Fusarium Lichenicola Research Articles

Deciphering the cytochrome P450 genes in the microbiome of a chronically polluted soil with history of agricultural activities

BackgroundCytochrome P450 monooxygenases (CYPs) are exciting biocatalysts that catalyzes diverse regio- and stereoselective reactions of a broad range of substrates. The cytochrome P450 genes (CYPomes) of a chronically polluted soil (3S) with history of agricultural activities were deciphered via functional annotation of putative ORFs (open reading frames) using KEGG KofamKOALA, PHMMER, the Cytochrome P450 Engineering Database CYPED v6.0, and the NCBI Batch Web CD-Search tool.ResultsAnnotation revealed the detection of seventy-seven CYP families and eight standalone CYPs cutting across the three domains of life. The prokaryote CYPome has 72 CYP families, 93 subfamilies, and seven standalone CYPs. The phylum Proteobacteria and the genera Streptomyces, Mycobacterium, and Bacillus with 17, 16, 24, and 5 CYP families were predominant, while the domain Archaea was represented by CYP119A1. The phylum Cyanobacteria has two families, while 23 actinobacterial CYPs (other than Streptomyces and Mycobacterium) were also detected. The detected prokaryote CYPs are responsible for biodegradation of camphor, hydroxylation of monoterpene alcohols, biosynthesis of secondary metabolites, and hydroxylation of fatty acids and steroidal compounds. The eukaryote CYPome was represented by seven fungal CYPs (CYP505A3, CYP505B1, CYP51A, CYP51C, CYP55A1, CYP55A2, and CYP55A3) from Acremonium egyptiacum, Fusarium oxysporum, Aspergillus oryzae, Gibberella moniliformis, Aspergillus flavus, and Fusarium lichenicola, respectively, and CYP524A1 from the slime mold, Dictyostelium discoideum. The fungi CYPs were involved in biosynthesis of secondary metabolites, hydroxylation of fatty acids, and nitrate reduction and denitrification.ConclusionsThis study has established the diverse roles played by CYPs in soil, its implication for soil health and resilience, and its potentials for industrial application.

Fungal Keratitis Due to Fusarium lichenicola: A Case Report and Global Review of Fusarium lichenicola Keratitis.

Fusarium species are among the most commonly isolated causes of fungal keratitis. Most species of the genus Fusarium belong to Fusarium solani species complex (FSSC). Fusarium lichenicola, a member of the FSSC complex, is a well-established plant and human pathogen. However, reports of fungal keratitis due to Fusarium lichenicola have not been frequently reported. To the best of our knowledge, only twelve cases of Fusarium lichenicola keratitis have been reported in the past fifty years. Clinical cases of Fusarium lichenicola may have most likely been misidentified because of the lack of clinical and microbiological suspicion, as well as inadequate diagnostic facilities in many tropical countries where the burden of the disease may be the highest. We report a case of fungal keratitis caused by Fusarium lichenicola and present a global review of the literature of all cases of fungal keratitis caused by this potentially blinding fungus.

The Fusarium solani species complex infecting cannabis (Cannabis sativa L., marijuana) plants and a first report of Fusarium (Cylindrocarpon) lichenicola causing root and crown rot

Greenhouse-grown cannabis (Cannabis sativa L., marijuana) plants with yellowing, crown rot and root-browning symptoms were sampled from six production facilities during 2019–2020. Among 34 fungal isolates recovered, 28 were identified as Fusarium solani and six isolates were provisionally identified as Cylindrocarpon sp. based on morphology. These latter isolates produced slow-growing colonies with grey-white aerial mycelium and a chestnut-brown colour below. Cylindrical 1–3 septate conidia without a distinctive foot cell were produced. Microconidia were absent and chlamydospores were produced in culture. Phylogenetic analysis of three isolates based on the elongation factor (TEF-1 α) and ITS1-5.8S-ITS2 regions identified them as Fusarium lichenicola (formerly Cylindrocarpon lichenicola), a member of F. solani species complex (FSSC) subclade 16. Pathogenicity tests using a mycelial and spore suspension were performed on cannabis cuttings and rooted plants. Isolates of F. solani originating from diseased crowns caused symptoms in 10–14 days, while those of F. lichenicola caused yellowing and wilting after 3 weeks, suggesting that F. lichenicola is less virulent. Inoculum of F. lichenicola was detected in coco coir samples used for plant propagation. Previous reports of F. lichenicola are from tropical climates, where the fungus has been associated with dermal and ocular infections of human tissues, with a few reports of it causing diseases on pomelo fruits, taro corms and tea plants. This study demonstrates the first occurrence worldwide of F. lichenicola on cannabis plants, on which it is considered a weak introduced tropical pathogen, likely to have originated from coco coir imported into Canada.

