Full Text Available The paper presents a summary of examinations on the variation of pycnidia and conidia of the following Opegrapha species occurring in Poland: O. atra, O. calcarea, O. dolomitica, O. gyrocarpa, O. niveoatra, O. rupestris, O. varia, O. vermicellifera, O. viridis and O. vulgata.
Enzien, M; Margulis, L
During and after the floods of 1979-80 Niebla ceruchis growing epiphytically on Lycium brevipes was one of the dominant aspects of the vegetation in the coastal dunal complex bordering the microbial mats at Laguna Figueroa, Baja California Norte, Mexico. The lichen on denuded branches of Lycium was far more extensively distributed than Lycium lacking lichen. Unusual traits of this Niebla ceruchis strain, namely localization of lichen compounds in the mycobiont reproductive structures (pycnidia and apothecia) and simultaneous presence of bilocular and quadrilocular ascospores, are reported. The abundance of this coastal lichen cover at the microbial mat site has persisted through April 1988.
Boerema, G.H.; Gruyter, de J.
This paper deals with ten species of Phoma, characterized by thick-walled pseudoparenchymatous pycnidia. They superficially resemble the thick-walled pycnidial phenotype in species of Phoma sect. Plenodomus, but scleroplectenchyma is lacking and teleomorphs belong to Didymella, not Leptosphaeria. Ke
Cousin, A.; Mehrabi, R.; Guilleroux, M.; Dufresne, M.; Lee, van der T.A.J.; Waalwijk, C.; Langin, T.; Kema, G.H.J.
In eukaryotes, a family of serine/threonine protein kinases known as mitogen-activated protein kinases (MAPKs) is involved in the transduction of a variety of extracellular signals and in the regulation of growth and development. We identified a MAPK-encoding gene in Mycosphaerella graminicola
Mehrabi, R.; Kema, G.H.J.
As in many fungi, asexual reproduction of Mycosphaerella graminicola in planta is a complex process that requires proper differentiation of the infectious hyphae in the substomatal cavities of foliar tissue before pycnidia with conidia can be formed. In this study, we have investigated the role of t
Mehrabi, R.; Kema, G.H.J.
As in many fungi, asexual reproduction of Mycosphaerella graminicola in planta is a complex process that requires proper differentiation of the infectious hyphae in the substomatal cavities of foliar tissue before pycnidia with conidia can be formed. In this study, we have investigated the role of
Mehrabi, R.; Kema, G.H.J.
As in many fungi, asexual reproduction of Mycosphaerella graminicola in planta is a complex process that requires proper differentiation of the infectious hyphae in the substomatal cavities of foliar tissue before pycnidia with conidia can be formed. In this study, we have investigated the role of t
Full Text Available During a survey of fungi associated with Russian olive fruit rot in Northern Iran, a coelomycete fungus with setose pycnidia was isolated from symptomatic fruits. The fungus was identified as Chaetopyrena penicillata based on morphological characteristics and sequence data of ITS and LSU rDNA. A hyphomycete synanamorph, which was observed in pure cultures of this species for the first time, is described. The morphology and phylogeny of Chaetopyrena penicillata is discussed.
Full Text Available Neofusicoccum luteum is reported for the first time from olives (Olea europaea, causing fruit rot and leaf necrosis. Affected fruits initially became brown with pycnidia developing on the surface, later drying out and becoming mummified. The fungus was shown to be pathogenic on both fruits and leaves. The association of Botryosphaeriaceae with rotting olive fruits in Mediterranean regions and in New South Wales, Australia indicates that these fungi play a significant role in fruit rots of olives and deserve greater attention.
Latif R. Susuri
Full Text Available Phoma medicaginis has recently been spreading on alfalfa causing black leaf and stem in irrigation fields near Prizren. The average number of lesions is from 18 up to 30 on leaves with an average diameter of 1-10 mm. The average size of pycnidia from diseased alfalfa leaves, stems and PDA is 325 x 338 μm, whereas the average size of pycnidiospores is 7.3 x 3.6 μm. Maximum spore production in average was on PDA 140.9 x 104/ml.
Antoni Józef Filipowicz
Full Text Available Fifty five isolates of Ascochyta fabae Speg. were investigated. They were selected from 1650 isolates of this fungus obtained from horse bean seeds in 1974-1976. All the isolates grew and sporulated on Potato Dextrose Agar, Malt Agar and Horse Bean Agar. The rate of their growth amounted to 1-4 mm per 24 hours. The variability of isolates in size of pycnidia and conidia and number of sepia was noticed. A few spores with untypical shapes were observed as well.
