Isolation Of Pathogenic Fungi Research Articles

Phytochemical Identification of Alkaloidic Compounds from Cinnamomum cassia Cortex and Estimation of their Antifungal Efficacy

Cinnamomum caresia is defined as a medical and traditional plant grows in diverse countries in the world. It has therapeutic effects for treating various diseases resulting from infection by different microorganisms. In the current study, six alkaloids compounds were isolated and characterized from cinamom cortexes by using the GC-MS technique. The synergistic interaction was applied for the alkaloidic mixture against growth of two isolates of pathogenic fungi represented by Urocystis agropyri and Candida albicans by using the concentrations (25, 50, 75, 100, and 125 mg/ml) which recorded diverse diameters of inhibition equal to 58, 66, 72, 74, and 78 mm and 68, 52, 70, 72, and 74 mm, respectively. As a result, these alkaloidic compounds are recommended for use as natural therapy for diseases caused by the current pathogenic fungi.

Biological potentials of Landolphia owariensis leaf methanolic extract against pathogenic fungi isolates from different Dioscorea species

Abstract Regarding economic significance, the Dioscoreaceae family, which includes the well-known Dioscorea (yam) species, is the fourth most important tuber crop globally. A basic meal found all across the world, yams encourage and ensure the food security of households. Although they are challenging to preserve and store however a post-harvest deterioration control must be developed. Over the years, Nigerian farmers have employed medicinal herbs to manage post-harvest pest invasion; nevertheless, the scientific basis for this fungal management has not yet been well documented. As a result, Landolphia owarensis leaf extract was used as a biological control, and fungi were isolated from Dioscorea cayenensis, Dioscorea alata, and Discorea rotundata. Samples of yam tubers – both rotten and healthy – were procured in the markets and brought to the lab for fungus isolation and identification. Leaves of Landolphia oweriensis were collected, air-dried, milled, and macerated in pure methanol for 72 h, extracted and concentrated with a rotary evaporator. The agar-well diffusion method was used for the biological control assay against the fungal isolates. The biological control results were presented as mean ± SD (standard deviation) while analysis of variance (Anova) was used to deduce least significant difference (LSD). A total number of 605 fungi isolates were observed in which D. cayenensis had the highest, 50.58 %, D. alata and Discorea rotundata 24.71 % respectively. Aspergillus niger and Aspergillus fumigatus were found in the three species while Aspergillus flavus, Rhizopus stolonifer, Collentotricum spp. and Penicillium spp. in either of the species. L. owarensis methanolic leaves extracts possesses biological potentials against Colletotrium spp., A. fumigatus, A. niger and A. flavus only. The problem of postharvest fungal invasion of Dioscorea species can be solved with the inhibition observed with L. owarensis methanolic leaves extracts as a biological control measure thereby sustaining food security in the world.

A Comparative Study of the Antifungal Activity of Fresh and Dried Solanum anguivi Fruits on Candida albicans and Trichophyton rubrum

In Côte d'Ivoire, as elsewhere in Africa, Solanum anguivi Lam is widely used in traditional medicine to treat bacterial and fungal infections. Given the importance of this plant, the extracts 70%, 80% and 100% from fresh and dried fruits was evaluated for the in vitro growth of two isolates of pathogenic fungi (Candida albicans and Trichophyton rubrum), as well as its anti-free radical activity. 
 Antifungal tests were carried out by plating 1000 cells of each isolate on Sabouraud agar medium using the double dilution method in inclined tubes. Both extracts were active on the different strains tested, according to a dose-response relationship based on the principle of the method used.
 However, extracts from fresh fruit showed good activity on C. albicans, while the dried fresh fruit extracts were highly active on T. rubrum.

Production and characterization of rhamnolipid biosurfactant from thermophilic Geobacillus stearothermophilus bacterium isolated from Uhud mountain.

