Ludwig Beenken

Rust fungi on Annonaceae II: the genus Dasyspora Berk. & M.A. Curtis

Dasyspora gregaria, the single species of the allegedly monotypic rust genus Dasyspora (Basidiomycota, Pucciniales), was investigated by light microscopy and DNA sequencing (ITS1–5.8S–ITS2 region, partial LSU and SSU of the nuclear rDNA, mt cytochrome oxidase subunit 3). Both methods indicated that D. gregaria is not a single species but can be split in 11 distinct taxa, each of which appear confined to a single Xylopia species (Annonaceae) host. Herein nine of these are described as new. Both the phylogenetic analyses and morphology show that the species are grouped into two main clades designated Dasyspora gregaria and D. winteri. The first comprises D. gregaria, the type species of the genus, which is restricted to X. cayennensis, two new species on X. aromatica, D. segregaria from northern South America and D. echinata from Brazil. The second clade is formed by D. winteri, recombined from Puccinia winteri on X. sericea, and the new species D. amazonica on X. amazonica, D. emarginatae on X. emarginata, D. frutescentis on X. frutescens, D. ferrugineae on X. frutescens var. ferruginea, D. guianensis on X. benthamii, D. mesoamericana on X. frutescens, and D. nitidae on X. nitida. Dasyspora frutescentis and D. mesoamericana were not clearly distinguishable by their morphology and host associations but differed from another in their sequences and geographic distributions. They are considered cryptic species. An identification key and the distributions are given for all recognized species. Along with molecular data we discuss the systematic position of Dasyspora in the Pucciniales.

Morphological and molecular analyses of fungal endophytes of achlorophyllous gametophytes of Diphasiastrum alpinum (Lycopodiaceae)

PREMISE OF THE STUDY To understand the early evolution of mycorrhizal symbioses, it is important to know the fungal partners of gametophytes and sporophytes for basal lineages of vascular plants. Subterranean mycotrophic gametophytes of the clubmoss Diphasiastrum alpinum found at three localities gave an opportunity to study their morphology and anatomy and to identify and describe their hitherto unknown fungal endophytes. In addition, sporophytes were screened for fungal partners. METHODS Gametophytes with attached young sporophytes were excavated, and their anatomy and their associated fungi were studied by light microscopy. DNA was isolated and amplified with both universal and group-specific fungal primers for the ITS region, the large subunit and small subunit of the nuclear rDNA, respectively, to identify the fungal partner. KEY RESULTS Gametophytes were uniformly colonized by a fungus with septate hyphae forming coils and vesicles. Its morphology resembles that of the sebacinoid genus Piriformospora. Both ITS and LSU sequences were identified as Sebacinales group B, a basal clade of the Agaricomycetes (Basidiomycota). This fungus was detected in 11 gametophytes from two localities and in rootlets of adjacent Calluna vulgaris (Ericaceae) plants, but was absent in roots of sporophytes. In addition, several ascomycetes and glomeromycetes were found by DNA sequencing. CONCLUSIONS Our study suggests a fungus belonging to Sebacinales group B as the main fungal host of the D. alpinum gametophytes. However, Sebacinales group B fungi occur as well in adjacent Ericaceae plants; therefore, we assume the mycoheterotrophic gametophyte to be epiparasitic on Ericaceae, which would explain the steady association of these plants.

Pucciniales on Annona (Annonaceae) with special focus on the genus Phakopsora

The known species of Pucciniales on the tree genus Annona (Annonaceae), Phakopsora cherimoliae, Batistopsora crucis-filii, B. pistila, as well as the anamorphic species of Aecidium annonae and Uredo rolliniae, were investigated by light microscopy and DNA sequencing. For DNA extraction, N-Phenacylthiazolium bromide (PTB) was used to achieve a higher yield of DNA from herbarium specimens. The phylogenetic analyses were based on the ITS1–5.8S–ITS2 region, partial LSU and SSU of the nuclear rDNA, and the mitochondrial cytochrome oxidase subunit 3. The molecular as well as the morphologic investigations indicated that the genus Batistopsora is synonymous with Phakopsora. The two Batistopsora species appeared in all phylogenies within Phakopsora. They form a monophyletic clade together with P. cherimoliae as well as with the anamorphic Uredo rolliniae and the herein newly described species Phakopsora annonae-sylvaticae. Therefore, the following new combinations have been made: Phakopsora crucis-filii, P. pistila and P. rolliniae. Phakopsora crucis-filii and P. pistila could not be distinguished by the used sequences but are morphologically and ecologically well separated. This contradiction is discussed. Phakopsora crucis-filii is firstly reported as a pathogen on the fruit tree Annona squamosa. The species show host preferences to species groups of Annona at the sub-generic level and distribution patterns similar to those of their hosts. In comparison with the rust fungal genus Dasyspora, which occurs on Xylopia (Annonaceae) also in the Neotropics, the Phakopsora spp. on Annona show similar phylogeographical patterns. The redetermination of the host plants has shown that A. annonae does not occur on Annonaceae but on Diospyros hispida (Ebenaceae). Therefore, the new species, Aecidium verannonae, has to be described for the Aecidium species, which occurs really on Annona. It did not appear to be closely related to the Phakopsoraceae in the phylogenetic analysis. An identification key for all known rust fungi on Annona is given.