Stewart, Ethan L; Hagerty, Christina H; Mikaberidze, Alexey; Mundt, Christopher C; Zhong, Ziming; McDonald, Bruce A
Zymoseptoria tritici causes Septoria tritici blotch (STB) on wheat. An improved method of quantifying STB symptoms was developed based on automated analysis of diseased leaf images made using a flatbed scanner. Naturally infected leaves (n = 949) sampled from fungicide-treated field plots comprising 39 wheat cultivars grown in Switzerland and 9 recombinant inbred lines (RIL) grown in Oregon were included in these analyses. Measures of quantitative resistance were percent leaf area covered by lesions, pycnidia size and gray value, and pycnidia density per leaf and lesion. These measures were obtained automatically with a batch-processing macro utilizing the image-processing software ImageJ. All phenotypes in both locations showed a continuous distribution, as expected for a quantitative trait. The trait distributions at both sites were largely overlapping even though the field and host environments were quite different. Cultivars and RILs could be assigned to two or more statistically different groups for each measured phenotype. Traditional visual assessments of field resistance were highly correlated with quantitative resistance measures based on image analysis for the Oregon RILs. These results show that automated image analysis provides a promising tool for assessing quantitative resistance to Z. tritici under field conditions.
Stewart, Ethan L; Croll, Daniel; Lendenmann, Mark H; Sanchez-Vallet, Andrea; Hartmann, Fanny E; Palma-Guerrero, Javier; Ma, Xin; McDonald, Bruce A
We conducted a comprehensive analysis of virulence in the fungal wheat pathogen Zymoseptoria tritici using quantitative trait locus (QTL) mapping. High-throughput phenotyping based on automated image analysis allowed the measurement of pathogen virulence on a scale and with a precision that was not previously possible. Across two mapping populations encompassing more than 520 progeny, 540 710 pycnidia were counted and their sizes and grey values were measured. A significant correlation was found between pycnidia size and both spore size and number. Precise measurements of percentage leaf area covered by lesions provided a quantitative measure of host damage. Combining these large and accurate phenotypic datasets with a dense panel of restriction site-associated DNA sequencing (RADseq) genetic markers enabled us to genetically dissect pathogen virulence into components related to host damage and those related to pathogen reproduction. We showed that different components of virulence can be under separate genetic control. Large- and small-effect QTLs were identified for all traits, with some QTLs specific to mapping populations, cultivars and traits and other QTLs shared among traits within the same mapping population. We associated the presence of four accessory chromosomes with small, but significant, increases in several virulence traits, providing the first evidence for a meaningful function associated with accessory chromosomes in this organism. A large-effect QTL involved in host specialization was identified on chromosome 7, leading to the identification of candidate genes having a large effect on virulence.
Paula Rachel Rabelo Corrêa Basilio
Full Text Available Sphaeropsis sapinea is one of main pathogens that causes losses in commercial plantations of Pinus
spp. Studies for control based on genetic resistance can be done by inoculating different monosporic isolates on
pine populations and selectioning the resistant individuals. This work describes a methodology for pycnidia production in vitro and S. sapinea monoconidial cultures, using an agar-water medium with sterile pine needles. Four S. sapinea isolates were tested e pycnidia and mature conidia were observed after 14 days of incubation, under continuous fluorescent light, in BOD, at 25 °C. Pycnidia were triturated in sterile water and conidia germinated after two hours of incubation in water-agar, in BOD, at 25 °C. Germinated conidia formed colonies which were purified in malt extract-agar and maintained in test tubes with the same medium, covered with sterile mineral oil for preservation. This methodology revealed to be adequated for production of monoconidial colonies
of S. sapineaSphaeropsis sapinea é um dos principais patógenos causadores de perdas em plantios comerciais de Pinus spp. Estudos de controle por resistência genética podem ser feitos pela inoculação de vários isolados monospóricos em populações de pínus e selecionando-se os indivíduos resistentes. Este trabalho descreve uma metodologia de produção de picnídios in vitro e culturas monospóricas de S. sapinea, usando um meio ágarágua (AA com fragmentos de acículas de Pinus taeda esterilizadas. Quatro isolados de S. sapinea foram testados e os picnídios e conídios maduros foram observados após 14 dias de incubação, sob luz fria em BOD, a 25 °C. Os picnídios foram triturados em água e os conídios germinaram após duas horas de incubação em meio AA, em BOD, a 25 ºC. Os conídios germinados formaram colônias que foram purificadas em meio extrato de malteágar e mantidas em tubos de ensaio com o mesmo meio e imersas em óleo mineral est
LEE Sanghyun; KIM Kyunghee; PIAO Chungen; MOON Byungju
Chestnut blight caused by Cryphonectria parasitica is one of the major chestnut diseases occurred on stems and branches. Oriental chestnut has more resistance than American one. Twenty-five cultivars of chestnut tree including various cultivars such as Tsukuba, Okkwang, Rihei, Ginyose, Eunsan, etc. Were tested with a rapid, simple and reliable method. The cultivar Banseki is one of the most resistant cultivars tested and has the necrotic area of 0.40 cm2. However, the necrotic areas of the cultivars of American chestnut, Eunsan, Kwangjujoyul and Eaton, ranges from 3.35 to 2.61 cm2 and these cultivars are relatively susceptible to this pathogen. Many pycnidia of this pathogen were observed on the inner and outer bark tissues after incubating for 3 weeks.
