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1.
V. Mulholland G. A. MacAskill B. E. Laue H. Steele D. Kenyon S. Green 《Forest Pathology》2012,42(3):229-238
The overall aim of this study was to develop a new, reliable and rapid diagnostic assay for differentiating six European Armillaria species based on variation in their elongation factor‐1 alpha (EF‐1 α) gene sequences and to verify a set of species‐specific primers on 61 Armillaria isolates from Europe. Partial sequences of the EF‐1 α gene obtained in Armillaria borealis, Armillaria cepistipes, Armillaria gallica, Armillaria mellea, Armillaria ostoyae and Armillaria tabescens revealed sufficient interspecific variation to distinguish among species using nested primers. These primers gave unambiguous bands when tested on representative isolates of five of these species. However, the EF‐1 α sequences of European A. borealis isolates clustered into two distinct clades, termed here AbX and AbY. Specific primers were subsequently designed and tested successfully on both AbX‐type and AbY‐type A. borealis isolates. The taxonomy of A. borealis needs to be elucidated to determine whether a new, as yet unnamed Armillaria taxon exists in Europe. Three A. borealis isolates were also found to have heterozygous sites in their EF‐1 α sequences, which suggests that the gene could exist in more than one copy or that these isolates contain hybrid sequences. A pyrosequencing method was also developed, targeting a small region of EF‐1 α intron 4, which was able to differentiate European Armillaria isolates to the species level and additionally could distinguish AbX‐type and AbY‐type A. borealis isolates. 相似文献
2.
Armillaria causes problems of root rot, kill trees and decay wood in the forests of Serbia and Montenegro, but the species involved have not hitherto been identified. The aim of this study was to identify field isolates collected on 25 localities. Identification was based on restriction fragment length polymorphism (RFLP) analysis of intergenic spacer 1 (IGS1) region and comparisons of IGS1 sequence with those available on NCBI database. Phylogenetic analysis was performed on sequence information from selected isolates to determine possible interrelationships between isolates with different banding patterns and previously identified tester isolates of five European Armillaria species. Five Armillaria species were identified in 90 isolates obtained from forests in Serbia and Montenegro. Armillaria gallica was most frequently isolated, followed by A. cepistipes, A. mellea, A. ostoyae and A. tabescens; two isolates remained unidentified. Restriction digestion of IGS1 amplification products with AluI produced 10 RFLP patterns. Patterns G4 (400, 250, 180) for A. gallica and pattern X (400, 180, 140) for isolates 74 and 79 are reported for the first time in European isolates. Eight RFLP patterns were observed after restriction with TaqI. Two patterns each were observed for A. ostoyae and A. gallica, and one each for A. cepistipes, A. mellea, A. tabescens and isolates 74 and 79. Parsimony analyses based on the IGS1 region placed the isolates into four clades: one including A. mellea, the second containing A. gallica–A. cepistipes isolates, while isolates of A. ostoyae and A. borealis were in the third clade. Armillaria tabescens differed from all annulate species. Phylogenetic analysis supported the conclusion that European Armillaria species are closely related and separated from a common ancestor in the near past. According to this survey five European Armillaria species are present in the forests of Serbia and Montenegro, while A. borealis is not present in the studied ecosystems. 相似文献
3.
The basidiomycetes Armillaria cepistipes and Armillaria ostoyae frequently occur in the same forest stand. In this study, we determined the virulence of 20 isolates of A. cepistipes and 16 isolates of A. ostoyae on four different provenances of 2‐year‐old Norway spruce (Picea abies). Within 30 months after inoculation, 1.1 and 19.1% of the seedlings inoculated with A. cepistipes and A. ostoyae, respectively, had died or were dying. The incidence of dead and dying seedlings varied between 3 and 49% among the A. ostoyae isolates. The virulence of an isolate was positively correlated to its ability to produce rhizomorphs. One Norway spruce provenance showed significantly lower susceptibility to A. ostoyae than the other three. Rhizomorphs of both Armillaria species were attached to the root surface. The attached rhizomorphs of A. ostoyae, however, were associated with significantly more lesions. The virulence of the isolates was not correlated with their wood‐degrading capability for either of the Armillaria species. 相似文献
4.
