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A pair of atropisomers secofumitremorgins C (1a) and D (1b), together with fifteen known alkaloids (2-16), were isolated from a saltern-derived fungus Aspergillus fumigatus GXIMD00544. The structures of atropisomers 1a and 1b were elucidated by the detailed spectroscopic data, chemical reaction and quantum chemical calculations. Compounds 1 and 8 displayed antifungal spore germination effects against plant pathogenic fungus associated with sugarcane Fusarium sp. with inhibitory rates of 53% and 77% at the concentration of 100 µM, repectively. Atropisomers 1 also exhibited antifouling potential against Balanus amphitrite larval settlement with an inhibitory rate of 96% at the concentration of 100 µM. [ABSTRACT FROM AUTHOR]

The majority of invasive human fungal pathogens gain access to their human hosts via the inhalation of spores from the environment into the lung, but relatively little is known about this infectious process. Among human fungal pathogens the most frequent cause of inhaled fatal fungal disease is Cryptococcus, which can disseminate from the lungs to other tissues, including the brain, where it causes meningoencephalitis. To determine the mechanisms by which distinct infectious particles of Cryptococcus cause disseminated disease, we evaluated two developmental cell types (spores and yeast) in mouse models of infection. We discovered that while both yeast and spores from several strains cause fatal disease, there was a consistently higher fungal burden in the brains of spore-infected mice. To determine the basis for this difference, we compared the pathogenesis of avirulent yeast strains with their spore progeny derived from sexual crosses. Strikingly, we discovered that spores produced by avirulent yeast caused uniformly fatal disease in the murine inhalation model of infection. We determined that this difference in outcome is associated with the preferential dissemination of spores to the lymph system. Specifically, mice infected with spores harbored Cryptococcus in their lung draining lymph nodes as early as one day after infection, whereas mice infected with yeast did not. Furthermore, phagocyte depletion experiments revealed this dissemination to the lymph nodes to be dependent on CD11c+ phagocytes, indicating a critical role for host immune cells in preferential spore trafficking. Taken together, these data support a model in which spores capitalize on phagocytosis by immune cells to escape the lung and gain access to other tissues, such as the central nervous system, to cause fatal disease. These previously unrealized insights into early interactions between pathogenic fungal spores and lung phagocytes provide new opportunities for understanding cryptococcosis and other spore-mediated fungal diseases. [ABSTRACT FROM AUTHOR]

The use of Beauveria bassiana in biological control of agricultural pests is mainly hampered by environmental factors, such as elevated temperatures and low humidity. These limitations, further amplified in a global warming scenario, could nullify biological control strategies based on this fungus. The identification of thermotolerant B. bassiana isolates represents a possible strategy to overcome this problem. In this study, in order to maximize the probability in the isolation of thermotolerant B. bassiana, soil samples and infected insects were collected in warm areas of Syria. The obtained fungal isolates were tested for different biological parameters (i.e., growth rate, sporulation and spore germination) at growing temperatures ranging from 20°C to 35°C. Among these isolates (eight from insects and 11 from soil samples), the five with the highest growth rate, spore production and germination at 30°C were tested for their entomopathogenicity through in vivo assays on Ephestia kuehniella larvae. Insect mortality induced by the five isolates ranged from 31% to 100%. Two isolates, one from Phyllognathus excavatus and one from soil, caused 50% of the larval mortality in less than four days, reaching values exceeding 92% in ten days. These two isolates were molecularly identified as B. bassiana sensu stricto by using three markers (i.e., ITS, Bloc and EF1-α). Considering these promising results, further studies are ongoing, testing their efficiency in field conditions as control agents for agricultural insect pests in Mediterranean and Subtropical regions. [ABSTRACT FROM AUTHOR]

Abstract Catena -poly[bis(guanidinium) (μ-oxo)-bis(oxalato)-vanadium(IV)], 1 , a new 1D polymeric V(IV) salt has been synthesized by slow evaporation at room temperature and its structure has been elucidated by single-crystal X-ray diffraction, while bis [4-(dimethylamino)-pyridinium] aquabis (oxalato)oxidovanadate(IV) dihydrate's structure, 2 , has been previously reported. In addition to elemental analysis, single crystal X-ray diffraction and structural data report of 1 , both compounds 1 and 2 have been characterized by, FT-IR and UV–Vis spectroscopy, Rietveld refinement, TG–DSC analysis. Magnetic susceptibility of the compounds had been investigated and discussed in the context of their structures. The stability, availability and ease of synthesis of those compounds are an advantage for their antimicrobial activity investigation against different Gram-positive and Gram-negative bacteria, yeast and fungi microorganisms. Further investigations on the compounds' lysozyme activity and spore germination inhibition aim to go deeper in their mechanism of actions. Graphical abstract Image 1 Highlights • Compound 1 , the first (μ-oxo)-bis(oxalato)-vanadium(IV) 1D coordination polymer exhibits antiferromagnetic behavior. • Both compounds prove significant antibacterial activities against Gram-negative bacteria Escherchia coli. • Both compounds show high lysozyme activities against Gram-positive bacteria Staphylococcus aureus and Streptococcus agalactiae. • Both compounds prove eminent fungal spore germination inhibition of the two fungi Aspergillus niger and Penicillium spp. [ABSTRACT FROM AUTHOR]

When many gametes compete to fertilize a limited number of compatible gametes, sexual selection will favour traits that increase competitive success during mating. In animals and plants, sperm and pollen competition have yielded many interesting adaptations for improved mating success. In fungi, similar processes have not been shown directly yet. We test the hypothesis that sexual selection can increase competitive fitness during mating, using experimental evolution in the mushroom-forming fungus Schizophyllum commune (Basidiomycota). Mating in mushroom fungi occurs by donation of nuclei to a mycelium. These fertilizing ‘male’ nuclei migrate through the receiving ‘female’ mycelium. In our setup, an evolving population of nuclei was serially mated with a non-evolving female mycelium for 20 sexual generations. From the twelve tested evolved lines, four had increased and one had decreased fitness relative to an unevolved competitor. Even though only two of those five remained significant after correcting for multiple comparisons, for all five lines we found a correlation between the efficiency with which the female mycelium is accessed and fitness, providing additional circumstantial evidence for fitness change in those five lines. In two lines, fitness change was also accompanied by increased spore production. The one line with net reduced competitive fitness had increased spore production, but reduced fertilisation efficiency. We did not find trade-offs between male reproductive success and other fitness components. We compare these findings with examples of sperm and pollen competition and show that many similarities between these systems and nuclear competition in mushrooms exist. [ABSTRACT FROM AUTHOR]

Pseudogymnoascus destructans is the fungal pathogen responsible for White-nose Syndrome (WNS), a disease that has killed millions of bats in North America over the last decade. A major obstacle to research on P. destructans has been the lack of a tractable infection model for monitoring virulence. Here, we establish a high-throughput model of infection using larvae of Galleria mellonella, an invertebrate used to study host-pathogen interactions for a wide range of microbial species. We demonstrate that P. destructans can kill G. mellonella larvae in an inoculum-dependent manner when infected larvae are housed at 13°C or 18°C. Larval killing is an active process, as heat-killed P. destructans spores caused significantly decreased levels of larval death compared to live spores. We also show that fungal spores that were germinated prior to inoculation were able to kill larvae 3–4 times faster than non-germinated spores. Lastly, we identified chemical inhibitors of P. destructans and used G. mellonella to evaluate these inhibitors for their ability to reduce virulence. We demonstrate that amphotericin B can effectively block larval killing by P. destructans and thereby establish that this infection model can be used to screen biocontrol agents against this fungal pathogen. [ABSTRACT FROM AUTHOR]

