| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Department of Plant Pathology, University of Stellenbosch, P. Bag X1, Matieland 7602, South Africa
Pedro W. Crous 1
Centraalbureau voor Schimmelcultures, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
J. Z. (Ewald) Groenewald
Department of Plant Pathology, University of Stellenbosch, P. Bag X1, Matieland 7602, South Africa
Walter Gams
Richard C. Summerbell
Centraalbureau voor Schimmelcultures, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
Petri disease, or black goo, is a serious disease of vines in most areas where grapevines are cultivated. The predominant associated fungus is Phaeomoniella chlamydospora (Chaetothyriales). Several species of Phaeoacremonium (Pm.) also are associated, of which Pm. aleophilum is the most common. Although no teleomorph is known for Phaeoacremonium, the genus Togninia previously has been linked to phaeoacremonium-like anamorphs. To investigate the possible anamorph-teleomorph connection of Phaeoacremonium to Togninia, anamorphs of Togninia minima, T. fraxinopennsylvanica and T. novae-zealandiae morphologically were compared with Pm. aleophilum and some representative cultures were mated in all combinations. Although no interspecies mating proved fertile, matings between isolates of Pm. aleophilum produced a Togninia teleomorph within 3–4 weeks. Certain field isolates of Pm. aleophilum commonly produced the teleomorph, demonstrating that both mating types can occur in the same vine and thus also explaining the genetic diversity observed for this fungus in some vineyards. To elucidate the phylogenetic relationships among these taxa, isolates were subjected to sequence analysis of the nuclear ribosomal internal transcribed spacers (ITS1, ITS2) and the 5.8S rRNA gene, as well as portions of the translation elongation factor 1 alpha (EF-1
) gene. The generic placement of teleomorphs within Togninia (Calosphaeriales) further was confirmed via phylogenetic analyses of 18S small subunit (SSU) DNA. From these sequences, morphological and mating data, we conclude that T. minima is the teleomorph of Pm. aleophilum, and that it has a biallelic heterothallic mating system. An epitype and mating type tester strains also are designated for T. minima.
Key words: Calosphaeriales, EF-1, ITS, 18S SSU DNA, sexual compatibility, systematics
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
). Affected grapevines exhibit a slow dieback as well as stunted growth. The predominant associated fungus is Phaeomoniella chlamydospora W. Gams, Crous, M.J. Wingf. & L. Mugnai (Chaetothyriales, Herpotrichiellaceae). Whether this fungus is the sole or only a contributing causal agent of the disease is uncertain. Several species of Phaeoacremonium (Pm.) (Diaporthales, Magnaporthaceae) also commonly grow from vines affected by Petri disease, including Pm. aleophilum W. Gams, Crous, M.J. Wingf. & L. Mugnai, Pm. angustius W. Gams, Crous & M.J. Wingf., Pm. inflatipes W. Gams, Crous & M.J. Wingf., Pm. mortoniae Crous & W. Gams, Pm. parasiticum (Ajello, Georg & C.J.K. Wang) W. Gams, Crous & M.J. Wingf., Pm. rubrigenum W. Gams, Crous & M.J. Wingf., and Pm. viticola Dupont. Of the Phaeoacremonium species associated with Petri disease, Pm. aleophilum consistently has been the most frequently isolated (Scheck et al 1998, Ari 2000, Gatica et al 2001). In various studies, Pm. aleophilum has been found to be associated with brown-streaking symptoms in Petri-diseased grapevines (Mugnai et al 1999, Ari 2000) and sectorial brown necrosis (Gatica et al 2001).
The genetic variation within populations of Phaeomoniella chlamydospora and Pm. aleophilum has been studied by various workers (Péros et al 2000, Tegli et al 2000a, b). Using RAPDs (Random Amplified Polymorphic DNA) and RAMS (Random Amplified Micro- or Mini-Satellites), Tegli et al (2000b) showed that considerable variation existed among isolates of Pm. aleophilum collected from the same field, suggesting that sexual reproduction might occur (Tegli 2000). Considerable genetic variation suggestive of ongoing recombination also was found in Universally Primed-PCR studies done with Pm. aleophilum isolates from Australia (Cottral et al 2001). Rooney et al (2002) subsequently reported inducing teleomorphs for Pm. inflatipes and Pm. aleophilum under laboratory conditions.