Toxic secondary metabolites are synthesized for attack or defence in competing cultures of different basidiomycete species. In combination with incompatibility reactions changes in the pattern of secondary metabolites were also detected in dual cultures of diploid isolates of different Armillaria species (Armillaria gallica, Armillaria borealis and Armillaria cepistipes) on agar. In dual cultures the response in A. cepistipes was most pronounced and occurred combined with increasing growth inhibition of the fungus. The toxic metabolites which were formed in monocultures disappeared and the newly arising metabolites showed no antibiotic activity. The chemical structures of the compounds have been elucidated (two are described for the first time) as sesquiterpene esters of orsellinic acid derivatives. The augmenting metabolites of A. cepistipes are dehydroxylation products. A new facet of the role of secondary metabolites in the ecological interactions of fungi is described, namely, the detoxification of toxins by a competitor. 相似文献
5.
The distribution of Armillaria species was investigated in Serbian forest ecosystems, in relation to the main host species attacked, forest‐types, geography and altitude. In total, 388 isolates were identified from 36 host species in 47 sites. Armillaria gallica was the most commonly observed species with the widest distribution and with an altitudinal range of 70–1450 m, it was the dominating Armillaria species in lowland alluvial forests and in Quercus and Fagus forests at higher elevations. Armillaria mellea occurred in Quercus spp. – dominated forests in the north and central regions at 70–1050 m. Sixty‐eight per cent of the A. mellea isolates were collected from living hosts, most commonly in declining conifer plantations. Armillaria ostoyae was distributed in the cooler coniferous forest types and plantations in the Dinaric Alps in the south of Serbia, at 850–1820 m. Armillaria cepistipes was found in the eastern and southern hilly and mountainous regions of the country, at 600–1900 m. Most isolates were obtained from conifers and rhizomorphs in the soil around decaying stumps. Armillaria tabescens was found only on dead oak material in the northern and eastern regions of the country at altitudes lower than 600 m. 相似文献
6.
Attempts to design species‐specific PCR primers from six European Armillaria species in the ribosomal RNA genes are reported. Primers were developed on the basis of the nucleotide sequence variability of the internal transcribed spacers (ITS) and the intergenic spacer (IGS1) of the ribosomal DNA. Four sets of primers gave specific PCR products for Armillaria tabescens, Armillaria mellea and Armillaria ostoyae. However, due to the high sequence similarities between Armillaria borealis and Armillaria ostoyae and between Armillaria cepistipes and Armillaria gallica no species specific amplification was obtained for these taxa. 相似文献
7.
In managed spruce forests, Armillaria cepistipes and A. ostoyae are efficient stump colonizers and may compete for these resources when they co‐occur at the same site. The aim of this experiment was to quantify the mutual competitive ability of the two Armillaria species in producing rhizomorphs and in colonizing Norway spruce (Picea abies) stumps. Five isolates of A. cepistipes and two isolates of A. ostoyae were simultaneously inoculated pair‐wise into pots containing a 4‐year‐old spruce seedling. For comparison, each isolate was also inoculated alone. One year after inoculation, stumps were created by cutting down the seedlings. Six months after creation of the stumps, rhizomorph production and stump colonization were assessed. Armillaria spp. were identified from 347 rhizomorphs and 48 colonized stumps. Armillaria cepistipes dominated both as rhizomorphs in the soil and on the stumps. Nevertheless, A. ostoyae was relatively more frequent on the stumps than in the soil and A. cepistipes was relatively more frequent in the soil than on the stumps. In both species, the ability to colonize the stumps in simultaneous inoculations was significantly reduced compared with single inoculations. In respect to rhizomorph production, simultaneous co‐inoculations had a slightly stimulatory effect on A. cepistipes and no significant effect on A. ostoyae. Our study suggests a rather neutralistic co‐existence of A. cepistipes and A. ostoyae as rhizomorphs in the soil. Concerning the ability to colonize stumps, the two species experience a mutual negative effect from the interaction, probably because of interspecific competition. 相似文献
8.
Distribution, host preference and pathogenicity of Japanese Armillaria species on conifers were investigated on the basis of field collections of 65 isolates. We identified seven Armillaria species from 19 conifer species including six major Japanese plantation conifers using mating tests and sequences of the translation elongation‐1 α gene. Armillaria mellea, Armillaria ostoyae, Armillaria cepistipes and Armillaria sinapina were frequently collected, whereas Armillaria nabsnona, Armillaria tabescens and a biological species Nagasawa’s E were rare. On the basis of host condition when the isolates were collected, A. mellea, A. ostoyae, A. cepistipes and A. tabescens are considered as moderate to aggressive pathogens of conifers in Japan. 相似文献
9.
