Fungal Infestation Research Articles

Aromia bungii

Aromia bungii

Recent investigations of ergot alkaloids incorporated into plant and/or animal systems.

Recent investigations of ergot alkaloids incorporated into plant and/or animal systems.

The use of near infrared transmittance kernel sorting technology to salvage high quality grain from grain downgraded due to Fusarium damage.

The mycotoxins associated with specific Fusarium fungal infections of grains are a threat to global food and feed security. These fungal infestations are referred to as Fusarium Head Blight (FHB) and lead to Fusarium Damaged Kernels (FDK). Incidence of FDK >0.25% will lower the grade, with a tolerance of 5% FDK for export feed grain. During infestation, the fungi can produce a variety of mycotoxins, the most common being deoxynivalenol (DON). Fusarium Damaged Kernels have been associated with reduced crude protein (CP), lowering nutritional, functional and grade value. New technology has been developed using Near Infrared Transmittance (NIT) spectra that estimate CP of individual kernels of wheat, barley and durum. Our objective is to evaluate the technology's capability to reduce FDK and DON of downgraded wheat and ability to salvage high quality safe kernels. In five FDK downgraded sources of wheat, the lowest 20% CP kernels had significantly increased FDK and DON with the high CP fractions having decreased FDK and DON, thousand kernel weights (TKW) and bushel weight (Bu). Strong positive correlations were observed between FDK and DON (r = 0.90); FDK and grade (r = 0.62) and DON and grade (r = 0.62). Negative correlations were observed between FDK and DON with CP (r = −0.27 and −0.32); TKW (r = −0.45 and −0.54) and Bu (r = −0.79 and −0.74). Results show improved quality and value of Fusarium downgraded grain using this technology.

Isolation and characterisation of a Sphingomonas strain able to degrade the fungicide ortho-phenylphenol.

Ortho-phenylphenol (OPP) is a fungicide used in fruit packaging plants for the control of fungal infestations during storage. Its application leads to the production of large wastewater volumes which according to the European legislation should be treated on site. In spite of this, no efficient treatment systems are currently available, and the development of biological systems based on tailored-made pesticide-degrading inocula for the treatment of these wastewaters is an appealing solution. Enrichment cultures from a soil collected from a wastewater disposal site resulted in the isolation of a pure Sphingomonas haloaromaticamans strain P3 able to degrade rapidly OPP and use it as an energy source. Its degrading capacity was dependent on the external supply of amino acids or on the presence of other bacteria that did not contribute to fungicide degradation. The isolated S. haloaromaticamans strain was able to metabolise up to 150 mg L(-1) of OPP within 7 days, in a wide range of pH (4.5-9) and temperatures (4-37 °C), and in the presence of other pesticides (thiabendazole and diphenylamine) co-used in the fruit packaging industry. Overall, the OPP-degrading bacterium isolated showed high potential for use in future biodepuration treatment systems and bioremediation strategies.

Biosynthesis and characterization of 15N6-labeled phomopsin A, a lupin associated mycotoxin produced by Diaporthe toxica

The hepatotoxin phomopsin A (PHO-A), a secondary metabolite mainly produced by the fungus Diaporthe toxica, occurs predominantly on sweet lupins. Along with the growing interest in sweet lupins for food and feed commodities, concerns have been raised about fungal infestations, and consequently, about the determination of PHO-A.High performance liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) represents the most suitable analytical technique for sensitive and selective detection of mycotoxins including PHO-A. However, isotopic labeled substances are needed as internal standards for a reliable and convenient quantification.As no isotope standard for PHO-A is currently available, a biosynthesis of fully 15N6-labeled PHO-A was established by cultivation of D. toxica on defined media containing Na15NO3 and 15N-labeled yeast extract as the only nitrogen sources. The identity of 15N6-PHO-A was confirmed by high resolution mass spectrometry.The new 15N6-labeled standard will facilitate the method development for PHO-A including a more accurate quantification by LC–MS/MS.

