Main Fungi Research Articles

Effects of H.uvarum combined with KGM on postharvest diseases of blueberry

The aim of this work was to evaluate the efficacy of an innovative edible coating that combines Hanseniaspora uvarum and konjac glucomannan to preserve blueberries. The antagonistic yeast and four main fungi (Aspergillus niger, Penicillium, Alternaria alterniformis, Pseudomonas spp.) isolated from blueberry pathogens were subjected to in vitro antibacterial experiments, and the optimal concentration of antagonistic yeast was determined as 1 × 108 CFU/mL. The antibacterial mechanism of yeast against pathogenic fungi was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, viscometry, measurement of electrospray droplet size and coating thickness. Finally, the resulting spray was used to treat blueberry wound rot and to store blueberries. After 14 days of storage, the konjac glucomannan/Hanseniaspora uvarum composite coating solution was found to be more effective in maintaining blueberry quality compared with the control and konjac glucomannan groups.

Fungal community structure analysis of peanut pod rot in soil in Hebei Province, China

In recent years, peanut yield and quality are more seriously affected by pod rot disease in China. However, managing this disease has proven challenging due to the wide host range of its pathogens. In this study, four soil samples were collected from fields with pod rot disease in Hebei Province, and 454 pyrosequencing was used to analyze the fungal communities structure within them. All 38 490 ITS high-quality sequences were grouped into 1203 operational taxonomic units, the fungal community diversity of four soil samples was evaluated and compared using Shannon index and Simpson index. The results showed that members of Ascomycota were dominant, followed by Basidiomycota. According to the BLAST results at the species level, Guehomyceshad the highest abundance, accounting for about 7.27%, followed by Alternaria, Fusarium, and Davidiella. The relative abundance of Fusarium oxysporum isolated from rotting peanuts in soil with peanut rot was higher than that in the control, indicating that Fusarium oxysporum might be one of the main pathogenic fungus of peanut rot in this area. This study delved into the broader fungal community associated with peanut pod rot, providing a theoretical foundation for preventing and treating this disease in agriculture.

Soil saprophytic fungi could be used as an important ecological indicator for land management in desert steppe

Soil microbes are among the most complex and diverse communities on Earth, actively participating in biogeochemical cycles while responding positively to environmental changes. Saprophytic fungi are important factors in soil carbon cycle, and the response and driving factors in grassland to forestland and grassland to farmland conversion in desert steppe are still poorly understood. Therefore, we analyzed the soil microbial community structure and saprophytic fungal communities in grasslands, shrub lands, and farmlands in typical desert grassland areas of northwest China. It was found that the cultivation of desert steppe plants/crops increased the proportion of silt in soil aggregates while decreasing soil salinity and increasing soil total carbon, nitrogen, and organic matter content. Proteobacteria, Actinobacteriota and Ascomycota were the dominant phyla in desert steppe soils, with Proteobacteria, Gemmatimonadota and Mucoromycota were more responsive to soil environment changes. The co-occurrence network relationship further characterized the process of niche sharing/competition between bacteria and fungi. The complexity of the co-occurrence network was deepened by land use, and fungi occupied more of the niche in shrub planting than in desert steppe and maize planting. Network relationships further characterized the process of niche sharing/competition between bacteria and fungi, and land use deepened the complexity of the co-occurrence network, with soil fungi occupying more ecological niches in shrub cultivation than in grassland and maize cultivation. In addition, saprophytic fungi are the main functional fungi in bacterial-fungal co-occurrence networks and are influenced by soil properties. Random forest analysis further explained the importance of saprophytic fungi in response to environmental changes in desert steppes. The enrichment of soil saprophytic fungi had an obvious correlation with soil aggregate stability, soil physical properties, and soil nutrients, especially in the background of shrub forestation in desert steppes. This study further highlights afforestation as one of the ways to benefit land management in desert steppes, while emphasizing the importance of saprophytic fungi as ecosystem indicators.

