| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-food Canada, Ottawa, Ontario, K1A 0C6 Canada
Thomas Kirisits
Institute of Forest Entomology, Forest Pathology and Forest Protection (IFFF), Universität für Bodenkultur Wien (BOKU), Hasenauerstrasse 38, A-1190 Vienna, Austria
Michael J. Wingfield
Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, South Africa
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
Two fungi associated with bark beetles, Graphium pseudormiticum (described in 1994) and Rhexographium fimbriisporum (described in 1995), have two micromorphological characters in common. Both species produce conidia with conspicuous basal frills, and the conidia align in chains, despite being produced in slime. The association of G. pseudormiticum with the pine bark beetle, Orthotomicus erosus, and the association of R. fimbriisporum with the spruce bark beetle, Ips typographus, suggest ecological differences between the two fungal species. Analyses of micromorphology and phylogenetic analyses of aligned 18S and ITS sequences suggest that these two species are congeneric and should be classified in Graphium but that they represent distinct species. A collection of strains tentatively identified as Graphium spp., isolated from Ips typographus on Picea abies, Ips cembrae on Larix decidua and Tomicus minor on Pinus sylvestris in Austria share the same unusual basal conidial frills and conidial chains. Isolates from spruce were identified as G. fimbriisporum and those from pine as G. pseudormiticum. The strains from Ips cembrae on Larix decidua, distinguished by the reddish color of their colonies, microscopic structures and molecular characteristics, are described as the new species Graphium laricis sp. nov., and the close relationship of this species with the other two species is confirmed.
Key words: conidium development, Graphium, Ips spp, Larix, phylogeny, Picea, Pinus, Rhexographium
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
, Whitney 1982, Kirschner 1998, Jacobs and Wingfield 2001). The insects act as vectors of these fungi, and specific associations exist among individual bark beetle species and certain fungi. Ophiostoma Syd. & P. Syd species and related mitosporic fungi, in particular Leptographium Lagerb. & Melin and Pesotum J.L. Crane & Schokn., are the most common fungi associated with bark beetle species such as Ips typographus L. and I. cembrae Heer (Mathiesen-Kaärik 1953, Solheim 1986, van der Westhuizen et al 1995, Kirisits 1996, Krokene and Solheim 1996, Jacobs et al 1998, Yamaoka et al 1997, 1998, Stauffer et al 2001). Until recently, synnematous anamorphs of Ophiostoma were accommodated in Graphium Corda (Upadhyay 1981, Seifert and Okada 1993). However, recent studies have shown that the synnematous anamorphs of Ophiostoma phylogenetically are distant from other species in Graphium and should be accommodated in a distinct taxon (Okada et al 1998, 2000). Synnematous anamorphs of Ophiostoma thus were transferred to Pesotum, but taxa with annellidic conidiogenensis and microascaceous affinities related to Graphium penicillioides Corda are retained in Graphium (Okada et al 1998, 2000).
Graphium pseudormiticum M. Mouton & M.J. Wingf. was isolated and described in 1994 from galleries of the bark beetle Orthotomicus erosus Wollaston infesting pine in South Africa (Tribe 1990, 1992, Mouton et al 1994). Orthotomicus erosus is native to Europe and accidentally was introduced into South Africa in the 1970s (Kfir 1986, Tribe 1990, 1992). The fungus is characterized by darkly pigmented synnemata, percurrently proliferating conidiogenous cells and aseptate conidia that accumulate in mucilagenous masses, characteristic of the anamorph genus Graphium. Unlike other species in Graphium, strains of G. pseudormiticum produce conidia with conspicuous basal frills that accumulate in a chain-like formation (Mouton et al 1994). A detailed study of the conidium development in this species revealed that these are not true chains (Minter et al 1982, 1983) and are composed of conidia that adhere to each other as a result of the attachment of the basal frills (Mouton et al 1994).
Morelet (1995) described Rhexographium fimbriisporum M. Morelet (as R. fimbriasporum) as a Graphium-like species almost identical to G. pseudormiticum, but he chose to separate it from Graphium in the monotypic genus Rhexographium M. Morelet based on apparent differences in conidiogenesis. Rhexographium fimbriisporum was isolated from the galleries of the bark beetle Ips typographus on Norway spruce (Picea abies [L.] Karst.) and is characterized by dark, synnematous conidiophores similar to those in Graphium. Morelet (1995) distinguished his strains from Graphium based on an apparently unique form of conidium development, although it was almost the same as that described for G. pseudormiticum. No reference was made to G. pseudormiticum because Morelet (1995) apparently was unaware of the study of Mouton et al (1994). This morphological similarity also was noted by Okada et al (1998), who speculated that R. fimbriisporum and G. pseudormiticum are synonomous.