In immunocompromised individuals, Aspergillus fumigatus causes invasive fungal disease that is often difficult to treat. Exactly how immune mechanisms control A. fumigatus in immunocompetent individuals remains unclear. Here, we use transparent zebrafish larvae to visualize and quantify neutrophil and macrophage behaviors in response to different A. fumigatus strains. We find that macrophages form dense clusters around spores, establishing a protective niche for fungal survival. Macrophages exert these protective effects by inhibiting fungal germination, thereby inhibiting subsequent neutrophil recruitment and neutrophil-mediated killing. Germination directly drives fungal clearance as faster-growing CEA10-derived strains are killed better in vivo than slower-growing Af293-derived strains. Additionally, a CEA10 pyrG-deficient strain with impaired germination is cleared less effectively by neutrophils. Host inflammatory activation through Myd88 is required for killing of a CEA10-derived strain but not sufficient for killing of an Af293-derived strain, further demonstrating the role of fungal-intrinsic differences in the ability of a host to clear an infection. Altogether, we describe a new role for macrophages in the persistence of A. fumigatus and highlight the ability of different A. fumigatus strains to adopt diverse modes of virulence. [ABSTRACT FROM AUTHOR]

Fungi assisted microalgae bioflocculation is an emerging, efficient and cost-effective microalgal harvesting method, but no study has systematically evaluated and compared fungal spore-assisted (FSA) and fungal pellet-assisted (FPA) microalgal harvesting methods. In this study, harvesting Chlorella sp. cells by co-culture with Penicillium sp. spores or pellets was compared. Temperature, glucose concentration, pH and fungi:algae ratio were the critical parameters for harvesting efficiency. The highest flocculation efficiency (99%) of FSA method was achieved in 28 h at 40 °C, 160 rpm, 5 g glucose/L and 1.1 × 10 4  cells/mL (spore). FPA method can harvest 98.26% algae cells in 2.5 h at 34 °C, 160 rpm, pH 4.0 with the fungi:algae ratio of 1:2. The carbon input for FPA is only half of that for FSA. FPA takes less time and needs less glucose input compared with FSA and may be more promising to be further developed as an effective microalgae bioflocculation method. [ABSTRACT FROM AUTHOR]

Light conditions during fungal growth are well known to cause several physiological adaptations in the conidia produced. In this study, conidia of the entomopathogenic fungi Metarhizium robertsii were produced on: 1) potato dextrose agar (PDA) medium in the dark; 2) PDA medium under white light (4.98 W m −2 ); 3) PDA medium under blue light (4.8 W m −2 ); 4) PDA medium under red light (2.8 W m −2 ); and 5) minimum medium (Czapek medium without sucrose) supplemented with 3 % lactose (MML) in the dark. The conidial production, the speed of conidial germination, and the virulence to the insect Tenebrio molitor (Coleoptera: Tenebrionidae) were evaluated. Conidia produced on MML or PDA medium under white or blue light germinated faster than conidia produced on PDA medium in the dark. Conidia produced under red light germinated slower than conidia produced on PDA medium in the dark. Conidia produced on MML were the most virulent, followed by conidia produced on PDA medium under white light. The fungus grown under blue light produced more conidia than the fungus grown in the dark. The quantity of conidia produced for the fungus grown in the dark, under white, and red light was similar. The MML afforded the least conidial production. In conclusion, white light produced conidia that germinated faster and killed the insects faster; in addition, blue light afforded the highest conidial production. [ABSTRACT FROM AUTHOR]

Input of allochthonous leaf litter is the main carbon source for heterotrophic metabolism in low-order forested streams. A major part of this leaf litter is accumulated at benthic retention structures or buried in the hyporheic zone. As a result of hyporheic sediment characteristics, hyporheic physicochemistry differs from that of the benthic zone selecting the microbial community. The present study aimed at understanding the influence of the hydrological and physiochemical differences between the benthic and hyporheic zone on microbial leaf litter decomposition and on the structure and function of the associated microbial community. Leached leaves of Alnus glutinosa were exposed for 62 days in 250-μm mesh bags in the benthic zone and buried in the hyporheic zone at a depth of 2–3 cm. Decomposition rates were comparable for both zones. In contrast, respiration, bacterial abundance, ergosterol content, fungal spore production and richness of fungal morphotypes were lower associated with hyporheic than with benthic leaves. Microbial community structure displayed zone-dependent temporal dynamics. Thus, the microbial community carried out leaf litter decomposition independently of its structure. These results suggest that carbon processing is not necessarily impaired by environmental constraints because the community structure may compensate those constraints (i.e. functional redundancy). [ABSTRACT FROM AUTHOR]

Moniliophthora Pod Rot (MPR) caused by the fungus Moniliophthora roreri (Cif.) Evans et al., is one of the main limiting factors of cocoa production in Latin America. Currently insufficient information on the biology and epidemiology of the pathogen limits the development of efficient management options to control MPR. This research aims to elucidate MPR development through the following daily microclimatic variables: minimum and maximum temperatures, wetness frequency, average temperature and relative humidity in the highly susceptible cacao clone Pound-7 (incidence = 86% 2008–2013 average). A total of 55 cohorts totaling 2,268 pods of 3–10 cm length, one to two months of age, were tagged weekly. Pods were assessed throughout their lifetime, every one or two weeks, and classified in 3 different categories: healthy, diseased with no sporulation, diseased with sporulating lesions. As a first step, we used Generalized Linear Mixed Models (GLMM) to determine with no a priori the period (when and for how long) each climatic variable was better related with the appearance of symptoms and sporulation. Then the significance of the candidate variables was tested in a complete GLMM. Daily average wetness frequency from day 14 to day 1, before tagging, and daily average maximum temperature from day 4 to day 21, after tagging, were the most explanatory variables of the symptoms appearance. The former was positively linked with the symptoms appearance when the latter exhibited a maximum at 30°C. The most important variables influencing sporulation were daily average minimum temperature from day 35 to day 58 and daily average maximum temperature from day 37 to day 48, both after tagging. Minimum temperature was negatively linked with the sporulation while maximum temperature was positively linked. Results indicated that the fungal microclimatic requirements vary from the early to the late cycle stages, possibly due to the pathogen’s long latent period. This information is valuable for development of new conceptual models for MPR and improvement of control methods. [ABSTRACT FROM AUTHOR]