Presencia de Phomopsis viticola (Saccardo Saccardo, agente causal de excoriosis, en viñedos de Córdoba, Argentina Presence of Phomopsis viticola (Saccardo Saccardo, causal agent of excoriosis, in vineyards of Córdoba, Argentina
Full Text Available Desde 2001 se observan en viñedos de Córdoba, Argentina, hojas de Vitis vinifera y V. labrusca con manchas cloróticas y centro necrótico. Las plantas presentan nervaduras, pecíolos, raquis y entrenudos con puntos necróticos que al confluir agrietan el tejido cortical. Las bayas pueden marchitarse y desprenderse. En invierno los sarmientos toman color blanquecino con manchas negras, y en ellos y en órganos secos aparecen picnidios con cirros blanco-crema con conidios alfa y beta. El objetivo fue confirmar la presencia de Phomopsis viticola (excoriosis y cuantificar su incidencia. Se realizaron aislamientos a partir de pecíolos, brotes, zarcillos, bayas y sarmientos que produjeron micelio claro con picnidios y conidios alfa (7,5m±1,5 x 2,8m±2 y beta (19m±1 x 1,2m±0,5 o sólo alfa, típicos de P. viticola. La identificación fue confirmada mediante secuenciación molecular. En brotes de las variedades Malbec y Pinot noir inoculados con 3 10(4 conidios/mL, las hojas mostraron lesiones y picnidios 8 días después, y las bayas cirros amarillos a los 15-18 días. P. viticola (Sacc. Sacc. fue reaislado de los cirros y las colonias produjeron picnidios y conidios característicos 10-20 días después. Se detectó excoriosis en 80% de los viñedos evaluados, con mayor incidencia en viñedos añosos de las variedades Pinot noir e Isabella.Leaves with chlorotic spots and necrotic centers have been observed in Vitis vinifera and V. labrusca in vineyards of Córdoba, Argentina, since 2001. Plants exhibit veins, petioles, rachises, and internodes with necrotic spots that coalesce to form cracks in the cortical tissue. Grape berries can shrivel and fall off. Winter canes became whitish with black spots; pycnidia appear in canes and in dry organs, exuding whitish-cream cirri with alpha and beta conidia. The aim of this work was to confirm the presence of Phomopsis viticola (excoriosis and quantify its incidence. Isolates obtained from petioles
Wang, Yan; Charkowski, Amy O; Zeng, Cuiyun; Zhu, Tiantian; Wang, Huizhen; Chen, Honggang
A new leaf spot disease was observed on leaves of Rheum palmatum (Chinese rhubarb) in Northwest China (Gansu Province) starting in 2005. A Septoria-like fungus was isolated and completion of Koch's postulates confirmed that the fungus was the casual agent of the leaf spot disease. Morphology and molecular methods were combined to identify the pathogen. The fungus produced conidiomata pycnidia and the conidia were 2~5 septate, 61.2~134.1 µm in length and 3.53~5.3 µm in width, which is much larger than the known Spetoria species that infects Polygonaceae species. Phylogenic analysis of the internal transcribed spacer region confirmed that this Spetoria-like fungus is within the Spetoria genus but distinct from known Spetoria species. Together, these morphological and phylogenetic data support that the R. palmatum infecting Spetoria strain is a newly-described plant pathogenic species.
Full Text Available Diaporthe/Phomopsis sp. was isolated from Xanthium italicum (Italian cockleburr for the first time in Eastern Croatia during 2004 year. As Diaporthe/Phomopsis species are known as pathogens of soybean, sunflower and other arable crops, it is important to study alternative hosts as a possible source of inoculum from an epidemiological point of view. This paper describes symptoms of infection on X. italicum, pathogen morphological and cultural characters on potato-dextrose agar (PDA, biometrical values of reproductive structures (pycnidia, beta conidia, perithecia, asci and ascospores of naturally infected plants and of cultures grown on PDA. Results obtained from undertaken studies indicate that our Phomopsis sp. isolates from X. italicum belong to the group of P. helianthi.
Full Text Available We report a case of fungal keratitis caused by the coelomycetous fungus Nattrassia mangiferae in a 70 year old gentleman, agriculturist by occupation, with a history of injury to his right eye. The scraping showed narrow septate fungal hyphae on a KOH mount, isolation of a fast growing black mould, which demonstrated hyphae and arthroconidia of varying widths typical of the Scytalidium synanamorph (S. dimidiatum. The formation of the pycnidia, which at maturity, expressed conidia. The patient was started on topical itraconazole one hourly and topical atropine thrice a day. The patient was lost to follow up hence we are not able to comment on the final outcome of the patient.