Emerging Dematiaceous and Hyaline Fungi Causing Keratitis in a Tertiary Care Centre From North India.

To report rare dematiaceous and hyaline fungal pathogens causing fungal keratitis (FK) at our center and review the published literature in this field. In a retrospective review of FK cases from 2005 to 2011, a total of 14 rare pathogens causing isolated cases of FK of a total of 393 isolates were revived from our collection and reconfirmed by using molecular techniques. The in vitro antifungal susceptibility testing (AFST) was performed against a 6-antifungal drug panel by the CLSI microbroth-dilution method. We reviewed the literature on keratitis due to these rare fungi. Two novel fungi, Alternaria tenuissima and Epicoccum nigrum, were reported in addition to 6 dematiaceous (black pigmented) fungi (Acrophialophora fusispora, Chaetomium globosum, Cladophialophora carionii, Nigrospora sphaerica, Papulaspora equi, and Scytalidium lignicola), 5 hyaline (colorless) fungi (Aspergillus tamarii, Fusarium chlamydosporum, Fusarium incarnatum, Fusarium lichenicola, and Fusarium sacchari), and one yeast (Trichosporon asahii). Amphotericin B had good in vitro activity (minimum inhibitory concentration [MIC] ≤1 μg/mL) against most dematiaceous fungi, but not hyaline fungi (MIC ≥1 μg/mL). Natamycin showed variable MIC, itraconazole and voriconazole had good in vitro activity, except in Fusarium species. Alternaria tenuissima and A. fusispora had a very high MIC (≥16 μg/mL) against echinocandins. Literature search revealed 27 FK cases due to F. lichenicola (n = 6), P. equi (n = 5), F. sacchari (n = 4), A. fusispora (n = 3), S. lignicola (n = 2), and others (n = 7), and more than 50% of these were reported from India. Plant fungal pathogens with variable antifungal susceptibility are an emerging cause of human keratitis with predominance of dematiaceous fungi. Identification and antifungal susceptibility testing are important for epidemiology and to optimize therapy and improve the patient outcome.

NO and N2 O transformations of diverse fungi in hypoxia: evidence for anaerobic respiration only in Fusarium strains.

Fungal denitrification is claimed to produce non-negligible amounts of N2 O in soils, but few tested species have shown significant activity. We hypothesized that denitrifying fungi would be found among those with assimilatory nitrate reductase, and tested 20 such batch cultures for their respiratory metabolism, including two positive controls, Fusarium oxysporum and Fusarium lichenicola, throughout the transition from oxic to anoxic conditions in media supplemented with . Enzymatic reduction of (NIR) and NO (NOR) was assessed by correcting measured NO- and N2 O-kinetics for abiotic NO- and N2 O-production (sterile controls). Significant anaerobic respiration was only confirmed for the positive controls and for two of three Fusarium solani cultures. The NO kinetics in six cultures showed NIR but not NOR activity, observed through the accumulation of NO. Others had NOR but not NIR activity, thus reducing abiotically produced NO to N2 O. The presence of candidate genes (nirK and p450nor) was confirmed in the positive controls, but not in some of the NO or N2 O accumulating cultures. Based on our results, we conclude that only the Fusarium cultures were able to sustain anaerobic respiration and produced low amounts of N2 O as a response to an abiotic NO production from the medium.

