Taxonomy and phylogeny of the genus Mycosphaerella and its anamorphs

Historically plant pathogenic species of Mycosphaerella have been regarded as host-specific, though this hypothesys has proven difficult to test largely due to the inavailability of fungal cultures. During the course of the past 20 years a concerted effort has been made to collect these fungi, and devise methods to cultivate them. Based on subsequent DNA sequence analyses the majority of these species were revealed to be host-specific, though some were not, suggesting that no general rule can be applied. Furthermore, analysis of recent molecular data revealed Mycosphaerella to be poly- and paraphyletic. Teleomorph morphology was shown to be too narrowly defined in some cases, and again too widely in others. Mycosphaerella and Teratosphaeria as presently circumscribed represent numerous different genera, many of which can be recognised based on the morphology of their 30 odd associated anamorph genera. Although Mycosphaerella is generally accepted to represent one of the largest genera of ascomycetous fungi, these data suggest that this is incorrect, and that Mycosphaerella should be restricted to taxa linked to Ramularia anamorphs. Furthermore, other anamorph form genera with Mycosphaerella-like teleomorphs appear to represent genera in their own right

The enigma of Calonectria species occurring on leaves of Ilex aquifolium in Europe

Species of Calonectria are common saprobes and plant pathogens on a wide range of hosts occurring in subtropical to tropical regions of the world. The aim of the present study was to resolve the status of new Calonectria collections obtained on Ilex leaves from France. Based on DNA sequence data of their b-tubulin and histone gene regions, as well as morphology, the new collections matched the ex-type strain of Cylindrocladium ilicicola. On the host and in culture, yellow to brownish-yellow perithecia were observed that did not strain red in 3 % KOH. Based on these results, C. ilicicola and its purported teleomorph, Ca. pyrochroa, were shown to represent two distinct species, as the latter has bright red perithecia that strain purple in KOH. A new combination, Ca. lauri, based on Tetracytum lauri, is subsequently proposed for C. ilicicola. Calonectria lauri is distinct from Ca. ilicicola, a pathogen commonly associated with Cylindrocladium black rot of peanut. Finally, Ca. canadiana is proposed asnew name for Cy. canadiense, which is a nursery pathogen involved with root rot of several tree genera in Quebec, Canada

Multigene phylogeny and mating tests reveal three cryptic species related to Calonectria pauciramosa

Calonectria pauciramosa is a pathogen of numerous plant hosts worldwide. Recent studies have indicated that it included cryptic species, some of which are identified in this study. Isolates from various geographical origins were collected and compared based on morphology, DNA sequence data of the ß-tubulin, histone H3 and translation elongation factor-1 regions and mating compatibility. Comparisons of the DNA sequence data and mating compatibility revealed three new species. These included Ca. colombiana sp. nov. from Colombia, Ca. polizzii sp. nov. from Italy and Ca. zuluensis sp. nov. from South Africa, all of which had distinguishing morphological features. Based on DNA sequence data, Ca. brasiliensis is also elevated to species leve

Colletotrichum species with curved conidia from herbaceous hosts

Colletotrichum (Glomerellaceae, Sordariomycetes) species with dark setae and curved conidia are known as anthracnose pathogens of a number of economically important hosts and are often identified as C. dematium. Colletotrichum dematium has been synonymised with many species, including the type of the genus, C. lineola. Since there is no living strain of the original material of either species available, we re-collected C. lineola from the original location to serve as an epitype of that name, and chose an appropriate epitype specimen and associated strain of C. dematium from the CBS collection. A multilocus molecular phylogenetic analysis (ITS, ACT, Tub2, CHS-1, GAPDH, HIS3) of 97 isolates of C. lineola, C. dematium and other Colletotrichum species with curved conidia from herbaceous hosts resulted in 20 clades, with 12 clades containing strains that had previously been identified as C. dematium. The epitype strains of C. lineola and C. dematium reside in two closely related clades. Other clades represent four previously undescribed species, C. anthrisci, C. liriopes, C. rusci and C. verruculosum, isolated respectively from Anthriscus in the Netherlands, Liriope in Mexico, Ruscus in Italy and Crotalaria in Zimbabwe. The new combinations C. spaethianum and C. tofieldiae are made. Colletotrichum truncatum is epitypified, as well as C. circinans, C. curcumae and C. fructi. Three further unidentified Colletotrichum taxa were detected in the phylogenetic analysis, which may require description after further research. Each species is comprehensively described and illustrate

Mycosphaerella podagrariae - a necrotrophic phytopathogen forming a special cellular interaction with its host Aegopodium podagraria

We present a new kind of cellular interaction found between Mycosphaerella podagrariae and Aegopodium podagraria, which is remarkably different to the interaction type of the obligate biotrophic fungus Cymadothea trifolii, another member of the Mycosphaerellaceae (Capnodiales, Dothideomycetes, Ascomycota) which we have described earlier. Observations are based on both conventional and cryofixed material and show that some features of this particular interaction are better discernable after chemical fixation. We were also able to generate sequences for nuclear ribosomal DNA (complete SSU, 5.8 S and flanking ITS-regions, D1–D3 region of the LSU) confirming the position of M. podagrariae within Mycosphaerellacea

Fungal phoenix rising from the ashes?