A new canker disease of peony was found and investigated in Luoyang, Henan Province. A fungus was isolated from diseased stems with typical symptom, cultured by single spore isolation and tested for pathogenicity according to Koch' s postulation. The rDNA ITS sequence of the fungus was analyzed for similarity. Its colony on PDA was initially white with irregular margin, then gradually turned to dark brown to cae-sious color. More pycnidia were produced on thick aerial hyphae, and some ascostroma were latterly formed. The pathogenicity test showed that the cultured fungus was pathogenic to peony. Based on the morphological characteristics and rDNA ITS sequence analysis, the fungus was identified as Botryosphaeria dothidea.
Full Text Available During a three year period (2004 to 2006 on locations of Eastern Croatia (Kneževi Vinogradi, Osijek, Brođanci and Krndija we collected plants of Achillea millefolium L. from which we isolated Phomopsis sp. Many of the collected plants exhibited no visible symptoms of infection but in spring pycnidia were noticed on overwintered plants. Isolation was done on PDA from naturally infected plants and morphological and molecular characteristics were studied. Biometrical values of reproductive structures developed on naturally infected plants and grown on PDA were measured. Internal transcribed spacers ITS rDNA of the examined isolates were sequenced. Although molecular analysis showed that isolates were grouped with Diaporthe arctii, we decided to classify isolates from A. millefolium as Phomopsis sp., the details of which were discussed in the paper.
Gummer Joel P A
Full Text Available Abstract Background It has been well established that the Gα subunit of the heterotrimeric G-protein in the wheat pathogen Stagonospora nodorum is required for a variety of phenotypes including pathogenicity, melanisation and asexual differentiation. The roles though of the Gγ and Gβ subunits though were unclear. The objective of this study was to identify and understand the role of these subunits and assess their requirement for pathogenicity and development. Results G-protein Gγ and Gβ subunits, named Gga1 and Gba1 respectively, were identified in the Stagonospora nodorum genome by comparative analysis with known fungal orthologues. A reverse genetics technique was used to study the role of these and revealed that the mutant strains displayed altered in vitro growth including a differential response to a variety of exogenous carbon sources. Pathogenicity assays showed that Stagonospora nodorum strains lacking Gba1 were essentially non-pathogenic whilst Gga1-impaired strains displayed significantly slower growth in planta. Subsequent sporulation assays showed that like the previously described Gα subunit mutants, both Gba1 and Gga1 were required for asexual sporulation with neither mutant strain being able to differentiate either pycnidia nor pycnidiospores under normal growth conditions. Continued incubation at 4°C was found to complement the mutation in each of the G-protein subunits with nearly wild-type levels of pycnidia recovered. Conclusion This study provides further evidence on the significance of cAMP-dependent signal transduction for many aspects of fungal development and pathogenicity. The observation that cold temperatures can complement the G-protein sporulation defect now provides an ideal tool by which asexual differentiation can now be dissected.
Ahmed, S A; van de Sande, W W J; Stevens, D A; Fahal, A; van Diepeningen, A D; Menken, S B J; de Hoog, G S
Eumycetoma is a chronic fungal infection characterised by large subcutaneous masses and the presence of sinuses discharging coloured grains. The causative agents of black-grain eumycetoma mostly belong to the orders Sordariales and Pleosporales. The aim of the present study was to clarify the phylogeny and taxonomy of pleosporalean agents, viz. Madurella grisea, Medicopsis romeroi (syn.: Pyrenochaeta romeroi), Nigrograna mackinnonii (syn. Pyrenochaeta mackinnonii), Leptosphaeria senegalensis, L. tompkinsii, and Pseudochaetosphaeronema larense. A phylogenetic analysis based on five loci was performed: the Internal Transcribed Spacer (ITS), large (LSU) and small (SSU) subunit ribosomal RNA, the second largest RNA polymerase subunit (RPB2), and translation elongation factor 1-alpha (TEF1) gene. In addition, the morphological and physiological characteristics were determined. Three species were well-resolved at the family and genus level. Madurella grisea, L. senegalensis, and L. tompkinsii were found to belong to the family Trematospheriaceae and are reclassified as Trematosphaeria grisea comb. nov., Falciformispora senegalensis comb. nov., and F. tompkinsii comb. nov. Medicopsis romeroi and Pseudochaetosphaeronema larense were phylogenetically distant and both names are accepted. The genus Nigrograna is reduced to synonymy of Biatriospora and therefore N. mackinnonii is reclassified as B. mackinnonii comb. Nov. Mycetoma agents in Pleosporales were phylogenetically quite diverse despite their morphological similarity in the formation of pycnidia, except for the ascosporulating genus Falciformispora (formerly in Leptosphaeria). Most of the species diagnosed from human mycetoma were found to be related to waterborne or marine fungi, suggesting an association of the virulence factors with oligotrophism or halotolerance.
