Fungal Infestation Research Articles

Assessment of the Impact of Different Treatments on the Technological and Antifungal Properties of Papyrus (Cyperus Papyrus L.) Sheets.

In the present work, sheets of Papyrus (Cyperus papyrus L.), manufactured by lamination from strips pre-treated with different treatments, were evaluated for their technological and fungal infestation properties (Aspergillus flavus AFl375, A. niger Ani245 and Colletotrichum gloeosporioides Cgl311). The results showed that the highest values of tensile strength, tear strength, burst index and double-fold number were observed in papyrus sheets produced from strips treated with nano-cellulose (0.25%), dimethyl sulfoxide (DMSO 10%), Tylose (0.25%) and nano-cellulose (0.5%), with values of 98.90 N·m/g, 2343.67 mN·m2/g, 1162 kpa·m2/g and 8.33, respectively. The percentage of brightness ranged from 49.7% (strips treated with KOH 2% + 100 mL NaClO) to 9.6% (strips treated with Eucalyptus camaldulensis bark extract 2%), while the percentage of darkness ranged from 99.86% (strips treated with Salix babylonica leaf extract 2% or E. camaldulensis bark extract 0.5%) to 67.26% (strips treated with NaOH (2%) + 100 mL NaClO). From the SEM examination, sheets produced from treated strips with extracts from P. rigida and E. camaldulensis or S. babylonica showed no growths of A. flavus and C. gloeosporioides. Additionally, other pre-treatments, such as Nano-cellulose+Tylose 0.5% (1:1 v/v) and Tylose 0.5%, were also found to have no growth of A. niger. In conclusion, strips pre-treated with nanomaterials and extracts were enhanced in terms of the technological and antifungal properties of produced Papyrus sheets, respectively.

Investigation of diversity and dominance of fungal biota in stored wheat grains from governmental warehouses in West Bengal, India.

Fungal infestation is a leading cause of qualitative and quantitative deterioration of stored wheat grains. Limited information is available on the spatial distribution of fungal biota associated with stored wheat grains in India. Fungi were isolated and characterized from nine stored wheat grain samples in three warehouses of the Food Corporation of India, located in three agro-climatic zones (Paschim Medinipur, Bankura and Purulia) of West Bengal in India. Maximum density and fungal diversity were observed in dichloran glycerol agar (DG-18) medium and the number increased with the increase of storage duration. Samples collected from Purulia showed maximum fungal diversity than that from Bankura and Paschim Medinipur. A total of 284 fungal isolates were obtained, classified into 29 operational taxonomic units (based on amplified ribosomal DNA restriction analysis of 18S and internal transcribed spacer sequences), and identified as 24 different fungal species. The majority of fungal isolates belonged to Aspergillus flavus (35%) followed by Rhizopus oryzae (13%) and Eurotium amstelodami (9%). Aspergillopepsin O (PEPO) gene and aflatoxin biosynthetic pathway gene, nor-1, were amplified by polymerase chain reaction (PCR) from 91% and 71% of Aspergillus flavus isolates, respectively, indicating their aflatoxin producing ability. Aflatoxin production was further confirmed by ammonia vapour test, thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC). The presence of toxigenic fungi in stored wheat grain emphasizes the necessity of quarantine measures of stored grains before placing them in the public domain to save consumers from health hazards. © 2019 Society of Chemical Industry.

Application of bacteria symbiotic with Butia archeri (Arecaceae) to the biocontrol of the phytopathogenic fungi that deteriorate seeds of Glycine max