In recent years, a number of intensive surveys of fungi associated with the bark beetle Ips cembrae on European larch (Larix decidua Mill.) have been conducted in Austria and Scotland (Kirisits et al 1998, 2000, Stauffer et al 2001). One of the aims of these surveys was to compare the ophiostomatoid fungi associated with I. cembrae with those of the closely related I. typographus, which have been well-studied (Mathiesen-Kaärik 1953, Solheim 1986, 1992, Kirisits 1996, Krokene and Solheim 1996, Viiri 1997). As part of these surveys, a fungus falling within the taxonomic circumscription of Graphium, and with conidium development similar to that of G. pseudormiticum and R. fimbriisporum, consistently was isolated from the galleries of I. cembrae in Scotland and Austria (Kirisits et al 1998, 2000, Stauffer et al 2001). Unlike G. pseudormiticum and R. fimbriisporum, this fungus is characterized by reddish-brown conidiophores and conidial masses.
The aim of this study was to re-evaluate the taxonomic placement of R. fimbriisporum and its relatedness to G. pseudormiticum. Furthermore, we have included a wide range of isolates, tentatively identified as Graphium spp., associated with bark beetles on spruce, larch and pine in Europe. Special consideration has been given to the identity of the commonly occurring red-colored fungus associated with I. cembrae.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
and Krokene and Solheim (1996). Direct isolations were made from the conidial masses of synnemata occurring in the galleries of the insects. The plates were incubated at room temperature. Pure cultures were obtained by transferring mycelia or conidial masses from primary isolation dishes onto fresh MEA plates. All strains are maintained in the culture collection of the Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria (CMW), and the culture collection of the Institute of Forest Entomology, Forest Pathology and Forest Protection (IFFF), Universität für Bodenkultur Wien (BOKU). Representative strains have been deposited in the Canadian Collection of Fungal Cultures and Herbarium (DAOM) and at Centraalbureau voor Schimmelcultures, Utrecht, The Netherlands (CBS).
|
, Jacobs et al 2003), incubated in the dark or in incidental light at 25 C. Measurements are reported as the maximum and minimum values of 50 measurements as well as the mean ± standard deviation. Fungal structures were mounted on slides in 85% lactic acid and examined with phase or differential interference contrast microscopy. Color codes were determined with the Methuen handbook of color (Kornerup and Wanscher 1978). Growth rates were determined on both MEA and OA at 25 C with incident light. Cycloheximide tolerance was determined on MEA plates amended with 100 mg/L cycloheximide at 25 C with incident light. For scanning electron microscopy (SEM), small blocks of agar about 5 mm wide were cut from sporulating colonies and fixed in 4% glutaraldehyde and 0.5% osmium tetroxide in a 0.1 M phosphate buffer, dehydrated in a graded ethanol series, then critical-point dried (Tousimis SAMDRI PVT-3). Specimens were mounted and coated with gold-palladium alloy (Technics Sputter Coater) and examined with a Phillips XL30 Environmental Scanning Electron microscope.
DNA sequencing and phylogenetic analyses –
Single conidial strains used for phylogenetic analysis were grown on commercial potato-dextrose agar (PDA) (Difco) for 10 d in the dark at 25 C. DNA extractions from pure cultures were prepared with the UltraCleanTM Microbial DNA kit (MoBio Laboratories, California, U.S.A.). Successful isolation of DNA was confirmed on 1% agarose gels. Amplifications of the 18S gene and ITS1–5.8S-ITS2 (internal transcribed spacer regions of the ribosomal DNA) were made using standard protocols for PCR reactions. PCR reactions were conducted with Ready-To-Go (RTG) PCR-beads (Amersham Pharmacia Biotech, Piscataway, New Jersey, U.S.A.) and the primers NS1 and ITS4 (White et al 1990). PCR products were purified with the UltraCleanTM PCR-cleanup kit (Mo-Bio Laboratories, California, U.S.A.) and sequenced with the Big-dye terminator cycle sequencing premix kit (Perkin Elmer Applied Biosystems California, U.S.A.) on an ABI PRISM 310 automatic sequencer (Perkin Elmer Applied Biosystems California, U.S.A.). Primers NS1, NS2, NS3, NS4, NS5, NS6, NS7, NS8, ITS1, ITS2, ITS3, and ITS4 (White et al 1990) were used to sequence both strands of the 18S and ITS regions. Sequence contigs were assembled with Sequencher version 4.0.5. (Gene Codes Corporation, Michigan, U.S.A.); a computer-generated alignment (Wisconsin Package Version 10.1, Genetics Computer Group (GCG), Madison, Wisconsin; Canadian Bioinformatics Resource (http://www.cbr.nrc.ca/) of the resulting sequences together with imported reference sequences from GenBank then was adjusted manually in PAUP* version 4.0b8 (Phylogenetic Analysis Using Parsimony) (Swofford 1999). Bases from the 3' end and 5' end of the 18S region and 5' ends of the ITS1 as well as the 5' end of large ribosomal subunit were excluded from the analysis of datasets to align them with sequences deposited in GenBank.