Interactions of the main pathogenic fungi of papaya (Carica papaya, L.) as a function of temperature

The temperature effect on the interaction between fungal isolates of papaya was studied. Rhizopus stolonifer, Colletotrichum cobbittiense, Fusarium pernambucarum, and Alternaria arborescens were grown in papaya agar in pairs, one against the other, at 13, 25, and 35 °C. The growth rate for each fungus was compared when grown alone or paired. Four types of interaction were observed: mutual intermingling, mutual antagonism on contact, dominance on contact, and dominance at a distance. At 13 and 35 °C, F. pernambucarum was more competitive whereas at 25 °C R. stolonifer does. In vivo validation showed R. stolonifer was the dominant fungus at 25 °C but coexists with C. cobbittiense forming a second infection. Then, a hierarchy may be established through a growth mechanism to infer which fungi may develop first and damage fruit to prevent postharvest losses. These findings could improve the management of papaya fruit in the postharvest stage.

Analysis of Fungal Diversity of Three Samples (dqjq_ck, dqjqcp and dqjp3) from Danquan Distillery

There are fungal communities in fermented grains and high-temperature Daqu of Danquan Baijiu, which had an important effect on Baijiu production. As a saccharifying and fermenting material, to a great extent, Daqu determines Baijiu flavour. However, in high-temperature Daqu “dqjq_ck” and “dqjqcp” (after fermentation for 45 d, 135 d) and fermented grains dqjp3 originated from Danquan distillery, fungal communities remain unclear. Therefore, this study analyzed fungal communities by high-throughput sequencing. Their fungal communities mainly included Ascomycota at phylum level. The most abundant fungal genera were Aspergillus, Issatchenkia and Zygosaccharomyces in dqjq_ck, dqjqcp, dqjp3, respectively. The dominant genera included Aspergillus (96.21%), Thermomyces (2.13%) in dqjq_ck. The dominant genera contained Issatchenkia (48.29%), Millerozyma (14.53%), Thermoascus (12.17%), Aspergillus (8.80%), Hyphopichia (3.28%), Rhizomucor (3.17%), Lichtheimia (2.62%), Thermomyces (2.27%), Monascus (1.37%) in dqjqcp. The dominant genera had Zygosaccharomyces (68.48%), Monascus (15.18%), Aspergillus (6.97%), Cladosporium (1.12%) in dqjp3. The main fungi included Aspergillus, Zygosaccharomyces, Issatchenkia, Monascus, Millerozyma, Thermoascus, Thermomyces, Hyphopichia, Rhizomucor, Lichtheimia and Cladosporium in three samples. The fungal succession of three samples were revealed in three key stages of Danquan Baijiu production. This paper will lay the basis for screening outstanding fungi to enhance Danquan Baijiu quality in near future.

Metabolic regulation mechanism of Trametes gibbosa CB1 on lignin

White rot fungi can degrade lignin and play a significant role in the recycling of carbon resources for environmental protection. Trametes gibbosa is the main white rot fungus in Northeast China. The main acids produced by T. gibbosa degradation, include long-chain fatty acids, lactic acid, succinic acid, and some small molecular compounds for example benzaldehyde. A variety of proteins respond to lignin stress and play an important role in xenobiotics metabolism, metal ion transport, and redox. Coordinated regulation and detoxification activation of H2O2 produced in oxidative stress by peroxidase coenzyme system and Fenton reaction. The Dioxygenase cleavage pathway and β-ketoadipic acid pathway are the main oxidation pathways of lignin degradation, which mediate the entry of “COA” into the TCA cycle. In the joint action of hydrolase and coenzyme, cellulose, hemicellulose, and other polysaccharides are degraded and finally converted to glucose to participate in energy metabolism. The expression of the laccase (Lcc_1) protein was verified by E. coli. Also, the Lcc_1 overexpression mutant was established. The morphology of mycelium was dense and the lignin degradation rate was improved. We completed the first non-directional mutation of in T. gibbosa. It also improved the mechanism of T. gibbosa in response to lignin stress.