Background: Chemical fungicides are widely used to control crop diseases, but these chemicals have adverse effects. They destroy the ecological environment and even have toxic effects on human beings. In this context, the development of botanical pesticides is relevant. One potential botanical pesticide is chelerythrine, a main alkaloid of Chelidonium majus L., which has high antitumor, fungistasis, and antiphlogosis bioactivity. Objective: This study was designed to present an ultrasonic extraction method for chelerythrine and spore germination experiments to inhibit pathogenic fungi. Fungistasis of chelerythrine is now centralized in basic microbiology experiments, such as observing bacteriostatic rings. This study investigates chelerythrine based on pathogenic fungal spore germination and the influence of germ tube elongation. Materials and Methods: Samples of C. majus L., which were wild used in this experiment, were picked from Harbin experimental forest farm of Northeast Forestry University. An L9 (34) orthogonal experiment was designed to optimize the ultrasonic extraction method. All the plant pathogenic fungus strains used in the experiment were preservation strains of Northeast Forestry University Microbial preservation center. Pathogenic fungi were cultivated by joining chelerythrine with and observed germ tube growth and spore germination. Results: The optimum ultrasonication extraction process for chelerythrine has a liquid/solid ratio of 1:8, 35 min of extraction time, 85% of ultrasonic frequency, and 75% of ethanol concentration. When the concentration of chelerythrine was 1.7 × 10-2 mg/ml, the inhibition rates of Septoria microspora Speg. spores and Curvularia lunata were 96.67% and 84.94%, respectively. Moreover, when the concentration of chelerythrine was 1.7 × 10-6 mg/ml, the inhibition rates of S. microspora spores and C. lunata were 47.64% and 12.05%, respectively. Conclusion: Fungistasis activity reached a high level with 1.7 × 10-6 mg/ml of chelerythrine. Chelerythrine has the characteristics of less dosage and obvious fungistasis and has a good prospect for botanical fungicide development. [ABSTRACT FROM AUTHOR]

Background: Moniliophthora perniciosa is a phytopathogenic fungus responsible for witches' broom disease of cacao trees (Theobroma cacao L.). Understanding the molecular events during germination of the pathogen may enable the development of strategies for disease control in these economically important plants. In this study, we determined a comparative proteomic profile of M. perniciosa basidiospores during germination by two-dimensional SDS-PAGE and mass spectrometry. Results: A total of 316 proteins were identified. Molecular changes during the development of the germinative tube were identified by a hierarchical clustering analysis based on the differential accumulation of proteins. Proteins associated with fungal filamentation, such as septin and kinesin, were detected only 4 h after germination (hag). A transcription factor related to biosynthesis of the secondary metabolite fumagillin, which can form hybrids with polyketides, was induced 2 hag, and polyketide synthase was observed 4 hag. The accumulation of ATP synthase, binding immunoglobulin protein (BiP), and catalase was validated by western blotting. Conclusions: In this study, we showed variations in protein expression during the early germination stages of fungus M. perniciosa. Proteins associated with fungal filamentation, and consequently with virulence, were detected in basidiospores 4 hag., for example, septin and kinesin. We discuss these results and propose a model of the germination of fungus M. perniciosa. This research can help elucidate the mechanisms underlying basic processes of host invasion and to develop strategies for control of the disease. [ABSTRACT FROM AUTHOR]

Microsporidia are a diverse group of eukaryotic organisms, capable of causing parasitic infections in both vertebrates and invertebrates. During the germination process, there is an increase in the osmotic pressure of microsporidian spores. As part of this study, we cloned a homologous aquaporin gene in Nosema bombycis, and named it Nosema bombycis aquaporin (NbAQP). Sequence analysis revealed that the NbAQP contains an open reading frame with a length of 750 bp and encodes a polypeptide of 249 amino acids. Amino acid sequence homology was greater than 50% that of five aquaporins from other microsporidian species. Indirect immunofluorescence (IFA) and immunogold electron microscopy showed NbAQP to be located predominantly in the spore wall of N. bombycis spores. The results of qRT-PCR analysis revealed that NbAQP expression remained high 0 h after inoculation and decreased sharply to 24 h, increased gradually from 2 days and peaked at 6 days. After expression of NbAQP in Xenopus laevis oocytes, it was observed that NbAQP can promote rapid penetration of water into oocytes. The associated permeation rate was 2–3 times that of the water-injected and uninjected oocytes. Antibody blocking experiments showed that the inhibition rate of spore germination was approximately 28% after antibody blocking. The difference in germination rate between the control group and the NbAQP group was significant (P < 0.05). This study shows for the first time that N. bombycis contains functional water channel proteins and provides a platform suitable for further research into the mechanisms underlying the regulation of NbAQP protein expression. Further study of NbAQP and their inhibitors may have significance for prevention of microsporidiosis. [ABSTRACT FROM AUTHOR]

During fungal spore germination, a resting spore returns to a conventional mode of cell division and resumes vegetative growth, but the requirements for spore germination are incompletely understood. Here, we show that copper is essential for spore germination in Schizosaccharomyces pombe. Germinating spores develop a single germ tube that emerges from the outer spore wall in a process called outgrowth. Under low-copper conditions, the copper transporters Ctr4 and Ctr5 are maximally expressed at the onset of outgrowth. In the case of Ctr6, its expression is broader, taking place before and during outgrowth. Spores lacking Ctr4, Ctr5, and the copper sensor Cuf1 exhibit complete germination arrest at outgrowth. In contrast, ctr6 deletion only partially interferes with formation of outgrowing spores. At outgrowth, Ctr4-GFP and Ctr5-Cherry first co-localize at the spore contour, followed by re-location to a middle peripheral spore region. Subsequently, they move away from the spore body to occupy the periphery of the nascent cell. After breaking of spore dormancy, Ctr6 localizes to the vacuole membranes that are enriched in the spore body relative to the germ tube. Using a copper-binding tracker, results showed that labile copper is preferentially localized to the spore body. Further analysis showed that Ctr4 and Ctr6 are required for copper-dependent activation of the superoxide dismutase 1 (SOD1) during spore germination. This activation is critical because the loss of SOD1 activity blocked spore germination at outgrowth. Taken together, these results indicate that cell-surface copper transporters and SOD1 are required for completion of the spore germination program. [ABSTRACT FROM AUTHOR]

Mucorales are an emerging group of human pathogens that are responsible for the lethal disease mucormycosis. Unfortunately, functional studies on the genetic factors behind the virulence of these organisms are hampered by their limited genetic tractability, since they are reluctant to classical genetic tools like transposable elements or gene mapping. Here, we describe an RNAi-based functional genomic platform that allows the identification of new virulence factors through a forward genetic approach firstly described in Mucorales. This platform contains a whole-genome collection of Mucor circinelloides silenced transformants that presented a broad assortment of phenotypes related to the main physiological processes in fungi, including virulence, hyphae morphology, mycelial and yeast growth, carotenogenesis and asexual sporulation. Selection of transformants with reduced virulence allowed the identification of mcplD, which encodes a Phospholipase D, and mcmyo5, encoding a probably essential cargo transporter of the Myosin V family, as required for a fully virulent phenotype of M. circinelloides. Knock-out mutants for those genes showed reduced virulence in both Galleria mellonella and Mus musculus models, probably due to a delayed germination and polarized growth within macrophages. This study provides a robust approach to study virulence in Mucorales and as a proof of concept identified new virulence determinants in M. circinelloides that could represent promising targets for future antifungal therapies. [ABSTRACT FROM AUTHOR]

