Celoporthe dispersa gen. et sp. nov. from native Myrtales in South Africa

In a survey for Cryphonectria and Chrysoporthe species on Myrtales in South Africa, a fungus resembling the stem canker pathogen Chrysoporthe austroafricana was collected from native Syzygium cordatum near Tzaneen (Limpopo Province), Heteropyxis canescens near Lydenburg (Mpumalanga Province) and exotic Tibouchina granulosa in Durban (KwaZulu-Natal Province). The fungus was associated with dying branches and stems on S. cordatum, H. canescens and T. granulosa. However, morphological differences were detected between the unknown fungus from these three hosts and known species of Chrysoporthe. The aim of this study was to characterise the fungus using DNA sequence comparisons and morphological features. Pathogenicity tests were also conducted to assess its virulence on Eucalyptus (ZG 14 clones), H. natalensis and T. granulosa. Plants of H. canescens were not available for inoculation. Results showed distinct morphological differences between the unknown fungus and Chrysoporthe spp. Phylogenetic analysis showed that isolates reside in a clade separate from Chrysoporthe and other related genera. Celoporthe dispersa gen. et sp. nov. is, therefore, described to accommodate this fungus. Pathogenicity tests showed that C. dispersa is not pathogenic to H. natalensis, but that it is a potential pathogen of Eucalyptus and Tibouchina spp

Microthia, Holocryphia and Ursicollum, three new genera on Eucalyptus and Coccoloba for fungi previously known as Cryphonectria

Cryphonectria havanensis is a fungus associated with Eucalyptus species in Cuba and Florida (U.S.A.). Until recently, there have been no living cultures of C. havanensis and it has thus not been possible to assess its taxonomic status. Isolates thought to represent this fungus have, however, emerged from surveys of Eucalyptus in Mexico and Hawaii (U.S.A.). Results of this study showed that these isolates represent C. havanensis but reside in a genus distinct from Cryphonectria sensu stricto, which is described here as Microthia. Isolates of an unidentified fungus occurring on Myrica faya in the Azores and Madeira also grouped in Microthia and were identical to other M. havanensis isolates. Cryphonectria coccolobae, a fungus occurring on sea grape (Coccoloba uvifera) in Bermuda and Florida, was found to be morphologically identical to Microthia and is transferred to this genus, but as a distinct species. Surveys for M. coccolobae on sea grape in Florida, yielded a second diaporthalean fungus from this host. This fungus is morphologically and phylogenetically distinct from M. coccolobae and other closely related taxa and is described as Ursicollum fallax gen. et sp. nov. Phylogenetic analyses in this study have also shown that isolates of C. eucalypti, a pathogen of Eucalyptus in South Africa and Australia, group in a clade separate from all other groups including that representing Cryphonectria sensu stricto. This difference is supported by the fact that Cryphonectria eucalypti has ascospore septation different to that of all other Cryphonectria species. A new genus, Holocryphia, is thus erected for C. eucalypti

New and rare coelomycetes with appendage-bearing conidia from Pondoland, South Africa

During a mycological excursion to the Pondoland region of South Africa in 2008, six interesting anamorphic fungi with appendage-bearing conidia were isolated. They are Bartalinia pondoensis, Crucellisporium umtamvunae, and Mycohypallage margaretae, all of which are new to science, Mycohypallage congesta with a new observation of gelatinous basal appendage, Mycotribulus mirabilis on a new host plant, Apodytes, and Chaetospermum camelliae. Morphological characters are described and notes provided. The teleomorphic affinity of C. umtamvunae to the Helotiales is proposed based on DNA sequence data.http://www.mycotaxon.com

Population structure of Chrysoporthe austroafricana in southern Africa determined using Vegetative Compatibility Groups (VCGs)

Chrysoporthe austroafricana is one of the most damaging pathogens of Eucalyptus trees in southern Africa. It also occurs on non-native Tibouchina granulosa trees and native Syzygium species. Additional isolates of the pathogen from previously unstudied countries in the region have become available from survey studies. The aim of this study was to use VCGs to consider the diversity in populations of isolates collected in various countries in southern Africa (Malawi, Mozambique, Namibia, South Africa and Zambia) and from different hosts. We also wanted to determine whether there are shared VCGs among these countries and hosts in southern Africa and establish a VCG tester strain data base. Results showed a high diversity amongst isolates from different countries and hosts, but suggested little movement of VCGs among countries or hosts based on the available isolates. A total of 108 VCG tester strains were identified for southern Africa.The University of Pretoria (UP), National Research Foundation (NRF), Forestry and Agricultural Biotechnology Institute (FABI) and Tree Protection Cooperative Program (TPCP).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1439-0329hb2016Microbiology and Plant Patholog