In a study of the genus Togninia Berl. (Calosphaeriales), Hausner et al (1992) treated Togninia minima (Tul. & C. Tul.) Berl. (lectotype of Togninia) and at the same time they described two new species, T. fraxinopennsylvanica (Hinds) Hausner, Eyjólfsdóttir & J. Reid and T. novae-zealandiae Hausner, Eyjólfsdóttir & J. Reid. Although no cultures of T. minima were available, the two newly described species were cultured and were shown to produce anamorphs that were intermediate between Acremonium Link : Fr. and Phialophora Medlar. Several anamorph genera in recent years have been described with this approximate appearance (Gams 2000). Of these, the genus Phaeoacremonium W. Gams et al closely fits the description of the Togninia anamorphs illustrated by Hausner et al (1992).
The first aim of the current study was to investigate the possible link between Phaeoacremonium and Togninia. Phaeoacremonium aleophilum, a species similar in appearance to the anamorphs illustrated by Hausner et al (1992), was chosen for morphological comparison with the anamorphs of T. minima, T. fraxinopennsylvanica and T. novae-zealandiae. A further aim was to determine if the formation of a teleomorph could be elicited in Pm. aleophilum. This was done by mating a selection of vine isolates in culture. A final aim was to elucidate the genetic diversity within and among these species and to clarify the higher-order phylogenetic placement of Togninia. To address this, a phylogenetic analysis was conducted using sequences of the nuclear ribosomal DNA region encompassing the internal transcribed spacers (ITS1, 5.8S and ITS2), as well as translation elongation factor 1 alpha (EF-1), and 18S ribosomal small subunit (SSU).
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
|
. Cultures are maintained in the collection of the Department of Plant Pathology at the University of Stellenbosch, and representative strains have been deposited at the Centraalbureau voor Schimmelcultures (CBS, Utrecht, the Netherlands). Reference strains of T. fraxinopennsylvanica (CBS 110212, ex-type), T. novae-zealandiae (UAMH 9589, UAMH 9590, ex-type) and T. minima (CBS 213.31, ex-type of Longoa paniculata Curzi) also were studied. Matings – Twenty-one Pm. aleophilum isolates were grown on MEA plates for 2 wk, using 10 plates per isolate. Conidia were dislodged from the agar surface by means of a glass rod, and suspensions were prepared in 5 mL sterile distilled water. Two aliquots of 100 µL each, representing two different isolates, were pipetted onto the canes of GWA plates. Isolates were mated in all possible combinations. Controls consisted of a 200 µL aliquot of one isolate only. Plates were incubated at 22 C under continuous white light. Successful crosses were noted 3–4 wk after mating. For a mating to be considered successful, perithecia had to produce large quantities of ascospores that germinated readily in culture. One such mating was chosen (LM 54 x LM 463), and 20 single ascospore isolates obtained (LM 227–LM 240, LM 243–LM 247, LM 249). Further crosses were made with these ascospore isolates using the procedure described above. Two strains found to be of opposite mating type arbitrarily were designated as MAT1-1 (LM 463) and MAT1-2 (LM 54). Inter-species matings were done to investigate the biological species boundaries of Pm. aleophilum, T. minima, T. novae-zealandiae and T. fraxinopennsylvanica.
DNA isolation and amplification –
Twenty-seven Pm. aleophilum isolates were selected for sequence comparisons (Table I). Sequences of the ITS, EF-1 and SSU of T. fraxinopennsylvanica (CBS 110212), T. novae-zealandiae (UAMH 9589 and UAMH 9590), T. minima (CBS 213.31) and an unknown Phaeoacremonium sp. (STE-U 3394) also were included. Genomic DNA was extracted using the isolation protocol of Lee and Taylor (1990). In studies intended to determine the degree of genetic diversity within Pm. aleophilum, the 5.8S nuclear ribosomal RNA gene and the flanking internal transcribed spacers (ITS1 and ITS2) were amplified with primers ITS1 and ITS4 (White et al 1990) and translation elongation factor 1 alpha (EF-1) was amplified with primers EF1-728F and EF1-986R (Carbone and Kohn 1999). These PCR amplification cycles run on a GeneAmp PCR System 2700 (Perkin-Elmer, Norwalk, Connecticut) were for both regions: 96 C for 5 min, followed by 36 cycles of (1) denaturation (94 C for 30 s), (2) annealing (50 C for 30 s) and (3) elongation (72 C for 90 s), and a final 7 min extension step at 72 C.