The coordination of chromosome segregation with cell growth is fundamental to the proliferation of any organism. In most unicellular bacteria, chromosome segregation is strictly coordinated with cell division and involves ParA that moves the ParB nucleoprotein complexes bi- or unidirectionally toward the cell pole(s). However, the chromosome organization in multiploid, apically extending and branching Streptomyces hyphae challenges the known mechanisms of bacterial chromosome segregation. The complex Streptomyces life cycle involves two stages: vegetative growth and sporulation. In the latter stage, multiple cell divisions accompanied by chromosome compaction and ParAB assisted segregation turn multigenomic hyphal cell into a chain of unigenomic spores. However, the requirement for active chromosome segregation is unclear in the absence of canonical cell division during vegetative growth except in the process of branch formation. The mechanism by which chromosomes are targeted to new hyphae in streptomycete vegetative growth has remained unknown until now. Here, we address the question of whether active chromosome segregation occurs at this stage. Applied for the first time in Streptomyces, labelling of the chromosomal replication initiation region (oriC) and time-lapse microscopy, revealed that in vegetative hyphae every copy of the chromosome is complexed with ParB, whereas ParA, through interaction with the apical protein complex (polarisome), tightly anchors only one chromosome at the hyphal tip. The anchor is maintained during replication, when ParA captures one of the daughter oriCs. During spore germination and branching, ParA targets one of the multiple chromosomal copies to the new hyphal tip, enabling efficient elongation of hyphal tube. Thus, our studies reveal a novel role for ParAB proteins during hyphal tip establishment and extension. [ABSTRACT FROM AUTHOR]

Little is known about the histologic features of a latent Monilinia fructicola infection and brown rot in infected fruit. This report informs on the results of an investigation whose aim was to analyze the microanatomy of nectarines with a latent and visible M. fructicola infection. Mature nectarines were inoculated with an M. fructicola isolate and incubated at 25°C for 0, 24, 48, 72, or 96 hours in the dark. For investigating the latent infection process, the inoculated nectarines were first incubated at 25°C for 24 hours in the dark and then incubated at 4°C for 72, 144, 216, and 288 hours in the dark. At the end of the incubation, samples of nectarine tissue were excised from the inoculation points and prepared for light and transmission electron microscopic examinations. No signs of disease were seen on the surface of nectarines with a latent infection over the 288-hour incubation period. When the tissue samples were microscopically examined, M. fructicola colonized the stomata and this stomatal colonization progressively increased over time and was associated with gradual collapse of the epidermal cells and colonization of the subepidermis. In nectarines with visible brown rot, the disease usually appeared after 24 hours on the surface and in the uppermost layers of epidermal cells, which began to collapse after 48 hours. Subsequently, the diseased tissues of the nectarines displayed (a) colonization of the epidermis and mesocarp by M. fructicola with thin and thick hyphae, (b) collapse and disruption of epidermal and mesocarpic cells, (c) lysogenic cavities in the subepidermis and mesocarp, (d) degradation of the cuticle and epidermis, and (e) M. fructicola sporulation. M. fructicola is active during latent infections because slow and progressive colonization of nectarine subcuticular cells by the fungus occurs. [ABSTRACT FROM AUTHOR]

Solenopsis invicta Buren is one of the most important pests in China, and control measures are mainly based on the use of synthetic pesticides, which may be inadequate and unsustainable. Hence, there is a growing interest in developing biological control alternatives for managing S. invicta, such as the use of entomopathogenic fungi. To facilitate the commercialization of entomopathogenic fungi against S. invicta, 10 Beauveria bassiana isolates originating from different hosts were tested for virulence in laboratory bioassays, and the most pathogenic strain, ZGNKY-5, was tested in field studies using an improved pathogen delivery system. The cumulative mortality rate reached 93.40% at 1×108 mL-1 conidia after 504 h. The germination and invasion of the spores were observed under a scanning electron microscope, and several conidia adhered to the cuticle of S. invicta after 2 h. Furthermore, the germ tubes of the conidia oriented toward the cuticle after 48 h, and the mycelium colonized the entire body after 96 h. Based on the efficacy observed in the laboratory trials, further experiments were performed with ZGNKY-5 strain to evaluate its utility in an injection control technology against S. invicta in the field. We found that three dosage treatments of ZGNKY-5 strain (500 mL, 750 mL, and 1,000 mL per nest) had significant control effects. Our results show that this strain of Beauveria bassiana and our control method were effective against S. invicta in both laboratory and field settings. [ABSTRACT FROM AUTHOR]

Fumonisins, being common in occurrence in maize-based feeds, pose a great threat to animal and human health. The present study is aimed at determining the antifungal activity of Lactobacillus plantarum MYS6 against a fumonisin producing fungus, Fusarium proliferatum MYS9. The isolate was subjected to standard tests for determining its probiotic attributes and antifungal properties. L. plantarum MYS6 thrived well at pH 3.0 and 6.0, and exhibited strong resistance up to 3% bile. The isolate showed a high degree of cell surface hydrophobicity corresponding to its strong adhesion to chicken crop epithelial cells. Co-inoculation with the fungus on modified de Man Rogosa Sharpe medium revealed the inhibitory effect of L. plantarum MYS6 on fungal growth and biomass. Observation using scanning electron microscopy showed distortion of hyphal structures, swollen tips and disrupted conidia. Conidia germination inhibition assay restrained germination and showed deformed hyphae. The bioprotective feature of the isolate was evident by the inhibition of fungal development in maize-kernel treated with the cell free supernatant of L. plantarum MYS6. Both the isolate and its extracellular metabolites lowered fumonisin content in feed model up to 0.505 mg/Kg of feed and 0.3125 mg/Kg of feed respectively when compared to the level of 0.870 mg/Kg of feed in control. The major antifungal compounds produced by the isolate were 10-Octadecenoic acid, methyl ester; palmitic acid, methyl ester; heptadecanoic acid, 16-methyl ester; stearic acid and lauric acid. L. plantarum MYS6 reduced 61.7% of fumonisin possibly by a binding mechanism. These findings suggest the application of L. plantarum MYS6 as an efficient probiotic additive and biocontrol agent in feed used in poultry industry. Additionally, the antifungal metabolites pose a conspicuous inhibition of Fusarium growth and fumonisin production. [ABSTRACT FROM AUTHOR]

Two stilbenes, resveratrol and pterostilbene, exhibit antifungal activity against Leptosphaeria maculans, the fungal pathogen responsible for blackleg (stem canker) in canola (Brassica napus). In vitro studies on the effect of these stilbenes on L. maculans mycelial growth and conidia germination showed that pterostilbene is a potent fungicide and sporicide, but resveratrol only exerted minor inhibition on L. maculans. Cell viability of hyphae cultures was markedly reduced by pterostilbene and SYTOX green staining showed that cell membrane integrity was compromised. We demonstrate that pterostilbene exerts fungicidal activity across 10 different L. maculans isolates and the compound confers protection to the blackleg-susceptible canola cv. Westar seedlings. The potential of pterostilbene as a control agent against blackleg in canola is discussed. [ABSTRACT FROM AUTHOR]