Puccorchidium and Sphenorchidium, two new genera of Pucciniales on Annonaceae related to Puccinia psidii and the genus Dasyspora

Two-celled puccinioid teliospores are widely distributed in the rust fungi and appear in several independent lineages of the Pucciniales. About 25 genera in 4 families have been described. Species with two-celled teliospores occurring on members of the Annonaceae are described in the genera Dasyspora, Sphaerophragmium, Diorchidium, Puccinia, and Sphenospora. The molecular and morphological investigations from this study show that Diorchidium polyalthiae, Puccinia popowiae and Sphenospora xylopiae do not belong to the genera in which they were originally assigned. Aecidium deightonii was very closely related to S. xylopiae. Two new genera are erected to accommodate these taxa: (1) Puccorchidium, with the two species P. polyalthiae and P. popowiae; and (2) Sphenorchidium, with the two species S. xylopiae and S. deightonii. They form a well-supported clade in the Pucciniales together with the genus Dasyspora, which also occurs on Annonaceae species, and Puccinia psidii the cause of myrtle rust. The type species of the genus Diorchidium, D. woodii, as well as Sphenospora pallida and S. smilacina appeared within the genus Puccinia. The endocyclic species Endophylloides guineensis occurs on the same host and in the same area as S. xylopiae and S. deightonii, but its relationship could not be determined without DNA data. A key for the rust fungi on Annonaceae with two-celled teliospores is given.

Rust fungi on Annonaceae: the genus Sphaerophragmium

Seven species of the rust genus Sphaerophragmium occur on members of the tropical plant family Annonaceae. Uropyxis gerstneri is recombined to S. gerstneri. A new species, S. xylopiae, is described from Xylopia acutiflora. The host plant of S. boanense is identified as Mitrella sp. Sphaerophragmium pulchrum is transferred to Dicheirinia. The anatomy of telia with teliospores and parasitizing mycelium is described and illustrated in detail. A new type of M-haustorium, which emanates laterally from intracellular hypha, is detected in S. monodorae. An identification key is given.

Lactarius megalopterus, a new angiocarpous species from a tropical rainforest in Central Africa, shows adaptations to endozoochorous spore dispersal

A new sequestrate Lactarius species was found in a humid evergreen tropical rainforest dominated by Fabaceae of the subfamily Caesalpinioideae in Cameroon, Central Africa. It is described here as new to science and is named Lactarius megalopterus, referring to its spore ornamentation of extraordinarily high wings. Anatomical characters and molecular systematic analyses confirm its relationship to Lactarius subgenus Plinthogali. Phylogenetic analyses based on two nuclear DNA regions revealed its close relationship to Lactarius angiocarpus, which is also an angiocarpous species from Zambia in Africa. Molecular studies have shown that tuber-like, sequestrate sporocarps evolved independently in several lineages of Basidiomycota. The findings of sequestrate fungi in tropical rainforests raise questions regarding the evolutionary benefit of enclosing the spore-producing hymenium. The enclosure of spore-producing tissue has often been associated with the protection of the delicate hymenium against desiccation in arid habitats or against frost in cold habitats. However, these cannot be the selective factors in warm and humid areas like the tropics. This controversy is exemplarily studied and discussed in the family of Russulaceae, especially in the genus Lactarius. Characters shown by the angiocarpous sporocarp of the new Lactarius, such as thick-walled statismospores, an aromatic smell and mild taste, can be interpreted as adaptations to endozoochorous spore dispersal by mammals. Therefore, here we prefer the alternative hypothesis that sequestrate sporocarps are the result of adaptation to endozoochorous spore dispersal.

Chaconia heliconiae and C. clusiae sp. novae from French Guiana with notes on the genus Chaconia (Uredinales/Pucciniales) in the neotropics

Chaconia clusiae on Clusia cf. palmicida (Clusiaceae) and C. heliconiae on Heliconia psittacorum, H. bihai and Heliconia sp. (Heliconiaceae) are described as new from French Guiana in northern South America. Clusiaceae and Heliconiaceae are new host families for members of Chaconia, Heliconiaceae is the first one from Monocotyledoneae. Chaconia clusiae, C. heliconiae and C. maprouneae formed tuberous to worm-like D-haustoria originating from haustorial mother cells that were part of the intercellular parasitic mycelium. A key to the recognized Chaconia spp. is provided.

DNA barcoding and phylogenetic analyses of the genus Coleosporium (Pucciniales) reveal that the North American goldenrod rust C. solidaginis is a neomycete on introduced and native Solidago species in Europe

Recently, an unknown rust fungus of the genus Coleosporium appeared in Germany and Switzerland on giant goldenrod, Solidago gigantea, an invasive neophyte from North America, and on the indigenous European goldenrod, S. virgaurea. For identification, DNA barcodes were assembled in the course of the German Barcode of Life (GBOL) project and the investigation of neomycetes in Switzerland. Phylogenetic analyses were performed using ITS and LSU sequences of Coleosporium species representing various host plants and geographic regions. These analyses resulted in the first molecular evidence of the North American rust Coleosporium solidaginis in Europe. Coleosporium solidaginis is split into two subclades that are closely related to Coleosporium asterum, a species on Aster s.l., which was formerly synonymized with C. solidaginis. The genus is divided into an American and a Eurasian clade. This phylogenetic pattern indicates that the geographic distribution, rather than the relationship with host plants, played a major role in the evolution of Coleosporium species. This finding particularly applies to the European species, which are genetically uniform according to the ITS and LSU sequences. Taxonomical consequences are discussed. Coleosporium solidaginis is fragmentarily distributed in Europe. The place of its introduction and host shift to S. virgaurea remains uncertain. Life cycle and propagation are mainly restricted to asexual urediniospores. Telia were found only once and the aecial stage was not observed at all on pine trees. The ecological impact of this neomycete is still unknown, but C. solidaginis has the potential to harm wild and cultivated goldenrods in Europe.