Siah, A; Deweer, C; Tisserant, B; Randoux, B; Halama, P; Reignault, Ph
Septoria tritici blotch caused by Mycosphaerella graminicola (anamorph: Zymoseptoria tritici) is currently the most devastating disease on wheat crops worldwide, especially in regions with suitable climate conditions such as Western Europe. Pathogen control relies mainly on the use of fungicides and resistant cultivars. However, the durability of chemical and genetic control strategies is increasingly compromised in the field since the fungus frequently develops resistance to fungicides and overcomes host resistance. Here, we assessed the association between pathogenicity and fungicide tolerance in eighteen different M. graminicola strains isolated in 2009 from Northern France. These strains were chosen because they exhibited in preliminary experiments a wide range of in vitro tolerance levels against six demethylation inhibitors (epoxiconazole, cyproconazole, fluquinconazole, propiconazole, prothioconazole and pyrefenox). Inoculation of the Scorpion susceptible wheat cultivar in the greenhouse with these strains revealed a great variability in their pathogenicity levels (disease symptoms ranged from 0 to 66% of leaf area bearing pycnidia). Interestingly, strains with high fungicide tolerance levels caused overall the highest disease symptoms (45% of diseased leaf area on average) when compared to those with low fungicide tolerance levels (22% of diseased leaf area on average), thus confirming the association between pathogenicity level and fungicide tolerance in M. graminicola. The occurrence and selection in the field of fungal genotypes combining both pathogenicity and fungicide resistance should be taken into account in disease management strategies.
Rodeva, R; Carrieri, R; Stoyanova, Z; Dacheva, S; Lahoz, E; Fanigliulo, A; Crescenzi, A
In 2011, coriander plants (Coriandrum sativum L.), showing symptoms of greyish to hell brown lesions with dark brown border between discoloured and asymptomatic tissues, were observed in Bulgaria. Pycnidia with small unicellular conidia appeared in the pale centre of the lesions. In this work, the identification of the causal agent of this disease was made applying Koch's postulates. Moreover, for a rapid and unambiguous identification of the fungal species, the internal transcribed spacers and the 5.8 rDNA gene (ITS1-5.8-ITS2) were amplified by PCR from DNA extracted from the isolated colonies. The amplicon was sequenced and analyzed using BLASTn, and showed a homology of 100% with a corresponding sequence of Phoma glomerata (accession number DQ093699). The fungus isolated, after the morphological and molecular characterization, was ascribed to the species Phoma glomerata (Corda) Wollenweber and Hochapfel. This is the first report of P. glomerata as agent of stem rot of coriander in Bulgaria and elsewhere.
Yueping ZHANG; Guangyu CHEN; Shaochun LUO; Huaxiang QU; Yongping TANG; Qixin XIE; Jinsong ZHOU
Abstract Fungal pathogen of asparagus stem blight was isolated. No significant ge- netic difference was detected among the three strains with 492 bp long ITS1-5.8S- ITS2 sequence. It was then identified through colony growth, conidia morphology, and molecular characterization. The physiological response to oxidation and osmosis stress, and virulence to Asparagus officinalis L. were analyzed. The results showed that the pathogen causing asparagus stem blight for A. officinalis L. in Jiangxi Province is Phomopsis asparagri （Sacc.） Bubok. Under pure culture conditions, the conidia were oval-shaped （a-type）, with colorless single spore and single nucleus, containing 0-2 oil balls. Its vegetative growth rate was higher when cultured on 0.2 x potato dextrose agar （0.2 x PDA） medium than that on oatmeal agar （OA） medium. However, the pycnidia appeared earlier on OA medium than on 0.2 earlier PDA medium. The vegetative growth rate was depressed under oxidation （H202） or osmo- sis （NaCI） stress conditions, and totally inhibited under 7 mmol/L H202 or 2.4 mol/L NaCI. All the strains caused typical pathogenic symptoms to Asparagus officinalis L. at 7 days-post-inoculation （dpi） with conidia.
months. The first visible symptoms of infection of the young shoots are in the form of brown necroses, resin bleeding and several short pairs of needles at the place. S. sapinea can infect male and female flowers, current year and second-year cones. The pycnidia with mature conidia can form on the shoots, needles, first-year and second-year cones during the year of infection. The first mature fructifications are mostly formed in the bark of young shoots, in the zone of infection, and they were recorded in late June at the earliest. They were recorded on the cones at the beginning of the third decade of July. Pycnidia are formed in the bark, on the needles and on the second-year and older cones, on male and female flowers, as well as on the cones in the first year of development. The size of S. sapinea conidia on different Pinus species is very variable throughout the world and ranges widely from 16.8-55.0×7.0-21.0 m. Our study shows that the size of pycnospores in our country is also variable and it ranges 14.8-51.4×9.7-20.2 m The optimal temperature for spore germination and germ tube growth is 27°C, and the optimal temperature for mycelial growth on the media PDA and MEA is 28°C. The formation of fruiting bodies in the culture is affected by light and the presence of sterilised needles on the mycelium The correct and timely control measures can contribute to reduce the consequences of this serious disease, by the combined application of silvicultural and chemical measures. Chemical control is recommended in the nurseries, severely infected plantations and in urban environments. The fungicides which showed the greatest efficiency are the preparations based on copper and Benomil.
