Chaiwat To-anun

Myrtaceae, a cache of fungal biodiversity

Twenty-six species of microfungi are treated, the majority of which are associated with leaf spots of Corymbia, Eucalyptus and Syzygium spp. (Myrtaceae). The treated species include three new genera, Bagadiella, Foliocryphia and Pseudoramichloridium, 20 new species and one new combination. Novelties on Eucalyptus include: Antennariella placitae, Bagadiella lunata, Cladoriella rubrigena, C. paleospora, Cyphellophora eucalypti, Elsinoë eucalypticola, Foliocryphia eucalypti, Leptoxyphium madagascariense, Neofabraea eucalypti, Polyscytalum algarvense, Quambalaria simpsonii, Selenophoma australiensis, Sphaceloma tectificae, Strelitziana australiensis and Zeloasperisporium eucalyptorum. Stylaspergillus synanamorphs are reported for two species of Parasympodiella, P. eucalypti sp. nov. and P. elongata, while Blastacervulus eucalypti, Minimedusa obcoronata and Sydowia eucalypti are described from culture. Furthermore, Penidiella corymbia and Pseudoramichloridium henryi are newly described on Corymbia, Pseudocercospora palleobrunnea on Syzygium and Rachicladosporium americanum on leaf litter. To facilitate species identification, as well as determine phylogenetic relationships, DNA sequence data were generated from the internal transcribed spacers (ITS1, 5.8S nrDNA, ITS2) and the 28S nrDNA (LSU) regions of all taxa studied.

Phylogenetic relationships of Polyporus and morphologically allied genera.

Polyporus accommodates morphologically heterogeneous species and is divided into six infrageneric groups based on macromorphological characters. On the other hand allied genera have macro- and microscopic characters similar to those of Polyporus. The phylogenetic relationships of Polyporus and allied genera were established from sequences of RNA polymerase II second largest subunit (RPB2), nuclear ribosomal large subunit (nucLSU) and mitochondrial ATPase subunit 6 (ATP6). The molecular phylogenetic trees confirmed that Polyporus is a polyphyletic genus and recognized six major clades (1–6) containing species of Polyporus and several allied genera. Among the clades one contained three infrageneric groups of Polyporus and two allied genera, Datronia and Pseudofavolus while one other contained group Polyporellus and Lentinus. Five of the six major clades contained species belonging to a single infrageneric group, Favolus, Melanopus, Polyporellus or Polyporus. This suggests that morphological characters used to define these groups have phylogenetic significance and reveals the need for a taxonomic revision of Polyporus and its allied genera.

Caulicolous Botryosphaeriales from Thailand

Members of Botryosphaeriales are commonly encountered as endophytes or pathogens of various plant hosts. The Botryosphaeriaceae represents the predominant family within this order, containing numerous species associated with canker and dieback disease on a wide range of woody hosts. During the course of routine surveys from various plant hosts in Thailand, numerous isolates of Botryosphaeriaceae, including Aplosporellaceae were collected. Isolates were subsequently identified based on a combination of morphological characteristics and phylogenetic analysis of a combined dataset of the ITS and EF1-α gene regions. The resulting phylogenetic tree revealed 11 well-supported clades, correlating with different members of Botryosphaeriales. Other than confirming the presence of taxa such as Lasiodiplodia theobromae, L. pseudotheobromae and Neofusicoccum parvum, new records for Thailand include Pseudofusicoccum adansoniae and P. ardesiacum. Furthermore, four novel species are described, namely Diplodia neojuniperi from Juniperus chinensis, Lasiodiplodia thailandica from Mangifera indica, Pseudofusicoccum artocarpi and Aplosporella artocarpi from Artocarpus heterophyllus, while a sexual morph is also newly reported for L. gonubiensis. Further research is presently underway to determine the pathogenicity and relative importance of these species on different woody hosts in Thailand.

Phylogeny and taxonomy of the genus Cylindrocladiella

The genus Cylindrocladiella was established to accommodate Cylindrocladium-like fungi that have small, cylindrical conidia and aseptate stipe extensions. Contemporary taxonomic studies of these fungi have relied on morphology and to a lesser extent on DNA sequence comparisons of the internal transcribed spacer regions (ITS 1, 2 and 5.8S gene) of the ribosomal RNA and the β-tubulin gene regions. In the present study, the identity of several Cylindrocladiella isolates collected over two decades was determined using morphology and phylogenetic inference. A phylogeny constructed for these isolates employing the β-tubulin, histone H3, ITS, 28S large subunit and translation elongation factor 1-alpha gene regions resulted in the identification of several cryptic species in the genus. In spite of the 18 new Cylindrocladiella species described in this study based on morphological and sequence data, several species complexes remain unresolved.

Mycoparasitic species of Sphaerellopsis, and allied lichenicolous and other genera.