For analysis, the 18S and ITS-datasets were constructed and compared with sequences of closely related species and genera deposited in GenBank. Phylogenetic relationships were inferred using a heuristic search in PAUP* version 4.0b8. The aligned 18S dataset consisted of 931 characters. In all sequences, characters were treated in the analysis as unweighted and gaps were treated as a fifth base. One area with only single-strand sequences was excluded from the 18S analysis (characters 451–564 in the aligned dataset). Five hundred fifty-one characters were constant, 105 parsimony uninformative and 275 parsimony informative. The aligned ITS dataset consisted of 549 characters. Three hundred six characters were constant, 69 parsimony uninformative and 174 parsimony informative. A heuristic search was performed on both datasets with tree-bisection-reconnection (TBR) branch swapping. Starting trees were obtained through stepwise addition. The resulting trees were used to obtain a consensus tree. Confidence levels were estimated using a Bootstrap analysis (1000 replicates) with the "fast" stepwise addition option.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
(Figs. 1–2). In both these fungi, conidia develop after percurrent proliferation of the conidiogenous cells and pronounced annellations are clearly visible (Figs. 3–4). Conidia in R. fimbriisporum display delayed secession (Fig. 5), similar to that observed in G. pseudormiticum (Mouton et al 1994) (not considered by Morelet 1995) (Table II). Rhexographium fimbriisporum, however, has larger conidia than those observed and documented for G. pseudormiticum (Mouton et al 1994, Morelet 1995). While G. pseudormiticum is characterized by dark olive-green colonies (K&W-3D7), R. fimbriisporum has camel brown (K&W-6D4) colonies. Thus, based on morphology, R. fimbriisporum and G. pseudormiticum are similar but probably represent distinct species within Graphium.
|
|
|
|
Rhexographium fimbriisporum M. Morelet, Ann. Soc. Sci. Nat. Aschéol. ToulonVar. 47, 90. 1995 (basionym). Strains from Larix decidua – Strains from Larix decidua infested by Ips cembrae are characterized by a pattern of conidium development similar to that observed in G. pseudormiticum and G. fimbriisporum. The conidia of these strains are characterized by conspicuous basal frills that are produced in chains (Figs. 10, 16). Unlike G. pseudormiticum and G. fimbriisporum, strains from Larix decidua have reddish (K&W-7D7) conidiophores and conidial masses. Furthermore, sequences of the 18S region showed that the strains from Larix phylogenetically are related closely to G. pseudormiticum and G. fimbriisporum (Fig. 8). However, the ex-type strain of G. pseudormiticum (CMW 506) is characterized by a 433 bp Group I intron in the 18S gene. The intron is located at nt1430 position of the model organism Saccharomyces cerevisiae. No introns were observed in strains from Larix decidua or G. fimbriisporum. In the analysis of the ITS dataset, the strains from Larix decidua formed a clade close to G. pseudormiticum and G. fimbriisporum but constituted a discrete group within the clade (Fig. 9). Thus, based on morphology, ecological characteristics and analyses of DNA sequences, we conclude that the red-colored Graphium, commonly occurring in the galleries of I. cembrae on L. decidua in Europe, represents a previously undescribed species for which we provide this description
|
|
Etymology; from the host Larix.
