Non-pathogenic Fungi Research Articles

Crystal structure of a chitinase (RmChiA) from the thermophilic fungus Rhizomucor miehei with a real active site tunnel

A chitinase gene (RmChiA) encoding 445 amino acid (aa) residues from a fungus Rhizomucor miehei was cloned and overexpressed in Escherichia coli. Two kinds of RmChiA crystal forms, with space groups P32 2 1 and P1, were obtained by sitting-drop vapor diffusion and the structures were determined by X-ray diffraction. The overall structure of RmChiA monomer, which is the first structure of bacterial-type chitinases from nonpathogenic fungi, adopts a canonical triosephosphate isomerase (TIM) barrel fold with two protruding chitinase insertion domains. RmChiA exhibited a unique NxDxE catalytical motif and a real active site tunnel structure, which are firstly found in GH family 18 chitinases. The motif had high structural homolog with the typical DxDxE motif in other GH family 18 chitinases. The tunnel is formed by two unusual long loops, containing 15 aa and 45 aa respectively, linked by a disulfide bond across the substrate-binding cleft. Mutation experiments found that opening the roof of tunnel structure increased the hydrolysis efficiency of RmChiA, but the thermostability of the mutants decreased. Moreover, the tunnel structure endowed RmChiA with the exo-chitinase character.

Would it be possible to use nonpathogenic fungi to improve the turnover of crop residues?

This study was aimed to assess the suitability of four fungal species for operating in the residues of three crops in Golestan province, Iran. For this, four experiments were conducted to analyze their ability to grow on five culture media (Experiment I) and on the residues (Experiment II) and their growth responses to different pHs (Experiment III) and temperature levels (Experiment IV). Then, the possibility of establishing these fungi in the cultivated lands of studied crops was examined. Fungal growth was high on soybean and cotton residues and low on those of rice, and all the fungi produced a significant reduction in the carbon to nitrogen ratios in relation to noninoculated residues. The amount of nitrogen in fungal-treated cotton residues increased about four times compared with the control and in other studied residues increased twice as much as the control. The lowest C:N values for cotton and rice residues were found for Pleurotus ostreatus while Aspergillus niger was the most efficient for those of soybean. The results also showed that these fungi will not show the best performance in respect to temperature and pH, but will not be ineffective. The results could be the basis for further studies on the use of these fungi to improve nutrient cycling, focusing on multicriteria zoning on climatic and soil-related components.

Spray-induced gene silencing for disease control is dependent on the efficiency of pathogen RNA uptake.

SummaryRecent discoveries show that fungi can take up environmental RNA, which can then silence fungal genes through environmental RNA interference. This discovery prompted the development of Spray‐Induced Gene Silencing (SIGS) for plant disease management. In this study, we aimed to determine the efficacy of SIGS across a variety of eukaryotic microbes. We first examined the efficiency of RNA uptake in multiple pathogenic and non‐pathogenic fungi, and an oomycete pathogen. We observed efficient double‐stranded RNA (dsRNA) uptake in the fungal plant pathogens Botrytis cinerea, Sclerotinia sclerotiorum, Rhizoctonia solani, Aspergillus niger and Verticillium dahliae, but no uptake in Colletotrichum gloeosporioides, and weak uptake in a beneficial fungus, Trichoderma virens. For the oomycete plant pathogen, Phytophthora infestans, RNA uptake was limited and varied across different cell types and developmental stages. Topical application of dsRNA targeting virulence‐related genes in pathogens with high RNA uptake efficiency significantly inhibited plant disease symptoms, whereas the application of dsRNA in pathogens with low RNA uptake efficiency did not suppress infection. Our results have revealed that dsRNA uptake efficiencies vary across eukaryotic microbe species and cell types. The success of SIGS for plant disease management can largely be determined by the pathogen’s RNA uptake efficiency.

First Report of Fusarium venenatum causing foot and root rot of wheat (Triticum aestivum) in Germany.

