Graminicolous Species Research Articles

Molecular phylogeny and morphology reveal two new graminicolous species, Curvularia aurantiasp. nov. and C. vidyodayana sp. nov. with new records of Curvularia spp. from Sri Lanka.

Despite being a small island, Sri Lanka is rich in fungal diversity. Most of the fungi from Sri Lanka have been identified as pathogens of vegetables, fruits, and plantation crops to date. The pleosporalean genus Curvularia (Dothideomycetes) includes phytopathogenic, saprobic, endophytic, and human/animal opportunistic pathogenic fungal species. The majority of the plant-associated Curvularia species are known from poaceous hosts. During the current study, 22 geographical locations of the country were explored and collections were made from 10 different poaceous hosts. Morphology and molecular phylogeny based on three loci, including nuclear internal transcribed spacers 1 and 2 with 5.8S nrDNA (ITS), glyceraldehyde-3-phosphate dehydrogenase (gapdh), and translation elongation factor 1-α (tef1) supported the description of two new species of fungi described herein as C. aurantia sp. nov. and C. vidyodayana sp. nov. Moreover, novel host-fungal association records for C. chiangmaiensis, C. falsilunata, C. lonarensis, C. plantarum, and C. pseudobrachyspora are updated herein. In addition, five species within the genus Curvularia, viz., C. asiatica, C. geniculata, C. lunata, C. muehlenbeckiae, and C. verruculosa represent new records of fungi from Sri Lanka. Citation: Ferdinandez HS, Manamgoda DS, Udayanga D, Munasinghe MS, Castlebury LA (2023). Molecular phylogeny and morphology reveal two new graminicolous species, Curvularia aurantia sp. nov. and C. vidyodayana sp. nov. with new records of Curvularia spp. from Sri Lanka. Fungal Systematics and Evolution 12: 219-246. doi: 10.3114/fuse.2023.12.11.

Molecular phylogeny and morphology reveal two new graminicolous species, Bipolaris adikaramae sp. nov and B. petchii sp. nov., with new records of fungi from cultivated rice and weedy grass hosts

Molecular phylogeny and morphology reveal two new graminicolous species, Bipolaris adikaramae sp. nov and B. petchii sp. nov., with new records of fungi from cultivated rice and weedy grass hosts

Curvularia eragrostidis isolates (Dematiaceae) for biocontrol of crabgrass (Digitaria spp.) in Canada

ABSTRACT Large crabgrass (Digitaria sanguinalis (L.) Scop.) and smooth crabgrass (Digitaria ischaemum (Schreb.) Schreb. ex Muhl.) arrived into North America from Eurasia with immigrants as promising grain and forage crops, but they have become troublesome invasive weeds in cropland and turfgrass. Twenty-three foliar pathogens were isolated from crabgrass near Ste-Anne-de-Bellevue, QC, Canada and evaluated as potential microbial herbicides. Four Curvularia eragrostidis (Henn.) J. A. Mey., [Anamorph, (Meyer, 1959). Moisissures du sol et des litières de la région de yangambi (Congo belge). Publications de L'Institut Agronomique du Congo Belge, 75, 211 pp., Synonym of Cochliobolus eragrostidis (Tsuda & Ueyama) Sivan, Teleomorph, (Sivanesan, 1987). Graminicolous species of Bipolaris, Curvularia, Drechslera. Exserohilum and Their Teleomorphs. Mycological Papers, 158, 1–261] isolates were pathogenic on both large and smooth crabgrass. Two isolates with superior virulence proceeded to a host range assessment on 21 non-target grass species. Many plant species tested were not damaged, but timothy, creeping bentgrass, colonial bentgrass, and smooth bromegrass, were highly susceptible to these isolates. In addition, oats, millet, and sorghum were also susceptible. Susceptibility of these crops raises conflicts of interest and highlights the non-target risks of proceeding with the development of this microbial herbicide. Contra-wise these forage grass species are also recognised as undesirable invasive weeds in native North American grasslands. When the efficacy of Canadian isolate Dip0307 was compared to C. eragrostidis QZ-2000 bioherbicide from China, there was no difference in the control of large crabgrass. Further studies with the isolates are needed to verify their microbial herbicide potential for crabgrass suppression. Resolution of any conflict of interest will require consultation amongst various stakeholders, and if there is an apparent conflict, this needs to be resolved, if not beforehand then at least in parallel with any further studies.

