Fusarium Species Research Articles

Silicon nonspecifically affects aggressiveness in Fusarium head blight pathogens

Silicon (Si) has been largely regarded to have no selection pressure on plant pathogens because it regulates plant defense system to reduce pathogen infection and development and does not directly affect pathogen itself; however, its effect seems to be specific in some pathogen-host plant interactions. In Fusarium head blight (FHB), associated with devastating agronomic effects on total yield and grain quality, which infects higher Si-absorbers and –accumulators wheat and barley plants; its effect on aggressiveness is unknown. To clarify the nature of reduction of FHB symptoms upon Si treatment at the earliest and latest development stages, we analyzed Si effect on nine aggressiveness components obtained under several experimental conditions. We used 16 fungal isolates of varying aggressiveness and eight bread wheat, durum wheat and barley cultivars with contrast susceptibility to disease. The positive effect of Si on enhancing host resistance against Fusarium infection in the young and adult host parts showed that the nine components evaluated in this study were negatively impacted by Si. Definitely, Si at 1.7 mM reduced equally FHB symptoms from the highest and least pathogenic isolates of the four tested Fusarium species regardless of botanical background for the used plant materials. This indicates for the first time that Si nonspecifically affects aggressiveness in FHB pathogens. Our results reveal that Si could be a valuable tool in integrated pathogen management by suppressing pathogen development on wheat and barley when affected by Fusarium. Most importantly, no hazard exists to emergence of Si-resistant pathogen populations upon Si applications on diverse FHB populations.

Влияние химических фунгицидов на содержание почвенных микромицетов в агроценозе рапса ярового в центральной зоне Краснодарского края

Different soil fungi infect many agricultural crops. They cause infectious diseases of plants and can be a serious threat for crop yield that leads to significant losses in the agricultural economics all over the world. Currently, a chemical method of Brassicaceae oil crops protection is the most spread. An important technique of this method is presowing seed treatment decreasing a level of internal and external infections. Fungicides must be both effective against diseases and environmentally friendly. Currently, there is no unequivocal opinion how the chemical fungicides influence on soil microflora. The purpose of the research was to study impact of some seed protectants on an amount of suppressor fungi from species Trichoderma Pers. and pathogenic fungi from species Fusarium Link. in soil in spring rapeseed agrocenosis. The research was conducted at the V.S. Pustovoit All-Russian Research Institute of Oil Crops in 2020–2022. Before sowing, the seeds were treated with protectants with active ingredients: thiram, WSC (400 g/l) (etalon), carboxin + thiram, WSC (200 + 200 g/l), imazalil + tebuconazole, OE (100 + 60 g/l), and fludioxonil, SC (25 g/l). Soil was sampled before planting of treated rapeseed seeds and in crop phases of 2–4 true leaves and yellow pods. The soil layer from 0 to 10 cm was studied as it contains the most amount of lateral roots of this crop. To the rapeseed maturation, amounts of suppressor fungi in variants with application of preparations was at the level of the control; it increased by 1.8–2.4 × 103 CFU/g and reached 7.3–8.0 × 103 CFU/g, maximal meaning was in variant with an active ingredient fludioxonil (25 g/l). The amount of pathogenic micromycetes Fusarium spp. was by 1.7–2.0 times lower the control to the rapeseed maturation in variants with application of preparations.

Phytotoxic Strains of Fusarium commune Isolated from Truffles.

Most Fusarium species are known as endophytes and/or phytopathogens of higher plants and have a worldwide distribution. Recently, information discovered with molecular tools has been also published about the presence of these fungi in the microbiome of truffle fruiting bodies. In the present work, we isolated and identified three Fusarium strains from truffle fruiting bodies. All isolates were assigned to the same species, F. commune, and the strains were deposited in the All-Russian Collection of Microorganisms under accession numbers VKM F-5020, VKM F-5021, and VKM F-5022. To check the possible effects of the isolated strains on the plants, the isolates were used to infect sterile seedlings of Sarepta mustard (Brassica juncea L.). This model infection led to a moderate suppression of the photosynthetic apparatus activity and plant growth. Here, we present characteristics of the F. commune isolates: description of the conidial morphology, pigmentation, and composition of the mycelium fatty acids. Overall, this is the first description of the Fusarium cultures isolated from truffle fruiting bodies. Possible symbiosis of the F. commune strains with truffles and their involvement in the cooperative fatty acid production are proposed.