Opportunistic Fungi as Etiologic Agents of Dermatitis - A Case of Alternaria Fungal Infestation in Canines

Opportunistic Fungi as Etiologic Agents of Dermatitis - A Case of Alternaria Fungal Infestation in Canines

An antifungal coating for dental silicones composed of chlorhexidine nanoparticles

ObjectivesThe aims of this study were to synthesise a range of chlorhexidine-containing nanoparticles (CHX-NPs), and investigate the feasibility of using these as an antifungal coating for dental silicones. MethodsCHX-NPs were precipitated in aqueous reaction by mixing solutions of CHX digluconate with solutions of sodium triphosphate (TP), trimetaphosphate (TMP) or hexametaphosphate (HMP). CHX-NPs were deposited on commercial dental silicones by immersion coating, and these were characterised for hydrophilicity (contact angle) and water uptake (mass change). Soluble CHX elution into artificial saliva was measured using ultraviolet spectrophotometry. Antifungal efficacy against Candida albicans was investigated using a cell proliferation assay. ResultsCoating silicones with CHX-NPs did not significantly affect hydrophilicity, as assessed using water contact angle, or water uptake as assessed by mass change following 16 weeks’ immersion in artificial saliva. CHX-NP-coated silicone specimens released soluble CHX into artificial saliva. The salt of CHX and the immersion time affected the rate, concentration and duration of CHX release, with CHX-HMP exhibiting a slow, sustained release and CHX-TP and CHX-TMP exhibiting a faster, more concentrated release. C. albicans metabolic activity was inhibited by presence of CHX-HMP-NPs in suspension. ConclusionsCHX-NPs provided a localised, controlled dose of soluble CHX at the surface of dental silicones without adversely affecting hydrophilicity or water uptake. CHX-HMP NPs provided effective antifungal control of C. albicans in a cell proliferation assay. Coating materials with these nanoparticles could be an effective way of delivering low, but clinically relevant, concentrations of chlorhexidine in the oral environment. Clinical significanceDenture stomatitis is a common oral infection and is associated with fungal infestation of denture soft lining and obturator materials, which are often silicones such as those used here. Our study suggests that CHX-NPs may be a useful strategy in design of antifungal coatings for these materials.

Near infrared assessment of biodegradability and mechanical properties of paper made of cellulose sulfate bleached coniferous pulp with addition of cationic starch and resinous adhesive

The goal of this work was to develop Fourier-transform-near-infrared-spectroscopy-based methodology for monitoring kinetics and estimating the biodegradation rate of coniferous pulp paper. Two experiments with paper-degrading fungi were tested: one with Chaetomium globosum alone and the other with a mixture of Aspergillus niger, Trichoderma viride, and Penicillium funiculosum. Paper sheets made of fibers with the addition of 0, 2, 3, or 5% of cationic starch and resinous adhesive were used as test samples. In order to quantify the resistance of the paper to biodegradation, tests of breaking length and evaluation of the degree of fungal infestation were performed during infestation. It was found that addition of cationic starch and resin adhesives improved mechanical properties of paper; however, it also increased susceptibility to fungal colonization. Degradation of paper colonized by C. globosum was more advanced and exhibited more rapid kinetics. Spectral analysis revealed that spectra were most varying in bands 4283, 4400, 4742, and 4808 cm−1, which correspond to –CH, and –OH functional groups of cellulose and hemicelluloses. Differences in spectra were in good agreement with the reference methods; therefore this technique has potential for monitoring the paper biodegradation process and predicting changes in the paper's mechanical properties.

Tree diversity and the role of non-host neighbour tree species in reducing fungal pathogen infestation.

The degree to which plant pathogen infestation occurs in a host plant is expected to be strongly influenced by the level of species diversity among neighbouring host and non-host plant species. Since pathogen infestation can negatively affect host plant performance, it can mediate the effects of local biodiversity on ecosystem functioning.We tested the effects of tree diversity and the proportion of neighbouring host and non-host species with respect to the foliar fungal pathogens of Tilia cordata and Quercus petraea in the Kreinitz tree diversity experiment in Germany. We hypothesized that fungal pathogen richness increases while infestation decreases with increasing local tree diversity. In addition, we tested whether fungal pathogen richness and infestation are dependent on the proportion of host plant species present or on the proportion of particular non-host neighbouring tree species.Leaves of the two target species were sampled across three consecutive years with visible foliar fungal pathogens on the leaf surface being identified macro- and microscopically. Effects of diversity among neighbouring trees were analysed: (i) for total fungal species richness and fungal infestation on host trees and (ii) for infestation by individual fungal species.We detected four and five fungal species on T. cordata and Q. petraea, respectively. High local tree diversity reduced (i) total fungal species richness and infestation of T. cordata and fungal infestation of Q. petraea and (ii) infestation by three host-specialized fungal pathogen species. These effects were brought about by local tree diversity and were independent of host species proportion. In general, host species proportion had almost no effect on fungal species richness and infestation. Strong effects associated with the proportion of particular non-host neighbouring tree species on fungal species richness and infestation were, however, recorded.Synthesis. For the first time, we experimentally demonstrated that for two common forestry tree species, foliar fungal pathogen richness and infestation depend on local biodiversity. Thus, local tree diversity can have positive impacts on ecosystem functioning in managed forests by decreasing the level of fungal pathogen infestation.