Field experiments were established in the 2018/19 and 2019/20 growing seasons at the experimental station in Neu-Eichenberg, Hessen, Germany to examine the suitability of multiple wheat cultivars for intercropping with pea and the effect of mixtures on diseases. Approximately 600 wheat tillers (BBCH 49-61, depending on the year and cultivar) were sampled in each year and assessed for severity of foot (lower stem) rot symptoms. Fungi from plants with Fusarium-like symptoms exhibiting reddish-brown discolorations on the stems were isolated following the methods described in Šišić et al. (2018). Surface disinfected (3% NaOCl for 10s) wheat stems and roots were cut into three 1 cm long pieces and placed on COONS agar (Coons, 1916). Following 7 - 12 days of incubation under constant blacklight blue fluorescent light, pure cultures were generated on potato dextrose and synthetic nutrient-poor agar (Nirenberg, 1976) using the hyphal tip transfer technique, and the resulting colonies examined microscopically. Based on morphology ca 15% of all Fusarium isolates recovered belonged to a distinct taxonomic unit and were initially identified as F. sambucinum-like (Leslie and Summerell, 2006). The identity of 16 randomly selected isolates (GenBank accession numbers MW085924 - MW085939) was confirmed by sequencing a portion of the translation elongation factor 1-alpha gene region (O'Donnell et al., 1998). Blast analysis in the FUSARIUM-ID (Geiser et al., 2004) and the NCBI databases revealed >99 to 100% identity match with the Fusarium venenatum accession numbers NRRL 22196, FRC R-09186 and MRC 2394. Pathogenicity tests were conducted on wheat cultivar Torborzo using six F. venenatum isolates. Inoculum was prepared using a sterile sand-millet mix infested with six agar plugs of each of the isolates. Once fully colonized, the inoculum was mixed with sterilized sand in a 1:7 ratio (by volume), transferred to 300 ml pots and 4 surface sterilized wheat seeds (5 min 70% alcohol) were sown in each pot. Non-inoculated controls were amended with sterilized inoculum. The experiment was conducted in a greenhouse in a completely randomized design with 5 replicates. Disease symptoms were assessed after four weeks. All isolates induced reddish-brown discolorations on the lower stems similar to those observed in the field grown plants. In addition, the infected plants developed dark brown to black discolorations on the crowns and roots and showed clear signs of stunted root growth. These symptoms were further accompanied by chlorosis (yellowing) of the lower leaves starting from the leaf tip. All isolates were successfully reisolated from the infected wheat plants but not from the controls. To the best of our knowledge, this is the first report of F. venenatum causing foot and root rot of wheat in Germany. Results from field and greenhouse inoculation experiments indicate that F. venenatum may be an important pathogen of wheat in Germany. Further studies on distribution and relative abundance of the species in the Fusarium foot and root rot complex of wheat in Germany are warranted. In addition, it is important to note that our results contrast the results from previous studies (Farr and Rossman, 2021) which reported F. venenatum primarily as a soil saprophyte and presumably non-pathogenic fungus in its nature. Our findings thus, also warrant the need to further investigate pathogenic potential of this species and the role it may play on other common rotational crops in Germany.

CcPmk1 is a regulator of pathogenicity in Cytospora chrysosperma and can be used as a potential target for disease control.

Fus3/Kss1, also known as Pmk1 in several pathogenic fungi, is a component of the mitogen‐activated protein kinase (MAPK) signalling pathway that functions as a regulator in fungal development, stress response, mating, and pathogenicity. Cytospora chrysosperma, a notorious woody plant‐pathogenic fungus, causes canker disease in many species, and its Pmk1 homolog, CcPmk1, is required for fungal development and pathogenicity. However, the global regulation network of CcPmk1 is still unclear. In this study, we compared transcriptional analysis between a CcPmk1 deletion mutant and the wild type during the simulated infection process. A subset of transcription factor genes and putative effector genes were significantly down‐regulated in the CcPmk1 deletion mutant, which might be important for fungal pathogenicity. Additionally, many tandem genes were found to be regulated by CcPmk1. Eleven out of 68 core secondary metabolism biosynthesis genes and several gene clusters were significantly down‐regulated in the CcPmk1 deletion mutant. GO annotation of down‐regulated genes showed that the ribosome biosynthesis‐related processes were over‐represented in the CcPmk1 deletion mutant. Comparison of the CcPmk1‐regulated genes with the Pmk1‐regulated genes from Magnaporthe oryzae revealed only a few overlapping regulated genes in both CcPmk1 and Pmk1, while the enrichment GO terms in the ribosome biosynthesis‐related processes were also found. Subsequently, we calculated that in vitro feeding artificial small interference RNAs of CcPmk1 could silence the target gene, resulting in inhibited fungal growth. Furthermore, silencing of BcPmk1 in Botrytis cinerea with conserved CcPmk1 and BcPmk1 fragments could significantly compromise fungal virulence using the virus‐induced gene silencing system in Nicotiana benthamiana. These results suggest that CcPmk1 functions as a regulator of pathogenicity and can potentially be designed as a target for broad‐spectrum disease control, but unintended effects on nonpathogenic fungi need to be avoided.