Schisandra chinensis extracts (SEs) have traditionally been used as an oriental medicine for the treatment of various human diseases, however, their further application in the biocontrol of plant disease remains poorly understood. This study was conducted to develop eco-friendly botanical pesticides from extracts of S. chinensis and assess whether they could play a key role in plant disease defense. Concentrated active fractions (SE-I, SE-II, and SE-III) were obtained from S. chinensis via specific extraction and separation. Then, lignan-like substances, such as Schisanhenol B, were detected via High-Performance Liquid Chromatography-ElectroSpray Ionization-Mass Spectrometry (HPLC-ESI-MS) analyses of the active fractions. Moreover, the results from biological tests on colony growth inhibition and spore germination indicated that SE-I, SE-II, and SE-III could inhibit hyphal growth and spore generation of three important plant pathogenic fungi (Monilinia fructicola, Fusarium oxysporum, and Botryosphaeria dothidea). The study of the mechanisms of resistant fungi revealed that the oxidation resistance system, including reactive oxygen species (ROS), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD), was activated. The expression of genes related to defense, such as pathogenesis-related protein (PR4), α-farnesene synthase (AFS), polyphenol oxidase (PPO), and phenylalanine ammonia lyase (PAL) were shown to be up-regulated after treatment with SEs, which suggested an increase in apple immunity and that fruits were induced to effectively defend against the infection of pathogenic fungi (B. dothidea). This study revealed that SEs and their lignans represent promising resources for the development of safe, effective, and multi-targeted agents against pathogenic fungi. [ABSTRACT FROM AUTHOR]

Orchidaceae is one of the most species-rich angiosperm families, and all orchids are fully dependent on fungi for their seed germination and their life cycle. The level of specificity of the association between orchid species and fungi can be related to the number of co-occurring orchid species. To investigate orchid mycorrhizal associations in adult-photosynthetic orchids, 16 Mediterranean orchid species belonging to 4 genera (Anacamptis,Ophrys,Orchis, andSerapias) at 11 different sites were subjected to DNA-based analysis. Eighteen operational taxonomic units representing two fungal families, Tulasnellaceae and Ceratobasidiaceae, were identified. All examined orchid species associated with different mycorrhizal fungi. Interestingly, there was a positive correlation between number of orchid species and number of mycorrhizal. Monospecific populations showed a lower number of fungi, while sympatric populations had a higher number of mycorrhizal fungi. Our results showed that Mediterranean orchid species associated with a higher number of mycorrhizal fungi confirming as photosynthetic orchids are typically generalists toward mycorrhizal fungi. Thus, photosynthetic orchids exhibit low specificity for fungal symbionts showing the potential for opportunistic associations with diverse fungi reducing competition for nutrient. We suggest that these characteristics could confer symbiotic assurance particularly in habitat with resource limitations or prone to stressful conditions. [ABSTRACT FROM AUTHOR]

Silk cocoons are composed of fiber proteins (fibroins) and adhesive glue proteins (sericins), which provide a physical barrier to protect the inside pupa. Moreover, other proteins were identified in the cocoon silk, many of which are immune related proteins. In this study, we extracted proteins from the silkworm cocoon by Tris-HCl buffer (pH7.5), and found that they had a strong inhibitory activity against fungal proteases and they had higher abundance in the outer cocoon layers than in the inner cocoon layers. Moreover, we found that extracted cocoon proteins can inhibit the germination of Beauveria bassiana spores. Consistent with the distribution of protease inhibitors, we found that proteins from the outer cocoon layers showed better inhibitory effects against B. bassiana spores than proteins from the inner layers. Liquid chromatography-tandem mass spectrometry was used to reveal the extracted components in the scaffold silk, the outermost cocoon layer. A total of 129 proteins were identified, 30 of which were annotated as protease inhibitors. Protease inhibitors accounted for 89.1% in abundance among extracted proteins. These protease inhibitors have many intramolecular disulfide bonds to maintain their stable structure, and remained active after being boiled. This study added a new understanding to the antimicrobial function of the cocoon. [ABSTRACT FROM AUTHOR]

Herbivore-induced plant volatiles (HIPVs) are clues that help predatory insects search for food. The hypothesis that entomopathogenic fungi, which protect plants, benefit from the release of HIPVs was tested. The plant Arabidopsis thaliana was used as the source of HIPVs. The insect herbivore Lipaphis erysimi (Kaltenbach) was used as the inducer, and the fungal pathogen of the aphid Lecanicillium lecanii was exposed to HIPVs to test our hypothesis. When exposed to aphid-induced A. thaliana volatiles, the mortality of aphids pre-treated with a conidial suspension of L. lecanii, the conidial germination and the appressorial formation were significantly increased compared with the control. The decan-3-ol and 4-methylpentyl isothiocyanate that were detected in the headspace seemed to have positive and negative affection, respectively. Moreover, HIPVs generated from groups of eight aphids per plant promoted significantly increased conidial germination and appressorial formation compared with HIPVs from groups of one, two and four aphids per plant. Our results demonstrated that the pathogenicity of the entomopathogenic fungus L. lecanii was enhanced when exposed to HIPVs and that the HIPVs were affected by the number of insect herbivores that induced them. [ABSTRACT FROM AUTHOR]

Rhizopus delemar and associated species attack a wide range of fruit and vegetables after harvest. Host nutrients and acidic pH are required for optimal germination of R. delemar, and we studied how this process is triggered. Glucose induced spore swelling in an acidic environment, expressed by an up to 3-fold increase in spore diameter, whereas spore diameter was smaller in a neutral environment. When suspended in an acidic environment, the spores started to float, indicating a change in their density. Treatment of the spores with HgCl2, an aquaporin blocker, prevented floating and inhibited spore swelling and germ-tube emergence, indicating the importance of water uptake at the early stages of germination. Two putative candidate aquaporin-encoding genes—RdAQP1 and RdAQP2—were identified in the R. delemar genome. Both presented the conserved NPA motif and six-transmembrane domain topology. Expressing RdAQP1 and RdAQP2 in Arabidopsis protoplasts increased the cells' osmotic water permeability coefficient (Pf) compared to controls, indicating their role as water channels. A decrease in R. delemar aquaporin activity with increasing external pH suggested pH regulation of these proteins. Substitution of two histidine (His) residues, positioned on two loops facing the outer side of the cell, with alanine eliminated the pH sensing resulting in similar Pf values under acidic and basic conditions. Since hydration is critical for spore switching from the resting to activate state, we suggest that pH regulation of the aquaporins can regulate the initial phase of R. delemar spore germination, followed by germ-tube elongation and host-tissue infection. [ABSTRACT FROM AUTHOR]

In this research, the inhibitory effect of 16 fungicides on Colletotrichum horri causing persimmon anthracnose was investigated using mycelial growth method and spore germination method. The results showed that among the 16 tested fungicides, 10% of Difenoconazole WG, 33.5% of Copper quinolate SC, 25% of Bromothalonil EC, 70% of Mancozeb WP, 430 g/L of Tebuconazole SC, 50% of Prochloraz-manganese chloride and 400 g/L of Flusilazole EC achieved the best inhibitory effect on mycelial growth of C. horri, with the inhibition rate of 100%; 70% of Polyram WG, 33.5% of Copper quinolate SC, 25% of Bromothalonil EC, 70F of Mancozeb WP, 50% of Chlorobromoisocyanuric acid AF, 50% of Triram WP and 400 g/L of Flusilazole achieved the best inhibitory effect on spore germination of C. horri, with the germination rate of 0. In conclusion, 33.5% of Copper quinolate SC, 25% of Bromothalonil EC, 70% of Mancozeb WP and 400 g/L of Flusilazole EC achieved the best inhibitory effect both in mycelial growth and spore germination, which could be used as the preference fungicides for the control of persimmon anthracnose, and 70% of Polyram WG and 50% of Triram WP achieved the secondly best inhibitory effect, which could be used as alternative fungicides. The results of this research could provide scientific evidence for the effective control of persimmon anthracnose, and more optional pesticides for utilization in the production practice of persimmon industry. [ABSTRACT FROM AUTHOR]

The article focuses on research into the synthesis of quarternary quinolinium salts and an investigation of their antifungal activity. It states the compounds inhibited spore germination and were studied on the phytopathogenic fungi Helminthosporium oryzae, Fusarium verticilloides, and Bipolaris sorokiniana. It mentions that the salts were synthesized through reflux of quinoline derivatives with alkyl halides. It reports standard fungicides were more effective than the synthesized compounds.