Trichoderma harzianum seed treatment controls Fusarium verticillioides colonization and fumonisin contamination in maize under field conditions

In northern Italy, the most frequently occurring class of mycotoxins in maize are fumonisins, mainly those produced by Fusarium verticillioides. Currently, good agricultural practices (GAPs) represent the best line of defense for controlling the contamination of maize by Fusarium-toxins. Annual fluctuations in weather conditions can strongly reduce the advantages conferred by GAPs, and thus integration with biological control strategies can be a sustainable way to achieve reliable control of Fusarium colonization and toxin contamination. Trichoderma harzianum is a good biocontrol agent against a wide range of plant pathogens, and previous studies have reported its ability to reduce F. verticillioides colonization under greenhouse conditions. Field trials were conducted in two locations to assess the effect of seed treatment with T. harzianum strain T22 on F. verticillioides kernel colonization and on fumonisin contamination under various natural conditions. An average reduction of 58% in fungal infestation and 53% in mycotoxin contamination was observed during our three-year experiments. This research suggests that seed biopriming with T. harzianum T22 can be a promising and environmentally friendly way to control F. verticillioides kernel colonization and fumonisin accumulation.

Plant essential oils as food preservatives to control moulds, mycotoxin contamination and oxidative deterioration of agri-food commodities – Potentials and challenges

Stored food items are frequently contaminated by fungal infestations, mycotoxins secreted by toxigenic fungi, and free radical generation due to oxidative stress. In order to ensure the safety of food items, there is a need for control measures which are effective by antimicrobial, mycotoxin inhibitory as well as antioxidative action. Some synthetic chemicals used as preservatives have been reported to cause harmful effects to consumers and the environment. Different plant essential oils (EOs), naturally occurring plant-based volatile components, have often been reported to possess strong antimicrobial and antioxidant potential. Some EO formulations are currently used as food preservatives and are kept in the category “GRAS” in view of their favourable safety profile. Being volatile in nature, such EOs may be used as plant-based fumigants for stored food commodities. Hence, EOs may play a significant role in overcoming storage losses and in enhancing food shelf- life. This review presents an overview on EOs reported to have prominent efficacy against storage fungi, mycotoxins, and as antioxidants. In addition, safety concerns and future prospects as plant-based preservatives are also discussed.

Plant Extract Control of the Fungi Associated with Different Egyptian Wheat Cultivars Grains

Abstract Grain samples of 14 Egyptian wheat cultivars were tested for seed-borne fungi. The deep freezing method was used. Five seed-borne fungi viz., Aspergillus flavus, A. niger, Curvularia lunata, Fusarium moniliforme and Penicillium chrysogenum were isolated from the wheat cultivars viz., Bani Suef 4, Bani Suef 5, Gemmiza 7, Gemmiza 9, Gemmiza 10, Giza 168, Misr 1, Misr 2, Sakha 93, Sakha 94, Shandaweel 1, Sids 1, Sids 2 and Sids 3. A. flavus, A. niger and F. moniliforme were the most prevalent fungal species. Their incidence ranged from 21.0-53.5%, 16.0-37.5%, and 12.0-31.0%, respectively. The antifungal potential of water extracts from aerial parts of five wild medicinal plants (Asclepias sinaica, Farsetia aegyptia, Hypericum sinaicum, Phagnalon sinaicum, and Salvia aegyptiaca) were collected from the Sinai Peninsula, Egypt. The antifungal potential of water extracts from the aerial parts of these five plants were tested in the laboratory against the dominant fungi isolated from the wheat cultivars. All the aqueous plant extracts significantly (p ≤ 0.05) reduced the incidence of the tested seed-borne fungi. But the extract of Asclepias sinaica exhibited the most antifungal activity on tested fungi at all concentrations used when compared with other plant extracts. Maximum infested grain germination was observed in Giza 168 and minimum in Bani Suef 5. Treating grains with plant extract of A. sinaica (10%) enhanced the percentage of grain germination of all cultivars in both laboratory and pot experiments. Maximum root and shoot length of seedlings was recorded in Bani Suef 4 during fungal infestation or treatment by plant extract. For one hour before sowing or storage, the aqueous extract of A. sinaica can be used to treat wheat grains, to reduce the fungal incidence. Aqueous extracts of the aerial parts of selected medicinal plants, particularly A. sinaica, are promising for protecting Egyptian wheat grain cultivars against major seed-borne fungi. The aqueous extracts are expected to improve crops.