Culturable Diversity of Lichen-Associated Yeasts through Enrichment Strategies

Lichens are symbiotic partnerships between a filamentous fungus and a photosymbiotic “alga”. Studies show that lichens harbor endothallic fungi, but that some taxa have been difficult to isolate from the main filamentous thallus-forming fungus and other faster growing lichenicolous/endothallic fungi. Therefore, we aimed to develop and evaluate liquid yeast-enrichment strategies to (1) isolate lichen-associated yeasts in pure culture, and (2) determine the taxonomic placement and breadth of the diversity of culturable yeasts. Eighty-two lichen samples were collected and washed with distilled water, and healthy thalli were ground up and added to seven different yeast-enrichment broths. Yeast colonies were isolated in pure culture and identified using molecular techniques. Initial isolates were identified using BLASTn analysis, and a taxonomic refinement was completed using PhyML analysis. In total, 215 isolates were obtained. The most prevalently isolated ascomycetous yeasts were within the Dothideomycetes (Aureobasidium, Plowrightia, and Dothiora), while the most frequently isolated basidiomycetous yeasts belonged to the genera Curvibasidium, Sporobolomyces, and Tremella. The generic placements could not be determined for 17 isolates, and in total 25 novel species were recovered. The results of this research indicate that (1) lichen-associated yeasts are diverse, (2) employing liquid enrichment strategies is effective for isolating many of these, and (3) lichen thalli represent a valuable untapped reservoir of diverse and novel yeast species.

Biology, Ecology and Ipm of Fall Army Worm <I>Spodoptera Frugiperda </I> (J E Smith): A Review

The fall armyworm, Spodoptera frugiperda (J E Smith) is an emerging polyphagous pest. Its primary food is the corn cob, which suffers significant damage with its larvae skeletonizing or “windowing” the leaves. Only the larval stage is seriously risky and small and large communities as well as researchers have used a variety of control methods A number of low-cost mitigation strategies are available and these strategies include encouraging smallholder farmers to plant crops directly after major rainstorms, using cultural methods, such as intercropping and crop rotation, and avoiding some of the ineffective insecticides. Understanding the function of natural enemies in agricultural systems requires monitoring them in the field. Chelonus insularis, Pristomerus spinator, Cotesia marginiventris, Meteorus laphygmae, Chelonus sonorensis, Orius insidiosus, Chelonus texanus, Archytas marmoratus, Elenomus remus, and Trichogramma spp. are parasitoids of S. frugiperda Metarhizium anisopliae, Erynia radicans, Fusarium solani, Nomuraea rileyi and Beauveria bassiana are the main entomopathogenic fungi. These biocontrol agents should be promoted to manage this pest in a sustainable manner.

Current research on fungi in chronic wounds.

The occurrence of chronic wounds is a major global health issue. These wounds are difficult to heal as a result of disordered healing mechanisms. The most common types of chronic wounds are diabetic ulcers, pressure ulcers, arterial/venous ulcers and nonhealing surgical wounds. Although bacteria are an important cause of chronic nonhealing wounds, fungi also play a substantial role in them. The fungal infection rate varies with different chronic wound types, but overall, the prevalence of fungi is extremely underestimated in the clinical treatment and management of chronic wounds. Wounds and ulcers can be colonized by host cutaneous, commensal or environmental fungi and evolve into local infections, causing fungemia as well as invasive fungal disease. Furthermore, the fungi involved in nonhealing wound-related infections help commensal bacteria resist antibiotics and the host immune response, forcing wounds to become reservoirs for multiresistant species, which are considered a potential key factor in the microbial bioburden of wounds and ulcers. Fungi can be recalcitrant to the healing process. Biofilm establishment is the predominant mechanism of fungal resistance or tolerance to antimicrobials in chronic nonhealing wounds. Candida albicans yeast and Trichophyton rubrum filamentous fungi are the main fungi involved in chronic wound infection. Fungal species diversity and drug resistance phenotypes in different chronic nonhealing wound types will be emphasized. In this review, we outline the latest research on fungi in chronic wounds and discuss challenges and future perspectives related to diagnosing and managing chronic wounds.

Essential Oils Antimicrobial Activity in Limiting the Development of Main Spoilage Fungi Associated with Stored Cereals

Fungal pathogens can significantly reduce the potential yield and seed quality of cereal crops, the major risk is contamination with toxic fungal secondary metabolites known as mycotoxins, which have negative consequences in human and animal health. The influence of different concentrations of the oregano, basil and thyme essential oils on the development of the mycelium of Fusarium, Aspergillus, Penicilium species was analyzed and action of inhibiting the capacity of molds’ occurrence and development at stored wheat and maize. The chemical composition of the all essential oils was determined by gas chromatography/mass spectrometry analysis. Oregano and basil essential oils inhibit completely development of Fusarium spp., Penicillium sp. and Aspergillus sp. pathogens at 2000-5000 ppm concentration exerted a fungitoxic effect. However, thyme oil in 10-100 µl/ml concentration was the strongest in fungicidal activity of the tested Fusarium, Penicilium, Aspergillus, species. In conclusion, all essential oils used in this study could be suitable for applications in the food industry to control molds and improve the safety of stored grain.