Contribution to the phylogeny and a new species of Coccodiella (Phyllachorales)

Coccodiella is a genus of plant-parasitic species in the family Phyllachoraceae (Phyllachorales, Ascomycota), i.e., tropical tar spot fungi. Members of the genus Coccodiella are tropical in distribution and are host-specific, growing on plant species belonging to nine host plant families. Most of the known species occur on various genera and species of the Melastomataceae in tropical America. In this study, we describe the new species C. calatheae from Panama, growing on Calathea crotalifera (Marantaceae). We obtained ITS, nrLSU, and nrSSU sequence data from this new species and from other freshly collected specimens of five species of Coccodiella on members of Melastomataceae from Ecuador and Panama. Phylogenetic analyses allowed us to confirm the placement of Coccodiella within Phyllachoraceae, as well as the monophyly of the genus. The phylogeny of representative species within the family Phyllachoraceae, including Coccodiella spp., graminicolous species of Phyllachora and taxa with erumpent to superficial stroma from several host families, suggests that the genus Phyllachora might be polyphyletic. Furthermore, tar spot fungi with superficial or erumpent perithecia seem to be restricted to the family Phyllachoraceae, independently of the host plant. We also discuss the biodiversity and host-plant patterns of species of Coccodiella worldwide.

First Report of Anthracnose Caused by Colletotrichum navitas on Switchgrass in New York.

Switchgrass (Panicum virgatum L.) is a perennial grass with significant potential as a biofuel crop. From 2007 to 2010, foliar lesions were observed in new and mature stands of switchgrass in various locations in New York. Lesions were elliptical with purple margins and white necrotic centers, generally <3 cm long, ~1 mm wide, often coalesced, and containing black setae. Upon incubation, symptomatic leaf tissue developed acervuli with masses of salmon-colored spores. The fungus was identified as Colletotrichum nativas Crouch on the basis of typical cultural characteristics and conidial morphology (1). Conidia were one-celled, hyaline, fusiform, and generally falcate. Conidial length averaged 40 μm (22 to 47 μm) and width averaged 5 μm (4 to 7 μm). Compared with other graminicolous species of Colletotrichum, the conidia were larger and varied from straight to irregularly bent. Sequences of the rDNA internal transcribed spacer (ITS) regions of three isolates (Cornell accession and corresponding GenBank Nos.: Cn071NY08 (from a >20-year-old naturalized stand of switchgrass in Steuben County), JF437053; Cn080NY08 (from 'Pathfinder' in Chemung County), JF437054; and Cn101NY09 (from 'Blackwell' in Chemung County), JF437055) exhibited 100% nucleotide identity to the type isolate of C. nativas (GenBank No. GQ919068) collected from switchgrass selection 'Brooklyn' in New Jersey (1). Pathogenicity of the sequenced isolates along with seven other isolates (Cn105NY09 from 'Sunburst' in Tompkins County; Cn107NY09 from 'Trailblazer' in Tompkins County; Cn109NY09 from 'Forestburg' in Tompkins County; Cn111NY09 and Cn112NY09 from 'Shelter' in Tompkins County; and Cn122NY09 and Cn123NY09 from 'Cave-in-Rock' in Genesee County) was evaluated in greenhouse experiments. Seven- to eight-week-old switchgrass plants were inoculated with conidial suspensions (1 × 106 conidia/ml) of C. nativas. Inoculum or sterilized water was sprayed until runoff. Three plants of each of 'Cave-in-Rock' and 'Kanlow' were sprayed per treatment and the experiment was repeated for 3 of the 10 isolates. Inoculated plants were placed in a mist chamber for 48 h before they were returned to the greenhouse and observed for disease development, which occurred within 1 week of inoculation for both cultivars. No symptoms developed on the control plants. Foliar lesions closely resembled those observed in the field. C. nativas was consistently reisolated from symptomatic tissue collected from greenhouse experiments. Switchgrass anthracnose associated with C. graminicola sensu lata has been reported in many U.S. states (2). On the basis of molecular phylogenetics and distinguishing morphological characters, Crouch et al. erected C. navitas as a novel species distinct from C. graminicola sensu stricto, a taxon restricted to the corn anthracnose pathogen (1). C. nativas was first documented on switchgrass in New Jersey (1) and appears to be the same pathogen causing anthracnose of switchgrass in the adjoining state of Pennsylvania (1,3). To our knowledge, this is the first report of C. nativas causing anthracnose of switchgrass in New York.