Biosurfactants have been given considerable attention as they are potential candidates for several biotechnological applications. In this study, a promising thermophilic biosurfactant-producing HA-2 was isolated from the volcanic and arid region of Uhud mountain, Madinah, Saudi Arabia. It was identified using 16S rRNA gene sequence analysis. The biosurfactant production ability was screened using different methods such as the drop collapse test, oil spreading test, hemolytic activity test, CTAB test, and emulsification index. The ability of rhamnolipid production by the tested strain was confirmed by the polymerase chain reaction (PCR) of rhlAB. The affinity of thermophilic HA-2 to hydrophobic substrates was also investigated. Optimization of biosurfactant production was conducted. The biological activities of produced surfactant were investigated. The isolated HA-1 was identified as Geobacillus stearothermophilus strain OR911984. It could utilize waste sunflower frying oil (WSFF) oil as a low-cost carbon source. It showed high emulsification activity (52 ± 0.0%) and positive results toward other biosurfactant screening tests. The strain showed high cell adhesion to hexane with 41.2% cell surface hydrophobicity. Fourier-transform infrared (FTIR) spectra indicated the presence of hydrophobic chains that comprise lipids, sugars, and hydrophilic glycolipid components. The optimization results showed the optimal factors included potato peel as a carbon source with 68.8% emulsification activity, yeast extract as a nitrogen source with 60% emulsification activity, a pH of 9 (56.6%), and a temperature of 50° (72%). The kinetics showed that optimum biosurfactant production (572.4 mg/L) was recorded at 5 days of incubation. The produced rhamnolipid biosurfactant showed high antimicrobial activity against some human and plant pathogenic bacterial and fungal isolates and high antioxidant activity (90.4%). In addition, it enhanced wheat (Triticum aestivum) growth, with the greatest enhancement obtained with the 5% concentration. Therefore, thermophilic G. stearothermophilus is a promising rhamnolipid biosurfactant producer that utilizes many organic wastes. The produced biosurfactant could be applied as a promising emulsifier, antimicrobial, antioxidant, and plant growth promoter.

CERCOSPORA CANESCENS: CAUSE OF LEAF SPOT DISEASE ON LETTUCE CROP IN BALI PROVINCE, INDONESIA

Cercospora leaf spot disease on lettuce (Lactuca sativa L.) caused losses in Tabanan Regency, Bali, Indonesia. Cercospora leaf spot in lettuce results from the pathogenic fungi Cercospora canescens. The preventive research aimed to identify the fungi on the morphological and molecular basis by using universal primers for PCR of ITS 1 and ITS 4. The study used Koch's Postulates method to isolate the pathogenic fungal isolates from lettuce plants and test for pathogenicity. Identification of fungi continued macroscopically, microscopically, and molecularly. The macroscopic and microscopic observations showed that the cause of cercospora leaf spot on lettuce is the fungal disease caused by pathogenic fungi Cercospora spp. The isolate creates a dull white and robust mycelium structure, sideways growth, branched and septate hyphae, branched conidiophores, and dark lanceolate conidia. Through molecular identification, it helped recognize that fungi Cercospora canescens isolate Cer11-18 (Accession Number: MN400290.1) is the foremost cause of a withered lettuce crop. It is also the first research on the cercospora leaf spot disease on lettuce caused by Cercospora spp. in Tabanan Regency, Bali, Indonesia.

A chromosome-level genome assembly of Zasmidium syzygii isolated from banana leaves.

Accurate taxonomic classification of samples from infected host material is essential for disease diagnostics and genome analyses. Despite the importance, diagnosis of fungal pathogens causing banana leaf diseases remains challenging. Foliar diseases of bananas are mainly caused by 3 Pseudocercospora species, of which the most predominant causal agent is Pseudocercospora fijiensis. Here, we sequenced and assembled four fungal isolates obtained from necrotic banana leaves in Bohol (Philippines) and obtained a high-quality genome assembly for one of these isolates. The samples were initially identified as P. fijiensis using PCR diagnostics; however, the assembly size was consistently 30 Mb smaller than expected. Based on the internal transcribed spacer (ITS) sequences, we identified the samples as Zasmidium syzygii (98.7% identity). The high-quality Zasmidium syzygii assembly is 42.5 Mb in size, comprising 16 contigs, of which 11 are most likely complete chromosomes. The genome contains 98.6% of the expected single-copy BUSCO genes and contains 14,789 genes and 10.3% repeats. The 3 short-read assemblies are less continuous but have similar genome sizes (40.4-42.4 Mb) and contain between 96.5 and 98.4% BUSCO genes. All 4 isolates have identical ITS sequences and are distinct from Zasmidium isolates that were previously sampled from banana leaves. We thus report the first continuous genome assembly of a member of the Zasmidium genus, forming an essential resource for further analysis to enhance our understanding of the diversity of pathogenic fungal isolates as well as fungal diversity.

