The rise of Ramularia from the Mycosphaerella labyrinth

Abstract

Highlights• Ramulariais the correct name for species in Mycosphaerella s. str.• Most species named in Mycosphaerella represent other genera.• Very few Ramularia spp. have confirmed Mycosphaerella sexual morphs.• Ramularia contains both host-specific, and wide host range species. AbstractIn this study we aimed to resolve the Ramularia endophylla species-complex by applying a polyphasic approach involving morphology and multi-gene phylogeny. Eleven partial genes were targeted for amplification and sequencing for a total of 81 isolates representing R. endophylla s. lat. and 32 isolates representing 11 Ramularia species that were previously linked to a Mycosphaerella sexual morph in literature. A Bayesian phylogenetic analysis, as well as a parsimony analysis, was performed on a combined five-locus dataset and the resulting trees showed significant support for three species within the complex, including the previously described R. endophylla and R. vizellae, and one novel species, Ramularia unterseheri. A parsimony analysis was also separately performed with mating-type gene sequences (MAT1-1-1 and MAT1-2-1) and the resulting tree topologies were in accordance with that of the multigene analysis. A bibliographic review of the proposed links between Ramularia spp. and their purported Mycosphaerella sexual morphs is also presented, confirming six connections in Ramularia. In spite of more than 10 000 species having been described in Mycosphaerella, the majority is shown to belong to other genera, suggesting that the taxa identified as Mycosphaerella in much of the plant pathology literature needs to be revisited.

The genus Asteromella (Fungi: Ascomycota) in Poland

“…str.) [66]. The analysis of data on synanamorphs associated (co-occurring) with Asteromella species in the type materials (Appendix 1) reveals that Asteromella fungi had been recorded either with Ramularia or Septoria morph.…”

“…Recently, this unreliability has further increased, with reports demonstrating joint occurrence of diverse Mycosphaerella species, e.g., in a single leaf lesion of Eucalyptus [64,65]. In the newest revision of the Ramularia endophylla complex, Videira et al [66] indicate that the role played by the Asteromella spermatial state in the development of the species still needs to be understood.…”

“…DNA sequence-data have proven to be an extremely useful tool for integrating different morphs of a holomorph [69]. Examples concern many ascomycetous taxa including Mycosphaerella s. l. as well as its segregates, Septoria and Ramularia (e.g., [66,[70][71][72]). In fact, the complex of Mycosphaerella and its anamorphs has recently been widely studied; roughly 35 000 sequences generated to date are available in the GenBank database [73].…”

“…Ramularia endophylla has been limited to Quercus-and Castanea-derived isolates. The role of the Asteromella state in the life cycle of R. endophylla has not been proven, nor has the spermatial state of R. vizellae and R. unterseheri been reported [66]. However, when a genetic connection of Ramularia and Asteromella is assumed, the host-specificity of Asteromella shall be questioned.…”

“…Recently, this unreliability has further increased, with reports demonstrating joint occurrence of diverse Mycosphaerella species, e.g., in a single leaf lesion of Eucalyptus [64,65]. In the newest revision of the Ramularia endophylla complex, Videira et al [66] indicate that the role played by the Asteromella spermatial state in the development of the species still needs to be understood.A third reason for the limited taxonomic interest in Asteromella fungi results from problems related to their culturing. Species which were attempted to cultivate did not germinate on any kind of the wide spectrum of cultural media used (e.g., [50,67,68]).…”