Polyacrylamide isoelectric focusing with specific staining for laccase activity was used to characterize laccase from European Armillaria species (Armillaria ostoyae, Armillaria mellea, Armillaria gallica, Armillaria cepistipes). The enzyme was extracted from culture media either supplemented, or not, with pine sawdust, and also from Pinus pinaster naturally infected by A. ostoyae, or artificially inoculated with A. mellea and A. ostoyae. Some differences in banding patterns were found for Armillana isolates according to the species and the culture media, but a common band at pI = 3.4 was found in all the extracts tested, independently of their origin (culture filtrate or wood). 相似文献
10.
Species of Armillaria were identified from 645 isolates obtained in a nation‐wide survey in Albania. The material was collected from ca. 250 permanent plots, established for monitoring forest health, and from forests and orchards attacked by Armillaria. Armillaria mellea s.s. occurred on several coniferous and broadleaved trees in most areas examined, although it was absent above 1100–1200 m in northern Albania. This species damaged Abies and Quercus spp. and, to a lesser extent, other forest trees. Armillaria mellea was also commonly recorded causing damage in orchards and vineyards. Armillaria gallica was a common saprophyte or weak pathogen in coniferous and deciduous forests at altitudes from 600 to 1600 m, and less commonly on oaks at lower altitudes. Armillaria ostoyae was rare in central and southern Albania, but common in northern Albania, causing significant damage to pine and other conifers, mostly at altitudes from 600 to 1800 m. Armillaria cepistipes was recorded at altitudes from 800 to 1800 m as a saprophyte or weak pathogen on conifers and deciduous trees, mostly in beech and silver fir forests. Armillaria tabescens was found in oak forests at altitudes from sea level to 900 m. In orchards, A. tabescens occasionally attacked almond and pear trees. Armillaria borealis was found in a few locations in northern Albania, at altitudes from 800 to 1800 m. 相似文献
11.
Armillaria species from Japan were characterized using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the intergenic spacer region-1 (IGS-1) of ribosomal DNA (rDNA). Eleven different digestion patterns by restriction endonuclease Alu I were found among 70 isolates of seven Armillaria species in Japan. Isolates within Armillaria nabsnona, A. ostoyae, A. cepistipes, and Japanese biological species E showed the same Alu I digestion patterns. Five Alu I patterns were detected for A. gallica, three patterns for A. mellea, and two patterns for A. tabescens. Seven Armillaria species in Japan were clearly distinguished by using the profiles obtained when PCR products were digested with Alu I, Msp I, and Hae III restriction enzymes. There was considerable variability of Alu I restriction sites within the IGS-1 between the isolates of five Armillaria species, A. gallica, A. nabsnona, A. cepistipes, A. mellea, and A. tabescens, in Japan and those of their European and North American counterparts. 相似文献
12.
《Scandinavian Journal of Forest Research》2012,27(4):337-346
Abstract Stem bases of 210 Fraxinus excelsior trees of three different health categories were sampled by the means of an increment borer in declining ash stands in northern Lithuania. From this number, 15 sound-looking, 132 declining and 63 dead trees from three discrete plots yielded 352 isolates, representing 75 fungal species. In addition, mycelial fans and rhizomorphs typical of Armillaria spp. from 205 and 20 trees, respectively, were sampled and subjected to fungal isolations. Species richness was similar in trees from each health category, but community structures differed, indicating that species composition of wood-inhabiting fungi in stems changes along with the changes in tree health condition. Armillaria cepistipes was the most common species (86 isolates from 210 wood samples, or 41.0%), isolated more frequently and consistently than any other potential tree pathogen. It also showed abundant occurrence on a majority of trees in the form of mycelial fans and rhizomorphs, from which 64 and 14 isolates of the fungus were obtained, respectively. The population structure of A. cepistipes revealed the presence of 53–93 genets per hectare, some of which extended up to 30–55?m. 相似文献
13.