Biodegradation Potentials of Aspergillus sydowii and Fusarium lichenicola on Total Petroleum Hydrocarbon in an Oilfield Wastewater in Rivers State

This study investigated the potential of Aspergillus sydowii and Fusarium lichenicola as mixed cultures in the biodegradation of Total Petroleum Hydrocarbons TPHs in oilfield wastewater. Oilfield wastewater was collected from an onshore oil producing platform and biodegradation of total petroleum hydrocarbons was investigated using standard methods. Fungi were isolated from oilfield wastewater contaminated soils obtained from the vicinity of the oil producing platform. Experimental control set-up and treatment with mixed culture of fungal isolates were periodically analyzed on days 7 and 21 intervals for total petroleum hydrocarbon degradation using Gas Chromatography (GC). The total amount of TPHs on day 1 recorded 381. 871 mg/l. The amount of TPHs on days 7 and 21 in the mixed culture of fungi was 108.975 mg/l and 21.105 mg/l respectively while TPHs in control was 342.891 mg/l and 240.749 mg/l respectively. There was a significant difference between the mixed culture and the control on days 7 and 21 at p≤0.05. The results therefore revealed actual and significant reduction of TPHs in the mixed culture. In addition, there was clearance of n-alkanes by the mixed culture. This suggests that fungi have great potentials in biodegradation of TPHs and in remediation of TPH contaminated environments.

First Report of Fusarium lichenicola as a Causal Agent of Fruit Rot in Pomelo (Citrus maxima)

First Report of <i>Fusarium lichenicola</i> as a Causal Agent of Fruit Rot in Pomelo (<i>Citrus maxima</i>)

Nitrous oxide production by the ectomycorrhizal fungi Paxillus involutus and Tylospora fibrillosa

Nitrous oxide (N(2)O) production by filamentous fungi has been demonstrated in pure culture and has been estimated indirectly in soils. However, it is unknown whether ectomycorrhizal fungi can also produce N(2)O. We demonstrate for the first time the ability of nitrogen (N)-tolerant ectomycorrhizal fungi (Paxillus involutus and Tylospora fibrillosa), found in forest soils under moderate to high rates of N deposition, to produce N(2)O from nitrate reduction. The N(2)O concentrations from the ectomycorrhizal fungal treatments after a 10-day pure culture experiment were 0.0117±0.00015 (P. involutus) and 0.0114±0.0003 (T. fibrillosa), and 0.0114±0.00043 μmol N(2)O L(-1) from a known fungal denitrifier (Fusarium lichenicola). No N(2)O was detected in the control treatment. Our results indicate the potential for these two N-tolerant ectomycorrhizal fungi to contribute to N(2)O production. Given that these species are abundant in many forest soils, the strength and regulation of fungal N(2)O production should now be verified in situ.

Occurrence and characterization of fungi and oomycetes transmitted via potting mixtures and organic manures

A study was conducted to investigate the most common fungal and oomycete pathogens introduced into farms in Oman via potting mixtures and organic manures. A total of 37 commercial types of potting mixtures (2 local and 35 imported from overseas), 4 commercial types of organic manures and 11 non-commercial types of organic manures were included in the study. Identification of the isolated species was based on morphological characteristics, except for the most common species which were further identified using sequences of the internal transcribed spacer region of the ribosomal DNA (ITS rDNA). Fusarium spp. (14%), Pythium aphanidermatum (3%), Alternaria spp. (5%), Helminthosporium spp. (5%) and Cladosporium spp. (3%) were recovered at different frequencies from samples of potting mixtures. Fusarium solani (40%) and Fusarium equiseti (47%) were recovered at high frequencies from samples of organic manures. Isolations from organic manures also yielded Pythium periplocum (7%), Rhizoctonia solani (7%), Fusarium lichenicola (7%), Helminthosporium spp. (27%) and Alternaria spp. (27%). Trichoderma spp., Penicillium spp., Aspergillus spp. and Rhizopus spp. were found to be common in samples of potting mixtures and organic manures. Investigating sensitivity to hymexazol among 9 isolates of F. equiseti and 13 isolates of F. solani revealed variations among different isolates. The EC 50 values ranged from 1 to over 1200 (avg. 192 μg ml −1) for F. equiseti isolates and from 135 to 789 (avg. 324 μg ml −1) for F. solani isolates, indicating presence of resistance to this important fungicide among some Fusarium isolates. This appears to be the first report of contamination with R. solani, P. periplocum, F. solani, F. equiseti and F. lichenicola of organic manures. This study appears to report for the first time F. lichenicola in Oman and appears to be the first report of occurrence of resistance to hymexazol among F. equiseti and F. solani isolates.