In studies intended to determine the higher order phylogeny of Togninia, primers NS1 and NS4 (White et al 1990) were used to amplify the 5' end of the 18S ribosomal DNA (SSU) gene for a subset of four isolates representing the different Togninia species and Pm. aleophilum. The cycling conditions consisted of an initial denaturation step of 94 C for 7 min, followed by 36 cycles of (1) denaturation (95 C for 45 s), (2) annealing (55 C for 60 s) and (3) elongation (72 C for 120 s), and finally a 2 min extension step at 72 C.
PCR products were analyzed by electrophoresis at 85 V for 30 min in a 0.8% (w/v) agarose gel in 0.5 x TAE buffer (0.4 M Tris, 0.05 M NaAc, and 0.01 M ethylene diamine tetraacetic acid [EDTA], pH 7.85) and visualized under UV light with a GeneGenius Gel Documentation and Analysis System (Syngene, Cambridge, United Kingdom) following ethidium bromide staining.
PCR products were purified according to the manufacturer's instructions using a commercial kit (Nucleospin Extract 2 in 1 Purification Kit, Machery-Nagel GmbH & Co., Germany). Sequencing reactions were carried out with ABI PRISM Big Dye Terminator version 3.0 Cycle Sequencing Ready Reaction Kit (PE Biosystems, Foster City, California), according to the manufacturer's recommendations, and were analyzed on an ABI Prism 3100 DNA Sequencer (Perkin-Elmer, Norwalk, Connecticut). Sequences were deposited at GenBank (Table I), and the alignment was deposited in TreeBase (ITS and EF-1: SN1269–3614; SSU: SN1269–3617).
Phylogenetic analysis –
Raw sequence data were analyzed using EditView 1.0.1 (http://www.appliedbiosystems.com), and sequences were manually aligned by inserting gaps. Phylogenetic analyses were conducted using PAUP (Phylogenetic Analysis Using Parsimony) version 4.0b10 (Swofford 2000). Gaps were treated as a fifth character, and all characters were unordered and of equal weight. Phialophora richardsiae (Nannf.) Conant (CBS 270.33, GenBank ITS = AY179948, EF-1 = AY179914) and Cercospora apii Fresen. (CBS 119.25, GenBank ITS = AY179949, EF-1 = AY179915) were used as outgroups for both the EF-1 and ITS analyses. Six Pm. aleophilum isolates (LM 44, LM 52, LM 75, LM 83, LM 113, and LM 115) were excluded from the combined analyses. Their respective EF and ITS sequences were 100% similar to the sequences of LM 24, LM 441, LM 466, LM 443, LM 440, LM 463, LM 460, LM 34 and LM 5. Maximum-parsimony analysis was performed using the heuristic search option with a 1000 random-taxon additions and tree bisection and reconstruction (TBR) as the branch-swapping algorithm. Bootstrap support for the ITS and EF-1 analysis for internal branches was evaluated from 1000 heuristic search replicates and 1000 random taxon additions. Tree length, consistency index (CI), retention index (RI) and the rescaled consistency index (RC) values also were calculated. A partition homogeneity test in PAUP (Swofford 2000) was conducted to test the congruence between the ITS and EF-1 sequence datasets. Small subunit sequences were added to an alignment obtained from TreeBase (M911). Sequences representative of the different orders within the class Sordariomycetes, as well as the order Chaetothyriales (Chaetothyriomycetes), were retrieved from GenBank and added to the alignment. Neighbor-joining analyses of the SSU alignment (using uncorrected "p", Kimura-2-parameter and Jukes-Cantor substitution models) were done with PAUP version 4.0b10 (Swofford 2000). Rhodosporidium toruloides Banno and Athelia bombacina Pers. were used as outgroups for the neighbor-joining analysis.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
, is provided below: Togninia minima (Tul. & C. Tul.) Berl., Icon. Fung. 3: 11. 1900. Figs. 1–24
|
Calosphaeria minima Tul. & C. Tul., Sel. Fung. Carpol. 2: 112, plate XIII:23–24. 1863.