Five new species of the Botryosphaeriaceae from Acacia karroo in South Africa

The Botryosphaeriaceae represents an important, cosmopolitan family of latent pathogens infecting woody plants. Recent studies on native trees in southern Africa have revealed an extensive diversity of species of Botryosphaeriaceae, about half of which have not been previously described. This study adds to this growing body of knowledge, by discovering five new species of the Botryosphaeriaceae on Acacia karroo, a commonly occurring native tree in southern Africa. These species were isolated from both healthy and diseased tissues, suggesting they could be latent pathogens. The isolates were characterized based on their morphology and compared to other species for which DNA sequence data are available, in phylogenetic analyses based on the ITS, TEF-1α, β-tubulin and LSU gene regions. The five new species were described as Diplodia allocellula, Dothiorella dulcispinae, Do. brevicollis, Spencermartinsia pretoriensis and Tiarosporella urbis-rosarum. Evidence emerging from this study suggests that many more species of the Botryosphaeriaceae remain to be discovered in the southern Africa.Members of the Tree Protection Cooperative Programme (TPCP), the DST/NRF Centre of Excellence in Tree Health Biotechnology (CTHB) and the University of Pretoria, South Africa.http://www.cryptogamie.com/pagint_en/recherche/affich_sommaire.php?cnumero=65hb201

Botryosphaeriaceae species overlap on four unrelated, native South African hosts

Botryosphaeriaceae represents an important and diverse family of latent fungal pathogens of woody plants. We address the question of host range of these fungi by sampling leaves and branches of four native South African trees, including Acacia karroo (Fabaceae), Celtis africana (Cannabaceae), Searsia lancea (Anacardiaceae), and Gymnosporia buxifolia (Celastraceae).Twonew species of the Botryosphaeriaceae, namely Tiarosporella africana sp. nov. and Aplosporella javeedii sp. nov. were identified, together with fiveknown species, including Neofusicoccum parvum, Neofusicoccum kwambonambiense, Spencermartinsia viticola, Diplodia pseudoseriata, and Botryosphaeria dothidea. Most Botryosphaeriaceae occurred on more than one host. With the exception of S. lancea, which was infected by A. javeedii all the hosts were infected by more than one Botryosphaeriaceae species. Collectively, the results suggest that some intrinsic host factors, possibly combined with local environmental conditions, affect the distribution and co-infectivity of various hosts by the Botryosphaeriaceae. This would counteract the general ability of a species in the Botryosphaeriaceae to infect a broad range of plants. The combination of host and environmental factors might also explain why some Botryosphaeriaceae with apparently broad host ranges, are found on different suites of hosts in different areas of the world.Tree Protection Cooperative Programme (TPCP), the DST/NRF Centre of Excellence in Tree Health Biotechnology (CTHB) and the University of Pretoria, South Africa.http://www.elsevier.com/locate/funbiohb201

Endophyte isolations from Syzygium cordatum and a Eucalyptus clone (Myrtaceae) reveal new host and geographical reports for the Mycosphaerellaceae and Teratosphaeriaceae

Speci e s of Mycosphaerellaceae and Teratosphaeriaceae (Ascomycetes) cause important leaf, shoot and canker diseases globally on a broad range of hosts, including Eucalyptus and other Myrtaceae. Recently, species of the Mycosphaerellaceae and Teratosphaeriaceae have been isolated as asymptomatic endophytes. In this study, endophytic species of Mycosphaerellaceae and Teratosphaeriaceae were isolated from samples taken from healthy native Syzygium cordatum (Myrtaceae) and related non-native Eucalyptus grandis x E. camaldulensis (hybrid clone) growing in Mtubatuba, KwaZulu Natal, South Africa. Multi-locus sequence analysis (MLSA) using the Internal Transcribed Spacer (ITS) region, the partial Large Subunit (LSU; 28S nrDNA) of the nuclear ribosomal DNA operon and Translation Elongation Factor-1α (TEF-1α) genes were used to correctly identify the 22 resulting isolates. The isolates grouped in five clades representing Readeriella considenianae that was isolated only from the Eucalyptus hybrid clone, Mycosphaerella marksii and M. vietnamensis from S. cordatum and Pseudocercospora crystallina from both S. cordatum and the Eucalyptus hybrid clone. Interestingly, the serious canker pathogen T. zuluensis was isolated from Eucalyptus leaves, although it is known only from stem and branch cankers. Of the species found, R. considenianae and M. vietnamensis were found in South Africa for the first time, while M. marksii, M. vietnamensis and P. crystallina were shown to naturally infect native S. cordatum for the first time. Despite the limited number of trees sampled, the new host and distribution reports show that more intensive sampling, especially following an endophyte approach, will reveal more complete patterns of host preference and geographical distribution for these fungi.Thutuka Funding programme of the National Research Foundation (NRF), members of the Tree Protection Co-operative Programme (TPCP) and the Department of Science and Technology (DST)/NRF Centre of Excellence in Tree Health Biotechnology (CTHB), South Africa.http://link.springer.com/journal/13313hb201