The wheat stem rust fungus Puccinia graminis f. sp. tritici (Pgt) is one of the most destructive pathogens of wheat. In this study, a draft genome was built for a founder Australian Pgt isolate of pathotype (pt.) 21-0 (collected in 1954) by next generation DNA sequencing. A combination of reference-based assembly using the genome of the previously sequenced American Pgt isolate CDL 75-36-700-3 (p7a) and de novo assembly were performed resulting in a 92 Mbp reference genome for Pgt isolate 21-0. Approximately 13 Mbp of de novo assembled sequence in this genome is not present in the p7a reference assembly. This novel sequence is not specific to 21-0 as it is also present in three other Pgt rust isolates of independent origin. The new reference genome was subsequently used to build a pan-genome based on five Australian Pgt isolates. Transcriptomes from germinated urediniospores and haustoria were separately assembled for pt. 21-0 and comparison of gene expression profiles showed differential expression in ~10% of the genes each in germinated spores and haustoria. A total of 1,924 secreted proteins were predicted from the 21-0 transcriptome, of which 520 were classified as haustorial secreted proteins (HSPs). Comparison of 21-0 with two presumed clonal field derivatives of this lineage (collected in 1982 and 1984) that had evolved virulence on four additional resistance genes (Sr5, Sr11, Sr27, SrSatu) identified mutations in 25 HSP effector candidates. Some of these mutations could explain their novel virulence phenotypes. [ABSTRACT FROM AUTHOR]

Cochliobolus heterostrophus Vel2 and Vos1, members of the velvet family of proteins, play crucial roles in sexual and asexual development as reflected by deletion mutant and overexpression strain phenotypes. vel2 and vos1vel2 mutants are female sterile. Pseudothecia from vel2 or vos1 mutant crosses to an albino wild-type tester strain produce asci, however no full tetrads are found in these crosses, in contrast to crosses between wild-type strains which typically yield asci with a full complement of ascospores. In addition, none of the progeny from crosses of vel2 or vos1 mutants to wild-type mating testers is mutant, thus vos1 and vel2 ascospores are unable to survive meiosis. vos1vel2 double mutants are also female sterile like vel2 single mutants, however, asci in pseudothecia formed in crosses to wild-type testers are devoid of ascospores. Vel2 and Vos1 negatively regulate production of asexual spores, but positively regulate their morphology. vel2 and vos1 single mutant conidia vary in size, in septum number, septum position in the spore, and in germination rate, and are more sensitive to oxidative and thermal stresses compared to wild-type conidia. Trehalose amounts are decreased in single mutants, supporting previous findings that this disaccharide is required for conidium health. [ABSTRACT FROM AUTHOR]

An isolate of the basidiomycete Puccinia striiformis, which causes yellow (stripe) rust on wheat , was selfed on the newly discovered alternate host, Berberis vulgaris. This allowed a study of the segregation of molecular markers and virulence in the progeny isolates, and of the development of fungal sexual structures and spore forms . Pycnia and aecia were obtained after inoculation of B. vulgaris with basidiospores resulting from germinating teliospores from infected wheat leaves. Subsequent inoculation of wheat with aeciospores from bulked aecia resulted in 16 progeny isolates of the S1 generation. Genotyping with 42 simple sequence repeat (SSR) markers confirmed a parental origin of progeny isolates. Of the 42 analyzed loci, 15 were heterozygous in the parental isolate and 14 revealed segregation in the progenies. This resulted in 11 new multilocus genotypes (MLGs), which confirmed segregation following sexual reproduction. Additionally, parental and progeny isolates were phenotyped using a genetic stock of wheat genotypes representing 21 resistance genes. All S1 progeny isolates had virulence for 14 out of 15 loci where the parental isolate was virulent. This was consistent with the hypothesis that virulence in plant pathogens is often recessive to avirulence, i.e. , only expressed in a homozygous state. Furthermore, no segregation was observed for five out of six loci, for which the parental isolate had an avirulent phenotype. The results for one of the two segregating virulence/avirulence loci suggested that the parental isolate was heterozygous with Avr alleles resulting in different but clearly avirulent phenotypes. The other locus indicated that additional genes modifying the phenotypic expression of avirulence were involved. [ABSTRACT FROM AUTHOR]

The role of salicylic acid (SA) in regulating wheat calli growth and peroxidase activity in the co-culture with bunt (Tilletia caries (D.C.) Tul.) and smut (Ustilago tritici Pers.) pathogens was studied in this work. We found that the influence of SA increased the number of globular high-density sites with meristema-like cells and reduced the number of low-structured sites with parenchyma-like cells in wheat calli. SA inhibited fungi spores germination, mycelium growth, and formation of its new spores during the co-cultivation of wheat calli with bunt or smut agent. Interaction of fungi mycelium with wheat calli treated by SA led to formation of zones with hypersensitive reaction in calli high-structured sites with meristema-like cells. The obtained data about the influence of SA on activation of wheat calli growth and the peroxidases with pI ~3.5 and ~9.8, which can bind to the mycelium of T. caries or U. tritici are discussed in this paper. [ABSTRACT FROM AUTHOR]

Abstract: This study assessed the effects of high-intensity violet light on selected yeast and mould fungi. Cell suspensions of Saccharomyces cerevisiae, Candida albicans, and dormant and germinating spores (conidia) of the mould Aspergillus niger were exposed to high-intensity narrow band violet light with peak output at 405 nm generated from a light-emitting diode (LED) array. All three fungal species were inactivated by the 405-nm light without a requirement for addition of exogenous photosensitiser chemicals. Of the fungal species tested, S. cerevisiae was most sensitive and dormant conidia of A. niger were most resistant to 405-nm light exposure. Five-log10 colony forming units per millilitre (CFU ml−1) reductions of the tested species required exposure doses of 288 J cm−2 for S. cerevisiae, 576 J cm−2 for C. albicans, and a much higher value of 2.3 kJ cm−2 for dormant conidia of A. niger. During germination, A. niger conidia became more sensitive to 405-nm light exposure and sensitivity increased as germination progressed over an 8 h test period. Light exposure under aerobic and anaerobic conditions, together with results obtained using ascorbic acid as a scavenger of reactive oxygen species, revealed that 405-nm light inactivation in fungi involved an oxygen-dependent mechanism, as previously described in bacteria. The inactivation results achieved with yeast cells and fungal spores together with operational advantages associated with the use of a visible (nonultraviolet (UV)) light source highlight the potential of 405-nm light for fungal decontamination applications. [Copyright &y& Elsevier]