Species-specific responses to environmental stress on germination and juvenile growth of two Bolivian Andean agroforestry species

Integrating native trees in farmland can support soil, water and biodiversity conservation. This is particularly important in regions characterized by long periods of drought and soil erosion, such as the Bolivian Andes, where agroforestry with native woody species is rarely applied. Better knowledge on the effects of environmental stress on propagation and establishment of such native plants is needed to optimize their cultivation. In our study, we tested the effects of temperature and scarification on seed germination, and assessed seedling survival and juvenile growth of two potential agroforestry species (Prosopis laevigata var. andicola, Schinus molle) under diverse soil and water conditions. Temperatures above 30 °C accelerated germination, but they increased fungi infestation in the case of S. molle. The application of acid and mechanical scarification significantly improved the germination capacity of P. laevigata var. andicola. Medium to high moisture levels in sand provided the most favourable conditions for plant growth. S. molle was more sensitive to dry and P. laevigata var. andicola more vulnerable to water-saturated clay loam. Mulching enhanced the survival and growth of S. molle juveniles, but increased P. laevigata var. andicola’s growth in sand and dry soils only. Our results may facilitate guidance on improving propagation of these two potential agroforestry species under environmental stress conditions. More generally, our study shows that easily applicable treatments, such as mulching, can significantly improve the cultivation of native species, provided that their habitat requirements and limiting factors are well known. This highlights the relevance of identifying and closing such knowledge gaps for native trees and shrubs in order to promote their potential for use in agroforestry.

Direct somatic embryogenesis with high frequency plantlet regeneration and successive cormlet production in saffron (Crocus sativus L.)

Saffron is a slowly propagating geophyte with fungal infestation of corms under field conditions. Moreover, genetic improvement through breeding is not possible due to male sterility. Therefore, tissue culture methods offer a great potential for mass propagation, and somatic embryogenesis is one of the efficient methods. In the present study, direct somatic embryogenesis from leaf base was obtained in thidiazuron (TDZ, 2.5μM) and picloram (2.0μM) supplemented Murashige and Skoog medium (Murashige and Skoog, 1962). Significantly higher secondary embryogenesis was observed in embryo proliferation medium (EPM; MS supplemented with TDZ 2.5μM and picloram 1.0μM). The origin and different developmental stages of somatic embryos were ascertained through histological and scanning electron microscopic studies. Stomata were also observed in some of the somatic embryos. An alluring observation was retention of embryogenic potential beyond 3years of culture. Percent germination of secondary embryos in MS medium was 60.48 when matured in ½ EPM. Freshly initiated somatic embryos also germinated to form plantlets without undergoing secondary embryogenesis in MS medium containing TDZ (2.5μM) and picloram (1.0 and 2.0μM). Somatic embryo derived shoots were multiplied in 6-benzylaminopurine (BAP; 26.64μM) and α-naphthaleneacetic acid (NAA; 1.0μM). Growth performance of cormlets obtained from these shoots was evaluated under green house conditions. Somatic embryogenesis holds tremendous importance for mass propagation of saffron with formation of ultimate propagating material i.e., cormlets.

The net return from animal activity in agro-ecosystems: trading off benefits from ecosystem services against costs from crop damage.