Inventory of Pathogenic Fungi by Red Chili Seeds (Capsicum annuum L.) from Deli Serdang Regency, North Sumatera

Red chilies known as Capsicum annuum L., hold significant importance as horticulture crops in Indonesia. The production of red chilies begins with the planting of seeds, making seed health a crucial factor in the process. Seeds contaminated with pathogens can serve as a reservoir for the transmission of diseases in the field, leading to the demise of seedlings and hindering their growth into fully mature plants, ultimately resulting in crop failure. This study used the blotter test technique to ascertain the morphology of a seed-borne pathogenic fungus. The research findings indicated that the blotter test technique detected four isolates of seed-borne pathogenic fungus, specifically TMIA with an infection rate of 0.5%, TMIB with an infection rate of 0.5%, TMIC with an infection rate of 2.5%, and TMIE with an infection rate of 3%. A single isolate of a seed-borne pathogenic fungus, named SRIA, was obtained from Sidodadi Ramunia village. The infection rate of this fungus was determined to be 0.5%. The chili seeds recovered were found to carry pathogenic fungal isolates belonging to Aspergillus sp., Penicillium sp., Verticillium sp., and Curvularia sp. based on morphological identification

Exploring the mechanisms of endophytic bacteria for suppressing early blight disease in tomato (Solanum lycopersicum L.).

Controlling early blight of tomatoes using endophytic bacteria is an eco-friendly and sustainable approach to manage this common fungal disease caused by Alternaria solani, Alternaria alternata, and Curvularia lunata. Endophytic bacteria are microorganisms that live inside plant tissues without causing harm and can help protect the host plant from pathogens. In this work, twenty endophytic bacterial isolates from tomato healthy plants were tested against pathogenic fungal isolates that caused early blight disease in vitro. Out of the 20 tested isolates, three (B4, B7, and B17) were considered effective isolates against the growth of fungal pathogens. The three isolates were recognized as Enterobacter cloacae HS-6 (B4), Pseudomonas gessardii HS-5 (B 7), and Pseudomonas mediterranea HS-4 (B17) using 16s-rDNA sequencing. Different concentrations of bacterial cultural diltrates at 20, 40, and 60% were tested for their antagonistic effects on the development of pathogenic fungi in vitro. The lowest dry weights of pathogenic isolates in all bacterial culture filtrates were discovered at 60%. In all culture filtrates, phenolic compounds showed the largest peak area. Under greenhouse conditions, the least disease severity of tomato early blight was found for E. cloacae and its culture filtrate compared to other treatments. Real-time PCR was used to examine the expression pattern of the defense response gene β-1.3 glucanase gene in infected tomato plants with pathogenic fungi (control) as well as its relations with efficient biocontrol agent (E. cloacae). The expression of the gene increased substantially and significantly after three days from the inoculation-infected plants with C. lunata and E. cloacae while it reached the maximum after five days from the inoculation with A. alternata, A. solani and E. cloacae. Our study concluded that the endophytic bacterial isolate E. cloacae can be considered a promising biocontrol agent for preventing tomato early blight.

First Record of Neofusicoccum luteum and Colletotrichum gloeosporioides Causing Anthracnose and Stem End Rot on Avocado Fruits in Greece.