Rhizospheric and endophytic microorganisms compete with phytopathogens for ecological niches, which led us to hypothesise that bacteria symbiotic with the palm Butia archeri may influence the germination of the seeds of Glycine max and provide effective biocontrol against phytopathogens. We evaluated seed biopriming with rhizospheric strains of the bacteria Enterobacter asburiae and Bacillus cereus, and endophytic strains of Enterobacter cloacae, Enterobacter sp., Bacillus sp. and Pantoea agglomerans. Seeds treated with E. cloacae and Enterobacter sp. presented higher germination potential, germination velocity index and accumulation of fresh biomass in the radicle than seeds that were untreated or treated with other bacteria. Seeds that were not treated were also most affected by fungi, in particular Fusarium and Penicillium, during storage. When treated with B. cereus and E. asburiae, fungal infestation of the stored seeds was reduced to levels similar to those found in seeds treated with chemical fungicide. Our combined analysis of the influence of these strains on radicular growth and the control of phytopathogens, indicates that the rhizospheric strains of B. cereus and E. asburiae may have the best potential for biocontrol. The present study also demonstrated that the microbiota associated with plants native to the Brazilian Cerrado may be a promising source of species or biomolecules with potential for the biocontrol of plant pathogens.

A STUDY OF DETERIORATION PHENOMENA OF FOOT CASE CARTONNAGE FROM SAQQARA AREA, EGYPT

The aim of this paper is to study deterioration phenomena of foot case cartonnage fromSaqqara area, Egypt. There are many damage problems such as: accumulation of dust,stains, cracks of ground layer and detachment of paint and gilded layers. An analyses andinvestigations of different samples were performed using a number of different analyticaltechniques. Light microscopy (LM), X-ray diffraction (XRD), scanning electron microscopy (SEM)equipped with an energy dispersive X-ray detector (EDS) and Fourier transform infraredspectroscopy coupled with attenuated total reflection (ATR-FTIR) were used. Analytical studiesindicated that, cartonnage was composed of two layers; the coarse ground layer consisted ofcalcite and quartz as while the finer ground layer contained calcite only. Two layers of preparingdouble of linen textile were used as a separate layer between the previous ground layers. Thepigments used for the decoration of cartonnage were identified as hematite, cinnabar andcuprorivaite. Gilded layer was identified as gold and silver. Microbiological investigation indicatedthe presence a fungal and bacterial infestation. The results obtained gave important knowledgeabout the deterioration processes of the foot case cartonnage.

Changes in sorption and electrical properties of wood caused by fungal decay

Abstract As wet wood is prone to degradation by wood-destroying fungi, the monitoring of the moisture content (MC) of wood can be used to quantify the risk of fungal infestation. Fungal decay alters the sorption and electrical conductivity of wood, and thus the goal of the present study was to measure the electrical resistance (R) of wood after fungal decay as a function of MC. Scots pine sapwood (Pinus sylvestris L.) and European beech wood (Fagus sylvatica L.) were submitted to decay by Coniophora puteana (a brown rot fungus, BR) and Trametes versicolor (a white rot fungus, WR) and the mass loss (ML) due to the fungal metabolism was measured. The sorption isotherms were determined by dynamic vapor sorption (DVS), and comparative gravimetric- and R-based MC measurements were conducted. BR and WR reduced the sorption of wood and lowered its R in the hygroscopic range, where the decay led to an overestimation of wood MC, while wood MC was dramatically underestimated above fiber saturation (FS). Specimens showed an MC well above FS if measured directly after harvesting and an increased R compared to undecayed wood at a given MC. BR-decayed specimens were dried and rewetted, and such specimens showed an elevated R beyond FS. In the case of WR-decayed wood, the R was reduced at a given MC.

Incidence of Maize Weevil (Sitophilus zeamais Motsch) and its Association with Green Fungus (Aspergillus flavus Link) in Maize Under Storage at Chitwan and Surkhet Districts of Nepal

A survey of maize-growing areas of Surkhet and Chitwan, Nepal (April to May 2017) was conducted to know about the incidence, relationship and loss in stored maize due to Maize weevil (Sitophilus zeamais Motsch) and (Aspergillus flavus Link). Sixty households from each district were surveyed and the data was analyzed using SPSS and Microsoft Excel. Result revealed that there is severe infestation of maize weevil and green fungus in stored maize. 97.5% of stored samples had incidence of Aspergillus, whereas 96.7 % samples had maize weevils. 15.7% of the farmers apply sun drying and removal of the A. falvus infested seed while remaining 84.3% of the farmers use no any measure of control. Results from Chi- Square test indicated significant relation (χ2 = 122.10, P<0.01) between incidence of weevil infestation and occurrence of green fungus in the study area. The Phi coefficient value (1.00) shows the perfect relationship exist between weevil and green fungus occurrence in the study areas. The overall annual damage by the A. flavus was 6.39%. Therefore, it can be said that maize weevil is the major insect while A. flavus is major pathogen of maize grains at storage. The relationship between the occurrences of both pests was highly significant which indicated the positive relationship, i.e. the weevil plays an essential role in growth and spread of fungus.

