Fungal pathogens associated with wilting of Neolitsea cassia trees

Neolitsea cassia, a tree species, belongs to family Lauraceae, is endemic to Sri Lanka. Few planted trees of Neolitsea cassia were severely affected by wilt disease. Two fungal pathogens were consistently isolated from collar region and roots of symptomatic trees. These two fungal species were identified as Colletotrichum and Pestalotiopsis by microscopic observations of conidia and culture characters of isolates on PDA. This is the first report of Colletotrichum and Pestalotiopsis species causing tree wilting of Neolitsea cassia in Sri Lanka. Application of 25 l of fungicide, Thiram + Thiophanate Methyl, 50+30% WP (Homai) solution (1g/l) around the base of each infected plant as a soil drenching was effectively controlled wilting of Neolitsea cassia caused by both pathogenic fungi.

Download Full-text

Mitotic Recombination and Adaptive Genomic Changes in Human Pathogenic Fungi

Genes ◽

10.3390/genes10110901 ◽

2019 ◽

Vol 10 (11) ◽

pp. 901 ◽

Cited By ~ 10

Author(s):

Asiya Gusa ◽

Sue Jinks-Robertson

Keyword(s):

Fungal Pathogens ◽

Repetitive Sequences ◽

Pathogenic Fungi ◽

Genetic Alterations ◽

Fungal Species ◽

Chronic Infections ◽

Yeast Saccharomyces Cerevisiae ◽

Genomic Changes ◽

Break Site ◽

Repair Mechanisms

Genome rearrangements and ploidy alterations are important for adaptive change in the pathogenic fungal species Candida and Cryptococcus, which propagate primarily through clonal, asexual reproduction. These changes can occur during mitotic growth and lead to enhanced virulence, drug resistance, and persistence in chronic infections. Examples of microevolution during the course of infection were described in both human infections and mouse models. Recent discoveries defining the role of sexual, parasexual, and unisexual cycles in the evolution of these pathogenic fungi further expanded our understanding of the diversity found in and between species. During mitotic growth, damage to DNA in the form of double-strand breaks (DSBs) is repaired, and genome integrity is restored by the homologous recombination and non-homologous end-joining pathways. In addition to faithful repair, these pathways can introduce minor sequence alterations at the break site or lead to more extensive genetic alterations that include loss of heterozygosity, inversions, duplications, deletions, and translocations. In particular, the prevalence of repetitive sequences in fungal genomes provides opportunities for structural rearrangements to be generated by non-allelic (ectopic) recombination. In this review, we describe DSB repair mechanisms and the types of resulting genome alterations that were documented in the model yeast Saccharomyces cerevisiae. The relevance of similar recombination events to stress- and drug-related adaptations and in generating species diversity are discussed for the human fungal pathogens Candida albicans and Cryptococcus neoformans.

Download Full-text

Morphological and Molecular Diversity of Ginger (Zingiber officinale Roscoe) Pathogenic Fungi in Chilga District, North Gondar, Ethiopia

Frontiers in Fungal Biology ◽

10.3389/ffunb.2021.765737 ◽

2022 ◽

Vol 2 ◽

Author(s):

Sefinew Tilahun ◽

Marye Alemu ◽

Mesfin Tsegaw ◽

Nega Berhane

Keyword(s):

Causative Agent ◽

Fungal Pathogens ◽

Pathogenic Fungus ◽

Management Strategies ◽

Infected Plant ◽

Pathogenic Fungi ◽

Zingiber Officinale ◽

Morphological Characterization ◽

Molecular Techniques ◽

Diseased Plant

Ginger diseases caused by fungal pathogens have become one of the most serious problems causing reduced production around the world. It has also caused a major problem among farmers in different parts of Ethiopia resulting in a huge decline in rhizome yield. However, the exact causative agents of this disease have not been identified in the state. Although there are few studies related to pathogenic fungus identification, molecular level identification of fungal pathogen was not done in the area. Therefore, this study was undertaken to isolate and characterized the fungal causative agent of ginger disease from the diseased plant and the soil samples collected around the diseased plant from Chilga district, Gondar, Ethiopia. Samples from infected ginger plants and the soil around the infected plant were collected. Culturing and purification of isolates were made using Potato Dextrose Agar supplemented with antibacterial agent chloramphenicol. The morphological characterization was done by structural identification of the isolates under the microscope using lactophenol cotton blue stains. Isolated fungi were cultured and molecular identification was done using an internal transcribed spacer (ITS) of ribosomal DNA (rDNA). A total of 15 fungal morphotypes including 11 Aspergillus spp. (73.3%), 2 Penicillium spp. (13.3%), and single uncultured fungus clone S23 were isolated from the samples representing all the plant organs and the soil. Aspergillus spp. (73.3%) was the most common and seems to be the major causative agent. To the best of our knowledge, this is the first report of ginger pathogenic fungi in Ethiopia identified using ITS rDNA molecular techniques. This study will lay foundation for the development of management strategies for fungal diseases infecting ginger.