In May 2022, rot symptoms were observed 5 days after storage on fresh avocado fruits cv "Lamb Hass" harvested from a 3.4 ha organic orchard in Chania, Crete exhibiting 30% symptom incidence. Brownish-green sunken lesions and soft rot with dark brown lesions covering up to 50% of the mesocarp on fruits and blackish soft lesions on fruit stem ends were observed. To isolate the pathogens, fruits were surface sterilized using 1% NaOCl for 1 min, placed in 70% ethanol for 30 s and washed twice with sterile distilled water. Then, small pieces were excised from the fruit rot margins and transferred on PDA amended with 0.015% streptomycin-sulfate. Single-spore isolates were incubated on PDA for 10 days and subjected to morphological examination. Two distinct pathogenic fungal isolates were obtained, and their symptoms were re-examined on avocado fruits. The first isolate (A1) obtained from the fruit stem end, initially produced hyaline dense aerial mycelia, being gray and black on the upper and lower surface of the Petri dishes, respectively. The second isolate (A2) obtained from the main body of the fruit, formed round, grayish colonies, with orange conidial aggregates. Based on morphological characteristics (Phillips et al.,2013; Weir et al., 2012), isolates were preliminary identified as Neofusicoccum sp. (A1) and Colletotrichum sp. (A2). Isolates were molecularly identified by sequencing of the ITS-5.8S rRNA, translation elongation factor 1-alpha (tef1) and beta-tubulin (tub2) genes. PCRs were conducted using primer pairs ITS4/ITS5, EF1-728F/EF1986R and Bt2a/Bt2b as well as ITS4/ITS5 and 5'-tef1/3'-tef1 and Bt2a/Bt2b for isolates A1 and A2, respectively (Carbone & Kohn, 1999; Glass & Donaldson, 1995; Rojas et al., 2010; Weir et al., 2012; White et al., 1990). The sequences were deposited into GenBank under the accession numbers OQ852465, OQ867962, OQ867965 for N. luteum and, OQ852466, OQ867963 and OQ867964 for C. gloeosporioides. Based on Multilocus sequence analysis (MLSA), a phylogenetic tree was constructed using concatenated sequences, following Kimura's two parameter model (1980), which confirmed their identity as N luteum and C. gloeosporioides strains. Mature avocado fruits (cv. Hass) were surface sterilized and dried. Consequently, incised fruits were inoculated with mycelial agar plugs (5 mm in diameter) cut from the edge of rapidly growing colonies of N. luteum and C. gloeosporioides strains. Fruits incubated in moist chambers and at 25°C for 5 days in the dark. Fruit bodies and stems were inoculated with the respective isolates and sterile agar plugs in the case of the control. Five fruits were used for each pathogenic trial per fungal isolate, which was repeated twice. After symptom occurrence, these pathogenic isolates were re-isolated successfully and molecularly identified, while exhibiting similar to original symptoms confirming Koch's postulates. While other reports exist on the presence of these pathogens in different countries worldwide, this is the first report of C. gloeosporioides and N. luteum as post-harvest pathogens of avocado, which is an economically important crop of Crete, in Greece (Akgül et al., 2016). This study provides the means for the accurate identification of these fungal pathogens causing avocado fruit rots and taking into consideration the available treatment options can contribute to establishing effective management strategies.

First report of Fusarium sporotrichioides causing Fusarium fruit rot on peaches in Pakistan.

Peach (Prunus persica) is an important stone fruit crop cultivated on 14,350 hectares in temperate areas of Pakistan, where post-harvest fungal rots cause major economic losses for growers. During April-August 2019, rotted peaches were observed in fruit markets of Rawalpindi district (33° 37' 33.8052'' N and 73° 4' 17.1912'' E), Punjab Province, Pakistan. Symptomatic fruit were surface sterilized for 3 min in 0.5% NaClO and 1 min in 70% ethanol, then rinsed three times in sterilized distilled water and air-dried for 30 minutes on filter paper. Tissue segments were excised from the margins of rot lesions and placed on potato dextrose agar (PDA), followed by incubation for one week at 25 +1o C. Furthermore, to maintain original sporodochial morphology and conidial description tissue segments were also grown on carnation leaf agar (CLA) and synthetic nutrient agar (SNA) (Sever et al., 2012). A total of 22 isolates were obtained from different fruit markets; colonies were fast-growing with pinkish-white, fluffy mycelia. Microconidia were abundant, 7.5 to 11.3 × 2.1 to 4.1 μm, oval to spindle-shaped, thin-walled, and hyaline whereas, macroconidia were thick-walled, sickle-shaped, 5- to 7-septate, hyaline, and 23.5 to 39.7 × 3.7 to 7.0 μm on carnation leaf agar. Virulence intensity of fungal isolates was confirmed after pathogenicity. Based on morphological characteristics, isolates were identified provisionally as Fusarium sporotrichioides (Leslie and Summerell 2006). For molecular identification, three target gene regions (ITS, elongation factor (EF), and β-tubulin benA) were amplified for highly pathogenic fungal isolates (FUS21K, FUS9SM, and FUS63KP) (O'Donnell et al. 2015). BLAST searches of the obtained sequences indicated 100% homology with GenBank accession number MN452643, and 99.56% homology with MT635298 for the ITS region, similarly 100% identity with GenBank accession numbers MN555016, MN555126, and MN555037 for the EF gene, and 100% homology with GenBank accession numbers MK435577, MH791363, and GQ915448 for β-tubulin benA of the F. sporotrichioides species complex (O'Donnell et al. 2015). Sequences were deposited in GenBank; accession numbers for each gene were as follows: ITS, ON180670, ON180671, and ON180672; EF, ON312093, ON312094, and ON312095; and β-tubulin benA, ON312090, ON312091, and ON312092. Maximum likelihood analysis on RPB1 and RPB2 nucleotide sequences of various fusaria was conducted which revealed that F. sporotrichioides formed a monophyletic relationship to terminal fusarium clade (TFC) comprising 22 strongly supported species complexes and 10 monotypic lineages, which were provisionally recognized as Fusarium. To complete Koch's postulates, 10μl aliquots of spore suspensions (106 spores/ml) of each FUS21K, FUS9SM and FUS63KP were pipetted individually onto six ripe, asymptomatic peaches. Sterile distilled water was applied as a negative control on four fruit. Fruit were incubated at 25 ± 1°C for one week in a sterile moist chamber, and the trial was conducted three times. Rot symptoms associated with pinkish-white fluffy mycelia were observed on inoculated fruits after 72 hours, whereas no mycelium was observed on the negative controls. The cultures on PDA, CLA and SNA from each of the inoculated fruit were morphologically identical to the original culture. The pathogen was confirmed as a member of F. sporotrichioides species complex based on pinkish-white mycelium, with red color on the underside of petri plates and the manner in which conidia are born on conidiophores. This is the first report of F. sporotrichioides on peaches from Pakistan, providing an important foundation for peach growers, agricultural advisers, plant pathologists, and plant breeders to improve the management of this economically damaging disease.