Calosphaeria (Erostella) minima (Tul. & C. Tul.) Sacc., Syll. Fung. 1: 101. 1882.
Erostella minima (Tul. & C. Tul.) Traverso, Fl. Ital. Crypt. 1: 156. (1905) 1906.
Togninia alnicola (Ellis & Everh.) Berl., Icon. Fung. 3: 10. 1900.
Anamorph. Phaeoacremonium aleophilum W. Gams, Crous, M.J. Wingf. & Mugnai, Mycologia 88: 791. 1996.
Mycelium consisting of branched, septate hyphae; hyphae occurring singly or in strands of up to 10, tuberculate (with warts to 1 µm) to verruculose, pale brown, becoming paler toward the conidiogenous region, 1.5–3 µm wide. Chlamydospores absent. Perithecia heterothallic, mostly aggregated, not valsoid, sometimes solitary, mostly subepidermal also on the surface of the epidermis; perithecia subglobose, sometimes obpyriform, with a long cylindrical neck, (160–)250–285(–420) µm diam and basal part (200–)285–325(–400) µm tall. Wall consisting of two regions of textura angularis: outer region dark brown, cells smaller and more rounded than inner layer, approx. 8–10 cells thick (individual cells not visible further outward), 20–40 µm thick; inner region hyaline (centrum) to pale brown, 5–7 cells and 12–28 µm thick; surface covered with brown, septate hyphal appendages that become hyaline towards their tips (more abundant on older perithecia). Perithecial necks black, 1–3(–6) per perithecium, curved, verrucose, with apex often proliferating secondarily upon aging and then appearing nodulose; nodules (–120 µm wide) also appearing lower down on the neck; necks 800–1800 (av. 1055) µm long, 35–130 (av. 69) µm wide at the base, and 20–60 (av. 41) µm wide at the apex, neck sometimes dividing into two near the apex. Multinecked perithecia often with a thin wall dividing the perithecial chamber. Paraphyses hyaline, septate, cylindrical, narrowing towards the tip, 45–125 (av. 83) µm long, 2–4 µm wide at the base and 1.5–2 µm at the apex, persistent. Asci arising in acropetal succession from sympodially proliferating ascogenous hyphae that appear spicate when mature, hyaline, clavate, with bluntly rounded apices and with sides straight or tapering towards the truncate or bluntly obtuse bases (17–)19–20(–27) x 4–5 µm; apical complex 0.5–1 µm thick, of indistinct structure, with a nonamyloid apical ring (negative in Melzer's reagent). Ascogenous hyphae hyaline, branched, smooth-walled, 2–3 µm wide (inflated bases -5 µm wide). Ascospores 1-celled, hyaline, oblong-ellipsoidal to allantoid with rounded ends, sometimes containing small guttules at the ends, (4–)4.5–5(–6.5) x 1–2 µm (av. 5 x 1.5 µm).
Conidiophores mostly micronematous, arising from aerial or submerged hyphae, erect, simple, frequently reduced to conidiogenous cells, rarely 1–2-septate, subcylindrical, pale brown, paler towards the tip, smooth to verruculose, straight to gently curved, 4–40 µm tall, 2–3 µm wide. Conidiogenous cells terminal or lateral, mostly monophialidic, subcylindrical to narrowly ellipsoidal, smooth to verruculose, subhyaline, 3–21 µm long, 1–2.5 µm wide at the base, 1–1.5 µm wide at the apex, with a terminal, inconspicuous, almost convergent, 0.5–1 µm long, 1 µm wide collarette. Conidia aggregating in slimy heads, hyaline, oblong-ellipsoidal to allantoid, when larger oblong to reniform, becoming 2-guttulate with age, (2.5–)3–4.5(–7) x 1.5–2.5(–3) µm (av. 4 x 2 µm).
Substrates and geographical distribution.