Evaluation of the Nematicidal and Antifungal Activity of Aqueous Extracts of Moringa oleifera Leaves and Seed in Cucumber Field

Abstract This aim of the two-year study was to evaluate the nematicidal and antifungal activity of Moringa oleifera extracts against Meloidogyne incognita and fungi infestation in cucumber field. The aqueous extracts of leaves and seeds of M. oleifera were used to treat the plants. The findings of the present study revealed that the plant extracts were active against the test pathogens. All treated plants were significantly higher than the control with respect to number of leaves and branches, vine length, fruit weight, and yield. Of the two varieties of cucumber used, combination of cucumber market with moringa aqueous leaf extracts gave higher results. The phytochemical screening revealed the presence of alkaloids, flavonoids, glycosides, saponins, and tannins. These possess nematicidal and antifungal activities. Combination of variety 2, Market More with Moringa leaves aqueous extract is being recommended to farmers for management of nematode and fungal diseases. Organic amendments have the advantage of controlling environmental effluence.

Chemically characterised Pimenta dioica (L.) Merr. essential oil as a novel plant based antimicrobial against fungal and aflatoxin B1 contamination of stored maize and its possible mode of action

The chemical characterisation of Pimenta dioica essential oil (PDEO) revealed the presence of 50 components, amongst which α-Terpineol (30.31%) was the major component followed by β-Linalool (6.75%) and γ-Terpinene (4.64%). The oil completely inhibited the growth of aflatoxin B1 secreting strain Aspergillus flavus LHP-VS-8 and aflatoxin B1 production at 2.5 µL/mL and 1.5 µL/mL, respectively. The oil caused dose dependent reduction of methylglyoxal (an AFB1 inducer), enhanced leakage of Ca2+, Mg2+ and K+ ions and significantly reduced ergosterol content of fungal plasma membrane. During in situ experiments, PDEO exhibited complete protection of fumigated maize cob slices from fungal infestation without affecting seed germination. The chemically characterised PDEO is recommended as a plant based preservative and shelf life enhancer of food commodities by preventing fungal growth, AFB1 production and lipid peroxidation. This is the first report on PDEO as inhibitor of AFB1 secretion and methylglyoxal biosynthesis.

Development of sensitive polyclonal antibodies against dominant stored wheat grain fungus for its immunological detection

Fungal infestation causes deterioration of stored food grains. Most fungal species produce secondary metabolites like aflatoxins which are highly toxic to animals and humans. Aspergillus flavus has been found to be the predominant contaminant in stored wheat grains collected from the godowns of Food Corporation of India, West Bengal. The present study focuses on the development of sensitive polyclonal antibodies (PAbs) for molecular immunological detection of dominant toxigenic fungus. Pure A. flavus isolate was cultured on coconut agar media and its spores were harvested and inactivated by 4% formaldehyde. The inactivated spores were injected into a rabbit along with Freund’s complete/incomplete adjuvant for the development of PAbs. Specificity of the raised antibodies in rabbit serum was examined by enzyme-linked immunosorbent assay (ELISA) using spore proteins as antigen obtained by bead beating method. Out of several proteins (ranging from 10 to 200 kDa present in spore, only two prominent proteins of around 76 kDa and 100 kDa were detected by western blot analysis using raised polyclonal antiserum. The PAbs were purified with protein A column followed by spore proteins conjugated CNBr activated sepharose column for its use in the detection of fungal antigens. This highly purified raised antibody can be used for the development of rapid, sensitive, and accurate techniques (such as dot blot/ELISA) for the detection of toxigenic fungi present in stored wheat grains.