Técnicas de imprint e espalhamento para isolamento e identificação de fungos subungueais em garras de gatos saudáveis

The aim of this study was to compare imprint and spreading techniques for the isolation and identification of colonies of pathogenic and non-pathogenic fungus in the claws of semidomiciliated cats. For that propose, 150 cats were evaluated, subdivided into three groups of 50 animals. In the first and second groups, the cats were submitted to the imprint technique in Petri dishes containing Selective Mycobiotic Agar: In the first group, the cats were subjected underwent antisepsis with 70% ethanol of the claws of the thoracic limbs and in the second group the animals were subjected underwent antisepsis with 70% ethanol of the claws of only one of the thoracic limbs. The third group was submitted to the spreading technique, whose material was collected by rubbing a sterile swab moistened with brain-heart infusion broth, in the claws of the forelimbs, where an aliquot of the material was transferred to Petri dishes containing Selective Mycobiotic Agar. The material was stored at 25°C for 30 days. The readings were performed on days 5, 7, 15, and 30 post incubation. Using the imprinttechnique performed under the conditions of this experiment, we were not able to isolate and identify the colonies because since day 5, they were overlapped. From the spreading technique, Mucor sp. (54,34%), Rhodotorula sp. (28,26%), Fusarium sp. (21,73%), Aspergillus sp. (21,73%), Trichoderma sp. (19,56%), Penicillium sp. (19,56%), Cladosporium sp. (10,86%), Rhizopus sp. (8,68%), Acremonium sp. (6,5%), Exophialia sp. (6,5%), Paecilomyces sp. (4,34%), Trichosporon sp. (4,34%), and Geotrichum sp. (2,17%) were isolated. It was concluded that the spreading technique proved to be useful in isolating fungal colonies from feline claws, and the animals do not present symptoms, which signals the importance of them as possible sources of exposure for tutors. The cats were negative for Sporothrix sp. by the imprint and spreading techniques.

Medical Application of Substances Derived from Non-Pathogenic Fungi Aspergillus oryzae and A. luchuensis-Containing Koji.

Although most fungi cause pathogenicity toward human beings, dynasties of the East Asian region have domesticated and utilized specific fungi for medical applications. The Japanese dynasty and nation have domesticated and utilized koji fermented with non-pathogenic fungus Aspergillus oryzae for more than 1300 years. Recent research has elucidated that koji contains medicinal substances such as Taka-diastase, acid protease, koji glycosylceramide, kojic acid, oligosaccharides, ethyl-α-d-glucoside, ferulic acid, ergothioneine, pyroglutamyl leucine, pyranonigrin A, resistant proteins, deferriferrichrysin, polyamines, Bifidobacterium-stimulating peptides, angiotensin I-converting enzyme inhibitor peptides, 14-dehydroergosterol, beta-glucan, biotin, and citric acid. This review introduces potential medical applications of such medicinal substances to hyperlipidemia, diabetes, hypertension, cardiovascular and cognitive diseases, chronic inflammation, epidermal permeability barrier disruption, coronavirus disease 2019 (COVID-19), and anti-cancer therapy.

Take-All Disease: New Insights into an Important Wheat Root Pathogen.

Take-all disease, caused by the fungal root pathogen Gaeumannomyces tritici, is considered to be the most important root disease of wheat worldwide. Here we review the advances in take-all research over the last 15 years, focusing on the identification of new sources of genetic resistance in wheat relatives and the role of the microbiome in disease development. We also highlight recent breakthroughs in the molecular interactions between G. tritici and wheat, including genome and transcriptome analyses. These new findings will aid the development of novel control strategies against take-all disease. In light of this growing understanding, the G. tritici-wheat interaction could provide a model study system for root-infecting fungal pathogens of cereals.

Proteomic Characterization of EVs in Non-pathogenic Yeast Cells.