The Species Composition and Seasonal Dynamics of Thrips (Thysanoptera) Populations on Maize (Zea Mays L.) in Southeastern Poland

The Species Composition and Seasonal Dynamics of Thrips (Thysanoptera) Populations on Maize (Zea MaysL.) in Southeastern PolandThrips species composition and seasonal abundance was studied on maize crops during two seasons (2006-2007), in southeastern Poland. Altogether 21 species have been identified, among themFrankliniella tenuicornis(Uzel 1895) andHaplothrips aculeatus(Fabricius 1803) which are a graminicolous species and were eudominants, comprising 96.8% in 2006 and 82.0% in 2007 of all collected specimens. Other species occurred only in low numbers. The frequent and numerous presence ofF. tenuicornisspecies in their immature stages in the samples, confirmed the role of the maize plant as the host.H. aculeatusprobably chose maize as a food source and substitute plant for breeding.

Thrips (Thysanoptera, Insecta) of the Babia Góra massif (Western Carpathians, Poland)

This first investigation of the Thysanoptera of the Babia Góra massif (Western Carpathians, Poland), carried out in 18 plant associations in five mountain belts, resulted in the collection of 64 species. By using a sweeping net 61 species were caught and by shaking flowering plants 53 species. The number of collected species decreased with altitude, from 62 in the lower forest belt to 21 in the alpine belt, as a result of the decreasing number of host plants and unfavorable abiotic factors. The proportion of graminicolous species increased from 22% in the foothills to 33% in the alpine zone (75% in Junco trifidi-Festucetum airoidis ). Four species characteristic of foothills and mountain areas were noted ( Oxythrips tatricus, Thrips trybomi, Haplothrips alpestris and H. alpicola ). O. tatricus was collected only on Pinus mugo in the sub-alpine belt and this was the second finding of this species in Poland.

Three new graminicolous species of Curvularia (anamorphic fungi) from Queensland, Australia

Three new species of Cuvularia, C. bothriochloae sp. nov., C. micrairae sp. nov. and C. queenslandica sp. nov., isolated from grass hosts in Queensland are described, illustrated and compared with closely related species.

A new species of endophytic Balansia from Veracruz, Mexico

A new graminicolous species of Clavicipitaceae, Balansia brunnans sp. nov., has been found to infect Panicum xalapénse. Staining of living host tissues indicates the presence of intercellular endophytic mycelium. Stromata develop just below the nodes on the culms. Balansia brunnans is comparable to Balansia aristidae, B. discoidea, B. gaduae, B. nigricans, and B. strangulans in development of stromata on culms and possession of an endophytic mycelial stage. Among the differences between Balansia brunnans and other comparable species is that it possesses a brown perithecial stroma, whereas comparable species have black perithecial stromata. A key is provided to distinguish B. brunnans from similar species.