In vascular bundles of vines and twigs of woody plants: Vitis vinifera (Argentina, Australia, Chile, France, Italy, New Zealand, South Africa, Spain, Turkey, U.S.A. and Yugoslavia), Actinidia sinensis (Italy), bark of a tropical rain forest tree (Papua New Guinea), Olea europaea (Italy) (Crous et al 1996, Larignon et al 1997, Ari 2000, Crous and Gams 2000, Armengol et al 2001, Groenewald et al 2001).
Cultural characteristics.
See Crous et al (1996).
Type specimens.
YUGOSLAVIA. On roots and stems of Vitis vinifera, 1990, M. Muntañola-Cvetkovi
(CBS 246.91 dried specimen and ex-type culture of Pm. aleophilum). SOUTH AFRICA. WESTERN CAPE PROVINCE: Wellington and Paarl, respectively, stems of Vitis vinifera, 2001, L. Mostert, LM 463 (MAT1-1 = CBS 111015) x LM 54 (MAT1-2 = CBS 110703), [epitype of T. minima, designated here] dried specimen, herb. CBS 6580.
Notes. No information previously has been available regarding the anamorph of T. minima. The only culture currently available that previously has been identified as T. minima is CBS 213.31. It differs from freshly isolated strains of Pm. aleophilum in several morphological characters. Phaeoacremonium aleophilum isolates in general have buff (19''d) to honey (21''b) colonies, while colonies of CBS 213.31 are white to buff (19''d) with woolly mycelial tufts. The difference might be due to cultural degeneration. Conidiogenous cells (1.5 µm at the base) and conidia (1 µm wide) of CBS 213.31 were slightly narrower than those of Pm. aleophilum (2.5 and 2 µm, respectively).
Phaeoacremonium aleophilum differs from anamorphs of T. fraxinopennsylvanica and T. novae-zealandiae. Conidia of T. fraxinopennsylvanica and T. novae-zealandiae were up to 9 and 10.5 µm long, respectively, significantly longer than those of Pm. aleophilum, which did not exceed 7 µm. Also, the collarettes of T. fraxinopennsylvanica and T. novae-zealandiae (1.0–1.8 µm) were longer than those of Pm. aleophilum (0.5–1 µm).
Matings –
Perithecia produced by crossing Pm. aleophilum isolates were contrasted with those described for T. minima, T. fraxinopennsylvanica and T. novae-zealandiae (Table II). No interspecies mating was observed, nor were any matings obtained with CBS 213.31. The teleomorph of Pm. aleophilum was identical, however, to that described by Hausner et al (1992) for T. minima. Furthermore, ascospores of T. minima are longer and perithecia are wider and have longer necks than those of T. fraxinopennsylvanica and T. novae-zealandiae (Table II).
|
|
|
) had a total length of 863 characters, of which 301 were constant, 329 were parsimony uninformative and 233 were parsimony informative. The result of the partition homogeneity test showed that the ITS and EF-1 datasets were congruent (P = 0.72) and therefore could be combined. Parsimony analysis of the combined datasets, using a heuristic search with 1000 random taxa additions, resulted in 10 most-parsimonious trees (Tree length = 901 steps, CI = 0.937, RI = 0.903, RC = 0.846 and HI = 0.063). Togninia minima (CBS 213.31) grouped in the clade with all Pm. aleophilum sequences, as well as the ex-type strain of Pm. aleophilum. The analysis clearly delimits the three Togninia species with good bootstrap support (Fig. 27). Some variation was observed within the Pm. aleophilum clade, as two isolates (CBS 100400, 101357) formed a subclade with 100% bootstrap support within the Pm. aleophilum clade. These two isolates differed from the rest of the Pm. aleophilum isolates at 11 (for EF-1) and two (for ITS) nucleotide positions. Another group within the Pm. aleophilum clade also received significant support (87%). These sequences, however, differed from the other isolates in the Pm. aleophilum clade at only two nucleotide positions in the EF-1 dataset. A total of 21 characters proved variable in the combined dataset (2.4%). The EF-1 area was found to be more variable (15 nucleotides, 4.6%) than the ITS area (6 nucleotides, 1.1%).
