Groeneveld', U. 'Lobel' and U. 'Sapporo Autumn Gold' were included. Depending on clone-isolate compatibility, infected twigs reacted by a walling off process, by barrier zone formation, or failed to resist the infection and died. Trees inoculated into the trunk reacted comparably but in the case of a compatible combination they always formed a barrier zone and the cambium never died in the year of inoculation.

Barrier zone formation in host and nonhost trees inoculated with Ophiostoma ulmi. I. Anatomy and histochemistry

1991 ◽  
Vol 69 (9) ◽  
pp. 2055-2073 ◽  
Author(s):  
Danny Rioux ◽  
G. B. Ouellette
Keyword(s):  
Principal Component ◽  
Dutch Elm Disease ◽  
Populus Balsamifera ◽  
Ulmus Americana ◽  
Zone Formation ◽  
Ophiostoma Ulmi ◽  
Parenchyma Cells ◽  
Zone Cell ◽  
Histochemical Tests ◽  
Barrier Zone

Barrier zone formation was studied in small branches of Ulmus americana L., Prunus pensylvanica L.f., and Populus balsamifera L. following inoculation with Ophiostoma ulmi (Buism.) Nannf. (the Dutch elm disease pathogen). Barrier zones were continuous in the nonhosts whereas they were generally discontinuous in U. americana; barrier zone formation also occurred at a later stage of infection in the latter than in the former. Barrier zones were formed of parenchyma cells and fibers in U. americana, mainly of parenchyma cells in Prunus pensylvanica, and of fibers in Populus balsamifera. Fibers as a principal component of barrier zones are described for the first time. Histochemical tests revealed that the proportion of lignin was higher in barrier zone cell walls than in elements of the noninvaded xylem. Barrier zones contained suberized cells, the number of which was progressively greater in the order U. americana, Prunus pensylvanica, and Populus balsamifera. However, many fibers of U. americana occasionally formed a continuous barrier zone and had an internal layer that was slightly suberized. In addition, phenolic compounds were usually detected within barrier zone cells of these species. Key words: Dutch elm disease, nonhost plants, Ophiostoma ulmi, Ulmus americana, anatomy, histochemistry.

The mitochondrial genome of Ophiostoma himal-ulmi and comparison with other Dutch elm disease causing fungi.

2021 ◽  
Author(s):  
Alvan Wai ◽  
Georg Hausner
Keyword(s):  
Mitochondrial Genome ◽  
Dutch Elm Disease ◽  
Mitochondrial Genomes ◽  
Western Himalayas ◽  
Ophiostoma Ulmi ◽  
Gene Synteny

The mitochondrial genome of Ophiostoma himal-ulmi, a species endemic to the Western Himalayas and a member of the Dutch elm disease-causing fungi, has been sequenced and characterized. The mitochondrial genome was compared with other available genomes for members of the Ophiostomatales, including other agents of Dutch elm disease (Ophiostoma ulmi, Ophiostoma novo-ulmi subspecies novo-ulmi and Ophiostoma novo-ulmi subspecies americana) and it was noted that gene synteny is highly conserved and variability among members of the Dutch-elm disease-causing fungi is primarily due to the number of intron insertions. Among the Dutch elm disease-causing fungi examined, O. himal-ulmi has the largest mitochondrial genomes ranging from 94 934 bp to 111 712 bp due to the expansion of the number of introns.

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