A New Species of Endophytic Balansia from Veracruz, Mexico

A new graminicolous species of Clavicipitaceae, Balansia brunnans sp. nov., has been found to infect Panicum xalapénse. Staining of living host tissues indicates the presence of intercellular endophytic mycelium. Stromata develop just below the nodes on the culms. Balansia brunnans is comparable to Balansia aristidae, B. discoidea, B. gaduae, B. nigricans, and B. strangulans in development of stromata on culms and possession of an endophytic mycelial stage. Among the differences between Balansia brunnans and other comparable species is that it possesses a brown perithecial stroma, whereas comparable species have black perithecial stromata. A key is provided to distinguish B. brunnans from similar species.

Chaunopycnis pustulata sp. nov., a new clavicipitalean anamorph producing metabolites that modulate potassium ion channels

Two morphologically similar strains of hyphomycetous fungi, MF5785 and MF5638, produced potent indole diterpene antagonists of the calcium-gated potassium ion channel, Maxi-K, and a diterpene blocker (nalanthalide) of the voltage-gated potassium channel, Kv1.3, respectively. The two strains were tentatively identified in the literature as Nalanthamala species. Analyses of their secondary metabolite profiles by HPLC and mass spectroscopy demonstrated that both produced a series of indole diterpenes, of which at least one was produced by both strains. Another strain, Chaunopycnis alba (MF6799), that produced the diterpene, nalanthalide, also produced indole diterpene metabolites. Morphological comparisons and phylogenetic studies based on 28S and ITS rDNA sequences indicated that MF5785 and MF5368, and another soil-derived strain GB6597, belonged to a monophyletic clade of the Clavicipitaceae that included the anamorph Chaunopycnis alba and several Cordyceps and Tolypocladium species. A new species of Chaunopycnis is therefore proposed to accommodate MF5785, MF5368, and GB6597. The possible synonymy of Albophoma yamanashiensis with C. alba also is discussed. Within the Clavicipitaceae, indole diterpenoid compounds have only been known from the graminicolous species (subfamily Clavicipitoideae); therefore delineation of a Chaunopycnis clade has revealed a previously unrecognized lineage of indole diterpene-producing fungi among the subfamily Cordycipitoideae. Taxonomical novelty: Chaunocycnis pustulata Bill, Polishook & J.F. White

Book Reviews

Books Reviewed in this Article: European Handbook of Plant Diseases, edited by I. M. Smith, J. Dunez, R. A. Lelliott, D. H. Phillips and S. A. Archer. Control of Plant Diseases: Costs and Benefits. edited for the British Society for Plant Pathology by B. C. Clifford and E. Lester. Biological Control of Pests, Pathogens and Weeds: Developments and Prospects, edited by R. K S. Wood and M.J. Way. A Reappraisal of Ascochytula and Ascochytella (Coelomycetes), by P. K. Buchanan. Graminicolous Species of Bipolar is, Curvularia, Drechslera, Exserohilum and their Teleomorphs, by A Sivanesan. Ascochyta II. Species on Monocotyledons (excluding grasses), Cryptogams and Gymnosperms by E. Punithalingam

The Taxonomy of "Helminthosporium" Species

Helminthosporium Link: Fr. is a generic name well known to plant pathologists.l It has been applied to some important pathogens, such as H. maydis Nisik. & Miyake, H. oryzae Breda de Haan, H. turcicum Pass. and H. teres Sacco These and similar species are commonly associated with leaf spots or blights, foot rots, and other disease syndromes on cultivated and wild Poaceae. Their ability to cause devastating disease has occasionally resulted in famine and loss of human life (82) or in great economic loss (121). Other plant groups are also affected: palms (27), cacti (13), Leucospermum spp. (123), beans (29), forage legumes (93), rubber, Musa (24), and coffee (l 05) are reported as hosts. In addition, mycoses in domestic animals and man increasingly are being attributed to these fungi (70). They have been im­ plicated in mycotoxicoses in grazing animals (97), and mycoparasitic activity by them has been reported (83). Their classification is therefore of more than academic interest, especially as the genus Helminthosporium should be re­ stricted to ca. 20 species (34), most of which are saprotrophs. It has been suggested that knowledge of the systematics of two segregate genera, Drech­ slera and Bipolaris, is inadequate (33). The subject of this review is the taxonomic and nomenclatural fate of the predominantly graminicolous species studied by plant pathologists and others.

