Prevalence of Soil-borne Diseases in Kalanchoe blossfeldiana Reveals a Complex of Pathogenic and Opportunistic Fungi

Greenhouse cultivation of ornamentals is subjected to a high incidence of soil-borne fungal pathogens. In Kalanchoe, these pathogens are responsible for root and stem rot, and for infection of the vascular tissue. Well-known soil-borne pathogens are believed to cause these diseases. Yet, a systematized survey of these pathogens is lacking for Kalanchoe produced commercially. Here, we studied the occurrence of soil-borne fungal pathogens associated with cultivation of Kalanchoe in Denmark and production of cuttings and stock plants in greenhouse facilities located in Turkey and Vietnam. Molecular identification of pathogens complemented mycological identification and pathogenicity testing of the soil-borne fungal pathogens. This study revealed that the fungi Corynespora cassiicola, Thielaviopsis basicola, Fusarium solani, and F. oxysporum are the most prevalent pathogens associated with root and stem rotting and wilt of Kalanchoe under the conditions studied. Furthermore, the study showed that some of the pathogens are part of an infection complex comprising both primary and opportunistic fungal species. The fact that some of the pathogens were present in some regions, while absent in others, suggests how they move between greenhouse facilities on infected plant material. This study generated important information about the soil-borne fungal complex affecting Kalanchoe, which is useful for a better understanding of the biology of the disease and for designing control strategies.

Download Full-text

Means, motive, and opportunity for biological invasions: genetic introgression in a fungal pathogen

10.1101/2021.09.25.461217 ◽

2021 ◽

Author(s):

Flávia Rogério ◽

Cock van Oosterhout ◽

Maisa Ciampi-Guillardi ◽

Fernando Henrique Correr ◽

Guilherme Kenichi Hosaka ◽

...

Keyword(s):

Genetic Variation ◽

Fungal Pathogens ◽

Plant Pathogens ◽

Population Genomics ◽

Crop Yields ◽

Control Strategies ◽

Fungal Species ◽

Genetic Introgression ◽

Fungal Plant Pathogens ◽

Genomic Studies

Invasions by fungal plant pathogens pose a significant threat to the health of agriculture ecosystems. Despite limited standing genetic variation, many invasive fungal species can adapt and spread rapidly, resulting in significant losses in crop yields. Here, we report on the population genomics of Colletotrichum truncatum, a polyphagous pathogen that can infect more than 460 plant species, and an invasive pathogen on soybean in Brazil. We study the whole-genome sequences of 18 isolates representing 10 fields from two major regions of soybean production. We show that Brazilian C. truncatum is subdivided into three phylogenetically distinct lineages that exchange genetic variation through hybridization. Introgression affects 2 to 30% of the nucleotides of genomes and varies widely between the lineages. We find that introgressed regions comprise secreted protein-encoding genes, suggesting possible co-evolutionary targets for selection in those regions. We highlight the inherent vulnerability of genetically uniform crops in the agro-ecological environment, particularly when faced with pathogens that can take full advantage of the opportunities offered by an increasingly globalized world. Finally, we discuss "The Means, Motive, and Opportunity" of fungal pathogens and how they can become invasive species of crops. We call for more population genomic studies because such analyses can help identify geographic areas and pathogens that pose a risk, thereby helping to inform control strategies to better protect crops in the future.

Download Full-text

Fungal pathogens associated with wilting of Neolitsea cassia trees

International Journal of Forestry, Ecology and Environment ◽

10.18801/ijfee.040221.19 ◽

2021 ◽

Vol 04 (02) ◽

pp. 172-176

Author(s):

A. L. M. Zuhry ◽

R. G. A. S. Rajapaksha ◽

J. Kahawatta ◽

S. Kohombange

Keyword(s):

Sri Lanka ◽

Tree Species ◽

Fungal Pathogens ◽

Infected Plant ◽

Pathogenic Fungi ◽

Fungal Species ◽

Wilt Disease ◽

Thiophanate Methyl ◽

First Report ◽

Collar Region

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

Post-translational regulation of autophagy is involved in intra-microbiome suppression of fungal pathogens

Microbiome ◽

10.1186/s40168-021-01077-y ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Jing Wang ◽

Chaoyun Xu ◽

Qiming Sun ◽

Jinrong Xu ◽

Yunrong Chai ◽

...