Application of semi-nested polymerase chain reaction targeting internal transcribed spacer region for rapid detection of panfungal genome directly from ocular specimens

The incidence of fungal endophthalmitis has dramatically increased in recent years and rapid detection of fungi using nucleic acid-based amplification techniques is helpful in management. To evaluate semi-nested polymerase chain reaction (PCR) targeting internal transcribed spacer (ITS) region for detection of panfungal genome in ocular specimens. Z test for two proportion. Standardization of PCR targeting ITS primers was carried out by determining analytical sensitivity and specificity. The sensitivity and specificity of PCR was determined by serial tenfold dilutions of C. albicans (ATCC 24433) DNA and DNA extracts of laboratory isolates of Aspergillus fumigatus, Fusarium lichenicola (4), other fungal and closely related bacterial strains and also human DNA. Semi-nested PCR was applied onto a total of 168 ocular specimens with clinically suspected fungal etiology during 2003-2005. PCR was specific and sensitive to detect 1fg of fungal DNA with ITS primers. PCR detected fungal genome in 90 (53.57%) in comparison with the conventional technique, positive in 34 (20.23%) by smear examination and in 42 (25%) by culture. The increase in clinical sensitivity by 28.57% using PCR was found to be statistically significant { P < 0.001 using Z test for two proportion}. The accuracy of the test was found to be 70.85%. PCR proved to be a rapid diagnostic technique for detection of panfungal genome directly from clinical specimens.

Nécrose du segment antérieur sur kératomycose à Fusarium polyrésistant : À propos d’un cas

Keratomycosis is a rare sight-threatening infection of the cornea, with greater morbidity than bacterial keratitis. Predisposing factors in its pathogenesis are corneal trauma, mostly of plant origin, and overuse of topical corticosteroids, associated or not with antibiotics. We report a case of a 71-year-old man who developed Fusarium (lichenicola or solani) keratitis, 15 days after beginning topical therapy with a corticosteroid and antibiotic. Despite aggressive antifungal therapy with fluconazole, he required a penetrating keratoplasty for impending corneal perforation, and finally, even after systemic use of itraconazole and topical use of amphotericin B, the infection progressed and an evisceration was required. In the evisceration material, a multidrug-resistant Fusarium lichenicola or solani, was found, partially sensitive to voriconazole only.

Analysis of phylogenetic relationship of Cylindrocarpon lichenicola and Acremonium falciforme to the Fusarium solani species complex and a review of similarities in the spectrum of opportunistic infections caused by these fungi.

An emerging pattern of similarity in medical case reports led to a project to compare the phylogenetic affinities of two well-known tropical fungal opportunistic pathogens, Cylindrocarpon lichenicola and Acremonium falciforme, to members of the Fusarium solani species complex. C. lichenicola and A. falciforme, despite their deviating conidial morphologies, were shown via sequencing of the ribosomal large subunit to be well instituted within a clade mainly consisting of typical F. solani strains and other species until recently considered variants of F. solani. The original name Fusarium lichenicola C. B. Massalongo is reestablished, and the new combination F. falciforme is made. Recognition of these species as fusaria is necessary for correct interpretation of current and future molecular diagnostic tests. Reevaluation of species morphology in light of the molecular findings showed that certain features, especially elongate filiform conidiophores with integrated terminal phialides, facilitate correct microscopic classification of these atypical Fusarium species. There is a strong and underrecognized overlap in the spectra of cases caused by members of the F. solani clade, particularly ocular infections, mycetomas, and, in the neutropenic host, disseminated and other serious systemic infections. A novel synthesis of case reports shows that patients from areas with warm climates may develop a distinctive fusarial intertrigo caused by F. solani, Fusarium lichenicola, or Fusarium oxysporum.