Correlation of curd‐associated fungi with NPK and Na concentrations in cauliflower

AbstractUnderstanding relations among nutrients and fungi infestation may help to produce fungi‐free cauliflower curds by managing plant nutrition. Structural equation modeling was used to express correlations among curd‐associated fungi and NPK and Na concentrations in 66 curds collected from 22 fields. Five out total nine isolated fungi were found correlated with the nutrients and Na as suggested by final fitted model. The model expressed 7–30% occurrence of the fungi because of estimated factors. In general, fungi infections were favored with nitrogen, phosphorus, and sodium concentrations whereas discouraged with potassium. The model highlighted the synergistic effect of Fusarium avenaceum and Aspergillus fumigatus on the occurrence of Fusarium polyphialidicum and Aspergillus nigar, respectively, and an antagonistic effect of A. nigar on Alternaria brassicicola. The findings indirectly discourage overdose of N and P, whereas encourage application of K and reclamation of sodic soils to reduce fungi infestation of cauliflower.Practical applicationsMicrobial analysis of cauliflower will help in recognizing possible fungal contaminants of apparently healthy curds. Relationship of these curd‐associated fungi with NPK and Na status of curds will highlight the importance of managing macronutrient fertilizers and reclamation of sodic soils in fungi‐free cauliflower production.

Prediction of coumestrol content in unirrigated lucerne crops using weather variables

ABSTRACTElevated coumestrol levels in lucerne (Medicago sativa L.) can reduce the reproductive performance of ewes. A model to predict coumestrol content of lucerne between summer and late autumn was developed to assess the risk of a crop having elevated levels. Data from previous studies have shown fungal damage to be the major contributor to coumestrol levels, but the fungal infestation levels that can cause a risk to reproduction in sheep are difficult to quantify. A number of variables were tested and the sum of rainfall and days where relative humidity was over 95% at 0900 h was found to have the best fit with coumestrol content of lucerne crops. The model was then tested with independent data from the literature and field. A decision tree is proposed as a practical user-friendly guide to predict whether coumestrol content is above or below a risk threshold of 25 mg/kg DM.

Management Control Points Related to the Lag Phase of Fungal Growth in a Stored Rapeseed Ecosystem

AbstractThe quality of rapeseed oil largely depends on the quality of postharvest preservation of raw seeds. Fungal infestation at early stages of the storage of rapeseeds is a major cause of their spoilage. The knowledge of relations between the storage conditions, fungal contamination, and technological quality of rapeseeds is essential to specify key control points that can be used to improve postharvest management systems and maintain rapeseed quality. The aim of this study was to define decisive control points on the basis of the kinetics of early mold growth in ecosystems of rapeseeds in a hazardous initial microbiological state, stored under various water activity and temperature conditions (a w =0.78–0.96 and t =12–30 °C). A correlation between the acid value (AV), germination, and fungal infestation of seeds was found in ecosystems with significant mold activity. The analysis of the mold growth kinetics with regard to AV, seed germination, and visible mold time showed that the detection of early (invisible) fungal growth could be a good basis for determining the time during which rapeseeds should be protected from deterioration. The research results showed how to use the length of the lag phase to identify decisive control points, which are necessary to improve the existing control systems of rapeseed preservation and storage.

EVALUATION OF SOILBORNE PLANT PATHOGENIC FUNGAL COUNT IN VARIOUS LAND USE TYPES OF DISTRICT OKARA

A field survey was conducted in district Okara to determine existing plant pathogenic fungal count in various land use types. The target sites were classified as orchard, barren land, fallow land, cultivated land and forest land use types. Field soil samples were collected from these land use types at different depths of 15, 30 and 45 cm respectively. Dilution of soil samples was made in sterilized distilled water and 1ml was poured on to the malt extract agar (MEA) medium in 90 mm diameter Petri plates incubated at 25±2°C for 5-7 days. Purified fungal colonies of Mucor spp., Fusarium solani, Aspergillus niger, Penicillium spp., Alternaria alternata, Curvularia spp., Rhizopus spp., and Helminthosporium spp. on potato dextrose agar (PDA) medium were identified based on their morphological descriptions. These fungal counts were recovered from the soil at 30 cm depth which indicates an alarming situation for deep-rooted crops to soilborne fungal pathogens infestation in future.

