Identifying and naming plant-pathogenic fungi: past, present, and future
Crous, P.W. ; Hawksworth, D.L. ; Wingfield, M.J. - \ 2015
Annual Review of Phytopathology 53 (2015). - ISSN 0066-4286 - p. 247 - 267.
molecular systematics - polyphyletic nature - polyphasic approach - mycorrhizal fungi - species concepts - taxonomy - genus - classification - identification - chromatography
Scientific names are crucial in communicating knowledge about fungi. In plant pathology, they link information regarding the biology, host range, distribution, and potential risk. Our understanding of fungal biodiversity and fungal systematics has undergone an exponential leap, incorporating genomics, web-based systems, and DNA data for rapid identification to link species to metadata. The impact of our ability to recognize hitherto unknown organisms on plant pathology and trade is enormous and continues to grow. Major challenges for phytomycology are intertwined with the Genera of Fungi project, which adds DNA barcodes to known biodiversity and corrects the application of old, established names via epi- or neotypification. Implementing the one fungus–one name system and linking names to validated type specimens, cultures, and reference sequences will provide the foundation on which the future of plant pathology and the communication of names of plant pathogens will rest.
Diaporthe: a genus of endophytic, saprobic and plant pathogenic fungi
Gomes, R.R. ; Glienke, C. ; Videira, S.I.R. ; Lombard, L. ; Groenewald, J.Z. ; Crous, P.W. - \ 2013
Persoonia 31 (2013). - ISSN 0031-5850 - p. 1 - 41.
internal transcribed spacer - south-africa - species concepts - sp-nov - coelomycete phomopsis - foeniculum-vulgare - multigene analysis - north-america - ribosomal dna - twig dieback
Diaporthe (Phomopsis) species have often been reported as plant pathogens, non-pathogenic endophytes or saprobes, commonly isolated from a wide range of hosts. The primary aim of the present study was to resolve the taxonomy and phylogeny of a large collection of Diaporthe species occurring on diverse hosts, either as pathogens, saprobes, or as harmless endophytes. In the present study we investigated 243 isolates using multilocus DNA sequence data. Analyses of the rDNA internal transcribed spacer (ITS1, 5.8S, ITS2) region, and partial translation elongation factor 1-alpha (TEF1), beta-tubulin (TUB), histone H3 (HIS) and calmodulin (CAL) genes resolved 95 clades. Fifteen new species are described, namely Diaporthe arengae, D. brasiliensis, D. endophytica, D. hongkongensis, D. inconspicua, D. infecunda, D. mayteni, D. neoarctii, D. oxe, D. paranensis, D. pseudomangiferae, D. pseudophoenicicola, D. raonikayaporum, D. schini and D. terebinthifolii. A further 14 new combinations are introduced in Diaporthe, and D. anacardii is epitypified. Although species of Diaporthe have in the past chiefly been distinguished based on host association, results of this study confirm several taxa to have wide host ranges, suggesting that they move freely among hosts, frequently co-colonising diseased or dead tissue. In contrast, some plant pathogenic and endophytic taxa appear to be strictly host specific. Given this diverse ecological behaviour among members of Diaporthe, future species descriptions lacking molecular data (at least ITS and HIS or TUB) should be strongly discouraged.
A multi-locus phylogenetic evaluation of Diaporthe (Phomopsis)
Udayanga, D. ; Liu, X. ; Crous, P.W. ; McKenzie, E.H.C. ; Chukeatirote, E. ; Hyde, K.D. - \ 2012
Fungal Diversity 56 (2012)1. - ISSN 1560-2745 - p. 157 - 171.