Species delineation in the tree pathogen genus Celoporthe (Cryphonectriaceae) in southern Africa

The genus Celoporthe was first described when C. dispersa was discovered in South Africa associated with dieback and cankers on trees in the Myrtales. Four additional species were recently described from Eucalyptus and Syzygium cumini in China as well as S. aromaticum and Eucalyptus in Indonesia. Inoculation trials have shown that all Celoporthe species, including those that have not been found on Eucalyptus species in nature, are pathogenic to Eucalyptus and they are thus potentially threatening to commercial Eucalyptus forestry. New isolates, morphologically similar to Celoporthe, have been collected from S. legatti in South Africa and S. guineense in Zambia. Multigene phylogenetic analyses based on DNA sequences of the ITS region, TEF1a gene and two areas of the b-tubulin gene revealed additional cryptic species in Celoporthe. Phylogenetic data were supported by morphological differences. These resulted in the description of two previously unknown species of Celoporthe, namely C. fontana and C. woodiana, for two of these cryptic groups, while the third group represented C. dispersa. These species all can readily infect Eucalyptus as well as several species of Syzygium, the latter of which are native to Africa.We thank the University of Pretoria (UP), National Research Foundation (NRF), Forestry and Agricultural Biotechnology Institute (FABI) and Tree Protection Cooperative Program (TPCP) for financial support.http://www.mycologia.org/am201

Multiple Phytophthora species associated with a single riparian ecosystem in South Africa

The diversity of Phytophthora spp. in rivers and riparian ecosystems has received considerable international attention, although little such research has been conducted in South Africa. This study determined the diversity of Phytophthora spp. within a single river in Gauteng province of South Africa. Samples were collected over 1 y including biweekly river baiting with Rhododendron indicum leaves. Phytophthora isolates were identified with phylogenetic analyses of sequences for the internal transcribed spacer (ITS) region of the ribosomal DNA and the mitochondrial cytochrome oxidase c subunit I (coxI) gene. Eight Phytophthora spp. were identified, including a new taxon, P. taxon Sisulu-river, and two hybrid species from Cooke’s ITS clade 6. Of these, species from Clade 6 were the most abundant, including P. chlamydospora and P. lacustris. Species residing in Clade 2 also were encountered, including P. multivora, P. plurivora and P. citrophthora. The detection of eight species in this investigation of Phytophthora diversity in a single riparian river ecosystem in northern South Africa adds to the known diversity of this genus in South Africa and globally.We further acknowledge financial support from the National Research Foundation (NRF), the Department of Science and Technology/National Research Foundation (DST/NRF) Centre of Excellence in Tree Health Biotechnology (CTHB) and the University of Pretoria, South Africa.http://www.mycologia.orgam2016Forestry and Agricultural Biotechnology Institute (FABI)Genetic

Temporal and spatial variation of Botryosphaeriaceae associated with Acacia karroo in South Africa

The Botryosphaeriaceae are common and diverse members of fungal communities infecting woody plants. They are also increasingly being used as model organisms to understand patterns in the global movement of latent pathogens. The aim of this study was to consider the species richness of the Botryosphaeriaceae associated with the native Acacia (Vachellia) karroo across South Africa, and the variation of species at specific local sites over time. The diversity of these fungi associated with different tissues of this host plant was also considered. These questions were addressed by sampling healthy A. karroo from 23 sites in South Africa and by more intensive hierarchical sampling conducted at 40 sites in one area over 3 yr. In total, 13 species of the Botryosphaeriaceae were identified, including seven that were isolated only from the more intensively sampled area. There was a clear geographical influence, with some species occurring only in some parts of the country. Significant variation in the species richness over time for the intensively sampled area was found and there was no evidence of tissue specificity for this group of fungi in leaves, branches and branchlets. Results of pathogenicity trials showed highly variable lesion sizes for the isolated species in comparison to the control, with Sphaeropsis variabilis, Lasiodiplodia theobromae and Neofusicoccumaustrale being the most pathogenic. The overall results revealed a rich diversity of Botryosphaeriaceae on this native host, which varied significantly both geographically and on individual trees, even in the absence of obvious disease.Members of the Tree Protection Cooperative Programme (TPCP), the DST/ NRF Centre of Excellence in Tree Health Biotechnology (CTHB) and the University of Pretoria, South Africa.http://www.elsevier.com/locate/funeco2016-06-30hb201