Coloniae in MEA 25 C pervenientes diametrum 15 mm post 12 dies, in OA ad 25 C pervenientes diametrum 25 mm post 12 dies. Cycloheximidum non tollitur. Coloniae perinum incoloratae in MEA et OA, poster rubescentes. Conidiophora macronematos, synnematos, stipes rubellus ad basim, hyalinum versus apicem. Synnemata (103–) 157 ± 32 (–218) µm longus, (10–) 30 ± 2 (–55) latus in medio, (18–) 44 ± 17 (–88) µm ad apicem, rhizoidea ad basim parce evoluta. Cellulae conidiogenae annellatae, hyalinae, (19–) 21 ± 8 (–52) µm longae. Conidia unicellularia, hyalina, cylindrica, subrotumda, fimbriis basilaribus prominentibus 4.0–6.0 µm x 1.0–2.0 µm. Holotypus: DAOM 229757.
Colonies on MEA reaching 15 mm diam., on OA reaching 25 mm diam after 12 d at 25 C. Not tolerant to low concentrations of cycloheximide (100 mg/L). Colony color on MEA white, becoming reddish-brown (K&W-7D7) toward the center, sporulation on MEA sparse, colony margin smooth, reverse white, becoming reddish-brown toward the center. Colony colorless on OA, becoming cinnamon brown (K&W-6D6) with age. Sporulation and formation of synnemata abundant on OA, sparse aerial mycelia developing with age. Mucilaginous conidial masses reddish-brown, giving the colony a reddish-brown appearance, reverse reddish-brown, colony margin smooth. Hyphae mostly submerged in agar with little aerial mycelium, hyaline, smooth-walled, not constricted at the septa, 2–5 µm wide. Synnemata arising singly or in groups, consisting of a stipe of parallel hyphae, a divergent capitulum of conidiogenous cells and a mucilaginous mass of conidia. Synnematal stipe, reddish at the base, becoming hyaline toward the apex, (103–) 157 ± 32 (–218) µm long, (10–) 30 ± 2 (–55) µm wide at the center, (18–) 44 ± 17 (–88) µm wide at the apex. Rhizoids at the base scanty. Conidiophores produced in the divergent capitulum with three series of branches, with 3–5 metulae or conidiogenous cells per branch point, metulae and conidiogenous cells (4–) 11 ± 7 (–21) long and 1.0–2.0 µm wide, conidium development annellidic, inconspicuous, conidial dehiscence sometimes delayed and thus giving the impression of sympodial proliferation. Conidia aseptate, hyaline, cylindrical rounded with conspicuous basal frill 4.0–6.0 µm x 1.0–2.0 µm, accumulating in hyaline mucilaginous masses forming chain-like formations at the apices of conidiophores, turning reddish-brown (K&W-7D7) with age.
HOLOTYPE: DAOM 229757, Austria, Styria, Kindberg, isolated from a larvae of Ips cembrae on Larix decidua, 1 Jul 1995, collected and isolated: T. Kirisits and P. Baier, (living cultures: CMW 5601 = IFFF IC/L/MEA/13). Additional specimens: DAOM 229754, United Kingdom, Scotland, Atholl, isolated from conidiophores in the galleries of Ips cembrae on Larix decidua, 28 Aug 1997, collected and isolated: T. Kirisits, M.J. Wingfield and D.B. Redfern, (living cultures: CMW 5598 = IFFF Scotland/4); DAOM559755, United Kingdom, Scotland, Elgin, isolated from conidiophores in the galleries of Ips cembrae on Larix decidua, 29 Aug 1997, collected and isolated: T. Kirisits, M.J. Wingfield and D.B. Redfern, (living cultures: CMW 5599 = IFFF Scotland/8); DAOM 229756, United Kingdom, Scotland, Peebles, isolated from conidiophores in the galleries of Ips cembrae on Larix decidua, 26 Aug 1997, collected and isolated: T. Kirisits, M.J. Wingfield and D.B. Redfern, (living cultures: CMW 5600 = IFFF Scotland/11); DAOM 229758, Austria, Styria, Glein, isolated from an adult Ips cembrae on Larix decidua, 25 Jun 1997, collected and isolated: T. Kirisits, (living cultures: CMW 5602 = IFFF IC/38); DAOM 229759, Austria, Styria, Glein, isolated from the sapwood of Larix decidua inoculated with Ips cembrae 6 wk earlier, 14 Aug 1997, collected and isolated: T. Kirisits, (living cultures: CMW 5603 = IFFF IC/GL/26/4); DAOM 229760, Austria, Tyrol, Ehrwald, isolated from conidiophores in the galleries of Ips cembrae on Larix decidua, Jul 1997, collected and isolated: T. Kirisits, (living cultures: CMW 5604 = IFFF Conidia/1).