Most research on extracellular vesicles (EVs) from non-pathogenic fungi has been conducted in S. cerevisiae, taking advantage of the tools available for this model organism; but a few studies on EVs from yeasts of biotechnological interest are also available. Proteomic analyses in EVs from different yeast species and under different culture conditions are consistent in the identification of proteins related to glycolysis and cell wall biogenesis. Consequently, cell wall metabolism and biosynthesis appear as major functions of EVs. Additional functions have been proposed attending to the known biological activities identified on EVs proteomes, including interspecific antagonism, protection against antimicrobial agents, or clearance of aggregates of misfolded proteins (e.g. prion-like proteins). However, caution should be taken since some of these proteins might play a different role in the intracellular space or EVs (including some well known moonlighting proteins). It is also possible that many proteins appear in EVs as an indirect consequence of cellular metabolism and protein traffic, not related to a specific role in the extracellular space. These considerations become especially relevant in the context of the increasing detection power of proteomic technologies, leading in some cases to the identification of thousands of different proteins in the EVs proteome. Mutations in different secretory pathways have been related to differences in protein cargo of EVs, but no mutation has been found completely abolishing the production of EVs. Further work on the composition and biogenesis of EVs is required to better understand their biological significance.

Levantamento de fungos micorrízicos arbusculares em associação a espécie vegetal Manihot esculenta Crantz

Cassava production in the state of Alagoas is mostly carried out by small rural producers who adopt little management technology, and who routinely do not replace nutrients due to the high cost of chemical inputs. In this agricultural production model, the knowledge and use of strategies that include natural biological processes in the soil, mainly of the microbiota present in this environment, such as arbuscular mycorrhizal fungi (AMF), can be presented as an alternative for biofertilization, since, Arbuscular mycorrhizae are symbiotic associations established between the roots of most plants and non-pathogenic fungi in the soil that have beneficial effects, which can improve plant growth and productivity and soil structure. Thus, the aim of this study was to evaluate the density of glomerospores and the native AMF genera present in the rhizosphere of cassava, Sergipana variety, as well as to determine mycorrhizal colonization in the evaluated culture. Soil collections were made in the cassava rhizosphere, at 90, 180, 270 and 360 days after planting (DAP). The average number of glomerospores in each treatment was evaluated at 90, 180, 270 and 360 DAP, and the main AMF genera present, and an evaluation of mycorrhizal colonization of the roots at 360 DAP was performed. Cassava cultivation showed an increase of approximately 174.46% at 360 DAP, showing a significant difference in the density of AMFs when compared to the 90 DAP period. The genera Diversispora sp, Entrophospora sp, Acaulospora sp, Scutellospora sp, and Racocetra sp. in cultivation, and a positive result for mycorrhizal colonization, with a 61% rate of colonization of the roots of the evaluated species.

Protective immune studies against fungi

The immune system is the host's defence against different agents and infections. Understanding the complex and highly dynamic interactions between fungi and host cells in a tissue-specific manner is crucial to facilitate the development of new therapeutic approaches to infections. Generally fungal pathogens rarely cause diseases in immunologically competent individuals. However, commensal and non-pathogenic environmental fungi can cause life-threatening infections in individuals with immune deficiency. Understanding the molecular and cellular bases of immunity to fungi has progressed significantly over the past few years. Despite close interactions with fungi today, how the immune system protects humans and animals from fungal pathogens has not been fully elucidated compared to the immune response to bacteria or viruses. The immune system is the host's defence against various foreign proteins and infections. Understanding the complex and highly dynamic interactions between fungi and host cells is crucial for the development of new therapeutic approaches to infections. Researchers from 15 countries in Europe, Asia, Australia, North and South America have provided the last five years review and original research articles that consist of a wide range of fungal pathogens, disease, effector, regulatory cells and molecular pathways of host immune responses to fungal exposure. In this review, we summarize an outline of the recent findings, perspectives, and reviews about the complex and highly dynamic interactions between fungi and host cells and a contemporary understanding of protective immunity against fungi. This review will allow an overview of the most exciting recent advances in antifungal immunity, discoveries that will help pave the way for the development of new strategies that are seriously needed to combat these devastating diseases.

