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Unravelling Mycosphaerella: do you believe in genera?

Crous PW, Summerell BA, Carnegie AJ, Wingfield MJ, Hunter GC, Burgess TI, Andjic V, Barber PA, Groenewald JZ - Persoonia (2009)

Bottom Line: The genus Schizothyrium with Zygophiala anamorphs is supported as belonging to the Schizothyriaceae, while Dissoconium and Ramichloridium appear to represent a distinct family.Several clades remain unresolved due to limited sampling.Mycosphaerella, which has hitherto been used as a term of convenience to describe ascomycetes with solitary ascomata, bitunicate asci and 1-septate ascospores, represents numerous genera and several families yet to be defined in future studies.

View Article: PubMed Central - PubMed

Affiliation: CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands;

ABSTRACT
Many fungal genera have been defined based on single characters considered to be informative at the generic level. In addition, many unrelated taxa have been aggregated in genera because they shared apparently similar morphological characters arising from adaptation to similar niches and convergent evolution. This problem is aptly illustrated in Mycosphaerella. In its broadest definition, this genus of mainly leaf infecting fungi incorporates more than 30 form genera that share similar phenotypic characters mostly associated with structures produced on plant tissue or in culture. DNA sequence data derived from the LSU gene in the present study distinguish several clades and families in what has hitherto been considered to represent the Mycosphaerellaceae. In some cases, these clades represent recognisable monophyletic lineages linked to well circumscribed anamorphs. This association is complicated, however, by the fact that morphologically similar form genera are scattered throughout the order (Capnodiales), and for some species more than one morph is expressed depending on cultural conditions and media employed for cultivation. The present study shows that Mycosphaerella s.s. should best be limited to taxa with Ramularia anamorphs, with other well defined clades in the Mycosphaerellaceae representing Cercospora, Cercosporella, Dothistroma, Lecanosticta, Phaeophleospora, Polythrincium, Pseudocercospora, Ramulispora, Septoria and Sonderhenia. The genus Teratosphaeria accommodates taxa with Kirramyces anamorphs, while other clades supported in the Teratosphaeriaceae include Baudoinea, Capnobotryella, Devriesia, Penidiella, Phaeothecoidea, Readeriella, Staninwardia and Stenella. The genus Schizothyrium with Zygophiala anamorphs is supported as belonging to the Schizothyriaceae, while Dissoconium and Ramichloridium appear to represent a distinct family. Several clades remain unresolved due to limited sampling. Mycosphaerella, which has hitherto been used as a term of convenience to describe ascomycetes with solitary ascomata, bitunicate asci and 1-septate ascospores, represents numerous genera and several families yet to be defined in future studies.

No MeSH data available.


Related in: MedlinePlus

Teratosphaeria australiensis (IMI 159079a). a. Leaf spot; b. erumpent pycnidium; c–e. conidiogenous cells giving rise to conidia. f. conidia. — Scale bar = 10 μm.
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Figure 6: Teratosphaeria australiensis (IMI 159079a). a. Leaf spot; b. erumpent pycnidium; c–e. conidiogenous cells giving rise to conidia. f. conidia. — Scale bar = 10 μm.

Mentions: Whether Kirramyces is the oldest generic name to use for anamorphs in this clade is open to debate. Phaeoseptoria (1908) appears to be an anamorph of the Phaeosphaeriopsis complex (Arzanlou & Crous 2006), rendering it unavailable for this group of anamorphs. However, the status of the type species of Leptomelanconium (1923) remains unknown (Fig. 5), the species occurring on Corymbia, namely L. australiensis (Fig. 6), is clearly an anamorph of Teratosphaeria. The same is true for several species of ‘Coniothyrium’ treated by Sutton (1980) and Crous (1998). Colletogloeum (1953) has hitherto been a somewhat confused genus, including many species that appear to belong to Teratosphaeria. However, the ITS sequence from DNA extracted from a specimen representative of the type species, C. sissoo (IMI 119162) (Fig. 7), clearly revealed Colletogloeum to be allied to the Pseudocercospora (1910) complex, clustering in the Mycosphaerellaceae (data not shown). Jubispora (1986) is another interesting candidate genus that predates Kirramyces, having conidia partially covered by a mucoid sheath, as observed in Readeriella patrickii. The phylogenetic position of Jubispora is, however, unknown. Due to the uncertainty surrounding available anamorph names in this clade, we apply a single generic name to this genus. The oldest name, Teratosphaeria (1912), was thus selected to apply to all taxa in this clade (Crous et al. 2009a).