Animals provide benefits to agriculture through the provision of ecosystem services, but also inflict costs such as damaging crops. These benefits and costs are mostly examined independently, rather than comparing the trade-offs of animal activity in the same system and quantifying the net return from beneficial minus detrimental activities. Here, I examine the net return associated with the activity of seed-eating birds in almond orchards by quantifying the economic costs and benefits of bird consumption of almonds. Pre-harvest, the consumption of harvestable almonds by birds cost growers AUD$57.50 ha (-1) when averaged across the entire plantation. Post-harvest, the same bird species provide an ecosystem service by removing mummified nuts from trees that growers otherwise need to remove to reduce threats from fungal infection or insect pest infestations. The value of this ecosystem service ranged from AUD$82.50 ha (-1)-$332.50 ha (-1) based on the replacement costs of mechanical or manual removal of mummified nuts, respectively. Hence, bird consumption of almonds yielded a positive net return of AUD$25-$275 ha (-1) averaged across the entire plantation. However, bird activity varied spatially resulting in positive net returns occurring primarily at the edges of crops where activity was higher, compared to negative net returns in crop interiors. Moreover, partial mummy nut removal by birds meant that bird activity may only reduce costs to growers rather than replace these costs completely. Similar cost-benefit trade-offs exist across nature, and quantifying net returns can better inform land management decisions such as when to control pests or promote ecosystem service provision.

The net return from animal activity in agro-ecosystems: trading off benefits from ecosystem services against costs from crop damage

Animals provide benefits to agriculture through the provision of ecosystem services, but also inflict costs such as damaging crops. These benefits and costs are mostly examined independently, rather than comparing the trade-offs of animal activity in the same system and quantifying the net return from beneficial minus detrimental activities. Here, I examine the net return associated with the activity of seed-eating birds in almond orchards by quantifying the economic costs and benefits of bird consumption of almonds. Pre-harvest, the consumption of harvestable almonds by birds cost growers AUD$57.50 ha -1 when averaged across the entire plantation. Post-harvest, the same bird species provide an ecosystem service by removing mummified nuts from trees that growers otherwise need to remove to reduce threats from fungal infection or insect pest infestations. The value of this ecosystem service ranged from AUD$82.50 ha -1–$332.50 ha -1 based on the replacement costs of mechanical or manual removal of mummified nuts, respectively. Hence, bird consumption of almonds yielded a positive net return of AUD$25–$275 ha -1 averaged across the entire plantation. However, bird activity varied spatially resulting in positive net returns occurring primarily at the edges of crops where activity was higher, compared to negative net returns in crop interiors. Moreover, partial mummy nut removal by birds meant that bird activity may only reduce costs to growers rather than replace these costs completely. Similar cost-benefit trade-offs exist across nature, and quantifying net returns can better inform land management decisions such as when to control pests or promote ecosystem service provision.

ANTIFUNGAL EFFECT OF CLITORIA TERNATEA L. LEAF EXTRACT ON SEEDS OF PISUM SATIVUM L. IN RELATION TO THE ACTIVITIES OF SOME ENZYMES

This paper highlights the antifungal activities of the leaf extract of Clitoria ternatea L. against Fusarium oxysporum ciceri. T he experiment al procedures include study of the activit ies of some ma rker enzymes of seeds of Pisum sativum L. T he leaf extract of C litoria showed antifun gal activity in relation to some enzyme activities. Fungus infestation increased activity level of some stress enzymes l ike catalase, peroxidase and Superoxide Dismutase which was controlled by the administration of the plant extract. Furthermore the activ ities of amylase, protease and dehydrogenase were decr eased by the fungal infestation which was overcome by application of the plant extract. The findings of the work thus supports that the formulation can be used as an a ntifungal agent against the fungus to overcome the de leterious effect caused by it on the pea seeds.