Download Full-text

First Report of Sclerotinia Blight Caused by Sclerotinia sclerotiorum on Peanut in Georgia

Plant Disease ◽

10.1094/pd-90-0111b ◽

2006 ◽

Vol 90 (1) ◽

pp. 111-111 ◽

Cited By ~ 5

Author(s):

J. E. Woodward ◽

T. B. Brenneman ◽

R. C. Kemerait ◽

A. K. Culbreath ◽

J. R. Clark

Keyword(s):

Fungal Pathogens ◽

Health Management ◽

Infected Plant ◽

First Report ◽

Small Water ◽

Plant Parts ◽

Sclerotinia Blight ◽

Initial Symptoms ◽

Symptomatic Tissue ◽

Lateral Branches

Sclerotinia blight is one of the most economically important diseases of peanut (Arachis hypogaea L.) in Oklahoma and Virginia. Yield losses of 10% are common in these areas; however, losses may exceed 50% in highly infested fields (1). While Sclerotinia minor is considered the primary causal agent, S. sclerotiorum may also incite the disease. Symptoms typically appear late in the season and are favored by cool temperatures and high relative humidity (RH). Initial symptoms include wilting and yellowing of main or lateral branches. Dense mats of white mycelium develop on diseased areas, and small water-soaked lesions are apparent near the soil line. Lesions become bleached and infected tissues have a shredded appearance. Sclerotia are produced on and inside infected plant parts (2). During October 2004, following a period of heavy rainfall and cool temperatures, peanut plants (cv. Tifrunner) with these symptoms were observed in a field near Surrency, GA. The field had been planted to cotton (Gossypium hirsutum L.) for many years and peanut was strip-tilled into a heavy rye (Secale cereale L.) cover. Disease foci were found throughout the field and final incidence was 20%. Stem sections were surface disinfested in 0.5% sodium hypochlorite for 1 min and plated on potato dextrose agar (PDA). Cultures of S. sclerotiorum (2) were recovered after incubation at 20°C for 2 weeks. Pathogenicity tests were conducted by inoculating wounded peanut mainstems with PDA plugs either with or without the fungus. Inoculation sites were wrapped with moistened cheesecloth, and plants were incubated in a dew chamber at 20°C and 95% RH. There were a total of four replications and the experiment was repeated once. Symptoms consistent with those observed in the field appeared after 3 days and lesion lengths were measured after 5 days. Average lesion lengths were 1.4 and 1.6 cm for cvs. Georgia Green and Tifrunner, respectively Controls remained symptomless. Sections of symptomatic tissue were plated on PDA, and S. sclerotiorum was reisolated from 100% of symptomatic tissue. Although S. sclerotiorum is a common pathogen of various winter crops and weeds found in the southeast, to our knowledge, this is a first report of Sclerotinia blight on peanut in the region. No other occurrences of the disease have been reported since the initial discovery; however, potential losses could be incurred if peanuts are planted in infested fields and harvest is delayed. References: (1) H. A. Melouk and P. A. Backman. Management of soilborne fungal pathogens. Pages 75–85 in: Peanut Health Management. H. A. Melouk and F. M. Shokes, eds. The American Phytopathologicial Society, St. Paul, MN, 1995. (2) D. M. Porter and H. A. Melouk. Sclerotinia blight. Pages 34–36 in: Compendium of Peanut Diseases. 2nd ed. N. Kokalis-Burelle et al., eds. The American Phytopathologicial Society, St. Paul, MN, 1997.

Download Full-text

Remote homology clustering identifies lowly conserved families of effector proteins in plant-pathogenic fungi

Microbial Genomics ◽

10.1099/mgen.0.000637 ◽

2021 ◽

Vol 7 (9) ◽

Author(s):

Darcy A. B. Jones ◽

Paula M. Moolhuijzen ◽

James K. Hane

Keyword(s):