Mycelial fan formation of three sympatric Armillaria species on excised stem segments of Picea abies 
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下载免费PDF全文 Mycelial fan formation was studied in five Armillaria cepistipes, ten A. borealis and ten diploid and six haploid A. ostoyae strains on excised stem segments of Picea abies. Stem segments were either non‐autoclaved or autoclaved, representing dying and dead wood, respectively. To confirm the identity of mycelial fans on non‐autoclaved stem segments, re‐isolations were made and isolates characterized with microsatellite markers. Mycelial fan formation on autoclaved stem segments was fast and reliable for most of the tested Armillaria strains. On non‐autoclaved stem segments, mycelial fan formation was slower, more erratic and less predictable. Mycelial fan formation was fastest in A. cepistipes closely followed by A. borealis and was slowest in A. ostoyae. For two A. cepistipes and four A. ostoyae strains (all diploid), growth rates of mycelial fans were estimated in a time course experiment. They ranged between 5.1 and 8.7 mm/day for autoclaved and between 1.4 and 4.7 mm/day for non‐autoclaved stem segments. The haploid A. ostoyae strains also formed mycelial fans on autoclaved stem segments, but typically slower and less reliably than the diploid strains. Whether haploid strains are able to produce mycelial fans on non‐autoclaved stem segments remains unknown because of accidental diploidization of the original haploid strains which was likely caused by basidiospores introduced into the study system on the non‐autoclaved stems. Overall, the method developed in this study may be useful for further investigations into the genetic, physiological and biochemical nature of mycelial fan formation in the genus Armillaria. 相似文献
14.
Initial characterization of an unidentified Armillaria isolate from Serbia using LSU‐IGS1 and TEF‐1‐α genes 下载免费PDF全文
下载免费PDF全文 Armillaria species have a global distribution and play variable ecological roles, including causing root disease of diverse forest, ornamental and horticultural trees. Accurate identification of Armillaria species is critical to understand their distribution and ecological roles. This work focused on characterizing an unidentified Armillaria isolate from a Serbian forest using pairing, sequencing of the partial large subunit and intergenic spacer‐1 regions of rDNA (LSU‐IGS1) and the translation elongation factor‐1 alpha gene (tef‐1α) genes, and phylogenetic analyses. Despite previously obtained LSU‐IGS1 RFLP patterns that matched the newly described North American Armillaria altimontana, pairing tests and phylogenetic analyses of LSU‐IGS1 and tef‐1α sequences clearly demonstrate that the unidentified isolate is not A. altimontana. Based on LSU‐IGS1, Armillaria gallica isolates were polyphyletic, and the Serbian isolate clustered with a subset of European A. gallica isolates within a well‐supported clade (99%). Based on tef‐1α, the Serbian isolate appeared as a separate, well‐supported clade (97%) that was basal to other poorly resolved, polyphyletic clades containing European A. gallica isolates. It is speculated that the unidentified Armillaria isolate from Serbia could represent an evolutionary ancestral state because of its separate, basal position compared with other clades comprising polyphyletic European A. gallica isolates. Alternatively, this unidentified Serbian isolate could represent an unusual hybrid because of its high‐level sequence heterogeneity, represented by multiple two‐nucleotide codes, within tef‐1α. Further characterization is needed to confirm the taxonomic status and ecological/evolutionary significance of this unique, unknown Armillaria isolate from Serbia. 相似文献
15.
Phylogenetic and genetic relationships among 10 North American Armillaria species were analysed using sequence data from ribosomal DNA (rDNA), including intergenic spacer (IGS‐1), internal transcribed spacers with associated 5.8S (ITS + 5.8S), and nuclear large subunit rDNA (nLSU), and amplified fragment length polymorphism (AFLP) markers. Based on rDNA sequence data, the nLSU region is less variable among Armillaria species than the ITS + 5.8S and IGS‐1 regions (nLSU < ITS + 5.8S < IGS‐1). Phylogenetic analyses of the rDNA sequences suggested Armillaria mellea, A. tabescens and A. nabsnona are well separated from the remaining Armillaria species (A. ostoyae, A. gemina, A. calvescens, A. sinapina, A. gallica, NABS X and A. cepistipes). Several Armillaria species (A. calvescens, A. sinapina, A. gallica, NABS X and A. cepistipes) clustered together based on rDNA sequencing data. Based on the isolates used in this study, it appears that techniques based on IGS‐1, ITS + 5.8S, and/or D‐domain/3′ ends of nLSU are not reliable for distinguishing A. calvescens, A. sinapina, A. gallica and A. cepistipes. However, AFLP data provided delineation among these species, and AFLP analysis supported taxonomic classification established by conventional methods (morphology and interfertility tests). Our results indicate that AFLP genetic markers offer potential for distinguishing currently recognized North American Biological Species (NABS) of Armillaria in future biological, ecological and taxonomic studies. 相似文献
16.