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
, Mathiesen-Kaärik 1953, Solheim 1986, 1992, Wingfield et al 1993, Krokene and Solheim 1996, Viiri 1997), and the synnematous anamorphs of these fungi generally have been classified in Graphium (Upadhyay 1981, Seifert and Okada 1993). However, the taxonomy of Graphium long has been in disarray and it has taken a recent series of studies based on DNA sequence data to resolve this problem. In the first of these studies, Okada et al (1998) re-established Pesotum for synnematous anamorphs of Ophiostoma and reserved Graphium for fungi related to the Microascales (Crane and Schocknecht 1973, Okada et al 1998). The next necessary step was the typification of the type species of Graphium, G. penicillioides [epitype designated by Okada et al (2000)], and this study confirmed that Graphium is unrelated to species of Ophiostoma. The results of this study provide further evidence that two phylogenetically unrelated groups of fungi produce synnematous anamorphs, present in the galleries of bark beetles.
Taxonomic confusion relating to Graphium has resulted in considerable difficulty in providing names for synnematous fungi in the galleries of bark beetles (Mathiesen-Kaärik 1953, Wingfield and Gibbs 1991, Viiri 1997, Zhou et al 2001, Jacobs et al 2003). These fungi tend to be similar morphologically, and identifications based on micromorphology and/or colony characters are likely to continue to be difficult. However, Graphium and Pesotum now are clearly separated and a reasonably robust set of sequence data is available for most species of Graphium. This study represents an example of the use of these sequence data, together with morphology and ecological information, to characterise fungi of previously confused taxonomic status.
Graphium pseudormiticum, G. fimbriisporum and G. laricis appear to represent a species complex within Graphium, characterized by apparently unique conidium ontogeny and morphology (Mouton et al 1994, Morelet 1995). Graphium pseudormiticum, G. fimbriisporum and G. laricis not only are similar in their patterns of conidium development, but all three species have synnemata ranging in length from 100 to 260 µm, although those of G. laricis, on average, are slightly shorter. Graphium fimbriisporum can be distinguished from the other two species based on its slightly longer conidia. Colony color is also a useful character to distinguish among these species. Graphium pseudormiticum is characterized by olivaceous-green (K&W-3D7) colonies, and G. fimbriisporum has colonies that are almost dark brown (K&W-6D4). This is in contrast to the colonies of G. laricis, which have a very obvious reddish (K&W-7D7) color.
The three species of Graphium treated in this study occupy three discrete ecological niches. Graphium pseudormiticum initially has been isolated from galleries of O. erosus on Pinus spp. in South Africa (Mouton et al 1994), and we suspect it to be associated with a wide variety of pine bark beetles in Europe. Graphium fimbriisporum appears to be commonly associated with Ips typographus infesting spruce in Europe (Morelet 1995, Kirisits 1996, Kirisits et al 2000). In surveys in Austria it also has been isolated from various other bark beetle species on Norway spruce, including Pityogenes chalcographus L., Ips amitinus Eichh., Hylurgops glabratus Zett., Hylurgops palliatus Gyll. and Dryocoetus autographus Ratz. (Kirisits 1996, Kirisits et al 2000). In contrast, G. laricis is one of the dominant fungi found on I. cembrae and in its galleries on Larix decidua in Austria and Scotland (Kirisits et al 1998, 2000, Stauffer et al 2001).
When G. pseudormiticum first was described, it was assumed that the fungus was of European origin. This is because of its association with Orthotomicus erosus, which is well known and native to Europe, from where it accidentally was introduced to South Africa (Tribe 1990, 1992). Kirschner (1998) investigated the fungi associated with bark beetles in Germany and reported Graphium pseudormiticum as a common associate of various bark beetles on spruce (Crypturgus cinereus, Crypturgus pusillus, Dryocoetes autographus, Hylurgops palliatus, Polygraphus poligraphus, Trypodendron lineatum, Pityogenes chalcographus and Ips typographus) and pine (Ips sexdentatus and Orthotomicus laricis). He did not distinguish between isolates from spruce (= G. fimbriisporum) and those from pine (= G. pseudormiticum) as separate species and might not have been aware of the description of G. fimbriisporum by Morelet (1995). In a recent survey of ophiostomatoid fungi associated with bark beetles in South Africa, Zhou et al (2001) failed to detect G. pseudormiticum. They thus considered this species to be an infrequent or occasional associate of O. erosus. A possible explanation for this could relate to a lack of ability to compete in its non-native environment or the fact that it naturally occurs at a low frequency.