Keyword(s):

Translational Regulation ◽

Fungal Pathogens ◽

Fungal Growth ◽

Fungal Species ◽

26S Proteasome ◽

Healthy Plant ◽

Autophagy Induction ◽

Histone Acetyltransferase Gcn5 ◽

Plant Microbiota ◽

Autophagic Process

Abstract Background Microbiome interactions are important determinants for ecosystem functioning, stability, and health. In previous studies, it was often observed that bacteria suppress potentially pathogenic fungal species that are part of the same plant microbiota; however, the underlying microbe-microbe interplay remains mostly elusive. Here, we explored antagonistic interactions of the fungus Fusarium graminearum and bacterium Streptomyces hygroscopicus at the molecular level. Both are ubiquitous members of the healthy wheat microbiota; under dysbiosis, the fungus causes devastating diseases. Results In co-cultures, we found that Streptomyces alters the fungal acetylome leading to substantial induction of fungal autophagy. The bacterium secrets rapamycin to inactivate the target of rapamycin (TOR), which subsequently promotes the degradation of the fungal histone acetyltransferase Gcn5 through the 26S proteasome. Gcn5 negatively regulates fungal autophagy by acetylating the autophagy-related protein Atg8 at the lysine site K13 and blocking cellular relocalization of Atg8. Thus, degradation of Gcn5 triggered by rapamycin was found to reduce Atg8 acetylation, resulting in autophagy induction in F. graminearum. Conclusions Autophagy homeostasis plays an essential role in fungal growth and competition, as well as for virulence. Our work reveals a novel post-translational regulation of autophagy initiated by a bacterial antibiotic. Rapamycin was shown to be a powerful modulator of bacteria–fungi interactions with potential importance in explaining microbial homeostasis in healthy plant microbiomes. The autophagic process provides novel possibilities and targets to biologically control pathogens.

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

Peach Brown Rot: Still in Search of an Ideal Management Option

Agriculture ◽

10.3390/agriculture8080125 ◽

2018 ◽

Vol 8 (8) ◽

pp. 125 ◽

Cited By ~ 13

Author(s):

Vitus Ikechukwu Obi ◽

Juan José Barriuso ◽

Yolanda Gogorcena

Keyword(s):

Fungal Pathogens ◽

Crop Production ◽

Control Strategies ◽

Brown Rot ◽

Management Option ◽

Management Options ◽

Pests And Diseases ◽

Resistant Varieties ◽

Rot Disease ◽

Post Harvest Loss

The peach is one of the most important global tree crops within the economically important Rosaceae family. The crop is threatened by numerous pests and diseases, especially fungal pathogens, in the field, in transit, and in the store. More than 50% of the global post-harvest loss has been ascribed to brown rot disease, especially in peach late-ripening varieties. In recent years, the disease has been so manifest in the orchards that some stone fruits were abandoned before harvest. In Spain, particularly, the disease has been associated with well over 60% of fruit loss after harvest. The most common management options available for the control of this disease involve agronomical, chemical, biological, and physical approaches. However, the effects of biochemical fungicides (biological and conventional fungicides), on the environment, human health, and strain fungicide resistance, tend to revise these control strategies. This review aims to comprehensively compile the information currently available on the species of the fungus Monilinia, which causes brown rot in peach, and the available options to control the disease. The breeding for brown rot-resistant varieties remains an ideal management option for brown rot disease control, considering the uniqueness of its sustainability in the chain of crop production.

Download Full-text

Deciphering Molecular Determinants Underlying Penicillium digitatum’s Response to Biological and Chemical Antifungal Agents by Tandem Mass Tag (TMT)-Based High-Resolution LC-MS/MS

International Journal of Molecular Sciences ◽

10.3390/ijms23020680 ◽

2022 ◽

Vol 23 (2) ◽

pp. 680

Author(s):

Lucía Citores ◽

Mariangela Valletta ◽

Vikram Pratap Singh ◽

Paolo Vincenzo Pedone ◽

Rosario Iglesias ◽

...

Keyword(s):

Fungal Pathogens ◽

Control Strategies ◽

Chemical Compounds ◽

Postharvest Disease ◽

Tandem Mass ◽

Cell Wall Degrading Enzymes ◽

Inhibitory Mechanisms ◽

Proteomic Approach ◽

Molecular Determinants ◽

Protein Toxins

Penicillium digitatum is a widespread pathogen responsible for the postharvest decay of citrus, one of the most economically important crops worldwide. Currently, chemical fungicides are still the main strategy to control the green mould disease caused by the fungus. However, the increasing selection and proliferation of fungicide-resistant strains require more efforts to explore new alternatives acting via new or unexplored mechanisms for postharvest disease management. To date, several non-chemical compounds have been investigated for the control of fungal pathogens. In this scenario, understanding the molecular determinants underlying P. digitatum’s response to biological and chemical antifungals may help in the development of safer and more effective non-chemical control methods. In this work, a proteomic approach based on isobaric labelling and a nanoLC tandem mass spectrometry approach was used to investigate molecular changes associated with P. digitatum’s response to treatments with α-sarcin and beetin 27 (BE27), two proteins endowed with antifungal activity. The outcomes of treatments with these biological agents were then compared with those triggered by the commonly used chemical fungicide thiabendazole (TBZ). Our results showed that differentially expressed proteins mainly include cell wall-degrading enzymes, proteins involved in stress response, antioxidant and detoxification mechanisms and metabolic processes such as thiamine biosynthesis. Interestingly, specific modulations in response to protein toxins treatments were observed for a subset of proteins. Deciphering the inhibitory mechanisms of biofungicides and chemical compounds, together with understanding their effects on the fungal physiology, will provide a new direction for improving the efficacy of novel antifungal formulations and developing new control strategies.