The geographical distribution of the annulate Armillaria species was studied in The Netherlands during the period 1983–1992. Armillaria gallica (incl. A. cepistipes), A. mellea and A. ostoyae appear to be widespread, the first two species being rather common on broad-leaved hosts growing on clay and loess soils, and the third species common on both broad-leaved and coniferous hosts on acid sandy soils. The distribution of the Armillaria species encountered was primarily determined by soil type. From a silvicultural point of view, A. ostoyae is the most important species, being pathogenic and occurring most frequently on sandy soils, the soil type predominantly used for forestry in The Netherlands. 相似文献
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18.
Armillaria spp. are some of the most important forest pathogens in mixed hardwood forests of southern New England, yet their role as prominent disturbance agents is still not fully appreciated. We investigated the distribution of Armillaria species across eight separate stands of northern hardwood and mixed oak forests in western Massachusetts. We were specifically interested in the Armillaria species distribution from live, symptomatic hosts and not in determining overall incidence in the forest. From 32 plots (16 within each forest type), 320 isolates were collected. Armillaria was routinely encountered causing disease of live trees. In total, 89% (286/320) of all isolations came from live hosts exhibiting symptoms of root and butt rot. Overall, A. gallica was the dominant species in each forest type, making up 88/160 (55%) isolates from northern hardwood and 153/160 (96%) of all isolations from mixed oak stands. However, northern hardwood forests showed much greater species diversity, as A. calvescens, A. gemina, A. ostoyae, and A. sinapina were all found. At one site, a northern hardwood forest surrounding a high elevation spruce-fir forest, A. ostoyae was the most abundant species encountered. All five Armillaria species were found causing disease of live hosts, including A. gemina, a species considered by some as weakly virulent. Armillaria gallica was found on 22/23 tree species’ sampled, and was found most often causing butt rot. 相似文献
19.
We describe a holistic in vitro technique for inoculating roots of Prunus species with Armillaria solidipes, which is faster and more successful than previous methods. This method allows associated active and passive host defences to be assessed. Sterile root segments of three Prunus spp. were placed next to or on top of 14‐day‐old cultures of A. solidipes. At 21 day, the success of fungal penetration and length of the fungal colonization, and host responses were evaluated. Also, an anti‐Armillaria and anti‐Cladosporium activity detection assays were conducted by utilizing the root periderm, the first tissue that needs to be penetrated by fungus. These methods revealed the variation in the relative tolerance of three Prunus spp. to A. solidipes. The overall success of fungal colonization in the wounded and intact root, host defence, and antifungal activity significantly differed among three Prunus spp. Results indicate that this in vitro method can be used as a preliminary step in screening tree species to Armillaria spp. 相似文献
20.
P. Tsopelas 《Forest Pathology》1999,29(2):103-116
Five Armillaria species were identified in a nationwide survey in Greece. Armillaria mellea was present in coniferous and broad-leaved forests in most of the areas examined, except the high altitudes (above 1100 m) of the mountains of north Greece. It was found to cause significant damage in fir forests as well as in fruit orchards and vineyards. Armillaria gallica was common in coniferous and broad-leaved forests in the high altitudes of central and northern Greece, predominating in the beech forests. The fungus was a weak parasite or a saprophyte of forest trees and was occasionally found on cultivated plants. Armillaria ostoyae was not found in southern and central parts of the country, but it has a wide distribution in the mountain forests of northern Greece and causes significant damage on fir, black pine, Scots pine and spruce. Armillaria cepistipes was recorded at high altitudes (1400–1800 m) on two mountains of northern Greece, mostly as a saprophyte in coniferous and broad-leaved forests. Armillaria tabescens was rare in the forests of Greece; it was found to cause disease in almond tree orchards. 相似文献