Conidial germination of Botryosphaeria dothidea (anamorph: Fusicoccum) in sterile distilled water and 1% sterile dextrose solution was evaluated at 4, 6, 12, 24 and 36 h after incubation. Also, it was described the anatomical changes on pitahaya stems induced by this fungus, collected in the field and artificially inoculated in the laboratory. Conidial germination was less than 30% in water and it was improved when 1% dextrose was added to the water. In 1% dextrose solution the germination was 90% after 4h of incubation and 100% at 6 h. Pathogen germ tubes had entered through wounds and sometimes through stomata and hyphae colonized intra and intercellularly in the parenchyma-chlorenchyma tissues. On naturally and artificially diseased stems the main alterations were: destruction of cuticle, hyperplasia of epidermal and collenchymatous hypodermal cells and conform the advance of the pathogen a layer of lignified periderm was formed surrounding the damaged tissues; however, it couldn't stop the advance of the pathogen and the cells that surrounded the lesion suffered necrosis. [ABSTRACT FROM AUTHOR]

Germination is the process by which a spore is transformed from a dormant state of metabolic activity to one of high activity. Effects of different fruit components, aeration and cold storage at 5°C on the germination of ascospores of Neosartorya fischeri after heat treatment were investigated by measuring rate and percentage germination and outgrowth of fungal biomass. Some activated spores reverted back to dormancy after 12 and 24 h of storage at 5°C. Ascospores germinated easily in acetate buffers. Germination of ascospores was retarded in medium containing citric acid and sugars. Ascospores cultured under low aeration showed no signs of germination. Different food components and growth conditions have varying effects on germination of ascospores. Significance and Impact of the Study The findings of this study can be used in the fruit industry to predict the effect of some fruit components on the germination of heat-resistant ascospores. The impact of cold storage on ascospores, which may be activated by heat schedules used to manufacture some types of fruit products, will help in determining the best storage conditions for enhanced shelf life to be adopted immediately after heat treatment. These findings also help to determine for how long a fruit juice is safe at room temperature after production before mycotoxin synthesis by heat-resistant fungi sets in. [ABSTRACT FROM AUTHOR]

Aspergillus nidulans responds to light in several aspects. The balance between sexual and asexual development as well as the amount of secondary metabolites produced is controlled by light. Here, we show that germination is largely delayed by blue (450 nm), red (700 nm), and far-red light (740 nm). The largest effect was observed with far-red light. Whereas 60 % of the conidia produced a germ tube after 20 h in the dark, less than 5 % of the conidia germinated under far-red light conditions. Because swelling of conidia was not affected, light appears to act at the stage of germ-tube formation. In the absence of nutrients, far-red light even inhibited swelling of conidia, whereas in the dark, conidia did swell and germinated after prolonged incubation. The blue-light signaling components, LreA (WC-1) and LreB (WC-2), and also the cryptochrome/photolyase CryA were not required for germination inhibition. However, in the phytochrome mutant, ∆ fphA, the germination delay was released, but germination was delayed in the dark in comparison to wild type. This suggests a novel function of phytochrome as far-red light sensor and as activator of polarized growth in the dark. [ABSTRACT FROM AUTHOR]

Abstract: Predictive mycology has dealt mainly with germination, growth and inactivation of fungi while the issue of mycotoxin production remains relatively unexplored. Very few studies provide biomass dry weight/colony size data along with mycotoxin data for the same sample times, thus the ratio mycotoxin accumulation per fungal biomass dry weight/colony size has rarely been reported. For this reason, the objective of the present study was to model the kinetics of mycotoxin production under the assumption of existing both no-growth-associated and growth-associated production. Aspergillus flavus was chosen as a model mycotoxigenic microorganism, and it was grown in maize agar medium and maize grain at 0.90 and 0.99 aw at 25°C. A significant positive correlation (p<0.05) was observed among the biomass responses (colony radius and biomass dry weight) in agar medium and colony radius in maize at both a w levels assayed. The Luedeking–Piret model was used to model AFB1 production and reasonable percentages of variability were explained. Moreover, AFB1 production was in general slightly better predicted through colony area. As conclusion, aflatoxin production may follow a mixed-growth associated trend, confirming that toxin formation does not present a clear delay in relation to growth under certain conditions. [Copyright &y& Elsevier]

Abstract: The substantial negative impact of some parameters on the germination of low-quality conidia (high proportion of slow-germinating propagules) was demonstrated, whereas for high-quality batches their effect was small or even absent. Germination was increased as the initial hydration status of conidia immediately prior to suspension preparation was increased, being ca. 33% and 80% for dehydrated Metarhizium anisopliae propagules (water activity ⩽0.314) from low- or high-quality batches after an 18h incubation period, respectively, and 63% and 95% for hydrated propagules (water activity=0.933). Germination of low-quality propagules also increased as the time dry conidia were kept in aqueous suspension prior to inoculation onto culture media (15min, 3 or 24h) or the incubation time at 25°C before counts (18, 48 or 72h) was increased. Depending on treatment conditions, average germination of low-quality conidia varied from 53% to 98%. On the other hand, germination for high-quality conidia was always ⩾94%. Regarding the relative humidity (RH) of the incubation atmosphere, the average germination rates for low-quality conidia on Potato Dextrose Agar (PDA) in Petri plates was 49%, while germination of these conidia on PDA blocks kept under lower RH inside plastic boxes was ⩽23%. Use of lactophenol-staining and/or use of coverslips had a negative effect when germination assessment was performed for low-quality conidia, resulting in distorted counts or increased standard deviations compared to high-quality conidial batches. The occurrence of dislodged conidia (ungerminated conidia outside the inoculation zone due to hydraulic pressure exercised by addition of stains and/or coverslips added to the substrate by the time germination is assessed) was common place, whereas dislodged conidia were not seen in treatments with high-quality batches. This work underscores the importance of a number of parameters that anyone working with low-quality fungi needs to be cognizant of in their research. [Copyright &y& Elsevier]

Abstract: Lactoferrin (LF), an 80kDa iron binding glycoprotein, was effective in the control of gray mould caused by Botrytis cinerea on tomato. LF strongly inhibited spore germination and germ tube elongation of B. cinerea in vitro, especially at 100mg/L. When viewed by fluorescence microscopy following staining with propidium iodide, the membrane integrity of B. cinerea conidia treated with LF (50mg/L) decreased to 68% at 2h. The leakage of carbohydrate and protein from mycelia increased as the dose of LF increased compared with the untreated controls. Furthermore, methane dicarboxylic aldehyde (MDA) content in B. cinerea spores exposed to LF increased markedly. The activities of superoxide dismutase and catalase in spores treated with LF were also 1.3, twice as high as those in the control at 6h, whereas ATP content was 1.5 times lower. In planta assays demonstrated that LF exhibited significant curative effect (76.3%, 100mg/L) against gray mould, compared with the preventive effect (52.6%, 100mg/L). The mechanisms by which LF decreased gray mould decay of tomato plant may be directly related to the severe damage to the conidia plasma membrane and loss of cytoplasmic materials from the hyphae. These findings suggest that LF has potential as an antifungal agent to reduce the severity of gray mould of tomato plants. [Copyright &y& Elsevier]