Wheat stem base diseases and their causal agents

Wheat stem base disease is an important disease complex, caused by various pathogens that are characterized by variable life cycles and ecological requirements. Wheat stem bases with symptoms of different stem diseases were collected in 2012-2018. Causal agents and other fungi were identified by mycological and molecular genetic methods. A total of 6787 isolates of fungi were obtained and identified to the genera/species level. Out of the total number of isolates, 50% belonged to causal agents of stem base diseases, 10% were causal agents of leaf spots, and 8% were different saprotrophs. Fungi from the genera Fusarium (51%) and Oculimacula (35%) were the most dominant causal agents of stem base diseases. An increasing occurrence of Microdochium nivale and M. bolleyi (totally 15%) was noticed. The dominant species of Fusarium were F. culmorum, F. avenaceum and F. tricinctum; other species were detected only in some cases. An unexpectedly high proportion (31%) of fungi from different ecological niches were isolated from wheat stems with stem base disease symptoms. Phaeosphaeria (most likely P. pontiformis) was the dominant fungus among non-pathogenic fungi. Further studies are required to clarify the interactions between this fungus, wheat, and causal agents of stem base diseases.

A common partitivirus infection in United States and Czech Republic isolates of bat white-nose syndrome fungal pathogen Pseudogymnoascus destructans

The psychrophilic (cold-loving) fungus Pseudogymnoascus destructans was discovered more than a decade ago to be the pathogen responsible for white-nose syndrome, an emerging disease of North American bats causing unprecedented population declines. The same species of fungus is found in Europe but without associated mortality in bats. We found P. destructans was infected with a mycovirus [named Pseudogymnoascus destructans partitivirus 1 (PdPV-1)]. The virus is bipartite, containing two double-stranded RNA (dsRNA) segments designated as dsRNA1 and dsRNA2. The cDNA sequences revealed that dsRNA1 dsRNA is 1,683 bp in length with an open reading frame (ORF) that encodes 539 amino acids (molecular mass of 62.7 kDa); dsRNA2 dsRNA is 1,524 bp in length with an ORF that encodes 434 amino acids (molecular mass of 46.9 kDa). The dsRNA1 ORF contains motifs representative of RNA-dependent RNA polymerase (RdRp), whereas the dsRNA2 ORF sequence showed homology with the putative capsid proteins (CPs) of mycoviruses. Phylogenetic analyses with PdPV-1 RdRp and CP sequences indicated that both segments constitute the genome of a novel virus in the family Partitiviridae. The purified virions were isometric with an estimated diameter of 33 nm. Reverse transcription PCR (RT-PCR) and sequencing revealed that all US isolates and a subset of Czech Republic isolates of P. destructans were infected with PdPV-1. However, PdPV-1 appears to be not widely dispersed in the fungal genus Pseudogymnoascus, as non-pathogenic fungi P. appendiculatus (1 isolate) and P. roseus (6 isolates) tested negative. P. destructans PdPV-1 could be a valuable tool to investigate fungal biogeography and the host–pathogen interactions in bat WNS.

Predicting disease occurrence with high accuracy based on soil macroecological patterns of Fusarium wilt.

Soil-borne plant diseases are increasingly causing devastating losses in agricultural production. The development of a more refined model for disease prediction can aid in reducing crop losses through the use of preventative control measures or soil fallowing for a planting season. The emergence of high-throughput DNA sequencing technology has provided unprecedented insight into the microbial composition of diseased versus healthy soils. However, a single independent case study rarely yields a general conclusion predictive of the disease in a particular soil. Here, we attempt to account for the differences among various studies and plant varieties using a machine-learning approach based on 24 independent bacterial data sets comprising 758 samples and 22 independent fungal data sets comprising 279 samples of healthy or Fusarium wilt-diseased soils from eight different countries. We found that soil bacterial and fungal communities were both clearly separated between diseased and healthy soil samples that originated from six crops across nine countries or regions. Alpha diversity was consistently greater in the fungal community of healthy soils. While diseased soil microbiomes harbored higher abundances of Xanthomonadaceae, Bacillaceae, Gibberella, and Fusarium oxysporum, the healthy soil microbiome contained more Streptomyces Mirabilis, Bradyrhizobiaceae, Comamonadaceae, Mortierella, and nonpathogenic fungi of Fusarium. Furthermore, a random forest method identified 45 bacterial OTUs and 40 fungal OTUs that categorized the health status of the soil with an accuracy >80%. We conclude that these models can be applied to predict the potential for occurrence of F. oxysporum wilt by revealing key biological indicators and features common to the wilt-diseased soil microbiome.