Studies on Graminicolous species, of Phyllachora Nke. in Fckl. VI. Additions and corrections to part V

The present contribution adds to a recent monograph of graminicolous species of Phyllachora and corrects some omissions and errors. Two new species, P. africana and P. oblongospora, are described, and four names previously put into synonym are reconstituted as belonging to valid species, viz. P. eximia, P. setariecola, P. sporobolica, and P. texensis. Three species names have been changed : P. acuminata to P. acutispora, P. gracilis (sensu Parbery 1967) to P. eximia, and P. bonariensis to P. setariecola. Two names have been put into different synonymy. P. caespitica is now regarded as synonymous with P. malabarensis instead of P. bambusina, and P. standleyi as P. paspalicola instead of P. punctum. A number of new hosts of Phyllachora as well as new geographic and host range extensions are recorded. Some comments are made on doubtful and excluded species as well as some general comment on the taxonomy of this genus.

Growth, sporulation and conidial characteristics of five graminicolous species of Helminthosporium: II. Effect of nitrogen and pH

Growth, sporulation and conidial characteristics of five graminicolous species of Helminthosporium: II. Effect of nitrogen and pH

Growth, sporulation and conidial characteristics of five graminicolous species of Helminthosporium: I. Effect of nutrients

The pH, asparagine concentration and (especially) nitrogen source all significantly affected growth, sporulation and morphology, colour and dimensions (particularly length) of conidia produced by Helminthosporium rostratum Drechsler, H. sorghicola Lefebvre & Sherwin, H. cynodontis Marigoni, H. hawaiiense Bugnicourt and H. australiense Bugnicourt in culture. The optimum for vegetative growth was often about 0–04 % nitrogen as asparagine and that for sporulation somewhat lower (0–02%), but H. australiense and H. hawaiiense had higher optima. Conidia tended to be shorter with increasing nitrogen. Potassium nitrate, asparagine, glycine and urea were with some exceptions suitable for growth, but ammonium nitrate, ammonium sulphate, sodium nitrite, methionine and lysine resulted in poor growth, in some cases probably due to marked acidification of the medium. Nitrogen source greatly affected the size of conidia, mean length in H. rostratum ranging from 75 μ with methionine to 115 μ with sodium nitrite. Maximum growth generally occurred on neutral to slightly acid media and maximum sporulation at a somewhat lower pH, but H. rostratum, H. hawaiiense and H. australiense seemed more tolerant of alkalinity than the other two species. The longest conidia usually developed at neutrality or slight acidity. Conidial variation in culture was mostly within the range occurring in nature, except that sodium nitrite produced greater variation in length.

Studies on Graminicolous Species of Phyllachora Fckl. I. Ascospores - their liberation and germination

The process of ascospore liberation is a moderately active one. Discharged ascospores collect on the host leaf surface in white, glutinous masses and are believed to be dispersed by rain splash. Ascospores of all species examined germinated in 2-12 hr at 14°C under laboratory conditions, but there were indications that the process was more rapid in the field. The pattern for spore germination and appressorium formation was similar for the six species studied. Each ascospore produced a single germ tube which, in 2-6 hr after germination began, formed an appressorium initial in the form of a swelling at its apex. Appressoria were completely developed 6-12 hr later. The process of appressorium development is described for species of Phyllachora for the first time. The swelling at the apex of the germ tube extended back along the germ tube towards the ascspore. In some species, e.g. P. cornispora, the entire germ tube was converted into an appressorium which consequently was sessile. In other species, such as P. parilis, only approximately half of the germ tube developed into appressorium. In P. parilis, temperatures greater than 26°C inhibited appressorium formation. Instead of producing appressoria, germ tubes continued to grow and became long and flexuous. Germination did not occur at temperatures of 30°C or greater. Evidence suggested that while contact with a surface was not necessary to initiate appressorium formation, contact with a grass leaf surface was required for appressoria to develop normally. The morphology of appressoria of individual species of Phyllachora was usually variable when these structures developed in vitro but constant and distinct when they developed on the host. Among the species examined three basic morphological types of appressoria were recognized.

