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SESSION 1 - Discovery - New horizons in plant pathology - page 40 / 65





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the samples are taken from various fruit orchards (small orchard at houses, large commercial orchard) and from fruit alley in the Czech Republic. Until now, the samples have been taken from 10 localities. The fungi are isolated from fine branches and roots and from peridemal bark, subperidermal bark and wood of medium branches and roots and coarse branches and roots. After surface sterilisation (96% ethanol, 10% sodium hypochlorite solution, 96% ethanol) branches and roots are cut into segments, placed onto malt extract agar and incubated at room temperature for up to four weeks. So far, 26 and four fungal species were isolated from apple branches and roots, respectively. Fungi occur most frequently in fine branches and roots and in peridermal bark of medium and coarse branches and roots. Wood of skeleton and medium branches and roots are colonised with lowest frequency. The most frequent fungi of apple branches are Pleurophoma cava, Alternaria alternata, Aureobasidium pullulans, Seimatosporium cf. pestalotioides¸ Phomopsis cf. mali, coelomycet sp. 1 and Coniothyrium cf. olivaceum. The differences in composition of communities of endophytic fungi are observed. The fungal community of apple roots is dominated by Phialophora cf. fastigiata and Cylindrocarpon sp. Bacteria are common in roots and branches, especially in wood of these organs. So far, seven species has been detected in pear branches and Seimatosporium cf. pestalotioides were most frequently recorded. So far, three strains of Pezicula have been isolated from apple branches, but Neofabraea spp. and Glomerella cingulata have not been recorded. Till now no herbarium specimens of Neofabraea, Pezicula or Glomerella cingulata from apple and pear tree from the Czech Republic are known. The present study is supported by the Grant Agency of Ministry of Agricultural of the Czech Republic (project No. QF 4074).


Mycobiota of oak roots in the Czech Republic in connection with oak decline.

David Novotný, Department of Mycology, Division of Plant Medicine, Research Institute of Crop Production, Drnovska 507, 161 06 Praha 6 – Ruzyne, Czech Republic, email: novotny@vurv.cz

Oak decline is a serious problem in oak stands of many parts of Europe observed during the twentieth century. Dieback of oaks was for the first time recorded in the Czech Republic in the 1950s and it was recorded very frequently in the 1970s, 1980s and 1990s. In the Czech Republic this disease is called “tracheomycosis” or “with tracheomycotic symptoms”. Mycobiota associated with oak decline is investigated in many countries of Europe. Most researchers in Europe study fungi of aboveground parts (stems, branches, leaves) of Quercus spp. The mycobiota of roots is investigated seldom. In 1994-1999, mycobiota inhabiting living roots (without any necrotic spots or other similar symptoms) of two oak species (Quercus petraea and Q. robur) from two regions (Central Bohemia and South-west Moravia) in the Czech Republic was investigated. The roots were taken from middle-aged healthy, died oaks or oaks with symptoms of decline in various stages. Moist chamber method and the strong surface sterilisation method were used in the present study. One hundred forty seven fungal species were isolated from roots of Quercus robur and Q. petraea. Roots of Quercus robur and Q. petraea harbour similar fungal communities. The composition mycobiota oak roots is independent on health state of aboveground parts of oaks. The living roots of healthy and diseased oaks harbour the same fungal community. Considerable attention was paid to ophiostomatoid fungi, because they were considered to be a possible reason of oak decline in the Czech Republic and the data about the ecology of these fungi in oaks are often contradictory. These fungi were observed in roots of healthy, died and diseased oaks. Abiotic factors are probably the primary reason of oak dieback in the study sites and ophiostomatoid fungi are secondary colonisers. Eighty-nine fungal species were isolated from roots of Q. petraea. Cystodendron-like hyaline anamorph, Phialophora cf. fastigiata, Umbelopsis nana, Cryptosporiopsis radicicola, sterile basidiomycete T, Trichoderma viride, dark septate endophyte, Oidiodendron griseum, Chloridium preusii, Sporidesmium cf. anglica, Cladosporium herbarum and sterile hyaline mycelium A were the most frequent fungi. The composition of mycobiota of roots from all study sites was similar. Four dominant species (Cystodendron-like hyaline anamorph, P. cf. fastigiata, U. nana, C. radicicola) occurred from all localities and in roots of oaks of all health categories. Eighty-two species of fungi were detected in roots of Q. robur. Cryptosporiopsis radicicola, dark sterile mycelium sp. 1, Cylindrocarpon destructans, Chaetomium globosum, Penicillium simplicissimum and Trichoderma koningii were dominant species observed by the strong surface sterilisation method. All these species were recorded in roots of healthy and diseased oaks. Using moist chamber method most of dominant species (Fusarium solani, F. proliferatum, Penicillium simplicissimum, P. glandicola, P. glabrum, P. purpurogenum, Cylindocarpon destructans, Sphaerostilbella aureonitens, Ophiostoma piceae s.l. and Gliocladium catenulatum) occurred in roots of healthy and diseased oaks. Acremonium curvulum, and Trichoderma viride, T. atroviride were isolated from roots of diseased oaks. Research was supported by the Grant Agency of Charles University (Project No. 243/1997/ B BIO/PřF) and the Ministry of Agriculture of the Czech Republic (Project No. 29-91-9106).


Vegetative compatibility groups of Verticillium dahliae from olive plantation soil in Spain

Maria Rataj-Guranowska, Aleksandra Czerwińska

Collection of Plant Pathogens, Institute of Plant Protection, ul. Miczurina 20, 60-318 Poznan, Poland

Verticillium dahliae is an economically important pathogen causing vascular wilt on more than 160 plant species. So far four different vegetative compatibility groups have been identified within pathogenic isolates of Verticillium dahliae in USA, however two of them: VCG 2B and VCG 4B seem to dominate in USA and in most European countries (France, Belgium, The Netherlands, UK, Germany) and Japan. VCG 1 was detected in Spain and Israel. A collection of 22 isolates of Verticillium dahliae originating from soil of olive plantation in Andalusia was assigned to VCG based on complementation between nitrate non-utilizing (nit) mutants. Genetic diversity found was limited to two groups. Nineteen isolates were assigned to VCG 1, the remaining 3 isolates were assigned to VCG 4 A. Moreover many of the isolates  were bridge isolates between VCG 1 and VCG 4 A or VCG 2. The obtained  results show that VCG diversity within the soil isolates is rather limited. The two VCGs

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