Detailed surveys of the fungi associated with Ips typographus and I. cembrae have been conducted in Japan (van der Westhuizen et al 1995, Yamaoka et al 1997, 1998, Jacobs et al 1998), where both insects are common on Yezo spruce (Picea jezoensis Carr.) and Japanese larch (Larix kaempferi [Lamb.] Carr.), respectively. Neither G. fimbriisporum nor G. laricis were found in these studies. Likewise, G. fimbriisporum and G. pseudormiticum have not been mentioned in most previous investigations of the mycobiota of bark beetles in Europe (e.g., Mathiesen-Käärik 1953, Solheim 1986, 1992, Krokene and Solheim 1996, Viiri 1997). We think that these fungi might have been overlooked in these surveys. After clarification of their taxonomic placement, further studies now are necessary to elucidate the biogeography and vectors of G. fimbriisporum, G. pseudormiticum and G. laricis.
While no observations are available for G. pseudormiticum, circumstantial evidence suggests that G. fimbriisporum and G. laricis are only very weak pathogens or saprophytes on their host species. They also are thought to display limited, if any, abilities to stain the sapwood of their hosts. In investigations in Austria, G. fimbriisporum and G. laricis commonly were isolated directly from Ips typographus and Ips cembrae, respectively, but less frequently were isolated from the sapwood of insect-infested spruce and larch (Kirisits 1996, Kirisits et al 2000, Kirisits, unpubl data). Isolation results indicate that G. fimbrisporum and G. laricis are secondary colonizers of the sapwood of infested trees, following primary invaders such as Ceratocystis polonica (Siemaszko) C. Moreau and Ceratocystis laricicola Redfern & Minter (Solheim 1992, Kirisits et al 2000, Kirisits, unpubl data). One isolate of G. laricis also was included in an inoculation experiment on European larch, in which it caused only small necrotic lesions in the phloem, no blue stain and only very little desiccation in the sapwood of test trees (Kirisits et al 2000, Kirisits, unpubl data).
Ips typographus and I. cembrae are well-known and important insect pests in Europe and Asia (Schmitschek 1931, Crooke and Bevan 1957, Nobuchi 1974, Postner 1974, Redfern et al 1987, Christiansen and Bakke 1988, Stauffer et al 2001) and both have high quarantine status in North America. Many studies have been conducted on fungi associated with the former species (Mathiesen-Kaärik 1953, Solheim 1986, 1992, Krokene and Solheim 1996, Kirisits 1996, Kirisits et al 2000, Jacobs et al 1998, Viiri 1997, Yamaoka et al 1997) but this is less so for the latter (van der Westhuizen et al 1995, Yamaoka et al 1998, Kirisits et al 1998, 2000, Stauffer et al 2001). One of the objectives of this study was to compare fungi associated with native and introduced I. cembrae in Austria and Scotland, respectively. The discovery of G. laricis as a common inhabitant in this niche in both locations perhaps is not surprising. It does, however, illustrate the fact that still relatively little is known about the fungi associated with important insect pests of conifers, many of which are greatly feared in terms of quarantine and international trade.
|
|
|
ACKNOWLEDGMENTS |
|---|
|
FOOTNOTES |
|---|
Accepted for publication October 25, 2002.