Full Text Available Field pea crops in central Alberta were surveyed for ascochyta blight from 2011 to 2012 and fungal isolates were recovered from foliar lesions on selected plants. Cultural and microscopic characterization of the 275 isolates obtained revealed that 272 were of Mycosphaerella pinodes and three were of Phoma medicaginis var. pinodella. Ascochyta pisi or Phoma koolunga were not identified. Isolates of M. pinodes were divided into two groups, GI and GII, based on visual assessment of culture characteristics. GI isolates (light to dark, mostly gray colony color; pycnidial distribution radial and concentric; conidia 10.5–14.5 × 4.2–6.2 μm most with one septum, occasionally two, constricted at the septum; spore mass light buff to flesh color were predominant (83%, while GII isolates (dark to gray colony color; pycnidia abundant; conidia 8–16 × 3.5–6.2 μm most with 1 septum, constricted at the septum; spore mass light buff to flesh color were less common (17%. The cultures of GII isolates were similar to recent descriptions of A. pisi, but they differed in spore color. In a host differential study, 13 pathotypes of M. pinodes were identified from 110 single-spore isolates. Pathotype I was predominant (88 isolates and virulent on all nine differential genotypes. The other pathotypes (pathotypes II–XIII were rare (1–6 isolates of each. Comparison of the present results with earlier studies suggests that pathotype I has been prevalent for many years, and that its aggressiveness on the host differentials has increased over time. Emphasis should be placed on breeding for resistance to M. pinodes in field pea cultivars intended for deployment in central Alberta.
A J Kindo
Full Text Available Aim: Fungi are increasing in incidence as human pathogens and newer and rarer species are continuously being encountered. Identifying these species from growth on regular culture media may be challenging due to the absence of typical features. An indigenous and cheap medium, similar to the natural substrate of these fungi, was standardised in our laboratory as an aid to species identification in a conventional laboratory setting. Materials and Methods: Ripe banana peel pieces, sterilised in an autoclave at 121°C temperature and 15 lbs pressure for 15 min promoted good growth of hyphae and pycnidia or acervuli in coelomycetes, flabelliform and medusoid fruiting bodies of basidiomycetes and fruit bodies such as cleistothecium in ascomycetes. The growth from the primary isolation medium was taken and inoculated onto the pieces of double-autoclaved ripe banana peel pieces in a sterile glass Petri dish with some moisture (sprinkles of sterile distilled water. A few sterile coverslips were placed randomly inside the Petri dish for the growing fungus to stick on to it. The plates were kept at room temperature and left undisturbed for 15–20 days. At a time, one coverslip was taken out and placed on a slide with lactophenol cotton blue and focused under the microscope to look for fruit bodies. Results: Lasiodiplodia theobromae, Macrophomina phaseolina, Nigrospora sphaerica, Chaetomium murorum, Nattrassia mangiferae and Schizophyllum commune were identified by characteristic features from growth on banana peel culture. Conclusions: Banana peel culture is a cheap and effective medium resembling the natural substrate of fungi and is useful for promoting characteristic reproductive structures that aid identification.
Goulin, Eduardo Henrique; Savi, Daiani Cristina; Petters, Desirrê Alexia Lourenço; Kava, Vanessa; Galli-Terasawa, Lygia; Silva, Geraldo José; Glienke, Chirlei
Phyllosticta citricarpa is the epidemiological agent of Citrus Black Spot (CBS) disease, which is responsible for large economic losses worldwide. CBS is characterized by the presence of spores (pycnidiospores) in dark lesions of fruit, which are also responsible for short distance dispersal of the disease. The identification of genes involved in asexual reproduction of P. citricarpa can be an alternative for directional disease control. We analyzed a library of mutants obtained through Agrobacterium tumefaciens transformation system, looking for alterations in growth and reproductive structure formation. Two mutant strains were found to have lost the ability to form pycnidia. The flanking T-DNA insertion regions were identified on P. citricarpa genome by using blast analysis and further gene prediction. The predicted genes containing the T-DNA insertions were identified as Spindle Poison Sensitivity Scp3, Ion Transport protein, and Cullin Binding proteins. The Ion Transport and Cullin Binding proteins are known to be correlated with sexual and asexual reproduction in fungi; however, the exact mechanism by which these proteins act on spore formation in P. citricarpa needs to be better characterized. The Scp3 proteins are suggested here for the first time as being associated with asexual reproduction in fungus. This protein is associated with microtubule formation, and as microtubules play an essential role as spindle machinery for chromosome segregation and cytokinesis, insertions in this gene can lead to abnormal formations, such as that observed here in P. citricarpa. We suggest these genes as new targets for fungicide development and CBS disease control, by iRNA.