|
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
). This viewpoint has been followed by Hausner et al (1992), as explained in Holm (1992), and also is accepted by Barr (M. E. Barr pers comm, 20 Feb 2002), contrasting with her earlier view (Barr et al 1993) that Togninia was a synonym of Pleurostoma Tul. & C. Tul. A more complicated issue addressed by Hausner et al (1992) was whether the genus name Togninia had precedence over Erostella. Erostella first was described as subgenus of Calosphaeria Tul. & C. Tul., and subsequently was elevated to generic level as Erostella (Sacc.) Trav. (1905) and again as Erostella (Sacc.) Sacc. (1906). Both Erostella and Togninia have Calosphaeria minima Tul. & C. Tul. as lectotype. The key to resolving this mystery lies in the precise interpretation of the Latin description of Togninia provided by Berlese (1900), who placed 12 species and one variety in this genus. The decision of Clements and Shear (1931) to designate T. minima as lectotype of Togninia is not obviously supported by Berlese's text. Berlese (1900, p. 20), stated "C.[alosphaeria] herbicola E.[llis] et E.[verhart] id. C. ambigua Berl.[ese] est novi generis Togninia typus." Two interpretations of this text are possible. The first is that Berlese actually typified Togninia by T. ambigua Berl.; in this case the lectotypification of Clements and Shear (1931) should be rejected and Erostella can be resurrected for the taxa treated by Hausner et al (1992), with Calosphaeria minima as lectotype. The second interpretation, which was explained by Holm (1992) and subsequently followed by Hausner et al (1992), is that Berlese did not consider C. herbicola to be synonymous with C. ambigua. Under the genus Togninia, Berlese (1900, p. 9) listed only T. ambigua, while he transferred C. herbicola to Jattaea on p 8 but C. minima to Togninia on p 11. The Latin "id.", "idem", means "the same as", but it also has been translated as "ditto", which is more appropriate here, as Berlese (1900) clearly did not treat C. herbicola as synonymous with C. ambigua but actually placed them in different genera. The species in this Calosphaeria complex are thus "novi generis Togninia typus", meaning that they are of the Togninia-type (Holm 1992), and consequently the lectotypification of Togninia with T. minima, as proposed by Clements and Shear (1931), can be accepted.
Because no authentic material of T. minima exists, Hausner et al (1992) designated the original illustration (Tulasne and Tulasne 1863) as iconotype. Togninia thus is conceived as a genus that has solitary to clustered, globose perithecia with papillate to beak-like apices that can be smooth or ornamented. Asci are unitunicate with truncate bases and thickened apices, appearing in a spicate arrangement on ascogenous hyphae. Paraphyses are present, hyaline, septate, and ascospores are hyaline, aseptate, allantoid to ellipsoidal. Anamorphs are acremonium- to phialophora-like (Hausner et al 1992). Hausner et al (1992) based their redescription of T. minima in part on two specimens, one collected from Alnus in the United States (N.A.F. 2514) and another from Prunus pennsylvanica collected in Canada (SSMF 725–7179). No cultures, however, were available for study. Clements and Shear (1931) treated Longoa Curzi as synonym of Calosphaeria, a genus that is heterogeneous (M. E. Barr pers comm). In her revision of the Calosphaeriales, Barr (1985) did not treat Longoa, but based on its morphology Eriksson and Hawksworth (1986) considered the type species, Longoa paniculata (CBS 213.31, ex-type), to be a synonym of T. minima. This synonymy is supported by the original description and molecular data obtained in this study.
A comparison of our fungus with the original descriptions of Togninia provided by Tulasne and Tulasne (1863) and Berlese (1900), as well as with the redescription of Hausner et al (1992), shows that our fungus clearly belongs in Togninia. Furthermore, its generic relationship with T. fraxinopennsylvanica and T. novae-zealandiae is confirmed via the tight cluster seen in 18S SSU sequence data (Fig. 28).
