Izumi Okane

Phylogeny of Discosia and Seimatosporium, and introduction of Adisciso and Immersidiscosia genera nova

Discosia (teleomorph unknown) and Seimatosporium (teleomorph Discostroma) are saprobic or plant pathogenic, coelomycetous genera of so-called ‘pestalotioid fungi’ within the Amphisphaeriaceae (Xylariales). They share several morphological features and their generic circumscriptions appear unclear. We investigated the phylogenies of both genera on the basis of SSU, LSU and ITS nrDNA and β-tubulin gene sequences. Discosia was not monophyletic and was separated into two distinct lineages. Discosia eucalypti deviated from Discosia clade and was transferred to a new genus, Immersidiscosia, characterised by deeply immersed, pycnidioid conidiomata that are intraepidermal to subepidermal in origin, with a conidiomatal beak having periphyses. Subdividing Discosia into ‘sections’ was not considered phylogenetically significant at least for the three sections investigated (sect. Discosia, Laurina, and Strobilina). We recognised Seimatosporium s.l. as a monophyletic genus. An undescribed species belonging to Discosia with its associated teleomorph was collected on living leaves of Symplocos prunifolia from Yakushima Island, Japan. We have therefore established a new teleomorphic genus, Adisciso, for this new species, A. yakushimense. Discostroma tricellulare (anamorph: Seimatosporium azaleae), previously described from Rhododendron species, was transferred to Adisciso based on morphological and phylogenetic grounds. Adisciso is characterised by relatively small-sized ascomata without stromatic tissue, obclavate to broadly cylindrical asci with biseriate ascospores that have 2 transverse septa, and its Discosia anamorph. Based on these features, it can easily be distinguished from Discostroma, a similar genus within the Amphisphaeriaceae.

Endophytic fungal community in stems and leaves of plants from desert areas in China

Endophytic fungi are known to play important ecological roles in protecting plants from various abiotic and biotic stresses. Therefore, it is valuable to investigate the endophytic fungal community associated with plants distributed in harsh environments, such as deserts. Fungal communities in the stems and leaves of ten plant samples belonging to eight species were collected from a desert area in China and tested after plant surface sterilization. The fungal compositions were different among plants. Salsola collina, Suaeda salsa, and Coriospermum declinatum possessed the highest fungal richness. The colonization rates of these samples were high, exceeding 50% in eight of the samples. However, the fungal diversity of the samples was low when measured using Shannon’s index, Fisher’s α, and Simpson’s index. Alternaria alternata, A. franseriae, Fusarium solani, and a second Fusarium species were most frequently isolated from all samples. The diversity of isolated species was low in desert areas, although the colonization rate was relatively high. It was concluded that fungal communities associated with plants in deserts had low diversity, but a small number of species colonized various plants with a high colonization rate. The Jaccard, Sorensen, and Bray–Curtis similarity indices for the fungal communities were low between stems and leaves. This indicated that different fungal communities colonized these two tissues. Phoma pomorum and Phoma sp. showed tissue preferences.

Surculiseries rugispora gen. et sp. nov., a new endophytic mitosporic fungus from leaves of Bruguiera gymnorrhiza.

Surculiseries rugispora gen. et sp. nov. is described as an endophytic fungus from leaves ofBruguiera gymnorrhiza in mangrove forests in the Iriomote Is., Okinawa, Japan. This fungus develops peculiar conditiongenous cells that resemble octopus legs with obvious sucker-like scars, and produces lentiform conidia with lines on surface. Sequence analysis of 18S rDNA places this new fungus in the family Xylariaceae and shows its close affinity to the genusAscotricha (anamorph:Dicyma).