Studies on Graminicolous Species of Phyllachora Fckl. II.. Invasion of the host and development of the fungus

Infection of grasses by species of Phyllachora Fckl. has been observed, and a detailed examination of the life cycle of two species of this genus has been made on hosts artificially inoculated while growing under glass-house conditions. Gemiiiatiiig ascospores of P. ischaemi and P. parilis prodced appressoria on the leaves of their respective hosts, Ischaemum australe and Paspalurn orbiculare. From each appressorium an infection peg penetrated into the lumen of an epidermal cell and expanded into a normal hypha. Some branches of this hypha invaded adjacent epidermal cells, thus laying the foundations of the clypeus, while other branches invaded the underlying mesophyll cells. At first all hyphae were intracellular and passed from cell to cell by means of fine infection hyphae produced by appressorium-like swellings of the hyphae appressed to the cell wall. Intercellular mycelium was found at a later stage when hyphae were forming perithecium initials. The observation that the clypeus developed independently of the perithecium dispels some existing confusion about its origin. The clypeus developed in the epidermal cells of the host and not as an outgrowth of the ostiolar region of the perithecium. The perithecium initial developed deep in the mesophyll, and in the case of Phyllachora parilis was preceded by the formation of a subclypeal pycnidium containing filiform spores. In each case, the perithecium expanded until its ostiolar region came into close contact with the clypeus. The ostiole then developed right through the ciypeus, and its development is believed to be lysigenous. The mouth of the ostiole remained closed by a membrane which appeared to be the undissolved cuticle. It was noted that asci of all species examined possessed an ascus crown, a structure not previously observed in species of this genus. It has been found that the anatomy of the host can determine the form of some structures of Phyllachora spp. Clypeus thickness is governed by the size of the epidermal cells, while its radial expansion is checked by the mechanical tissue associated with vascular bundles. Similarly, perithecium size and shape are influenced by the amount of mechanical tissue in a leaf. The time for P. ischaemi to complete its life cycle was influenced by seasonal conditions. Colonies arising from infections in April 1961 discharged ascospores in 32 days, whereas infections made 1 month later did not produce sporulating colonies until 54-58 days later. The full life cycle of P. parilis took 62-77 days when inoculations were made in May 196 1.

Studies on graminicolous species of Helminthosporium: I. H. phlei (Graham) comb.nov.

Since Drechsler (1923) published the results of his studies on some graminicolous species of Helminthosporium , no one has studied in detail a large number of species on grasses at the same time. In some species there is a great variation in dimensions and other characters under different environmental conditions. Especially variable are those species which produce their conidia in chains. In this paper one of these variable species is described in detail. Later papers will deal with several other species.

NOMENCLATURE OF DRECHSLERA AND BIPOLARIS, GRASS PARASITES SEGREGATED FROM ‘HELMINTHOSPORIUM’

As a result of a taxonomic study of some graminicolous fungi classed in ‘Helminthosporium’ the following conclusions concerning their nomenclature were reached. The original spelling of Helmisporium Link validated by S. F. Gray in 1821 is taken up instead of the illegitimate orthographic variant ‘Helminthosporium’ Link ex Pers. Helmisporium is restricted to the generic type and its chiefly lignicolous allies, all of which form conidia both apically and laterally on the conidiophores. The graminicolous species form conidia apically and a new apex is formed by subterminal growth. Sixteen species with cylindric conidia that germinate from all cells are included in Drechslera Ito. The lectotype, D. tritici-vulgaris (Nisikado) Ito, is designated and D. arundinis (Lév.) Ito is excluded. The generic name Bipolaris is proposed for the other major group of graminicolous species. These, like the holotype (basionym H. maydis Nisikado), form fusoid phragmospores that exhibit bipolar germination.