Neoseiulus paspalivorus, a predator from coconut, as a candidate for controlling dry bulb mites infesting stored tulip bulbs

The dry bulb mite, Aceria tulipae, is the most important pest of stored tulip bulbs in The Netherlands. This tiny, eriophyoid mite hides in the narrow space between scales in the interior of the bulb. To achieve biological control of this hidden pest, candidate predators small enough to move in between the bulb scales are required. Earlier experiments have shown this potential for the phytoseiid mite, Neoseiulus cucumeris, but only after the bulbs were exposed to ethylene, a plant hormone that causes a slight increase in the distance between tulip bulb scales, just sufficient to allow this predator to reach the interior part of the bulb. Applying ethylene, however, is not an option in practice because it causes malformation of tulip flowers. In fact, to prevent this cosmetic damage, bulb growers ventilate rooms where tulip bulbs are stored, thereby removing ethylene produced by the bulbs (e.g. in response to mite or fungus infestation). Recently, studies on the role of predatory mites in controlling another eriophyoid mite on coconuts led to the discovery of an exceptionally small phytoseiid mite, Neoseiulus paspalivorus. This predator is able to move under the perianth of coconuts where coconut mites feed on meristematic tissue of the fruit. This discovery prompted us to test N. paspalivorus for its ability to control A. tulipae on tulip bulbs under storage conditions (ventilated rooms with bulbs in open boxes; 23°C; storage period June-October). Using destructive sampling we monitored predator and prey populations in two series of replicated experiments, one at a high initial level of dry bulb mite infestation, late in the storage period, and another at a low initial dry bulb mite infestation, halfway the storage period. The first and the second series involved treatment with N. paspalivorus and a control experiment, but the second series had an additional treatment in which the predator N. cucumeris was released. Taking the two series of experiments together we found that N. paspalivorus controlled the populations of dry bulb mites both on the outer scale of the bulbs as well as in the interior part of the bulbs, whereas N. cucumeris significantly reduced the population of dry bulb mites on the outer scale, but not in the interior part of the bulb. Moreover, N. paspalivorus was found predominantly inside the bulb, whereas N. cucumeris was only found on the outer scale, thereby confirming our hypothesis that the small size of N. paspalivorus facilitates access to the interior of the bulbs. We argue that N. paspalivorus is a promising candidate for the biological control of dry bulb mites on tulip bulbs under storage conditions in the Netherlands.

No plant functional diversity effects on foliar fungal pathogens in experimental tree communities

Foliar fungal pathogens affect forest ecosystem processes by exerting highly species-specific impacts on growth and survival of trees. As many ecosystem processes in forests depend on functional diversity of specific tree species, a close relationship is expected between this and foliar fungal pathogen infestation. Testing for such a relationship in the German tree diversity experiment BIOTREE (Bechstedt), we hypothesized that pathogen richness and pathogen load decline with increasing functional diversity of tree communities. Using macro- and microscopic analyses, we assessed pathogen richness and load on 16 tree species in plots that, although differing in functional diversity, had the same tree species richness. We found no effects of functional diversity on pathogen richness or load. However, we encountered strong species identity effects in plot species composition, as susceptible tree species contributed positively to each community’s pathogen richness and load. Furthermore, testing for effects of particular leaf traits and geographical range size of host species revealed a significant effect of total leaf phenolics, which was unexpected as pathogen richness increased with increasing content in polyphenolics. Our study showed that at the community level, host species’ identity was more important for foliar fungal pathogen richness and load than the functional diversity of host trees. The positive relationship between pathogen richness and phenolics in leaves, along with the finding that pathogen richness is very much conserved in tree species, point to an evolutionary arms race between hosts and fungi resulting from fungi increasing their capacity to infect tree leaves and trees boosting their defences.

Fungal Infestation and Mycotoxin Contamination in Camel Feedstuffs

Currently, mycotoxins and toxigenic fungi feedstuffs are known causes of animal disease. The main aims of the current research were to investigate the mycoflora associated with feed samples consumed in Saudi Arabia and evaluate the occurrence of toxigenic species. Results of mycobiota showed that most samples were contaminated by moulds belonging to the genera, Alternaria, Aspergillus, Fusarium, Penicillium, Setosphaeria, and Nuersopra. In terms of the analyzed mycotoxins, F. verticillioides was the highest producer of fumonisin, zearalenone and DON (1050, 245, and 640 μg/kg, respectively. A. alternata was the highest producer of Altenuene Alternariol (52, and 29 μg/kg, respectively). Charm ROSA quantitative lateral flow assay method was used to quantify the total aflatoxin. The aflatoxin B1 was detected between 1-3.5 ppb in the collected camel feeds samples, while, feeds samples contained the midst concentration of total aflatoxins. In conclusion, camel feedstuffs can be seriously contaminated by mycotoxigenic fungal genera as well as mycotoxins that cause serious health problems for camel and animals.