Trichoderma matsushimae and T. aeroaquaticum: two aero-aquatic species with Pseudaegerita-like propagules

Four isolates tentatively identified as Pseudaegerita matsushimae on the basis of the morphology of bulbil-like propagules were collected from substrates submerged in water in Thailand and Japan. In culture studies the two Thai isolates were found to produce phialoconidia on conidiogenous cells and phialoconidiophores whose morphology was similar to that of Trichoderma. Phylogenetic analysis based on D1/D2 regions of LSU rDNA sequences showed that the four isolates were nested in Hypocrea/Trichoderma (Hypocreales) while P. corticalis, the type species of Pseudaegerita, belongs to Hyaloscypha (Helotiales). Preliminary analysis by ISTH Web tools based on 5.8S-ITS rDNA and phylogenetic analysis based on rpb2 and tef1-int4 genes showed that the isolates have specific sequences of Trichoderma (anchors 1–5) and belong to the Hamatum clade but they grouped apart from any known species of Trichoderma. The sequences of the tef1-int4 gene, which were amplified from the authentic specimen of P. matsushimae (IMI 266915), also showed that it belongs to the Hamatum clade closely clustering with T. yunnanense but separate from our four isolates. The morphology of P. matsushimae (IMI 266915), especially the sizes of phialides and phialoconidia, were different from T. yunnanense. Thus, we conclude that IMI 266915 and our isolates are to be assigned to two different species in the Hamatum clade of Trichoderma, although both species have similar morphology of bulbils and phialoconidia. Morphology and molecular data revealed that P. matsushimae should be assigned to the genus Trichoderma as T. matsushimae and the Thai and Japanese isolates are placed in T. aeroaquaticum sp. nov. This finding supports the interpretation that aero-aquatic fungi have evolved from terrestrial fungi. We assume that these fungi probably were derived from typically soil-inhabiting species of Trichoderma; an adaptation to aquatic environments is shown by formation of bulbil-like propagules floating on water.

Lanceispora amphibia gen. et sp.nov., a new amphisphaeriaceous ascomycete inhabiting senescent and fallen leaves of mangrove.

Lanceispora amphibia gen. et sp. nov. in the Amphisphaeriaceae is described from senescent and fallen leaves ofBruguiera gymnorrhiza in mangrove forests in the Southwest Islands, Japan. The fungus produces immersed ascomata in leaf tissue, cylindrical asci with an apical ring staining blue with iodine, and oblanceolate ascospores with a septum above the middle. Studies on the fungal succession on the mangrove leaves revealed thatL. amphibia infects senescent leaves on the tree and inhabits intertidal fallen leaves, showing the highest frequency of occurrence at the late stage of decomposition. In culture the optimal conditions for hyphal growth were 20 ppt salinity and 30°C, and those for sexual reproduction were 10 ppt salinity and 25°C. Growth at 0 ppt (fresh water) was depressed. The fungus has amphibious habits, growing on the tree and in intertidal water; and it is adapted to the high osmotic conditions in leaf tissues of the mangrove tree and to the subtropical, brackish water environment of mangrove forests.

Thielavia aurantiaca, a new species from Japanese soil

A new species ofThielavia (T. aurantiaca) isolated from field soil collected from Osaka is described and illustrated. The fungus is distinguished from other known species by having ascomata covered with yellowish orange mycelium and smaller size of ascomata and ascospores. A chlamydospore-like anamorph is formed.

Production of Bioactive Compounds Based on Phylogeny in the Genus Penicillium Preserved at NBRC

Penicillium strains (n=394) preserved at NBRC (the NITE Biological Resource Center) were compared as to groupings (11 species-clusters) based on phylogeny and the production of bioactive compounds. The strains in two clusters, of which P. chrysogenum and P. citrinum are representative, showed higher rates of positive strains with multi-biological activities.

Zoosporangium development, zoospore release and culture properties of Halophytophthora mycoparasitica

Halophytophthora mycoparasitica, a fungal parasite with unique zoosporangial ornamentation, was isolated from submerged fallen leaves of mangrove collected in the South-west Islands, Japan, since the original description from Malaysia. Isolates were examined for the development of zoosporangia and the process of the zoospore release. Scanning electron microscope observation revealed that the denticulate ornamentation of the surface of the zoosporangium is composed of many sets of assembling spines which are densely covered with mucilage. The mucilage is exuded from the spines and spreads over the zoosporangium as the zoosporangium develops. The mucilage works to gather spines into groups, which are angled towards the center of each assembly. Details were observed on the process from dehiscence plug development, through its ejection, to zoospore release. Mycoparasitic behavior was also observed in a mixed culture with a host fungus. Culture studies showed the species adapts well in its growth and asexual reproduction to brackish and sea water in a mangrove environment.