Unravelling Mycosphaerella: do you believe in genera?

Crous PW, Summerell BA, Carnegie AJ, Wingfield MJ, Hunter GC, Burgess TI, Andjic V, Barber PA, Groenewald JZ - Persoonia (2009)

Teratosphaeria australiensis (IMI 159079a). a. Leaf spot; b. erumpent pycnidium; c–e. conidiogenous cells giving rise to conidia. f. conidia. — Scale bar = 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2802725&req=5

Figure 6: Teratosphaeria australiensis (IMI 159079a). a. Leaf spot; b. erumpent pycnidium; c–e. conidiogenous cells giving rise to conidia. f. conidia. — Scale bar = 10 μm.
Mentions: Whether Kirramyces is the oldest generic name to use for anamorphs in this clade is open to debate. Phaeoseptoria (1908) appears to be an anamorph of the Phaeosphaeriopsis complex (Arzanlou & Crous 2006), rendering it unavailable for this group of anamorphs. However, the status of the type species of Leptomelanconium (1923) remains unknown (Fig. 5), the species occurring on Corymbia, namely L. australiensis (Fig. 6), is clearly an anamorph of Teratosphaeria. The same is true for several species of ‘Coniothyrium’ treated by Sutton (1980) and Crous (1998). Colletogloeum (1953) has hitherto been a somewhat confused genus, including many species that appear to belong to Teratosphaeria. However, the ITS sequence from DNA extracted from a specimen representative of the type species, C. sissoo (IMI 119162) (Fig. 7), clearly revealed Colletogloeum to be allied to the Pseudocercospora (1910) complex, clustering in the Mycosphaerellaceae (data not shown). Jubispora (1986) is another interesting candidate genus that predates Kirramyces, having conidia partially covered by a mucoid sheath, as observed in Readeriella patrickii. The phylogenetic position of Jubispora is, however, unknown. Due to the uncertainty surrounding available anamorph names in this clade, we apply a single generic name to this genus. The oldest name, Teratosphaeria (1912), was thus selected to apply to all taxa in this clade (Crous et al. 2009a).

Bottom Line: The genus Schizothyrium with Zygophiala anamorphs is supported as belonging to the Schizothyriaceae, while Dissoconium and Ramichloridium appear to represent a distinct family.Several clades remain unresolved due to limited sampling.Mycosphaerella, which has hitherto been used as a term of convenience to describe ascomycetes with solitary ascomata, bitunicate asci and 1-septate ascospores, represents numerous genera and several families yet to be defined in future studies.

View Article: PubMed Central - PubMed

Affiliation: CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands;

ABSTRACT
Many fungal genera have been defined based on single characters considered to be informative at the generic level. In addition, many unrelated taxa have been aggregated in genera because they shared apparently similar morphological characters arising from adaptation to similar niches and convergent evolution. This problem is aptly illustrated in Mycosphaerella. In its broadest definition, this genus of mainly leaf infecting fungi incorporates more than 30 form genera that share similar phenotypic characters mostly associated with structures produced on plant tissue or in culture. DNA sequence data derived from the LSU gene in the present study distinguish several clades and families in what has hitherto been considered to represent the Mycosphaerellaceae. In some cases, these clades represent recognisable monophyletic lineages linked to well circumscribed anamorphs. This association is complicated, however, by the fact that morphologically similar form genera are scattered throughout the order (Capnodiales), and for some species more than one morph is expressed depending on cultural conditions and media employed for cultivation. The present study shows that Mycosphaerella s.s. should best be limited to taxa with Ramularia anamorphs, with other well defined clades in the Mycosphaerellaceae representing Cercospora, Cercosporella, Dothistroma, Lecanosticta, Phaeophleospora, Polythrincium, Pseudocercospora, Ramulispora, Septoria and Sonderhenia. The genus Teratosphaeria accommodates taxa with Kirramyces anamorphs, while other clades supported in the Teratosphaeriaceae include Baudoinea, Capnobotryella, Devriesia, Penidiella, Phaeothecoidea, Readeriella, Staninwardia and Stenella. The genus Schizothyrium with Zygophiala anamorphs is supported as belonging to the Schizothyriaceae, while Dissoconium and Ramichloridium appear to represent a distinct family. Several clades remain unresolved due to limited sampling. Mycosphaerella, which has hitherto been used as a term of convenience to describe ascomycetes with solitary ascomata, bitunicate asci and 1-septate ascospores, represents numerous genera and several families yet to be defined in future studies.

No MeSH data available.


Related in: MedlinePlus