Before any teleomorph was known for Phaeoacremonium, the genus was considered to have affinities for the Magnaporthaceae (Dupont et al 1998). Members of this family generally are characterized by having long, hairy necks and septate ascospores (Kirk et al 2001). The family is considered to be close to the Diaporthales (Winka and Eriksson 2000). The Togninia teleomorphs of Phaeoacremonium differ strongly from those of other Magnaporthaceous fungi. In addition, our 18S rDNA sequence analysis shows that the Togninia and Phaeoacremonium species investigated here form a distinct clade apart from the Diaporthales (Fig. 28), supporting their placement in the order Calosphaeriales for reasons outlined by Barr (1985). Phylogenetic analyses of DNA sequence data have shown that T. minima forms a separate cluster with T. fraxinopennsylvanica and T. novae-zealandiae, as well as other species presently known in Phaeoacremonium (Groenewald et al 2001). Togninia teleomorphs also have been induced for several other Phaeoacremonium spp., which await further description once their mating strategies have been resolved.
Results from mating studies clearly have shown that T. minima has a biallelic heterothallic mating system. Such systems in fungi have been reviewed by Glass and Nelson (1994). Field isolates obtained from individual diseased vines could be induced to form the teleomorph in vitro on cane sections, indicating that compatible mating types co-occur in nature on the same vine. The conditions necessary for perithecial formation in the field remain unknown. The extent to which teleomorphs occur in the field also is unknown. The discovery of the teleomorph is important for the design and deployment of disease-control strategies, as well as for the overall understanding of the epidemiology of Petri disease.
|
|
|
|
ACKNOWLEDGMENTS |
|---|
|
FOOTNOTES |
|---|
Accepted for publication December 3, 2002.
|
LITERATURE CITED |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
|---|
Armengol J, Vicent A, Torné L, García-Figueres F, García-Jeménez J., 2001 Fungi associated with esca and grapevine declines in Spain: a three-year survey. Phytopathol Mediterr 40:S325-S329
Barr ME., 1985 Notes on the Calosphaeriales. Mycologia 77:549-565
———, Rogers JD, Ju JM., 1993 Revisionary studies in the Calosphaeriales. Mycotaxon 68:529-535
Berlese AN., 1900 Icones fungorum omnium hucusque cognitorum. Patavia 3:9–21
Carbone I, Kohn LM., 1999 A method for designing primer sets for speciation studies in filamentous ascomycetes. Mycologia 91:553-556
Clements FE, Shear CL., 1931 The genera of fungi. New York: H.W. Wilson Co. 58 plates, p 496
Cottral E, Ridgeway H, Pascoe I, Edwards J, Taylor P., 2001 UP-PCR analysis of Australian isolates of Phaeomoniella chlamydospora and Phaeoacremonium aleophilum. Phytopathol Mediterr 40:S479-S486
Crous PW, Gams W., 2000 Phaeomoniella chlamydospora gen. et comb. nov., a causal organism of Petri grapevine decline and esca. Phytopathol Mediterr 39:112-118
———, ———, Wingfield MJ, van Wyk PS., 1996 Phaeoacremonium gen. nov. associated with wilt and decline diseases of woody hosts and human infections. Mycologia 88:786-796
Dupont J, Laloui J, Roquebert MF., 1998 Partial ribosomal DNA sequences show an important divergence between Phaeoacremonium species isolated from Vitis vinifera. Mycol Res 102:631-637
Eriksson O, Hawksworth DL., 1986 Notes on Ascomycete Systematics. Syst Ascom 5:113-174
Gams W., 2000 Phialophora and some similar morphologically little-differentiated anamorphs of divergent ascomycetes. In: Seifert K, Gams W, Crous PW, Samuels GJ, eds. Molecules, morphology and classification: towards monophyletic genera in the Ascomycetes. Stud Mycol 45:187–199
Gatica M, Césari C, Magnin S, Dupont J., 2001 Phaeoacremonium species and Phaeomoniella chlamydospora in vines showing "hoja de malvón" and young vine decline symptoms in Argentina. Phytopathol Mediterr 40:S317-S324