Abstract: Mating of compatible haploid cells of Ustilago maydis is essential for infection and disease development in the host. For mating and subsequent filamentous growth and pathogenicity, the transcription factor, prf1 is necessary. Prf1 is in turn regulated by the cAMP and MAPK pathways and other regulators like rop1 and hap1. Here we describe the identification of another putative Prf1 regulator, med1, the ortholog of the Aspergillus nidulans medusa (medA) transcription factor and show that it is required for mating and full virulence in U. maydis. med1 deletion mutants show both pre- and post-mating defects and are unresponsive to external pheromone. The expression of prf1 is down-regulated in Δmed1 compared to the wild type, suggesting that med1 is upstream of prf1. Additionally, indicative of a role in secondary metabolism regulation, deletion of the med1 gene de-represses the production of glycolipids in U. maydis. [Copyright &y& Elsevier]

Abstract: Chitosan (CS) and oligochitosan (OCS), as natural antifungal agents, have been primarily used as alternatives to synthetic chemical fungicides to control postharvest diseases of fruits. The effectiveness of these two agents on the growth of Monilinia fructicola to control brown rot has not yet been reported. Both spore germination and mycelial growth of M. fructicola were strongly inhibited by CS and OCS treatments in this study. Moreover, the inhibitory effect of both agents was more obvious on mycelial growth than on spore germination. By comparison of the half maximal inhibitory concentration (IC50) of each, OCS treatment conferred a little better inhibitory effect on fungal growth in vitro, but the effectiveness of both treatments on brown rot control in peach fruit stored at 25 °C was very similar. The integrity of the plasma membrane of CS- or OCS-treated spores was obviously lower than that of the control. Cytoplasm leakage was significantly higher in chitosan-treated mycelia than that of the control. These results suggest that both chitosan and oligochitosan used in this study are promising natural fungicides for control of brown rot of peach. [Copyright &y& Elsevier]

Abstract: Ergothioneine (EGT) is a histidine derivative with sulfur on the imidazole ring and a trimethylated amine; it is postulated to have an antioxidant function. Although EGT apparently is only produced by fungi and some prokaryotes, it is acquired by animals and plants from the environment, and is concentrated in animal tissues in cells with an EGT transporter. Monobromobimane derivatives of EGT allowed conclusive identification of EGT by LC/MS and the quantification of EGT in Colletotrichum graminicola and Neurospora crassa conidia and mycelia. EGT concentrations were significantly (α =0.05) higher in conidia than in mycelia, with approximately 17X and 5X more in C. graminicola and N. crassa, respectively. The first EGT biosynthetic gene in a fungus was identified by quantifying EGT in N. crassa wild type and knockouts in putative homologs of actinomycete EGT biosynthetic genes. NcΔEgt-1, a strain with a knockout in gene NCU04343, does not produce EGT, in contrast to the wild type. To determine the effects of EGT in vivo, we compared NcΔEgt-1 to the wild type. NcΔEgt-1 is not pleiotropically affected in rate of hyphal elongation in Vogel’s medium either with or without ammonium nitrate and in the rate of germination of macroconidia on Vogel’s medium. The superoxide-producer menadione had indistinguishable effects on conidial germination between the two strains. Cupric sulfate also had indistinguishable effects on conidial germination and on hyphal growth between the two strains. In contrast, germination of NcΔEgt-1 conidia was significantly more sensitive to tert-butyl hydroperoxide than the wild type; germination of 50% (GI50) of the NcΔEgt-1 conidia was prevented at 2.7mM tert-butyl hydroperoxide whereas the GI50 for the wild type was 4.7mM tert-butyl hydroperoxide, or at a 1.7X greater concentration. In the presence of tert-butyl hydroperoxide and the fluorescent reactive oxygen species indicator 5-(and-6)-carboxy-2′,7′-dichlorodihydrofluorescein diacetate, significantly (P =0.0002) more NcΔEgt-1 conidia fluoresced than wild type conidia, indicating that EGT quenched peroxides in vivo. While five to 21-day-old conidia of both strains germinated 100%, NcΔEgt-1 conidia had significantly (P <0.001) diminished longevity. Linear regression analysis indicates that germination of the wild type declined to 50% in 35days, in comparison to 25days for the NcΔEgt-1, which is equivalent to a 29% reduction in conidial life span in the NcEgt-1 deletion strain. Consequently, the data indicate that endogenous EGT helps protect conidia during the quiescent period between conidiogenesis and germination, and that EGT helps protect conidia during the germination process from the toxicity of peroxide but not from superoxide or Cu2+. Based on an in silico analysis, we postulate that NcEgt-1 was acquired early in the mycota lineage as a fusion of two adjacent prokaryotic genes, that was then lost in the Saccharomycotina, and that NcEgt-1 catalyzes the first two steps of EGT biosynthesis from histidine to hercynine to hercynylcysteine sulfoxide. [Copyright &y& Elsevier]

Abstract: The germination of Penicillium expansum and Aspergillus niger spores was monitored microscopically on malt extract agar at isothermal conditions ranging from 0 to 33°C and 5 to 41.5°C, respectively. The obtained germination data, expressed as percentage of germination (% P) versus time, were fitted to the modified Gompertz equation for the estimation of the germination kinetic parameters (lag time, λ g, and germination rate, μ g), which were further modeled as a function of temperature via the use of Cardinal Models with Inflection (CMI). The effect of temperature on these parameters was similar with that previously reported for mycelium growth kinetics of the tested isolates. The germination of spores was also studied at various dynamic time–temperature conditions including single or sequential temperature shifts. The germination of spores at fluctuating temperatures was predicted using the modified Gompertz equation in conjunction with the CMI models for λ g and μ g and based on the assumptions that i) a temperature shift does not result in any additional λ g and, thus, the total lag can be calculated by adding relative parts of the lag time, and ii) after a temperature shift the germination rate μ g adapts instantaneously to the new temperature. The comparison between predicted and observed data showed that the germination of spores is strongly affected by the extent of the temperature shift, the percentage of germinated spores at the time of the shift and the fungal species. Apart from the scientific interest in understanding the dynamics of spores'' germination, the models developed in this study can be used as tools in effective quality management systems for fungi control in foods. [Copyright &y& Elsevier]

Abstract: Wind-blown dry fungal spores and mycelial fragments from the nearest landmass or terrestrial run-off may find their way to the deep sea by hitching a ride on other sinking detrital particles. Once in the deep, they are affected by elevated hydrostatic pressure, low temperature and low nutrients. We have examined effects of these on germination of spores from a few deep-sea Aspergillus isolates. Spores from most of the fungi germinated under elevated hydrostatic pressure at 30°C. The ambient temperature of the deep sea, ∼4–5°C, was found to inhibit spore germination totally. Sediment extracts prepared in seawater promoted spore germination as did additions of dimethylsulfoxide and sucrose, but only at 30°C/200bar pressure and not at 4–5°C. Heat shock of 15min at 50°C helped in breaking the dormancy of the spores and induced germination at 5°C at 1bar pressure but not at 200bar. More than 90% of the spores from several deep-sea Aspergillus isolates and the terrestrial isolate of Aspergillus terreus lost viability within 16–17 days of incubation at 5°C/1bar. About 2–3% remained viable for more than 3 months at 5°C/1bar. Mycelial fragments showed growth and biomass production under elevated pressure at 5°C. These results indicate that building biomass under deep-sea conditions from spores is not a viable option for the deep-sea Aspergillus isolates. Mycelial fragments, on the other hand, are more likely to grow. [Copyright &y& Elsevier]