multiple sequence alignment - plant-pathogenic fungi - species concepts - south-africa - primer sets - genes - phaseolorum - longicolla - pcr - phylogeography
The genus Diaporthe (Phomopsis) includes important plant pathogenic fungi with wide host ranges and geographic distributions. In the present study, phylogenetic species recognition in Diaporthe is re-evaluated using a multi-locus phylogeny based on a combined data matrix of rDNA ITS, and partial sequences from the translation elongation factor 1-a (EF 1-a), ß tubulin (TUB) and calmodulin (CAL) molecular markers. DNA sequences of available ex-type cultures have been included, providing a multi-locus backbone tree for future studies on Diaporthe. Four utilizable loci were analyzed individually and in combination, and ITS, EF 1-a and multi-locus phylogenetic trees are presented. The phylogenetic tree inferred by combined analysis of four loci provided the best resolution for species as compared to single gene analysis. Notes are provided for nine species previously known in Phomopsis that are transferred to Diaporthe in the present study. The unraveling of cryptic species complexes of Diaporthe based on Genealogical Concordance Phylogenetic Species Recognition (GCPSR) is emphasized.
A phylogenetic and taxonomic re-evaluation of the Bipolaris - Cochliobolus - Curvularia Complex
Manamgoda, D.S. ; Cai, L. ; McKenzie, E.H.C. ; Crous, P.W. ; Madrid, H. ; Chukeatirote, E. ; Shivas, R.G. ; Tan, Y.P. ; Hyde, K.D. - \ 2012
Fungal Diversity 56 (2012)1. - ISSN 1560-2745 - p. 131 - 144.
species concepts - sequences - pseudocochliobolus - helminthosporium - pathogens - alignment - genes - fungi - genus - rdna
Three genera, Cochliobolus, Bipolaris and Curvularia form a complex that contains many plant pathogens, mostly on grasses (Poaceae) with a worldwide distribution. The taxonomy of this complex is confusing as frequent nomenclatural changes and refinements have occurred. There is no clear morphological boundary between the asexual genera Bipolaris and Curvularia, and some species show intermediate morphology. We investigated this complex based on a set of ex-type cultures and collections from northern Thailand. Combined gene analysis of rDNA ITS (internal transcribed spacer), GPDH (glyceraldehyde 3-phosphate dehydrogenase), LSU (large subunit) and EF1-a (translation elongation factor 1-a) shows that this generic complex divides into two groups. Bipolaris and Cochliobolus species clustered in Group 1 along with their type species, whereas Curvularia species (including species named as Bipolaris, Cochliobolus and Curvularia) clustered in Group 2, with its generic type. The nomenclatural conflict in this complex is resolved giving priority to the more commonly used established generic names Bipolaris and Curvularia. Modern descriptions of the genera Bipolaris and Curvularia are provided and species resolved in this study are transferred to one of these genera based on their phylogeny.
Phylogeny and systematics of the genus Calonectria
Lombard, L. ; Crous, P.W. ; Wingfield, B.D. ; Wingfield, M.J. - \ 2010
Studies in Mycology 66 (2010)1. - ISSN 0166-0616 - p. 31 - 69.
internal transcribed spacers - sp-nov - cylindrocladium-floridanum - species concepts - dna-sequences - ribosomal dna - beta-tubulin - morphology - polymorphism - spathiphylli
Species of Calonectria are important plant pathogens, several of which have a worldwide distribution. Contemporary taxonomic studies on these fungi have chiefly relied on DNA sequence comparisons of the ß-tubulin gene region. Despite many new species being described, there has been no phylogenetic synthesis for the group since the last monographic study almost a decade ago. In the present study, the identity of a large collection of Calonectria isolates from various geographic regions was determined using morphological and DNA sequence comparisons. This resulted in the discovery of seven new species; Ca. densa, Ca. eucalypti, Ca. humicola, Ca. orientalis, Ca. pini, Ca. pseudoscoparia and Ca. sulawesiensis, bringing the total number of currently accepted Calonectria species to 68. A multigene phylogeny was subsequently constructed for all available Calonectria spp., employing seven gene regions, namely actin, ß-tubulin, calmodulin, histone H3, the internal transcribed spacer regions 1 and 2 and the 5.8S gene of the ribosomal RNA, 28S large subunit RNA gene and translation elongation 1-alpha. Based on these data 13 phylogenetic groups could be distinguished within the genus Calonectria that correlated with morphological features. Dichotomous and synoptic keys to all Calonectria spp. currently recognised are also provided.