Glass NL, Nelson MA., 1994 Mating-type genes in mycelial Ascomycetes. In: Wessels JGH, Meinhardt F, eds. The mycota I: growth, differentiation and sexuality. Berlin, Germany: Springer-Verlag. p 295–306
Groenewald M, Kang JC, Crous PW, Gams W., 2001 ITS and ß-tubulin phylogeny of Phaeoacremonium and Phaeomoniella spp. Mycol Res 105:651-657
Hausner G, Eyjoflsdottir GG, Reid J, Klassen GR., 1992 Two additional species of the genus Togninia. Can J Bot 70:724-734
Holm L., 1992 On the typification of pyrenomycete generic names. Syst Ascom 2:29-30
Kirk PM, Cannon PF, David JC, Stalpers JA., 2001 Ainsworth and Bisby's dictionary of the fungi. 9th ed. Oxon, U.K.: CABI Publishing, CAB International. 655 p
Larignon P, Dubos B., 1997 Fungi associated with esca disease in grapevine. Eur J Pl Pathol 103:147-157
Lee SB, Taylor JW., 1990 Isolation of DNA from fungal mycelia and single spores. In: Innis MA, Gelfand DH, Sninsky JJ, White TJ, eds. PCR protocols: a guide to methods and applications. New York: Academic Press. p 282–287
Mugnai L, Graniti A, Surico G., 1999 Esca (black measles) and brown wood-streaking: two old and elusive diseases of grapevines. Pl Dis 83:404-416
Péros JP, Jamaux-Despréaux I, Berger G., 2000 Population genetics of fungi associated with esca disease in French vineyards. Phytopathol Mediterr 39:150-155
Rayner RW., 1970 A mycological colour chart. Kew, Surrey: CMI and British Mycological Society. 17 sheets, 34 p
Rooney SN, Askalen A, Gubler WD., 2002 First report of the teleomorph of Phaeoacremonium spp., the cause of esca and decline of grapevines. Phytopathol News 36:116.
Scheck HJ, Vasquez SJ, Gubler WD., 1998 First report of three Phaeoacremonium spp. causing young grapevine decline in California. Pl Dis 82:590.
Swofford DL., 2000 PAUP* 4.0: phylogenetic analysis using parsimony. Sunderland, Massachusetts: Sinauer Associates Inc
Tegli S., 2000 A hypothesis about the reproductive modes of Phaeoacremonium aleophilum and Phaeomoniella chlamydospora. Phytopathol Mediterr 39:289-298
———, Bertelli E, Surico G., 2000a Sequence analysis of ITS ribosomal DNA in five Phaeoacremonium species and development of a PCR-based assay for the detection of P. chlamydosporum and P. aleophilum in grapevine tissue. Phytopathol Mediterr 39:134-149
———, Santilli E, Bertelli E, Surico G., 2000b Genetic variation within Phaeoacremonium aleophilum and P. chlamydosporum in Italy. Phytopathol Mediterr 39:125-133
Tulasne LR, Tulasne C., 1863 Selecta Fungorum Carpologia. Paris. Vol. 2. Parisiis: 34 plates, 319 p
White TJ, Bruns T, Lee S, Taylor J., 1990 Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In: Innis MA, Gelfand DH, Sninsky JJ, White TJ, eds. PCR protocols: a guide to methods and applications. New York: Academic Press. p 315–322
Winka K, Eriksson OE., 2000 Papulosa amerospora accommodated in a new family (Papulosaceae, Sordariomycetes, Ascomycota) inferred from morphological and molecular data. Mycoscience 41:97-103
This article has been cited by other articles:
 |
|
 |
|
  H. B. Lee, J. Y. Park, H. S. Jung, and R. C. Summerbell Phaeomoniella zymoides and Phaeomoniella pinifoliorum spp. nov., new acid-tolerant epiphytic fungi isolated from pine needles in Korea. Mycologia, July 1, 2006; 98(4): 598 - 611. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. W. Baddley, L. Mostert, R. C. Summerbell, and S. A. Moser Phaeoacremonium parasiticum Infections Confirmed by {beta}-Tubulin Sequence Analysis of Case Isolates. J. Clin. Microbiol., June 1, 2006; 44(6): 2207 - 2211. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 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]
|
|
|
|
|
|
L. Mostert, J. Z. Groenewald, R. C. Summerbell, V. Robert, D. A. Sutton, A. A. Padhye, and P. W. Crous Species of Phaeoacremonium Associated with Infections in Humans and Environmental Reservoirs in Infected Woody Plants J. Clin. Microbiol., April 1, 2005; 43(4): 1752 - 1767. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