Safety and Quality Assessment of Smallholder Farmers' Maize in the Western Highlands of Guatemala

Maize ( Zea mays) is a staple in many developing countries but is known to be prone to pest (insects, birds, and rodents) and fungal infestation. In Guatemala, mycotoxin contamination of cultivated products may occur owing to such factors as environmental conditions and the use of traditional agriculture operations. To assess the current maize conditions in Guatemala, a small-scale study was performed. Mold and insect counts and mycotoxin (aflatoxin and fumonisin) concentrations were determined on 25 farms in two townships (Chiantla and Todos Santos) of the Huehuetenango Department. Total fungal counts were 3.6 to 6.83 log CFU/g with no significant differences ( P > 0.05) across farms at different altitudes. Farms where maize was not produced but was purchased were at higher risk of fumonisin contamination, whereas local producers were mostly affected by aflatoxins. Aflatoxin was present in maize from 100% of farms at 1.0 to 85.3 ppb, and fumonisin was detected on 52% of farms at 0.4 to 31.0 ppm. Average mycotoxin consumption amounts were above the recommended maximum intake for aflatoxin in both produced and purchased maize and above the provisional maximum tolerable daily intake for fumonisin in purchased maize. Estimated daily intake was 0.01 to 0.85 μg/kg of body weight per day for aflatoxin and 2.9 to 310.0 μg/kg of body weight per day for fumonisin. An entomological analysis revealed overall 32% prevalence of Ephestia kuehniella (flour moth), 16% prevalence of Sitophilus zeamais (maize weevil), and 8% prevalence of Tribolium sp. (flour beetle) on the analyzed farms. This study highlighted poor agricultural practices used in the highlands of Guatemala. Current practices should be revised for the production of maize that is safe for consumption by the population in this region.

Wheat black point: Role of environment and genotype

Wheat black point is an important quality defect in many areas of the world. The aims of this study were to identify grain tissues involved and to develop a better understanding of the genetic and environmental mechanisms that control black point. Results (of microscopic and genetic investigations) were consistent with control of pigment synthesis being resident in the tissues comprising the grain coat. Analysis of data for a black point susceptible variety revealed a strong correlation between black point and rainfall 20–30 days after anthesis. Application of overhead misting to wheat plots during grain ripening in field experiments appeared to validate this relationship and black point symptoms preceded the appearance of any fungal infestation. A 3-years trials at a high risk field site involving commercial varieties and a doubled haploid population derived from a resistant x susceptible cross indicated significant contributions from genotype, environment and genotype x environment. Germination rate of black pointed developing and ripe grains increased, with no apparent impact on seed viability. The results suggest that black point development can be independent of fungal presence. Furthermore, dark pigment synthesis in susceptible genotypes appears to occur if specific environmental conditions coincide with a sensitive period in grain development.

Trichoderma harzianum: Inhibition of mycotoxin producing fungi and toxin biosynthesis

A quarter of the world-wide crop is spoiled by filamentous fungi and their mycotoxins and weather extremes associated with the climate change lead to further deterioration of the situation. The ingestion of mycotoxins causes several health issues leading in the worst case to cancer in humans and animals. Common intervention strategies against mycotoxin producing fungi, such as the application of fungicides, may result in undesirable residues and in some cases to a stress induction of mycotoxin biosynthesis. Moreover, development of fungicide resistances has greatly impacted pre- and postharvest fungal diseases. Hence there is the need to develop alternative strategies to reduce fungal infestation and thus mycotoxin contamination in the food chain. Such a strategy for natural competition of important plant-pathogenic and mycotoxin producing fungi could be Trichoderma harzianum, a mycoparasitic fungus. Especially in direct comparison to certain tested fungicides, the inhibition of different tested fungal species by T. harzianum was comparable, more sustainable and in some cases more effective, too. Besides substantially reduced growth rates, a transcriptional based inhibition of mycotoxin biosynthesis in the competed Aspergillus species could be shown. Furthermore it could be clearly observed by high-resolution Scanning Electron Microscopy (SEM) that T. harzianum actively attaches to the competitor species followed by subsequent enzymatic lysis of those mycelial filaments. The analyzed isolate of T. harzianum MRI349 is not known to produce mycotoxins. In this study it could be successfully proven that T. harzianum as a biological competitor is an effective complement to the use of fungicides.