Fungal Pathogens ◽

Pathogenic Fungi ◽

Comparison Method ◽

Fungal Species ◽

Effector Proteins ◽

Plant Diseases ◽

Plant Host ◽

Homology Inference ◽

Developing Area ◽

Inference Methods

Plant diseases caused by fungal pathogens are typically initiated by molecular interactions between ‘effector’ molecules released by a pathogen and receptor molecules on or within the plant host cell. In many cases these effector-receptor interactions directly determine host resistance or susceptibility. The search for fungal effector proteins is a developing area in fungal-plant pathology, with more than 165 distinct confirmed fungal effector proteins in the public domain. For a small number of these, novel effectors can be rapidly discovered across multiple fungal species through the identification of known effector homologues. However, many have no detectable homology by standard sequence-based search methods. This study employs a novel comparison method (RemEff) that is capable of identifying protein families with greater sensitivity than traditional homology-inference methods, leveraging a growing pool of confirmed fungal effector data to enable the prediction of novel fungal effector candidates by protein family association. Resources relating to the RemEff method and data used in this study are available from https://figshare.com/projects/Effector_protein_remote_homology/87965.

Download Full-text

First Report of Diaporthe phaseolorum on Sunflower (Helianthus annuus) in Croatia

Plant Disease ◽

10.1094/pdis-93-10-1074c ◽

2009 ◽

Vol 93 (10) ◽

pp. 1074-1074 ◽

Cited By ~ 2

Author(s):

K. Vrandecic ◽

J. Cosic ◽

D. Jurkovic ◽

T. Duvnjak ◽

L. Riccioni

Keyword(s):

New York ◽

Helianthus Annuus ◽

Morphological Characteristics ◽

Aerial Mycelium ◽

Petri Dish ◽

Aluminum Foil ◽

Pathogenic Fungi ◽

Fungal Species ◽

Universal Primers ◽

First Report

Sunflower (Helianthus annuus L.) is a crop that is grown worldwide for the production of edible oil. In Croatia, it has considerable economic significance. From 2004 to 2007, sunflower stems showed light-to-dark brown lesions of different sizes and shapes. The lesions were observed for the presence of pycnidia in affected areas. Isolations from infected tissue on potato dextrose agar (PDA) yielded in two fungal species. One, which was isolated in most cases, was the well known sunflower pathogen Diaporthe helianthi Munt. Cvet. Morphological characteristics, stromata pattern, formation of alpha and beta conidia, and ascostromata characteristic of the other isolated fungus matched the description of D. phaseolorum (Cooke & Ellis) Sacc. (2). D. phaseolorum frequency was 5%. On PDA, the fungus formed white, floccose, aerial mycelium that filled a petri dish (9 cm) in 6 days. D. phaseolorum produces conidiomata in black stromatic structures, which consist of pycnidia with alpha and beta conidia. The alpha conidia were unicellular, hyaline, ellipsoidal to fusiform, and 5.6 to 10.0 × 1.9 to 4.8 μm. The beta conidia were hyaline, elongated, filiform, straight, curved at one or both ends, and 11.7 to 27.6 × 0.7 to 2.0 μm. After 50 days, perithecia were formed. Asci were clavate and 27.64 to 40.1 × 5.70 to 8.2 μm. Eight ascospores formed within asci. Ascospores were two-celled, elliptic, hyaline, and slightly constricted at the septa, and 8.93 to 13.5 × 2.1 to 4.0 μm. Amplification and sequencing of the internal transcribed spacer (ITS) rDNA region were performed with ITS4 and ITS5 universal primers (3) on two isolates (Su9 and Su10) and data were deposited in GenBank (Accession Nos. GQ149763 and GQ149764). Comparison of sequences available in GenBank revealed that the ITS sequence was identical to D. phaseolorum found on Stokesia laevis Hill (Greene) (U11323/U11373) and identical to the strain CBS 116020 isolated from Aster exilis Elliot. (AY745018). On the basis of the obtained results of morphological characteristics and molecular approaches, the pathogen was identified as D. phaseolorum. Pathogenicity evaluation consisted of artificial infections on field-grown sunflower plants at the full button stage as described by Bertrand and Tourvielle (1). A leaf test was done by placing a mycelial plug of 5 × 5 mm from a cork borer of two isolates (Su9 and Su10) on the tip of the main vein. The inoculation site was covered with moistened, cotton wool and wrapped in aluminum foil to prevent the inoculum from drying out. Ten plants of each of the four replications were inoculated. Control plants were inoculated with pure PDA plugs. Lesions of 12 to 40 mm long were observed on the sunflower leaf 10 days after inoculation. Control plants did not develop symptoms. The pathogen was reisolated from the infected plants. To our knowledge, this is the first report of the finding of D. phaseolorum on sunflower in Croatia and we have no literature data about the occurrence of this fungus on sunflower in the world. References: (1) F. Bertrand and D. Tourvielle. Inf. Tech. CETIOM 98:12,1972. (2) E. Punithalingma and P. Holliday. No. 336 in: Descriptions of Pathogenic Fungi and Bacteria. CMI/CAB, Kew, Surrey, England, 1972. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, Inc., New York, 1990.