Morphological Identification of the Main Fungi Associated with Sesame in Burkina Faso

Morphological Identification of the Main Fungi Associated with Sesame in Burkina Faso

Micromycetes associated with wheat and their significance as pathogens in Russia

Fungal diseases of wheat are widely studied due to economic importance at global scale. Nevertheless, incorrect
 names of diseases and respective pathogen species, as well as inaccurate indication of their practical significance, is
 found in in the scientific literature. This may lead to confusion and misinterpretation of the phytosanitary situation. This
 review collects and structures the information about the main wheat diseases and pathogenic fungi causing them, as well
 as species emerging as a potential threat to wheat crops. The modern taxonomic status of the fungal species associated
 with different organs of wheat is given, their geographical distribution and the impact on the crop yield are characterized.
 Micromycetes are divided into three groups according to their phytosanitary significance. The first group is represented
 by fungi possessing great importance as pathogens causing the 25 main wheat diseases. The second group includes three
 diseases not found in Russia but significant for wheat production in other countries, thus posing potential risk for Russian
 grain farming. The third group consists of fungi causing 29 minor and poorly studied diseases with unverified harmfulness
 and controversial significance, for which the available data needs to be reviewed and confirmed. This dataset can be used
 as a reference for a more accurate and correct description of the phytosanitary situation. The review will also be helpful for
 more targeted studies using molecular methods to determine the area of fungi that cause wheat diseases, to track changes
 in their distribution boundaries and to clarify the harmfulness of poorly studied species.

Bacillomycin D with calcium propionate effectively inhibited microbial growth and reduced deoxynivalenol on maize kernels during storage

Maize kernels contaminated with deoxynivalenol (DON) reduced their nutritional and economic values and were exposed to greater risks under high moisture conditions. In this study, an antifungal combination of bacillomycin D (BD) with calcium propionate (CP) was used in maize polluted by microorganisms and DON. During the storage of maize kernels, BD combined with calcium propionate (BD+CP) treatment inhibited the growth of fungi and bacteria. High dose (250 μg/g BD and 1800 μg/g CP) treatments reduced fungal growth to less than 4 lg CFU/g, while BD+CP groups with 14% and 16% moisture content both maintained bacterial counts below 4 lg CFU/g at the end of storage. High-throughput sequencing results showed that the main contaminating fungi in the samples were Fusarium spp. with a percentage of 32.52%, and the average value of initial DON content in the samples was 210.49 ng/g. The high-dose treatment groups of BD+CP almost completely inhibited the production of DON with 217.99 ± 8.07–247.33 ± 53.34 ng/g (P < 0.05). Furthermore, the production of free fatty acid values (FAV), and the decomposition of protein components were also controlled. BD+CP treatment could effectively inhibit the growth of microorganisms in maize kernels during storage, slow the production of DON, and prolong the shelf life of maize kernels. These results showed that BD+CP could be applied to the storage of naturally contaminated grain, and it is a broad-spectrum fungicide combination with practical application value.

Exogenous Dopamine and MdTyDC Overexpression Enhance Apple Resistance to Fusarium solani.

Fusarium solani, one of the main pathogenic fungi involved in apple replant disease (ARD), is a serious threat to apple growth and development. Dopamine and tyrosine decarboxylase (TyDC), a key enzyme in the dopamine synthesis pathway, have been reported to play an active role in plant responses to biotic and abiotic stresses, but little is known about the functions of dopamine and Malus domestica TyDC (MdTyDC) in the interaction between F. solani and apple roots. In this study, seedlings treated with exogenous dopamine and apple plants overexpressing MdTyDC were inoculated with F. solani; both treatments reduced the root system damage caused by F. solani. After inoculation with F. solani, exogenous dopamine increased dopamine content in the seedlings; alleviated the inhibition of biomass accumulation; increased root metabolic activity, photosynthetic efficiency, and antioxidant enzyme activities; reduced reactive oxygen species accumulation; and upregulated the expression of genes encoding chitinase, β-1,3-glucanase, and pathogenesis-related proteins. Similar results were observed in MdTyDC-overexpressing apple plants. In addition, the overexpression of MdTyDC increased tyramine content and the deposition of cell wall-bound amines in roots. Overall, our results reveal that exogenous dopamine and overexpression of MdTyDC enhance apple resistance to F. solani, which is an important application for the prevention of ARD.