Species of Sphaerellopsis (sexual morph Eudarluca) are well-known cosmopolitan mycoparasites occurring on a wide range of rusts. Although their potential role as biocontrol agents has received some attention, the molecular phylogeny of the genus has never been resolved. Based on morphology and DNA sequence data of the large subunit nuclear ribosomal RNA gene (LSU, 28S) and the internal transcribed spacers (ITS) and 5.8S rRNA gene of the nrDNA operon, the genus Sphaerellopsis is shown to belong to Leptosphaeriaceae in Dothideomycetes. Sphaerellopsis is circumscribed, and the sexually typified generic name Eudarluca treated as a synonym on the basis that Sphaerellopsis is more commonly used in literature, is the older generic name, and is the morph commonly encountered by plant pathologists in the field. A neotype is designated for Sphaerellopsis filum, and two new species are introduced, S. macroconidialis and S. paraphysata spp. nov. Species previously incorrectly placed in Sphaerellopsis are allocated to Neosphaerellopsis gen. nov. as N. thailandica, and to the genus Acrocalymma, as A. fici. The genus Rhizopycnis is nestled among species of Acrocalymma, and reduced to synonymy based on its morphology and DNA phylogeny, while Acrocalymmaceae is introduced as novel family to accommodate members of this genus in the Dothideomycetes. Furthermore, Sphaerellopsis proved to be phylogenetically closely allied to a lichenicolous complex of phoma-like taxa, for which the new genera Diederichomyces and Xenophoma are established. Several new combinations are introduced, namely D. xanthomendozae, D. ficuzzae, D. caloplacae, D. cladoniicola, D. foliaceiphila, and X. puncteliae combs. nov, while Paraphaeosphaeria parmeliae sp. nov. is newly described.

Botryosphaeriaceae associated with diseases of mango (Mangifera indica)

Fungal species of Botryosphaeriaceae have a cosmopolitan distribution and are important pathogens of a wide range of plant hosts. This study aims to use phylogenetic inference to review the geographical distribution of botryosphaeriacous species that have been associated with diseases of mango (Mangifera indica) globally. The phylogenetic analyses were performed based on the combined sequence datasets of the internal transcribed spacer (ITS) region of the nuclear rDNA and a partial region of the translation elongation factor 1-alpha (EF1-α) gene. The phylogenetic study revealed seven clades with distinct morphological characters from several countries, including Australia, Brazil, Egypt, Iran, Mali, Peru, South Africa, Taiwan and Thailand. Lasiodiplodia theobromae appears to be a dominant species on mango with the largest geographical distribution, whereas L. crassispora and Barriopsis iraniana have only been reported on mango in Brazil and Iran, respectively. These finding indicate that most of the species reported from mango are not restricted to specific geographical regions, although some genera appear to have a limited distribution.

Molecular and morphological characterization of Phyllactinia cassiae-fistulae (Erysiphaceae; Ascomycota) from Thailand

Phyllactinia cassiae-fistulae and its Ovulariopsis anamorph, a causal agent of powdery mildew on Cassia fistula, have been found in Thailand for the first time. Phylogenetic analysis using the 28S ribosomal DNA sequences clearly demonstrated that P. cassiae-fistulae distinctly formed a unique clade at the basal part of Phyllactinia with 100% bootstrap support. This phylogenetic analysis supports the unique morphology of P. cassiae-fistulae anamorph having cylindrical-ellipsoil conidia and short conidiophores similar to Oidium species.

Host affinity and phylogenetic position of a new anamorphic fungus Beltraniella botryospora from living and fallen leaves of evergreen oaks

A new anamorphic fungus, Beltraniella botryospora, is described and illustrated with line drawings and photographs. This fungus was isolated frequently from living and fallen leaves of Quercus acuta, but rarely or never from other evergreen oaks and Castanopsis sieboldii grown at the same investigation site, suggesting that this new fungus might have strong host affinity to Quercus acuta. The phylogenetic relationships of Beltraniella botryospora and allied beltranioid fungi, such as Beltrania rhombica, Beltraniella sp. and Beltraniopsis sp., were estimated by molecular phylogenetic analysis using 28S rDNA D1/D2 region sequences. The constructed phylogenetic tree suggests that beltranioid fungi, including Beltraniella botryospora, an ascomycete Pseudomassaria carolinensis, which has a Beltraniella anamorphic stage, and a hyphomycete Subramaniomyces fusisaprophyticus, make a monophyletic group. This clade is located in the Xylariales lineage and is closely related to Amphisphaeriaceae. The phylogenetic relationships of the new anamorphic species and allied fungi are briefly discussed and a polyphyly of the anamorphic genus Beltraniella is suggested.

Subsessila turbinata gen. et. sp. nov. (Beltraniaceae), a Beltrania-like fungus from Thailand

A new monotypic Beltrania-like genus, Subsessila, with its type species S. turbinata, is described, illustrated and compared with similar genera. The new genus is introduced in the family Beltraniaceae based on phylogenetic analysis and morphological characters. Subsessila can be easily distinguished from other Beltrania-like genera by dark setae arising from radially lobed basal cells, mostly lacking macronematous conidiophores. Conidiogenous cells are ampulliform or doliiform and produce turbinate to clavate conidia with rostrate proximal end and rounded distal end. Evidence for establishment of the new genus is provided based on morphological comparison and DNA sequence data analyses.

Chocolate spot disease of Eucalyptus

Chocolate Spot leaf disease of Eucalyptus is associated with several Heteroconium-like species of hyphomycetes that resemble Heteroconium s.str. in morphology. They differ, however, in their ecology, with the former being plant pathogenic, while Heteroconium s.str. is a genus of sooty moulds. Results of molecular analyses, inferred from DNA sequences of the large subunit (LSU) and internal transcribed spacers (ITS) region of nrDNA, delineated four Heteroconium-like species on Eucalyptus, namely H. eucalypti, H. kleinziense, Alysidiella parasitica, and one isolate resembling a novel species in a clade separate from the holotype of Heteroconium, H. citharexyli. Based on molecular phylogeny, morphology and ecology, the Heteroconium-like species associated with Chocolate Spot disease are reclassified in the genus Alysidiella, which is shown to have mycelium that is immersed in and superficial on the host tissue and conidiogenous cells that can have loci that are either inconspicuous or proliferating percurrently. Furthermore, conidiogenous cells can either occur solitary on hyphae, or be sporodochial, arranged on a weakly developed stroma, which further distinguishes Alysidiella from Heteroconium.