Full Text Available Delphinella shoot blight (Delphinella abietis attacks true firs (Abies spp. in Europe and North America. Especially subalpine fir (A. lasiocarpa, one of the main Christmas tree species in Norway, is prone to the disease. The fungus kills current year needles, and in severe cases entire shoots. Dead needles become covered with black fruiting bodies, both pycnidia and pseudothecia. Delphinella shoot blight has mainly been a problem in humid, coastal regions in the northwestern part of Southern Norway, but, probably due to higher precipitation in inland regions during recent years, heavy attacks were found in 2011 in a field trial with 76 provenances of subalpine fir in Southeastern Norway. However, the amount of precipitation seemed less important once the disease had established in the field. Significant differences in susceptibility between provenances were observed. In general, the more bluish the foliage was, the healthier the trees appeared. The analysis of provenance means indicated that, at least for the southern range, the disease ratings were correlated with foliage color. This study also includes isolation, identification, a pathogenicity test, a seed test and electron microscopy of the wax layer on the needles. The fungus was identified based on the morphology of spores and by sequencing the Internal Transcribed Spacer (ITS regions of the ribosomal DNA. Koch’s postulates were fulfilled. The fungus was found present on newly harvested seeds and may therefore spread via international seed trade. When comparing the wax layers on green and blue needles, those of the latter were significantly thicker, a factor that may be involved in disease resistance.
Seid Ahmed Kemal
Full Text Available Chickpea (Cicer arietinum L. is an important food and rotation crop in many parts of the world. Cold (freezing and chilling temperatures and Ascochyta blight (Didymella rabiei are the major constraints in chickpea production. The effects of temperature stresses on chickpea susceptibility and pathogen aggressiveness are not well documented in the Cicer-Didymella pathosystem. Two experiments were conducted under controlled conditions using chickpea genotypes and pathogen isolates in 2011 and 2012. In Experiment 1, four isolates of D. rabiei (AR-01, AR-02, AR-03 and AR-04, six chickpea genotypes (Ghab-1, Ghab-2, Ghab-3, Ghab-4, Ghab-5 and ICC-12004 and four temperature regimes (10, 15, 20, and 25°C were studied using 10 day-old seedlings. In Experiment 2, three chickpea genotypes (Ghab-1, Ghab-2, and ICC-12004 were exposed to 5 and 10 days of chilling temperature exposure at 5°C and non-exposed seedlings were used as controls. Seedlings of the three chickpea genotypes were inoculated with the four pathogen isolates used in Experiment 1. Three disease parameters (incubation period, latent period and disease severity were measured to evaluate treatment effects. In Experiment 1, highly significant interactions between genotypes and isolates; genotypes and temperature; and isolate and temperature were observed for incubation and latent periods. Genotype x isolate and temperature x isolate interactions also significantly affected disease severity. The resistant genotype ICC-12004 showed long incubation and latent periods and low disease severity at all temperatures. The highly aggressive isolate AR-04 caused symptoms, produced pycnidia in short duration as well as high disease severity across temperature regimes, which indicated it is adapted to a wide range of temperatures. Short incubation and latent periods and high disease severity were observed on genotypes exposed to chilling temperature. Our findings showed that the significant interactions of
Onychomycosis caused by Scytalidium dimidiatum. Report of two cases. Review of the taxonomy of the synanamorph and anamorph forms of this coelomycete Onicomicose por Scytalidium dimidiatum. Registro de dois casos. Revisão da taxonomia das formas sinanamorfas e anaforma deste celomiceto
Carlos da Silva LACAZ
Full Text Available The authors report two cases of onychomycosis in the dystrophic form, one of them involving an HIV-positive patient, provoked by Scytalidium dimidiatum, previously called Scytalidium lignicola. The subject is reviewed from the taxonomic viewpoint, considering the anamorph Hendersonula toruloidea as a synonym of Nattrassia mangiferae, and having Scytalidium dimidiatum as the major synanamorph. According to many mycologists, Scytalidium hyalinum may be a separate species or a hyaline mutant of Scytalidium dimidiatum. Scytalidium lignicola Pesante 1957 was considered to be the type-species of the genus by ELLIS (197113 and later to be a "conidial state" of Hendersonula toruloidea by the same