Download Full-text

Fungal pathogens of the genus Fusarium in winter wheat Triticum aestivum L. protected with fungicides in north-eastern Poland

Acta Agrobotanica ◽

10.5586/aa.2013.027 ◽

2013 ◽

Vol 66 (2) ◽

pp. 95-106 ◽

Cited By ~ 2

Author(s):

Agnieszka Pszczółkowska ◽

Adam Okorski ◽

Jacek Olszewski ◽

Joanna Jarmołkowicz

Keyword(s):

Winter Wheat ◽

Fungal Pathogens ◽

Crop Protection ◽

Pathogenic Fungi ◽

Triticum Aestivum L ◽

Fungal Species ◽

Diagnostic Methods ◽

Growth Stages ◽

Monthly Precipitation ◽

Wheat Grain

Various diagnostic methods were used to evaluate the effect of fungicide protection on the prevalence of pathogenic fungi in wheat grain. Winter wheat cv. Nutka and Zyta was grown during a field experiment established in the Production and Experimental Station in Bałcyny in 2006–2007. The experimental factor was chemical crop protection: epoxiconazole, kresoxim-methyl and fenpropimorph applied at growth stages BBCH 33–35 as well as dimoxystrobin and epoxiconazole applied at BBCH 51–53. In this experiment, microscopic observations and conventional PCR assays were used as complementary methods. The quantification of Fusarium poae DNA by qPCR demonstrated the effectiveness of chemical protection against the analyzed fungal species. Lower monthly precipitation levels and higher daily temperatures intensified grain infections, in particular those caused by F. poae. A significant correlation was determined between the number of F. poae cultures isolated from winter wheat grain and the quantity of pathogenic DNA in grain identified by qPCR. Grain infections caused by F. poae lowered yield and thousand seed weight.

Download Full-text

Fungi colonizing and damaging different parts of some medicinal plants

Herba Polonica ◽

10.1515/hepo-2017-0009 ◽

2017 ◽

Vol 63 (2) ◽

pp. 18-26 ◽

Cited By ~ 2

Author(s):

Katarzyna Wielgusz ◽

Katarzyna Seidler-Łożykowska

Keyword(s):

Medicinal Plants ◽

Botrytis Cinerea ◽

Infected Plant ◽

Severe Infection ◽

Pathogenic Fungi ◽

Fungal Species ◽

Raw Material ◽

Lemon Balm ◽

Golovinomyces Cichoracearum

Summary Introduction: Many fungal species infect medicinal plants during their cultivation, causing great damage to the yield and decreasing the quality of raw material. Objective: Due to the increase in contamination of raw material and the damage caused by pathogenic fungi, the main species of medicinal plants cultivated in Poland were subject to the investigation. Methods: In 2012–2014, an experiment was conducted on eight medicinal plant species breeding nurseries grown in the field in Plewiska. The following species and cultivars were investigated: lemon balm, peppermint, St. John’s wort cv. ‘Topaz’, lovage cv. ‘Amor’, valerian cv. ‘Polka’, caraway cv. ‘Kończewicki’, sweet basil cv. ‘Wala’, marjoram cv. ‘Miraż’. Results: Fourteen species of eleven genera of pathogenic fungi were isolated from the investigated medicinal plants: Fusarium avenaceum, F. culmorum, F. equiseti, F. oxysporum, Botrytis cinerea, Alternaria alternata, Cladosporium sp., Rhizoctonia solani, Septoria sp., Boeremia exiqua, Golovinomyces cichoracearum, Penicillium sp., Ramularia sp., and Sclerotinia sclerotiorum. The most severe infection was caused by Fusarium sp. and Botrytis cinerea. Also Cladosporium sp. (4 species), A. alternata and Septoria sp. (3 species) infected plant tissue. Leaves and stems were the most infected parts of the tested plants. Lemon balm, lovage and valerian were the most infected species, while marjoram was infected only with Fusarium sp.