|
LITERATURE CITED |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
Crane JL, Schocknecht JD., 1973 Conidiogenesis in Ceratocystis ulmi, Ceratocystis piceae, and Graphium penicillioides. Am J Bot 60:346-354
Crooke M, Bevan D., 1957 Note on the first British occurrence of Ips cembrae Heer (Col. Scolytidae). Forestry 30:21-28
Furniss MM, Solheim H, Christiansen E., 1990 Transmission of blue-stain fungi by Ips typographus (Coleoptera: Scolytidae) in Norway spruce. Ann Entomol Soc Am 83:712-716
Gams W, Hoekstra ES, Aptroot A., 1998 CBS course of mycology. 4th ed. Baarn, Delft, Netherlands: Centraalbureau voor Schimmelcultures. p. 322
Jacobs K, Wingfield MJ, Wingfield BD, Yamaoka Y., 1998 Comparison of Ophiostoma huntii and O. europhioides and description of O. aenigmaticum. Mycol Res 102:289-294
———, Seifert KA, Harrison KJ, Kirisits T., 2003 Identity and phylogenetic relationships of ophiostomatoid fungi associated with invasive and native Tetropium spp. (Coleoptera: Cerambycidae) in Atlantic Canada. Can J Bot 81:316–329
Kfir R., 1986 Releases of natural enemies against the pine bark beetle Orthotomicus erosus (Wollaston) in South Africa. J Ent Soc S Afr 49:391-392
Kirisits T., 1996 Untersuchungen über die Vergesellschaftung von Bläuepilzen (Ceratocystis/Ophiostoma spp.) mit den rindenbrütenden Borkenkäfern Ips typographus L., Pityogenes chalcographus L. and Hylurgops glabratus Zett. in Österreich. [Studies on the association of blue-stain fungi (Ceratocystis/Ophiostoma spp.) with the phloem-feeding bark beetles Ips typographus L., Pityogenes chalcographus L. and Hylurgops glabratus Zett. in Austria] [Diploma Thesis]. Vienna, Austria: Universität für Bodenkultur, Institute of Forest Entomology, Forest Pathology and Forest Protection. 175 p
———, Wingfield MJ, Redfern DB., 1998 Ophiostomatoid fungi associated with the larch bark beetle Ips cembrae in Central Europe and in Scotland. Poster presentation at the 7th International Congress of Plant Pathology, Edinburgh, Scotland, U.K., 9–16 August 1998. Proceedings, Volume 3, Abstract No. 3.7.35
———, Grubelnik R, Führer E., 2000 Die ökologische Bedeutung von Bläuepilzen für rindenbrütige Borkenkäfer. [The ecological role of blue-stain fungi for phloem-feeding bark beetles]. In: F. Müller, ed. Mariabrunner Waldbautage 1999—Umbau sekundärer Nadelwälder. FBVA-Berichte, Schriftenreihe der Forstlichen Bundesversuchsanstalt Wien. 111 p. 117–137
Kirschner R., 1998 Diversität mit Borkenkäfern assoziierter filamentöser Mikropilze [Dissertation]. Tübingen, Germany: Eberhard-Karls-Universität. 573 p
Kornerup A, Wanscher JH., 1978 Methuen handbook of color. London: Eyre Methuen
Krokene P, Solheim H., 1996 Fungal associates of five bark beetle species colonizing Norway spruce. Can J For Res 26:2115-2122
Mathiesen A., 1951 Einige neue Ophiostoma-Arten in Schweden. Sv Bot Tidskr 45:203-232
Mathiesen-Käärik A., 1953 Eine Übersicht über die gewöhnlichsten mit Borkenkäfern assoziierten Bläuepilze in Schweden und einige für Schweden neue Bläuepilze. Meddn St Skogforsk Inst 43:1-74
Minter DW, Kirk PM, Sutton BC., 1982 Holoblastic phialides. Trans Br Mycol Soc 79:75-93
———, ———, ———. 1983 Thallic phialides. Trans Br Mycol Soc 80:39-66
Morelet M., 1995 Notes de Mycologie Appliquée. Ann Soc Sci Nat Aschéol. Toulon Var 47:89-94
Mouton M, Wingfield MJ, van Wyk PW, van Wyk PWJ., 1994 Graphium pseudormiticum sp. nov.: a new hyphomycete with unusual conidiogenesis. Mycol Res 98:1272-1276
Okada G, Seifert KA, Takematsu A, Yamaoka Y, Miyazaki S, Tubaki K., 1998 A molecular phylogenetic reappraisal of the Graphium complex based on 18S rDNA sequences. Can J Bot 76:1495-1506
———, Jacobs K, Kirisits T, Louis-Seize GW, Seifert KA, Sugita T, Takematsu A, Wingfield MJ, 2000 Epitypification of Graphium penicillioides Corda, with comments on the phylogeny and taxonomy of Graphium-like synnematous fungi. Stud Mycol 45:169-188
Nobuchi A., 1974 Studies on Scolytidae XII: the bark beetles of the tribe Ipini in Japan (Coleoptera). Bull Gov For Exp Sta (Japan) 266, 33–66 + 4 plates