The Most Important Parasitic and Saprophytic Fungi on Flowering Ash (Fraxinus ornus) in Parks of Serbia and Montenegro

In order to fulfil the gap in domestic literature about biotic causes of flowering ash (Fraxinus ornus) decline in urban conditions, this paper presents the results of a five-year investigation of the most important parasitic and saprophytic fungi on this tree species in parks of Serbia and Montenegro. In total, 21 fungal taxa were recorded. Within recorded taxa, 2 taxa were found on leaves, 1 taxon was found on root, thin branches and bark, while 16 taxa were found on the trunk. On leaves Ascochyta spp. was recorded. The most significant fungi were Armillaria mellea, Phellinus igniarius aff. and Inonotus hispidus. Species Meripilus giganteus and Schizophyllum commune were the main successive fungi and were often found on substrate damaged by the most significant fungi or abiotic disorders. Species Hymenoscyphus fraxineus was recorded on single trees, as well as taxon Neonectria spp. The majority of recorded taxa, including invasive pathogen Hymenoscyphus fraxineus were for the first time found on flowering ash (Fraxinus ornus) in Serbia and Montenegro, especially in urban conditions of these countries. Better protection strategies of flowering ash (Fraxinus ornus) in this part of the region could be achieved based on these results.

Extracellular vesicles of Candida albicans regulate its own growth through the L-arginine/nitric oxide pathway.

Candida albicans is the main conditional pathogenic fungus among the human microbiome. Extracellular vesicles (EVs) secreted by C. albicans are important for its pathogenesis. However, the effects and mechanisms of EVs on C. albicans own growth are not clear. Here, we isolated EVs from C. albicans cells grown in four culture media, including RPMI 1640, DMEM, YPD, and YNB, and measured their effects on the own growth of C. albicans in these media. All the C. albicans EVs from the four media could promote the growth of C. albicans in RPMI 1640 and DMEM media, but had no effects in YPD and YNB media, indicating that the effects of EVs on C. albicans growth were dependent on some media contents. By comparing the media contents and transcriptome analysis, arginine was identified as the key factor for the growth promotion of C. albicans EVs. EVs activated the L-arginine/nitric oxide pathway to promote the growth of C. albicans through that EVs increased the NO levels and upregulated the expression of NO dioxygenase gene YHB1 to reduce the intracellular reactive oxygen species (ROS) and cell apoptosis. During the host cell infections, C. albicans EVs synergistically enhanced the destructive effects of C. albicans to host cells, including RAW264.7, HOK, TR146, and HGEC, suggesting that the growth promotion by EVs enhanced the pathogenesis of C. albicans. Our results demonstrated the important roles of EVs on C. albicans own growth for the first time and highlight its synergism with C. albicans to increase the pathogenesis. KEY POINTS: • C. albicans extracellular vesicles (EVs) promoted its own growth. • EVs activated the l-arginine/NO pathway to reduce ROS and apoptosis of C. albicans. • EVs enhanced the damage to the host cell caused by C. albicans.

Candida albicans the main opportunistic pathogenic fungus in humans

Candida albicans is a commensal of the mammalian microbiome and the primary pathogenic fungus of humans. It becomes a severe health problem in immunocompromised patients and can cause a wide variety of mucosal and systemic infections. The interaction between C. albicans and host cells is characterized by the expression of virulence factors such as adhesins and invasins, the secretion of hydrolytic enzymes, a transition from yeast to filamentous hyphae form, and the ability to form biofilms; these features collectively result in cell adhesion, invasion, and damage. This review describes complex commensal interactions of C. albicans with host cells and the cellular events that it triggers in a pathogenic environment. We also review the host immune response induced by C. albicans antigens and the mechanisms developed by this fungus to avoid the action of antifungal agents.