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

Epidemiology, Clinical Profile and Treatment Outcomes of Bacterial and Fungal Keratitis

10.21203/rs.3.rs-573494/v1 ◽

2021 ◽

Author(s):

Nabila Mabrouk ◽

Mohamed Abdelkader ◽

Mohamed Abdelhakeem ◽

Khaled Mourad ◽

Ahmed Abdelghany

Keyword(s):

Treatment Outcomes ◽

Fungal Pathogens ◽

Fungal Growth ◽

Fungal Species ◽

Clinical Findings ◽

Fungal Keratitis ◽

Clinical Profile ◽

Clinical Series ◽

Vegetative Matter ◽

Department Faculty

Abstract Purpose: The purpose of the study is to determine the microbiological aetiology, epidemiological factors, and clinical profile and treatment outcomes of infective keratitis in Ophthalmology department, Minia University. EgyptMethods:Prospective, non-randomized, observational clinical series of cases, including 150 patients with mean age 30 (range 12 to 85 years), 90 patients (60 %) were males and 60 (40%) were females, clinically diagnosed as infective corneal ulcer, attending the Ophthalmology Department – Faculty of Medicine. Minia University, Minia, Egypt. From 2018 to 2020.Detailed history taking and all clinical findings were collected. Corneal scrapings were obtained from patients and subjected to staining and culture for bacterial and fungal pathogens; Bacterial and fungal growth were identified by standard laboratory procedures.Results:Corneal trauma by a vegetative matter was the commesnest risk factor associated with infective keratitis in 92 cases (61.3%). Smear and Culture was positive in 83 cases (58.4%) of 142 corneal scrapings obtained, of which 60 cases were fungal (72.3%), 21 cases were bacterial (25.3%) and 2 cases were mixed bacterial and fungal (2.4%), Aspergillus species was the commonest fungal species isolated in fungal keratitis. 142 cases (94.67 %) healed completely with scar. Only 6 cases (4%) required evisceration due to aggressive presentation from the start and keratoplasty was performed for 2 cases (1.33%).Conclusions:Fungal keratitis was the commonest type in cases attending to our department. Adequate diagnosis, management and follow up helped in achieving high successful curative outcomes. Clinical Trials.gov ID: NCT04894630. Time of registration 1 December 2018

Download Full-text

Mycoflora of sawn timbers in Benin City

Acta Mycologica ◽

10.5586/am.1987.016 ◽

2014 ◽

Vol 23 (2) ◽

pp. 89-95

Author(s):

J. A. Okhuoya ◽

S. O. Itaman

Keyword(s):

Moisture Content ◽

Pleurotus Ostreatus ◽

Fungal Species ◽

High Moisture Content ◽

High Moisture ◽

Benin City ◽

The Poor ◽

High Incidence

In a fungal suryey of sawn timbers in scattared localities in Benin City, fungal species isolated were mainly members of Hyphomycetes, with few Ascomycetes and Basidiomycetes. Cellulolytic abilities of isolates were determined and found to be highest in a basidiomycete, Pleurotus ostreatus. The high incidence of these isolates was traced to the poor ventillation in the shades where the timbers arę sold and the high moisture content of timber before display for sale.

Download Full-text

Localization and Visualization of Specific Gene Products in Fungal Plant Pathogens

Microscopy and Microanalysis ◽

10.1017/s1431927600035893 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 680-681 ◽

Cited By ~ 2

Author(s):

T. M. Bourett ◽

K. J. Czymmek ◽

T. M. Dezwaan ◽

J. A. Sweigard ◽

R. J. Howard

Keyword(s):

Fungal Pathogens ◽

Plant Pathogens ◽

Protein Localization ◽

Infected Plant ◽

Cell Interaction ◽

Specific Gene ◽

Gene Products ◽

Tem Analysis ◽

Fungal Plant Pathogens ◽

Plant Pathogenesis

Specific gene products of both pathogens and hosts have been implicated as decisive elements during plant pathogenesis. While expression of some of these genes is constitutive, that of others is likely ephemeral and activated only during a particular stage of the interaction. Because the relative timing of expression may be critical, transcription and translation have often been addressed by extracting mRNA and proteins from infected plant tissue. This approach, however, cannot readily detect proteins of low abundance in bulk samples nor offer much useful information on cell-cell interaction. Only a cytological analysis that employs microscopy can resolve the temporal and spatial details of gene expression. Typically, such protein localization studies have required specific antibodies, but these large probe molecules do not diffuse into living or conventionally fixed cells of either fungal pathogens or plant hosts. For TEM analysis, these permeability-imposed limitations have been reduced by thin sectioning to render accessible antibody binding sites.

Download Full-text