Postner M., 1974 Scolytidae (Ipidae), Borkenkäfer. In: W. Schwencke. ed. Die Forstschädlinge Europas. Vol. 2. Hamburg, Berlin, Germany: Paul Parey Verlag. p 334–482
Redfern DB, Stoakley JT, Steele H, Minter DW., 1987 Dieback and death of larch caused by Ceratocystis laricicola sp. nov. following attack by Ips cembrae. Plant Pathology 36:467-480
Schimitschek E., 1931 Der achtzähnige Lärchenborkenkäfer Ips cembrae Heer—Zur Kenntnis seiner Biologie und Ökologie sowie seines Lebensvereins. Z Angew Ent 17:253-344
Seifert KA, Okada G., 1993 Graphium anamorphs of Ophiostoma species and similar anamorphs of other ascomycetes. In: Wingfield MJ, Seifert KA, and Webber JF, eds. Ceratocystis and Ophiostoma: taxonomy, ecology and pathogenicity. St. Paul, Minnesota, U.S.A.: APS Press. p 27–41
Solheim H., 1986 Species of Ophiostomataceae isolated from Picea abies infested by the bark beetle Ips typographus. Nord J Bot 6:199-207
———. 1992 Fungal succession in sapwood of Norway spruce infested by the bark beetle Ips typographus. Eur J For Path 22:136-148
Stauffer C, Kirisits T, Nussbaumer C, Pavlin R, Wingfield MJ., 2001 Phylogenetic relationships between the European and Asian eight-spined larch bark beetle populations (Coleoptera: Scolytidae) inferred from DNA sequences and fungal associates. Eur J Ent 98:99-105
Swofford DL., 1999 PAUP* (version 4.0) phylogenetic analysis using parsimony (*and other methods). Sunderland, Massachusetts, U.S.A.: Sinauer Associates
Tribe GD., 1990 Phenology of Pinus radiata log colonization and reproduction by the European bark beetle Orthotomicus erosus (Wollaston) (Coleoptera: Scolytidae) in the south-western Cape Province. J Ent Soc S Afr 53:117-126
———. 1992 Colonization sites on Pinus radiata logs of the bark beetles, Orthotomicus erosus, Hylastes angustatus and Hylurgus ligniperda (Coleoptera: Scolytidae). J Ent Soc S Afr 55:77-84
Upadhyay HP., 1981 A monograph of Ceratocystis and Ceratocystiopsis. Athens, Georgia, U.S.A.: University of Georgia Press. p. 176
Viiri H., 1997 Fungal associates of the spruce bark beetle Ips typographus L. (Col. Scolytidae) in relation to different trapping methods. J App Ent 121:529-533
van der Westhuizen K, Wingfield MJ, Yamaoka Y, Kemp GHJ, Crous PW., 1995 A new species of Ophiostoma with a Leptographium anamorph from larch in Japan. Mycol Res 99:1334-1338
White TJ, Bruns T, Lee S, Taylor J., 1990 Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis AM, Gelfand DH, Sninsky JJ, White TJ, eds. PCR protocols: a guide to methods and applications. San Diego: Academic Press. p 315–322
Whitney HS., 1982 Relationships between bark beetles and symbiotic organisms. In: Mitton JB, Sturgeon KB, eds. Bark beetles in North American conifers. Texas, U.S.A.: University of Texas Press. p 183–211
Wingfield MJ, Gibbs JN., 1991 Leptographium and Graphium species associated with pine-infesting bark beetles in England. Mycol Res 95:1257-1260
———, Seifert KA, Webber JF., 1993 Ceratocystis and Ophiostoma: taxonomy, ecology and pathogenicity. St. Paul, Minnesota, U.S.A.: APS Press. 293 p
Yamaoka Y, Wingfield MJ, Takahashi I, Solheim H., 1997 Ophiostomatoid fungi associated with the spruce bark beetle Ips typographus japonicus in Japan. Mycol Res 101:1215-1227
———, ———, Oshawa M, Kuroda Y., 1998 Ophiostomatoid fungi associated with Ips cembrae in Japan and their pathogenicity to Japanese larch. Mycoscience 39:367-378
Zhou XD, de Beer ZW, Wingfield BD, Wingfield MJ., 2001 Ophiostomatoid fungi associated with three pine-infesting bark beetles in South Africa. Sydowia 53:290-300
This article has been cited by other articles:
 |
|
 |
|
  P. W. Crous, I. H. Rong, A. Wood, S. Lee, H. Glen, W. Botha, B. Slippers, W. Z. de Beer, M. J. Wingfield, and D. L. Hawksworth How many species of fungi are there at the tip of Africa? Stud Mycol, January 1, 2006; 55: 13 - 33. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