During May 2010, sporocarps of what appeared to be an Armillaria sp. were found in large clumps in historic Kirstenbosch Botanical Gardens on the foot of Table Mountain, Cape Town, South Africa. These sporocarps could be physically linked to the roots of unidentified dead trees and Protea spp. The aim of this study was to identify the Armillaria sp. found fruiting in Kirstenbosch. To achieve this goal isolates were made from the mycelium under the bark of dead roots linked to sporocarps. The ITS and IGS-1 regions were sequenced and compared to sequences of Armillaria spp. available on GenBank. Cladograms were generated using ITS sequences to determine the phylogenetic relationship of the isolates with other Armillaria spp. Sequence comparisons and phylogenetic analyses showed that the isolates represented A. mellea. They were also identical to isolates of this species previously discovered in the Company Gardens in South Africa and introduced from Europe apparently by the early Dutch Settlers. Armillaria mellea is alien and apparently invasive in Cape Town, fruits profusely and has the potential to spread to sensitive native forests on the foothills of the City

Calonectria species associated with cutting rot of Eucalyptus

Decline in the productivity of Eucalyptus hybrid cutting production in the Guangdong Province of China is linked to cutting rot associated with several Calonectria spp. The aim of this study was to identify these fungi using morphological and DNA sequence comparisons. Two previously undescribed Calonectria spp., Ca. pseudoreteaudii sp. nov. and Ca. cerciana sp. nov. were identified together with Ca. pauciramosa. Calonectria pseudoreteaudii resides in the Ca. reteaudii complex and Ca. cerciana is closely related to Ca. morganii. Connected to the discovery of Ca. pseudoreteaudii, species in the Ca. reteaudii complex were re-considered and the group is shown to accommodate two cryptic species. These originate from Australia and are described as Ca. queenslandica sp. nov. and Ca. terrae-reginae sp. nov

Ophiostoma gemellus and Sporothrix variecibatus from mites infesting Protea infructescences in South Africa

Ophiostoma (Ophiostomatales) represents a large genus of fungi mainly known from associations with bark beetles (Curculionidae: Scolytinae) infesting conifers in the northern hemisphere. Few southern hemisphere native species are known, and the five species that consistently occur in the infructescences of Protea spp. in South Africa are ecologically unusual. Little is known about the vectors of Ophiostoma spp. from Protea infructescences, however recent studies have considered the possible role of insects and mites in the distribution of these exceptional fungi. In this study we describe a new species of Ophiostoma and a new Sporothrix spp. with affinities to Ophiostoma, both initially isolated from mites associated with Protea spp. They are described as Ophiostoma gemellus sp. nov. and Sporothrix variecibatus sp. nov. based on their morphology and comparisons of DNA sequence data of the 28S ribosomal, ß-tubulin and internal transcribed spacer (ITS1, 5.8S, ITS2) regions. DNA sequences of S. variecibatus were identical to those of a Sporothrix isolate obtained from Eucalyptus leaf litter in the same area in which S. variecibatus occurs in Protea infructescences. Results of this study add evidence to the view that mites are the vectors of Ophiostoma spp. that colonize Protea infructescences. They also show that DNA sequence comparisons are likely to reveal additional cryptic species of Ophiostoma in this unusual niche

A fissitunicate ascus mechanism in the Calosphaeriaceae, and novel species of Jattaea and Calosphaeria on Prunus wood

During a survey of Prunus wood from South Africa, isolations were made of three presumably Calosphaerialean fungi that formed hyphomycetous, phialidic anamorphs in culture. In order to reveal the phylogenetic relationship of these fungi, they were characterised on a morphological and molecular (LSU and ITS rDNA) basis. Two isolates that formed a teleomorph in culture are newly described as Calosphaeria africana sp. nov. Although asci of Calosphaeria are characterised by having non-amyloid apical rings, two functional wall layers were observed in asci of C. africana, which has hitherto not been observed in any member of the Calosphaeriaceae. However, Calosphaeriaceae (Calosphaeriales, Sordariomycetes) are not closely related to other bitunicate fungi like Dothideomycetes, Chaetothyriales and bitunicate lichens. Possession of two separating wall layers is considered to be a result of both inherited abilities and convergent evolution under a strong selection pressure of the environmental conditions that favour an extension of the ascus. The other two species represented a separate lineage within Calosphaeriaceae, and formed phialophora-like anamorphs. By obtaining the teleomorph in culture, one of them could be identified as a species of Jattaea, described here as Jattaea prunicola sp. nov., while the second, which only produced the anamorph, is named as Jattaea mookgoponga sp. nov. These findings suggest that some species of Jattaea are true members of the Calosphaeriaceae, though the phylogenetic relation of the type, J. algeriensis, remains unknown. Furthermore, it also represents the first report of Jattaea on Prunus wood, and from South Africa