Fungal systematics and evolution最新文献

The hypogeous, sequestrate ascomycete genus Elaphomyces is one of the oldest known truffle-like genera. Elaphomyces has a long history of consumption by animals in Europe and was formally described by Nees von Esenbeck in 1820 from Europe. Until recently most Elaphomyces specimens in North America were assigned names of European taxa due to lack of specialists working on this group and difficulty of using pre-modern species descriptions. It has recently been discovered that North America has a rich diversity of Elaphomyces species far beyond the four Elaphomyces species described from North America prior to 2012. We describe eight new Elaphomyces species (E. dalemurphyi, E. dunlapii, E. holtsii, E. lougehrigii, E. miketroutii, E. roodyi, E. stevemilleri and E. wazhazhensis) of eastern North America that were collected in habitats from Quebec, Canada south to Florida, USA, west to Texas and Iowa. The ranges of these species vary and with continued sampling may prove to be larger than we have established. Castellano has studied authentic material of all European Elaphomyces species published through 2016 and it is interesting to note that many Elaphomyces species from eastern North America have morphological similarities but with distinct morphological differences to a number of European Elaphomyces species. Citation: Castellano MA, Crabtree CD, Mitchell D, Healy RA (2020). Eight new Elaphomyces species (Elaphomycetaceae, Eurotiales, Ascomycota) from eastern North America. Fungal Systematics and Evolution 7: 113-131. doi: 10.3114/fuse.2021.07.06.

Holocarpic oomycetes convert their entire cytoplasm into zoospores and thus do not form dedicated sporangia or hyphal compartments for asexual reproduction. The majority of holocarpic oomycetes are obligate parasites and parasitoids of a diverse suite of organisms, among them green and red algae, brown seaweeds, diatoms, fungi, oomycetes and invertebrates. Most of them are found among the early diverging oomycetes or the Peronosporomycetes, and some in the early-diverging Saprolegniomycetes (Leptomitales). The obligate parasitism renders it difficult to study some of these organisms. Only a few members of the genus Haliphthoros s. l. have been cultured without their hosts, and of the parasitoid Leptomitales, some transient cultures have been established, which are difficult to maintain. Here, the cultivation of a new holocarpic oomycete genus of the Leptomitales, Bolbea, is presented. Bolbea is parasitic to ostracods, is readily cultivable on malt extract agar, and upon contact with water converts its cytoplasm into zoospores. Its morphology and phylogenetic relationships are reported. Due to the ease of cultivation and the ready triggering of zoospore development, similar to some lagenidiaceous oomycetes, the species could be a promising model to study sporulation processes in detail.

Species of Raffaelea (Ophiostomatales: Ascomycota) are obligate symbionts of ambrosia beetles, some of which pose a substantial threat to forest trees. Leucaena leucocephala is a small mimosoid tree species that is considered as an invasive weed in most of its introduced range globally. During a field expedition on the French island of Réunion, dying L. leucocephala trees were observed. Samples were taken from these trees and isolations made from symptomatic wood tissues that included beetle tunnels, but in the absence of the beetles themselves. Multiple isolates of a fungus resembling a Raffaelea species were obtained from the discoloured wood associated with the beetle tunnels. To determine their identity, microscopic examination was performed and DNA sequences for three gene regions (ITS, LSU, TUB) were obtained. Phylogenetic analyses based on these gene regions revealed that the isolates represent a new species of Raffaelea, described here as R. borbonica sp. nov. A pathogenicity test was conducted with the fungus, which was shown to cause lesions on the inoculated seedlings, but with a low level of aggressiveness.