Mosquito Mycobiota: An Overview of Non-Entomopathogenic Fungal Interactions.

The growing expansion of mosquito vectors leads to the emergence of vector-borne diseases in new geographic areas and causes major public health concerns. In the absence of effective preventive treatments against most pathogens transmitted, vector control remains one of the most suitable strategies to prevent mosquito-borne diseases. Insecticide overuse raises mosquito resistance and deleterious impacts on the environment and non-target species. Growing knowledge of mosquito biology has allowed the development of alternative control methods. Following the concept of holobiont, mosquito-microbiota interactions play an important role in mosquito biology. Associated microbiota is known to influence many aspects of mosquito biology such as development, survival, immunity or even vector competence. Mosquito-associated microbiota is composed of bacteria, fungi, protists, viruses and nematodes. While an increasing number of studies have focused on bacteria, other microbial partners like fungi have been largely neglected despite their huge diversity. A better knowledge of mosquito-mycobiota interactions offers new opportunities to develop innovative mosquito control strategies. Here, we review the recent advances concerning the impact of mosquito-associated fungi, and particularly nonpathogenic fungi, on life-history traits (development, survival, reproduction), vector competence and behavior of mosquitoes by focusing on Culex, Aedes and Anopheles species.

3-level Box–Behnkenoptimization of hexavalent chromium reduction by chromate resistant Trichoderma asperellum cells from simulated and industrial effluent

Hexavalent chromium tolerant non-pathogenic fungi isolated from lab waste were used for the reduction of toxic Cr(VI) (hexavalent chromium) from simulated and tannery effluent. The fungal cells were identified as Trichoderma asperellum (T. asperellum) through genomic DNA sequencing. Surface morphology of the cells and the functional groups embedded on their cells were studied using Scanning Electron Microscopy (SEM) and Fourier Transform infrared spectroscopy (FT-IR). The minimum inhibitory Cr(VI) concentration that the cells can tolerate was determined to be 11.53 mM. The effect of batch parameters influencing Cr(VI) reduction was numerically optimized by three parameter Box–Behnken response surface model (RSM) to evaluate two responses, Cr(VI) removal percentage and residual Cr(VI) concentration. The optimized process parameters for a maximum Cr(VI) removal of 86.73% and residual Cr(VI) concentration of 0.2013 mM were found to be pH 3.29, temperature 301 K and an initial Cr(VI) concentration of 1.33 mM. Crude extracellular and intracellular enzymes have been isolated and their activities over Cr(VI) reduction were determined as 0.0582 mM min − 1 mL − 1 and 0.0135 mM min − 1 mL − 1 respectively. Michelis–Menten parameters (V max and Km) of the enzymatic Cr(VI) reduction were depicted as 0.0015 mM s − 1 and 13.11 mM respectively. Tannery effluent containing an initial Cr(VI) concentration of 1.023 mM was reduced to 0.446 mM with the cells at optimum conditions. The results showed that free T. asperellum cells can be utilized for detoxification of simulated and real Cr(VI) containing aqueous solutions. • Non pathogenic Cr(VI) tolerant fungi has been isolated and utilized for Cr(VI) reduction. • Molecular Characterization of the fungi has been performed. • Optimization of process parameters for maximum removal of Cr(VI) have been carried out using Response surface methodology. • Extracellular and intracellular crude enzymes have been isolated and checked for Cr(VI) reductase activity. • Efficacy of the cells in reducing Cr(VI) from the real tannery effluent was also checked.

Evaluation of bio control potential of AgNPs synthesized from Trichoderma viride

Currently, there is a global effort to reduce the use of harmful substances, particularly chemical pesticides in cultivation. The biological mechanism of soil-borne phytopathogens has proven to be a good alternative to the use of chemical pesticides. In recent times, synthesis of nanoparticle from fungus is a trustworthy and sustainable method. The current study explores the synthesis of silver nanoparticles (AgNPs) using Trichoderma viride (T. viride), non-pathogenic fungi isolated from soil. The isolates were confirmed by morphological characters. The cell filtrate of isolates of T. viride was used for the formation of AgNPs from silver nitrate. The synthesised AgNPs were characterised by using UV, XRD, FTIR, SEM and zeta potential analyser. The SEM images indicated that the nanoparticles were spherical and irregular-like in shape and polydispersed in size. XRD analyses were performed to check the crystal-like nature of nanoparticles. Zeta potential study confirms the stability of nanosuspension. In the present study, developed AgNPs of T. viride act as a suitable and persistent biocontrol agent against rice pathogenic fungi such as Rhizoctonia solani and Fusarium moniliforme and provide an improved opportunity for application in crop and disease controlling.