Download Full-text

Biodiversity of pathogenic wood fungi isolated from Xylotrechus arvicola (Olivier) galleries in vine shoots

OENO One ◽

10.20870/oeno-one.2013.47.2.1540 ◽

2013 ◽

Vol 47 (2) ◽

pp. 73 ◽

Cited By ~ 2

Author(s):

Pablo García Benavides ◽

Pedro Martin Zamorano ◽

Carlos Alvar Ocete ◽

Lara Maistrello ◽

Rafael Ocete

Keyword(s):

Fungal Pathogens ◽

Plant Pathogens ◽

Pathogenic Fungi ◽

Fungal Species ◽

Its2 Sequence ◽

Plant Diseases ◽

Northern Spain ◽

Grapevine Decline ◽

La Rioja

Aim: Grapevine decline caused by wood fungi seriously threatens viticulture worldwide. In Spain, the polyphagous borer Xylotrechus arvicola (Coleoptera, Cerambycidae) is becoming a serious pest in different Qualified Designation of Origin (DOC) wine regions. The aim of the present work was to identify the fungal species growing in the galleries excavated by X. arvicola larvae inside the vine branches and investigate the possible relationship between wood pathogenic fungi and this borer.Methods and results: Wood samples from branches of Tempranillo vines and Prunus pisardi trees affected by the borer X. arvicola were collected in La Rioja DOC vineyards (Northern Spain) and analyzed for the presence of fungi using both morphological techniques and genetic tools based on Internal Transcribed Spacer 2 (ITS2) sequence. Among the 20 different fungal species/isolates identified, 7 belonged to fungi associated with grapevine decline (esca, Petri disease, and Eutypa dieback), 6 were plant pathogens, 6 were saprophytic and one was entomopathogenic (Beauveria bassiana).Conclusion: The fact that 65 % of the fungi detected inside X. arvicola galleries belong to species recognized as plant pathogens suggests that this borer, in addition to causing a progressive decay of the branches, could facilitate the transmission of plant diseases, further threatening the vineyards by spreading grapevine decline pathogens.Significance and impact of the study: The present work represents a first step in recognizing the association between the fungal pathogens associated with grapevine decline and the borer X. arvicola, suggesting a possible role of this insect as a vector in the transmission of these fungi.

Download Full-text

The RAM Network in Pathogenic Fungi

Eukaryotic Cell ◽

10.1128/ec.00044-12 ◽

2012 ◽

Vol 11 (6) ◽

pp. 708-717 ◽

Cited By ~ 35

Author(s):

Sarah Saputo ◽

Yeissa Chabrier-Rosello ◽

Francis C. Luca ◽

Anuj Kumar ◽

Damian J. Krysan

Keyword(s):

Fungal Pathogens ◽

Pathogenic Fungi ◽

Fungal Species ◽

Specific Gene ◽

Content Type ◽

Network Function ◽

Cellular Processes ◽

Ram Network ◽

Recent Developments ◽

Protein Kinase Signaling

ABSTRACT The r egulation of A ce2 and m orphogenesis (RAM) network is a protein kinase signaling pathway conserved among eukaryotes from yeasts to humans. Among fungi, the RAM network has been most extensively studied in the model yeast Saccharomyces cerevisiae and has been shown to regulate a range of cellular processes, including daughter cell-specific gene expression, cell cycle regulation, cell separation, mating, polarized growth, maintenance of cell wall integrity, and stress signaling. Increasing numbers of recent studies on the role of the RAM network in pathogenic fungal species have revealed that this network also plays an important role in the biology and pathogenesis of these organisms. In addition to providing a brief overview of the RAM network in S. cerevisiae , we summarize recent developments in the understanding of RAM network function in the human fungal pathogens Candida albicans , Candida glabrata , Cryptococcus neoformans , Aspergillus fumigatus , and Pneumocystis spp.

Download Full-text

Multicopper Oxidases in Saccharomyces cerevisiae and Human Pathogenic Fungi

Journal of Fungi ◽

10.3390/jof6020056 ◽

2020 ◽

Vol 6 (2) ◽

pp. 56

Author(s):

Tanmoy Chakraborty ◽

Renáta Tóth ◽

Joshua D. Nosanchuk ◽

Attila Gácser

Keyword(s):

Saccharomyces Cerevisiae ◽

Environmental Conditions ◽

Defense Mechanisms ◽

Fungal Pathogens ◽

Lignin Degradation ◽

Pathogenic Fungi ◽

Fungal Species ◽

Multicopper Oxidases ◽

Fungal Virulence ◽

Physiological Processes

Multicopper oxidases (MCOs) are produced by microscopic and macroscopic fungal species and are involved in various physiological processes such as morphogenesis, lignin degradation, and defense mechanisms to stress inducing environmental conditions as well as fungal virulence. This review will summarize our current understanding regarding the functions of MCOs present in Saccharomyces cerevisiae and in different human fungal pathogens. Of the two main MCO groups, the first group of MCOs is involved in iron homoeostasis and the second includes laccases. This review will also discuss their role in the pathogenesis of human fungal pathogens.

Download Full-text