Antimicrobial activity of aqueous extract of Citrullus colocynthis L.fruit

The aqueous extract of C. Colocynthis fruit was tested for its antimicrobial activity against certain pathogenic fungal and bacterial isolates using agar well diffusion method. The activity of the extract was determined through measuring the diameter of inhibition zone and minimal inhibitory concentration. The study revealed that all the fungal and bacterial isolates are sensitive to the extract . Fungal isolates are more sensitive than bacterial isolates. All concentrations of the extract used in this experiment showed antifungal activity against the Cladosporium cladosporides. The activity of Citrullus colocynthis L. extract is significantly better than the standard antifungal drugs, nystatin and fluconazole in a concentration of 0.25 mg/ml .The inhibitory effect of C. colocynthis fruit aqueous extract may attributed to active compounds present in the extract.

LABORATORY INVESTIGATIONS FOR FUNGAL INFECTION OF ORAL CAVITY : AN EAGLE EYE VEIW

The incidence of invasive infections caused by fungi has been increasing for the last few decades. This is primarily due to the significant increases in the populations of at-risk patients; this includes those receiving immunosuppressive chemotherapy for various malignancies, solid organ transplant recipients and those receiving prolonged steroid treatment. New diagnostic approaches have been developed based on non-culture-based methods, which may allow early diagnosis and treatment of fungal infections. Laboratory procedures in diagnostic mycology are directed mainly toward the direct demonstration of the pathogenic fungi in clinical specimens by microscopy along with successful isolation of pathogenic fungi by using various culture techniques. They also help in the prediction of possible therapeutic outcome by determining antifungal susceptibility and can also be used in epidemiological studies by tracing the source of infection. The purpose of our review is to provide the reader with comprehensive and up-to-date information on diagnostic methods.

Characterization and Fungicide Screening of a New Pathogen That Causes Leaf Spot on Rehmannia glutinosa

Outbreaks of leaf spot disease occurred in Rehmannia glutinosa fields in Henan Province, China, in 2019, with the incidence ranging from 20% to 40%. R. glutinosa plants with diseased leaves were collected, and 25 isolates were obtained. Pathogenicity tests, morphological observations, and phylogenetic analyses were conducted to identify the pathogens, and the biological characteristics and control agents of the pathogens were studied. Five isolates of pathogenic fungi were isolated. Three isolates were identified as Fusarium equiseti, which is a new pathogen causing R. glutinosa leaf disease; the other two isolates were identified as Fusarium acuminatum. The mycelia of F. equiseti grew fastest on Czapek medium, and the optimal temperature and pH were 25 °C and 10.0, respectively. The mycelia of F. equiseti grew from 5 °C t o 35 °C, and the lethal temperature was 55 °C. The optimal carbon and nitrogen sources were soluble starch and peptone, respectively. Eight fungicides had inhibitory effects on the mycelial growth of F. equiseti and F. acuminatum. Prochloraz had higher activities against F. equiseti and F. acuminatum, with EC50 values of 0.139 mg·L−1 and 0.123 mg·L−1, respectively. These results provide useful information that will aid the development of management strategies to control leaf diseases of R. glutinosa caused by F. equiseti and F. acuminatum.