author, today known as Nattrassia mangiferae. The microorganism lives only on the roots of certain plants (mainly Platanus and Pinus. It produces pycnidia and is not considered to be a pathogen, although it is considered as a possible emerging agent capable of provoking opportunistic fungal lesions. The importance of this topic as one of the most outstanding in fungal taxonomy, so likely to be modified over time, as well as its interest in the field of dermatologic mycology, are emphasized.Os Autores registraram dois casos de onicomicose sob forma distrófica, sendo um em paciente HIV-positivo, provocados pelo Scytalidium dimidiatum, no passado considerado como Scytalidium lignicola. Fazem uma revisão da matéria sob o ponto de vista taxonômico, considerado o anamorfo Hendersonula toruloidea como sinônimo de Nattrassia mangiferae, tendo como sinanamorfo principal o Scytalidium dimidiatum. Scytalidium hyalinum seria para muitos micologistas espécie à parte ou mutante hialina do Scytalidium dimidiatum. Scytalidium lignicola Pesante 1957, foi considerada por ELLIS (197113 como espécie-tipo do gênero e mais tarde (197614, pelo mesmo Autor como "estado conidiano" de Hendersonula toruloidea, atualmente Nattrassia mangiferae. Vive somente em raízes de
Hirooka, Y; Rossman, A Y; Samuels, G J; Lechat, C; Chaverri, P
perithecia are immersed, large ascospores, and peculiar anamorphs that form pycnidia or sporodochia either on their natural substrate or in culture. In this study the evolution of species, morphology, and ecology of the three genera, Allantonectria, Nectria, and Pleonectria, are discussed based on the phylogenetic analyses. In addition, descriptions, illustrations, and keys for identification are presented for the 56 species in Allantonectria, Nectria, and Pleonectria. New species:Nectria argentinensis Hirooka, Rossman & P. Chaverri, Nectria berberidicola Hirooka, Lechat, Rossman, & P. Chaverri, Nectria himalayensis Hirooka, Rossman, & P. Chaverri, Nectria magnispora Hirooka, Rossman, & P. Chaverri, Nectria mariae Hirooka, Fournier, Lechat, Rossman, & P. Chaverri, Nectriapyriformis Hirooka, Rossman & P. Chaverri, Pleonectria boothii Hirooka, Rossman & Chaverri, Pleonectria clavatispora Hirooka, Rossman & P. Chaverri, Pleonectria ilicicola Hirooka, Rossman & P. Chaverri, Pleonectria okinawensis Hirooka, Rossman & P. Chaverri, Pleonectria pseudomissouriensis Hirooka, Rossman & P. Chaverri, Pleonectria quercicola Hirooka, Checa, Areual, Rossman & P. Chaverri, Pleonectria strobi Hirooka, Rossman & P. Chaverri. New combinations:Cosmospora proteae (Marinc., M.J. Wingf. & Crous) Hirooka, Rossman & P. Chaverri, Nectricladiellaviticola (Berk. & M.A. Curtis) Hirooka, Rossman & P. Chaverri, Neocosmospora guarapiensis (Speg.) Hirooka, Samuels, Rossman & P. Chaverri, Neocosmospora rehmiana (Kirschstein) Hirooka, Samuels, Rossman & P. Chaverri, Pleonectria aquifolii (Fr.) Hirooka, Rossman & P. Chaverri, Pleonectria aurigera (Berk. & Rav.) Hirooka, Rossman & P. Chaverri, Pleonectria chlorinella (Cooke) Hirooka, Rossman & P. Chaverri, Pleonectria coryli (Fuckel) Hirooka, Rossman & P. Chaverri, Pleonectria cucurbitula (Tode: Fr.) Hirooka, Rossman & P. Chaverri, Pleonectria lonicerae (Seeler) Hirooka, Rossman & P. Chaverri, Pleonectria rosellinii (Carestia) Hirooka, Rossman & P. Chaverri
赵桂华; 许俊杰; 李观和; 孟庆兰; 石立岩; 杨怀光
2008年4月～2011年6月，通过对I-107杨溃疡病病原分离、野外接种致病性测定试验、病原菌的形态观察及ITS序列分子鉴定，结果表明，该病的病原菌鉴定为大孢不高双胞菌，在我国的杨树上属于首次报道，由它引起I-107杨溃疡病为杨树新病害。野外接种1年生I-107杨树幼苗，10天后的发病率为100％；该病原菌的分生孢子器为黑色，分生孢子梗缺；产孢细胞瓶梗状，无色，4.5～9.6μm×4.5～7.4μm；分生孢子圆柱形到长圆形，或窄卵圆形，成熟的分生孢子有2个细胞，无色，基部细胞窄，顶部细胞略宽，分隔处缢缩，2个细胞的分生孢子比单细胞的分生孢子更大，23.1～31.6μm ×6.7～9.8μm，平均为27.7μm ×8.9μm；未成熟的分生孢子为单细胞，16.5～26.1μm ×6.2～8.5μm，平均为22.7μm ×8.9μm。%Canker fungus of Populus ×euramericana CL ‘74/76’ was isolated in laboratory , inoculated pathoge-nicity tests in field , morphological observation of pathogenic fungus and ITS sequences identification were also car -ried out from April 2008 to June 2011.The results show that the pathogenic fungus is identified as Apiocarpella ma-crospora, which is reported for the first time and also a new disease on the poplar in China.One-year poplar seed-lings are inoculated in field and then the incidence is 100 % after ten days .Pycnidia of the pathogenic fungus is black, conidiophores absent; conidiogenous cell is phialide , hyaline, 4.5~9.6 μm ×4.5~7.4 μm.Conidia are cylindrical to long circle , or narrow ovoid in shape , mature conidia have 1 euseptate , hyaline , narrow base cells, apex cells slightly wide , constriction at separating .Two cell conidia are larger than one cell conidia , 23.1~31.6μm ×6.7~9.8μm, average 27.7μm ×8.9μm.Immature conidia are 1cell, 16.5~26.1μm ×6.2~8.5 μm, average 22.7 μm ×8.9 μm.