Septate hyphae (Rhizoctonia sp) in sputum cytology

Diverse types of structures (hyphae, yeasts, conidia, and phialides) corresponding to both pathogenic and non-pathogenic fungi can be observed on cytological smears under light microscopy. Hyphae are long cellular filaments belonging to the fungi. Septate hyphae have cross-walls (called septa) that divide the cytoplasm into segments. In this study, we show the presence of long branched yellowish filamentous structures (± 10 µm wide) in a conventional sputum smear stained by the Papanicolaou method (Figure 1A), corresponding to a 55-year-old male who started immunosuppressive therapy six months ago due a kidney transplant. The patient was febrile (38.3ºC) and had a productive cough for 4 days. A chest CT scan suggestedconsolidationin therightupper lobe.

S-methyl Methanethiosulfonate: Promising Late Blight Inhibitor or Broad Range Toxin?

(1) Background: S-methyl methanethiosulfonate (MMTS), a sulfur containing volatile organic compound produced by plants and bacterial species, has recently been described to be an efficient anti-oomycete agent with promising perspectives for the control of the devastating potato late blight disease caused by Phytophthora infestans. However, earlier work raised questions regarding the putative toxicity of this compound. To assess the suitability of MMTS for late blight control in the field, the present study thus aimed at evaluating the effect of MMTS on a wide range of non-target organisms in comparison to P. infestans. (2) Methods: To this end, we exposed P. infestans, as well as different pathogenic and non-pathogenic fungi, bacteria, the nematode Caenorhabditis elegans as well as the plant Arabidopsis thaliana to MMTS treatment and evaluated their response by means of in vitro assays. (3) Results: Our results showed that fungi (both mycelium and spores) tolerated MMTS better than the oomycete P. infestans, but that the compound nevertheless exhibited non-negligible toxic effects on bacteria, nematodes and plants. (4) Conclusions: We discuss the mode of action of MMTS and conclude that even though this compound might be too toxic for chemical application in the field, its strong anti-oomycete activity could still be exploited when naturally released at the site of infection by plant-associated microbes inoculated as biocontrol agents.

PCR and Sequencing Base Detection of Gummosis Disease on Citrus aurantifolia Caused by Lasiodiplodia theobromae and Evaluation of Its Antagonisms

Diplodia gummosis disease caused by Lasiodiplodia theobromae is an economically important postharvest fruit decay that occurs on all types of citrus grown in Bangladesh. The present investigation was conducted to isolate and identify the pathogenic fungus responsible for postharvest diplodia gummosis disease (DGD) of citrus as well as the evaluation of its biological control through microbial antagonists. DGD causing pathogen was identified by physiological, morphological and molecular methods. The pathogenic fungus was isolated from the surface of postharvest lime fruits. The optimum growth of the fungi was observed in maltose, 2% NaCl, 15% sugar and pH 7 containing PDA medium at 35⁰C. PCR products of the internal transcribed spacer (ITS) region of the fungus showed approximately 650 bp size clear band in gel electrophoresis. The amplified region of the fungus showed 99.62% similarities with the sequences of L. theobromae. Artificially inoculation of the fungus in malta, musumbi, sweet orange, lime, and guava fruits showed similar size clear band and typical diplodia gummosis disease symptom. Methanol extracts of Datura metal displayed the highest inhibition (75.25%) against the isolated fungus. Non-pathogenic fungi Trichoderma viride showed the highest antagonistic efficiency followed by Neofusicoccum mangifera against the isolated fungus. The tested soil bacteria did not show significant antagonistic activity against the isolated fungus. Therefore, the DGD of citrus control system should be integrated into the overall citrus postharvest decay control system to reduce all citrus postharvest diseases and to protect fresh citrus fruit values.