Prevalence and Eco-friendly Management of Dry Rot of Potato in Rawalpindi and Islamabad

The dry rot disease of potato is caused by Fusarium species is a disastrous disease of potato as postharvest disease that can contribute huge losses of potato during storage. During current study market based survey was done in Rawalpindi and Islamabad during year 2021to estimate the disease prevalence and diseases losses during storage of different potato verities in different months. It revealed that maximum dry rot disease prevalence of potato was 1.90%, 1.86% in Rawalpindi and Islamabad respectively. Fungi isolates were isolated from diseases samples and were preserved and identified on the basis of cultural and morphological keys. The pathogenicity test confirmed the virulence of pathogenic fungal isolates. Among the cultivars, average loss of dry rot of potato within the three months; August and September, October were found in cultivar Kuroda and Lady Rosetta was 1.36% and 1.21% respectively in Rawalpindi while 1.86% and 1.48% average loss was estimated in Kuroda and Lady Rosetta respectively in Islamabad. During disease management studies in which biocontrol agent (Pseudomonas fluorescence, Bacillus subtilis and Bacillus cereus) were used during the dual culture technique and P. fluorescence was found most effective which reduced the 70% growth of fungal isolates and the maximum zone of inhibition 16mm was calculated. These preliminary postharvest disease studies will ultimately a source of information for the researchers and industrialist to develop cost effective and ecofriendly management against dry rot disease of potato during storage conditions.

Evaluation of antifungal susceptibility and clinical characteristics in fungal keratitis in a tertiary care center in North India.

To study the antifungal susceptibility of common corneal pathogenic fungi to antifungal agents in the North Indian population. Prospective study of the antifungal sensitivity testing (natamycin, amphotericin B, voriconazole, itraconazole, fluconazole, posaconazole, caspofungin, micafungin) of fungal isolates from 50 cases of culture positive fungal keratitis by using E test method. Details noted included demographic data, visual acuity, clinical details, grade of keratitis, healing time, and success in medical management. Of 50 patients with fungal keratitis (mean age: 40.28 ± 16.77 years), 12 eyes healed within 3 weeks, 14 had a delayed healing response, and 24 had chronic keratitis. Among the 15 cases of Fusarium isolates, 93.3% were sensitive to natamycin, while 40% to amphotericin B; 66.6% to voriconazole, 13.4% to itraconazole and fluconazole each. 80% of Fusarium cases (n = 12) showed susceptibility to posaconazole. Among Aspergillus flavus isolates, 53.4% (n = 8) were sensitive to natamycin, with only 40% (n = 7) showing sensitivity to amphotericin B and good susceptibility to azoles. MIC against susceptible Fusarium spp. for natamycin was 3-16 μg/mL, amphotericin B: 1-8 μg/mL, voriconazole: 0.5-1.5 μg/mL, itraconazole: 0.5-12 μg/mL, posaconazole: 0.094-1.5 μg/mL. MIC against Aspergillus flavus was natamycin: 8-32 μg/mL, amphotericin B: 0.5-16 μg/mL, voriconazole: 0.025-4 μg/mL, itraconazole: 0.125-8 μg/mL, posaconazole: 0.047-0.25 μg/mL; against Aspergillus niger isolates, to natamycin was 6 μg/mL (n=1), amphotericin B 8-12 μg/mL (n = 3), voriconazole: 0.125-0.19 μg/mL (n = 3), itraconazole: 0.38-0.75 μg/mL, posaconazole: 0.064-0.19 μg/mL and against Aspergillus fumigatus (n = 1), was natamycin4 μg/mL, amphotericin B - 8 μg/mL, voriconazole 0.25 μg/mL, itraconazole 1 μg/mL, and posaconazole 0.19 μg/mL. MIC against susceptible Acremonium spp. for natamycin was 1.5-16 μg/mL, amphotericin B: 0.5-8 μg/mL, voriconazole: 0.19-3 μg/mL, itraconazole: 0.125 μg/mL, posaconazole: 0.125-0.5 μg/mL and against susceptible Curvularia was natamycin 0.75-4 μg/mL, amphotericin B 0.5-1 μg/mL, voriconazole 0.125-0.19 μg/mL, itraconazole 0.047-0.094 μg/mL, posaconazole 0.047-0.094 μg/mL. MIC against Mucor spp.+ Rhizopus spp. (n = 1) was natamycin: 8 μg/mL, amphotericin B: 0.75 μg/mL, posaconazole: 1.5 μg/mL. MIC against of Alternaria (n = 1) was voriconazole: 0.19 μg/mL, posaconazole: 0.094 μg/mL. MIC against Penicillium (n=1) was natamycin: 8 μg/mL, voriconazole: 0.25 μg/mL, itraconazole: 0.5 μg/mL, and Posaconazole: 0.125 μg/mL. Our observations highlight the variations in susceptibility to antifungal agents. Posaconazole seems to be effective with low MIC against common corneal pathogenic fungal isolates.