Reduction of Mycotoxigenic Fungi Growth and Their Mycotoxin Production by Bacillus subtilis QST 713.

The use of chemical pesticides to control the occurrence of mycotoxigenic fungi in crops has led to environmental and human health issues, driving the agriculture sector to a more sustainable system. Biocontrol agents such as Bacillus strains and their antimicrobial metabolites have been proposed as alternatives to chemical pesticides. In the present work, a broth obtained from a commercial product containing Bacillus subtilis QST 713 was tested for its ability to inhibit the growth of mycotoxigenic fungi as well as reduce their mycotoxin production. Mass spectrometry analysis of Bacillus subtilis broth allowed to detect the presence of 14 different lipopeptides, belonging to the iturin, fengycin, and surfactin families, already known for their antifungal properties. Bacillus subtilis broth demonstrated to be a useful tool to inhibit the growth of some of the most important mycotoxigenic fungi such as Aspergillus flavus, Fusarium verticillioides, Fusarium graminearum, Aspergillus carbonarius, and Alternaria alternata. In addition, cell-free Bacillus subtilis broth provided the most promising results against the growth of Fusarium graminearum and Alternaria alternata, where the radial growth was reduced up to 86% with respect to the untreated test. With regard to the mycotoxin reduction, raw Bacillus subtilis broth completely inhibited the production of aflatoxin B1, deoxynivalenol, zearalenone, and tenuazonic acid. Cell-free broth provided promising inhibitory properties toward all of the target mycotoxins, even if the results were less promising than the corresponding raw broth. In conclusion, this work showed that a commercial Bacillus subtilis, characterized by the presence of different lipopeptides, was able to reduce the growth of the main mycotoxigenic fungi and inhibit the production of related mycotoxins.

Phylogenetic Analysis and Toxigenic Profile of Alternaria Species Isolated from Chickpeas (Cicer arietinum) in Argentina

Chickpeas are a very important legume due to their nutritional richness and high protein content and they are used as food for humans and as fodder for livestock. However, they are susceptible to fungal infections and mycotoxin contamination. The Alternaria genus was among the main fungi isolated from chickpea samples in Argentina. The species within this genus are able to produce several mycotoxins such as alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TA). So, the objectives of this study were to identify the Alternaria spp. found in the chickpea samples and to determine their toxigenic potential in vitro. A phylogenetic analysis of 32 Alternaria strains was carried out based on the combined sequences of the tef1, gpd, and Alt a1 genes. All Alternaria strains clustered into the section Alternaria and were identified as A. alternata and A. arborescens. Further, the toxigenic profile of each strain was determined in a ground rice–corn steep liquor medium and analysed by HPLC. Most strains were able to co-produce AOH, AME, and TA. These results indicate a potential risk for human health when consuming chickpeas since this legume could be contaminated with Alternaria and its mycotoxins, which are not yet regulated in food.

Winter Cereal Reactions to Common Root Rot and Crown Rot Pathogens in the Field

In Australia, Fusarium pseudograminearum and F. culmorum are the two main fungi causing crown rot, while Bipolaris sorokiniana is the causal agent of common root rot. Fusarium graminearum is typically linked with Fusarium head blight; however, it has been associated with crown rot in Australia and other parts of the world. This study investigated the reactions of single cultivars of barley, bread wheat, durum wheat, oat, and triticale to inoculation with strains of F. pseudograminearum, F. culmorum, F. graminearum and B. sorokiniana in field trials across two seasons. Fusarium pseudograminearum and F. culmorum caused greater visual discolouration than F. graminearum and B. sorokiniana on both stems and sub crown internodes of all hosts. Fusarum pseudograminearum caused the greatest reduction in plant dry weight across hosts in both years. Durum wheat (cv. Hyperno) barley (cv. Grimmett), bread wheat (cv. Livingston) and triticale (cv. Endeavour) observed significantly high levels of visual discolouration on stems when inoculated with F. pseudograminearum, while oat (cv. Genie) exhibited the least visual discolouration. Despite variation in the visual discolouration, the DNA of all pathogens were detected in all cultivars. This research further highlights the complicated nature of the pathogen × strain × cultivar × environment interaction, which remains a challenge in breeding for genetic resistance. The specific infection of each fungus and the host responses in these field trials improves our understanding of disease development and its importance in cropping systems.