Unravelling unexplored diversity of cercosporoid fungi (Mycosphaerellaceae, Mycosphaerellales, Ascomycota) in tropical Africa

Cercosporoid fungi (Mycosphaerellaceae, Mycosphaerellales, Ascomycota) are one of the largest and most diverse groups of hyphomycetes causing a wide range of diseases of economically important plants as well as of plants in the wild. Although more than 6000 species are known for this group, the documentation of this fungal group is far from complete. Especially in the tropics, the diversity of cercosporoid fungi is poorly known. The present study aims to identify and characterise cercosporoid fungi collected on host plants belonging to Fabaceae in Benin, West Africa. Information on their morphology, host species and DNA sequence data (18S rDNA, 28S rDNA, ITS and tef1) is provided. DNA sequence data were obtained by a simple and non-culture-based method for DNA isolation which has been applied for cercosporoid fungi for the first time in the context of the present study. Among the loci used for the phylogenetic analysis, tef1 provided the best resolution together with the multigene dataset. Species delimitation in many cases, however, was only possible by combining molecular sequence data with morphological characteristics. Based on forty specimens recently collected in Benin, 18 species are presented with morphological descriptions, illustrations and sequence data. Among these, six species in the genus Cercospora and two species in Pseudocercospora are proposed as species new to science. The newly described species are Cercospora (C.) beninensis on Crotalaria macrocalyx, C. parakouensis on Desmodium tortuosum, C. rhynchophora on Vigna unguiculata, C. vignae-subterraneae on Vigna subterranea, C. tentaculifera on Vigna unguiculata, C. zorniicola on Zornia glochidiata, Pseudocercospora sennicola on Senna occidentalis and Pseudocercospora tabei on Vigna unguiculata. Eight species of cercosporoid fungi are reported for Benin for the first time, three of them, namely C. cf. canscorina, C. cf. fagopyri and C. phaseoli-lunati are new for West Africa. The presence of two species of cercosporoid fungi on Fabaceae previously reported from Benin, namely Nothopassalora personata and Passalora arachidicola, is confirmed.

Polyphasic Taxonomy of Four Passalora-like Taxa Occurring on Fruit and Forest Trees

Species of Passalora s. lat. are eminent phytopathogenic fungi that cause generally leaf spot diseases on a broad variety of plants throughout the world. During our investigations exploring cercosporoid fungi associated with leaf spot symptoms of fruit and forest trees in northern and north-western Iran, several passalora-like infections were isolated from symptomatic leaves of different trees belonging to the Fabaceae, Malvaceae, Rosaceae and Ulmaceae. A polyphasic taxonomic approach by applying molecular data, morphological features and host data, was employed to identify the isolates. In a multi-gene phylogenetic analysis (LSU, ITS and RPB2), these isolates clustered in four clades in the Mycosphaerellaceae. The revealed taxa encompass Paracercosporidium microsorum on Tilia platyphyllos, Prathigadoides gleditsiae-caspicae gen. et. sp. nov. on Gleditsia caspica, Pruniphilomyces circumscissus on Prunus avium and Prunus cerasus, and Sirosporium celtidis on Celtis australis. The new genus Prathigadoides and its type species Prathigadoides gleditsiae-caspicae are molecularly distinct from all phylogenetically related genera, and some characteristics of the conidiophores and conidia differs from those of the morphologically similar species Prathigada condensata on the North America Gleditsia triacanthos.

Exploring the overlooked diversity of plant-associated Cerrado Microfungi

In this review, we present an historic account of the work on the diversity of fungi associated with plants of the Cerrado Biome, including an overview of the studies carried out by the research group of the Mycological Collection connected to the Herbarium UB (Universidade de Brasília), and the rust fungi in Herbarium IBI (Instituto Biológico, São Paulo). The contributions to Cerrado mycology from the early 19th century to the present days were highlighted. Illustrative maps were included to show the geographical distribution of the main fungal groups, associated with native plants of the Cerrado, belonging to the five predominant orders: Pucciniales (rust fungi), Phyllachorales (tar-spot fungi), Capnodiales (cercosporoid fungi: Family Mycosphaerellaceae), as well as Meliolales and Asterinales (black mildews).

Phytopathogenic Cercosporoid Fungi—From Taxonomy to Modern Biochemistry and Molecular Biology

Phytopathogenic cercosporoid fungi have been investigated comprehensively due to their important role in causing plant diseases. A significant amount of research has been focused on the biology, morphology, systematics, and taxonomy of this group, with less of a focus on molecular or biochemical issues. Early and extensive research on these fungi focused on taxonomy and their classification based on in vivo features. Lately, investigations have mainly addressed a combination of characteristics such as morphological traits, host specificity, and molecular analyses initiated at the end of the 20th century. Some species that are important from an economic point of view have been more intensively investigated by means of genetic and biochemical methods to better understand the pathogenesis processes. Cercosporin, a photoactivated toxin playing an important role in Cercospora diseases, has been extensively studied. Understanding cercosporin toxicity in relation to reactive oxygen species (ROS) production facilitated the discovery and regulation of the cercosporin biosynthesis pathway, including the gene cluster encoding pathway enzymes. Furthermore, these fungi may be a source of other biotechnologically important compounds, e.g., industrially relevant enzymes. This paper reviews methods and important results of investigations of this group of fungi addressed at different levels over the years.

Pseudocercospora seropedicensis & P. solani-cernui spp. nov. on Solanum from Brazil

Using stereo- and light microscopy, two leaf-spotting cercosporoid fungi, collected from areas of the Brazilian Atlantic Forest in the states of Minas Gerais and Rio de Janeiro, were shown to represent two new species (Pseudocercospora seropedicensis on Solanum asperum and P. solani-cernui on S. cernuum), which are herein described and illustrated.

Taxonomy and phylogeny of cercosporoid fungi (Mycosphaerellaceae) from China 1

Cercosporoid fungi include a large number of mostly plant pathogenic fungi with a wide geographic distribution, being usually associated with leaf spots on a broad range of plant hosts. Here we initiate a series of studies on Chinese cercosporoid fungi, focussing on the identification of some common, rare and new plant diseases caused by these leaf-spotting ascomycetes. The aim of the series is to resolve the taxonomy and DNA phylogeny of this important group of phytopathogens in China. In this study, nine isolates of cercosporoid fungi were collected from five host species. Partial nucleotide sequence data of four gene loci (ITS, LSU, TUB and tef1-α rDNA) were generated for all isolates. Based on morphological characters in vivo and in vitro and phylogenetic data, a new species, Pseudocercospora pauciseptata (on living leaves of Pyracantha fortuneana), is introduced including a detailed description, illustration and comparison with similar species. In addition, Passalora circumscissa, Pseudocercospora cercidis-chinensis, P. lindericola, and P. prunicola are described, illustrated and phylogenetically characterized. Cerasus pseudocerasus represents a new host record for Passalora circumscissa in China, while Lindera reflexa is a new host for P. lindericola.