Identification of pathogenic fungal isolates of the Fusarium oxysporum and the Fusarium fujikuroi species complex, causing fusariosis in ornamental pineapple, and antifungal activity of elicitors

Identification of pathogenic fungal isolates of the Fusarium oxysporum and the Fusarium fujikuroi species complex, causing fusariosis in ornamental pineapple, and antifungal activity of elicitors

Identification and distribution of fungal pathogens associated with seedling blight of rice in the southern United States

AbstractSurveys were conducted in the five southern rice‐producing states of Arkansas, Louisiana, Mississippi, Missouri and Texas in the United States during the 2018 and 2019 cropping seasons to determine the distribution and pathogenicity of fungal pathogens associated with seedling blight in rice. A total of 349 pathogenic fungal isolates were collected and identified as belonging to four genera: Rhizoctonia solani, Fusarium spp., Sclerotium rolfsii and Marasmius graminum based on morphological characteristics, molecular analysis and Koch's postulates. R. solani (252 out of 349 pathogenic isolates) was the most prevalent fungus isolated from diseased samples. Of the 252 pathogenic R. solani isolates, 245 were further classified as anastomosis group 11 (AG‐11) and 7 as AG‐4. Isolates of R. solani AG‐4 and M. graminum were the most aggressive, with the highest stand loss (63% to 100%) and median disease rating (DR; 5.0), followed by isolates of R. solani AG‐11 (stand loss = 4% to 100% and DR = 0.6 to 5.0), Fusarium spp. (stand loss = 26% to 48% and DR = 2.0 to 5.0) and S. rolfsii (stand loss = 33% to 48% and DR = 2.0 to 3.0) in causing seedling blight in rice. R. solani (62% to 83% of total pathogenic isolates) and Fusarium spp. (10% to 24% of total pathogenic isolates) were predominant in all the five states surveyed. S. rolfsii and M. graminum were present only in Louisiana and Texas. The results of this first systematic survey of rice seedling diseases in the southern United States will help develop effective fungicide seed treatment strategies for control of stand loss caused by seedling blight, one of the major factors limiting rice production.

Human Clinical Isolates of Pathogenic Fungi Are Host to Diverse Mycoviruses.

ABSTRACTFungi host viruses from many families, and next-generation sequencing can be used to discover previously unknown genomes. Some fungus-infecting viruses (mycoviruses) confer hypovirulence on their pathogenic hosts, raising the possibility of therapeutic application in the treatment of fungal diseases. Though all fungi probably host mycoviruses, many human pathogens have none documented, implying the mycoviral catalogue remains at an early stage. Here, we carried out virus discovery on 61 cultures of pathogenic fungi covering 27 genera and at least 56 species. Using next-generation sequencing of total nucleic acids, we found no DNA viruses but did find a surprising RNA virus diversity of 11 genomes from six classified families and two unclassified lineages, including eight genomes likely representing new species. Among these was the first jivivirus detected in a fungal host (Aspergillus lentulus). We separately utilized rolling circle amplification and next-generation sequencing to identify ssDNA viruses specifically. We identified 13 new cressdnaviruses across all libraries, but unlike the RNA viruses, they could not be confirmed by PCR in either the original unamplified samples or freshly amplified nucleic acids. Their distributions among sequencing libraries and inconsistent detection suggest low-level contamination of reagents. This highlights both the importance of validation assays and the risks of viral host prediction on the basis of highly amplified sequencing libraries. Meanwhile, the detected RNA viruses provide a basis for experimentation to characterize possible hypovirulent effects, and hint at a wealth of uncharted viral diversity currently frozen in biobanks.IMPORTANCE Fungal pathogens of humans are a growing global health burden. Viruses of fungi may represent future therapeutic tools, but for many fungal pathogens there are no known viruses. Our study examined the viral content of diverse human-pathogenic fungi in a clinical biobank, identifying numerous viral genomes, including one lineage previously not known to infect fungi.