Extent of Microbial Contamination of Refined and Unrefined Vegetable oils sold in South-west Nigeria

Oils constitute a major source of plant-based protein. A major limitation to optimal oil consumption in sub-tropical region is fungal infestation and consequent mycotoxin contamination. Ten refined and eight unrefined vegetable oils were randomly purchase from open markets and screened for microbial contamination using standard microbial procedures. Twenty six fungi isolates were obtained from the vegetable oil samples, the isolates were identified as Aspergillus fumigatus (43.0%), Mucor (17.9%), Saccharomyces cerevisiae (10.7%), Aspergillus niger (7.1%), Aspergillus flavus (7.1%), Penicillium spp (7.1%), Aspergillus oryzae (3.6%), Mucor (17.9%) and Rhizopus spp (3.6%). Five out of the ten refined vegetable oil samples had no fungal contamination. A. flavus and A. oryzae were absent in all the refined oil samples while A. niger was absent in all the unrefined oil samples. Isolation of mycotoxigenic fungi such as Aspergillus spp. is of vital importance in the food industry. Education and training of processors and consumers is recommended.

Identifying unusual mortality events in bats: a baseline for bat hibernation monitoring and white‐nose syndrome research

AbstractBat population trends are particularly affected by adult mortality, especially when large numbers of individuals die, as evidenced by white‐nose syndrome in North America. We obtained baseline mortality data from 318 European hibernacula. Mortality was low and negatively associated with elevation but not with fungal infestation. Mortality events involving more than seven bats at a hibernaculum should be considered unusual, and above this threshold, pathological or microbiological analysis should be carried out. To increase understanding of mortality in bats, there is an urgent need to develop and co‐ordinate national and international programs for monitoring and investigating mortality and diseases.

The prospect of micropropagating Gonystylus bancanus (Miq.) Kurz, a tropical peat swamp forest timber species through tissue culture technique - Review

Gonystylus bancanus (Miquel) Kurz is one of the most valuable timber species in tropical peat swamp forest. Its timber is widely used for furniture, decorative cabinets and interior decoration. Due to its higher demand, G. bancanus continues to be harvested which leads to its disappearance in the wild. This is worsened by the fact that germination rates in the wild are very poor due to rapid insect and fungal infestation. Even though vegetative propagation via stem cuttings has been successful, proper protocols on tissue culture need to be explored as a viable way of mass production of a large number of planting stock in a relatively shorter time for forest rehabilitation and enrichment planting purposes.

Unmanned aerial vehicles (UAV) for assessment of qualitative classification of Norway spruce in temperate forest stands

The study investigates the potential of UAV-based remote sensing technique for monitoring of Norway spruce health condition in the affected forest areas. The objectives are: (1) to test the applicability of UAV visible an near-infrared (VNIR) and geometrical data based on Z values of point dense cloud (PDC) raster to separate forest species and dead trees in the study area; (2) to explore the relationship between UAV VNIR data and individual spruce health indicators from field sampling; and (3) to explore the possibility of the qualitative classification of spruce health indicators. Analysis based on NDVI and PDC raster was successfully applied for separation of spruce and silver fir, and for identification of dead tree category. Separation between common beech and fir was distinguished by the object-oriented image analysis. NDVI was able to identify the presence of key indicators of spruce health, such as mechanical damage on stems and stem resin exudation linked to honey fungus infestation, while stem damage by peeling was identified at the significance margin. The results contributed to improving separation of coniferous (spruce and fir) tree species based on VNIR and PDC raster UAV data, and newly demonstrated the potential of NDVI for qualitative classification of spruce trees. The proposed methodology can be applicable for monitoring of spruce health condition in the local forest sites.