Isolation and Identification of Entomopathogenic Fungi from of Green Peach Aphid Myzus Persicae and Evaluation of Their Activity for Insect Control

Twenty-one different fungal isolates were isolated from samples of infected insects from different areas in Salah El-Din Governorate. A preliminary screening of the isolated fungi was carried out using different stages of green peach insect for the purpose of estimating its pathogenicity. The results showed that the fungal spores suspension and fungal filtrates of isolates (RA-4, RA-5, RA-9, RA-10, RA-12, RA-13, RA-14, RA-16, RA-23, RA-24) significantly superior on other isolates in killing green peach insects, the isolate (RA-5) achieved the highest mortality rate of 95.3% during the 72 hours period. All the selected (highest pathogenic) isolates showed their production of chitinase, the fungal isolates (RA-24, RA-4, RA-12, RA-14) superior on other isolates in the activity of chitinase, reaching 6.62, 3.31, 2.53, and 2.15 units/ml, respectively compared to 1.76 units/ml in the commercial fungicide strain B.bassiana. The isolates (RA-5, RA-24, RA-4, RA-9) were significantly superior to the protease activity, which reached 2.42, 1.88, 1.86, and 1.83 units/ml, respectively, compared to 1.64 units/ml in the commercial fungicide strain B. bassiana. These isolates were phenotypically and molecularly identified to the species level based on the nucleotide sequences of the ITS1 and ITS4 region within the 5.8 S rRNA gene. To study the compatibility of the highest pathogenic fungal isolates with different concentrations of the chemical pesticide Dominant, the results showed that all fungal isolates were able to grow in the presence of this pesticide, the highest compatibility was in present of Dominant at 1%, with P. oxalicum (RA-13), M. anisopliae(RA-24) and T. longibrachiatum (RA-5) in which the fungal growth rate reached 89, 88.57 and 83.44%, respectively. The results also showed that there was a significant superiority of all treatments that included M. anisopliae (RA-24) and T. longibrachiatum (RA-5) with the pesticide Dominant (0.5%) in the mortality rate of green peach insect stages compared with the other treatments, the highest mortality rate reached 100% after 3 days of treatment (M. anisopliae + Dominant 0.5) and (T. longibrachiatum + Dominant 0.5) while the lowest mortality rate was 66.66% in the treatment of M.anisopliae.

THE MORPHOLOGY OF PATHOGENIC FUNGI AS THE CAUSE OF ROTTEN CACAO (THEOBROMA CACAO L.) FRUITS IN TUMBA VILLAGE

The purpose of this qualitative descriptive study was to find out the types of pathogenic fungi that caused rotten cacao fruits based on morphological characteristics in Tumba village. Fungi isolation was performed by employing the moist chamber method with the PDA medium. Moreover, the identification of pathogenic fungal isolates followed the morphological characteristics mentioned earlier. The results showed that four fungal isolates contributed to the rotting of cacao fruits in the site area. Fungal isolate Tumba 1 (T1) had morphological characteristics of a white colony with smooth surface, and oval sporangium with a bulge on its tip; fungal isolate Tumba 2 (T2) consisted of morphological characteristics of a white colony with a pink circle in the middle, and having a sickle-shaped and oval macroconidia; fungal isolate Tumba 3 (T3) comprised morphological characteristics of a dark black colony with irregular shape, uneven edge, and having a long conidiophore with a big conidial head; fungal isolate Tumba 4 (T4) had morphological characteristics of a black colony with a white circle in the middle, uneven edge, and having a tube-shaped conidium. As based on the morphological characteristics, it was assumed that the four fungal isolates causing the rotten cacao fruit were similar to the types of fungi, i.e., Phytopthora palmivora, Fusarium sp, Aspergilus niger, and Gloeosprorium sp.