The Differentiation of the Infestation of Wheat Grain with Fusarium poae from Three Other Fusarium Species by GC–MS and Electronic Nose Measurements

The massive import of uncontrolled technical grain from the East into the European Community poses a risk to public health when it ends up in the mills to be used as flour for food purposes instead of being burnt (biofuel). In fungal infections of wheat, the most dangerous species belong to the genus Fusarium. F. poae is a pathogen that is most commonly isolated from cereals worldwide and causes various types of diseases in animals and humans due to the numerous toxins it produces. The manuscript reports an attempt to distinguish between four species of Fusarium, F. avanceum, F. langsethiae, F. poae, and F. sporotrichioides, in wheat grains by measuring the volatiles emitted. The patterns obtained from the signals captured by the electronic nose PEN3 were used to build the Random Forests classification model. The recall and precision of the classification performance for F. poae reached 91 and 87%, respectively. The overall classification accuracy reached 70%. Gas chromatography coupled with mass spectrometry (GC–MS) was used to analyze the chemical composition of the emitted volatiles. The patterns found in the GC–MS results allowed an explanation of the main patterns observed when analyzing the electronic nose data. The mycotoxins produced by the Fusarium species analyzed were detected. The results of the reported experiment confirm the potential of the electronic nose as a technology that can be useful for screening the condition of the grain and distinguishing between different pathogenic infestations.

Marine actinomycetes for biocontrol of Fusarium solani in tomato plants: In vitro and in vivo studies

Using microorganisms as biocontrol agents of phytopathogens has been an alternative to synthetic fungicides. Actinomycetes isolated from soil and plants have reduced diseases caused by phytopathogens; however, microorganisms from marine environments may be an option as biocontrol agents. The tomato crop possesses an important economic impact worldwide, being Mexico the main exporter. Several species of Fusarium cause damage to tomato crops and are controlled with synthetic fungicides. The objective of this work was to determine the effect of marine actinomycetes as biocontrol on Fusarium solani in tomato plants. Four strains of marine actinomycetes (A20, A19, A18, and A15) and one terrestrial actinomycete (ED48) were used. The actinomycetes strains used, produced siderophores. The greatest inhibition of mycelial growth of F. solani due to iron competition was obtained by strain A19 with 74.28%. Only two actinomycetes showed antifungal activity by VOCs (A19 and A18), strain A19 showed the highest antagonistic activity with PICR of 76.75%. Actinomycetes treatments showed significant differences with synthetic fungicide application in growth, disease severity (SE), and disease incidence (DI) variables. The application of marine actinomycete (A19) on plants infested with F. solani increased the levels of enzyme activity (SOD, POD, CAT, and PAL) versus plants in that only F. solani and distilled water (control) were applied. Actinomycetes of marine origin are an option as biocontrol agents for F. solani.

Molecular Identification and Pathogenicity of Fusarium Species Associated with Wood Canker, Root and Basal Rot in Turkish Grapevine Nurseries.

Fusarium species are agriculturally important fungi with a broad host range and can be found as endophytic, pathogenic, or opportunistic parasites in many crop plants. This study aimed to identify Fusarium species in bare-rooted, dormant plants in Turkish grapevine nurseries using molecular identification methods and assess their pathogenicity. Asymptomatic dormant plants were sampled from grapevine nurseries (43) in different regions of the country, and fungi were isolated from plant roots and internal basal tissues. The Fusarium strains were identified by performing gene sequencing (TEF1-α, RPB2) and phylogenetic analyses. Pathogenicity tests were carried out by inoculating mycelial agar pieces of strains onto the stem or conidial suspensions into the rhizosphere of vines (1103 Paulsen rootstock). Laboratory tests revealed that Fusarium species were highly prevalent in Turkish grapevine nurseries (41 out of 43). Gene sequencing and phylogenetic analyses unraveled that 12 Fusarium species (F. annulatum, F. brachygibbosum, F. clavum, F. curvatum, F. falciforme, F. fredkrugeri, F. glycines, F. nanum, F. nematophilum, F. nirenbergiae, F. solani, and Fusarium spp.) existed in the ready-to-sale plants. Some of these species (F. annulatum, F. curvatum and F. nirenbergiae) consistently caused wood necrosis of seedling stems, rotting of the basal zone and roots, and reduced root biomass. Although the other nine species also caused some root rot and root reduction, their virulence was not as severe as the pathogenic ones, and they were considered opportunistic parasites or endophytic species. This study suggests that Fusarium species might play an important role in root-basal rot, wood canker symptoms, and young vine decline in Turkish grapevine nurseries and that these species need to be considered for healthy seedling production.

Identification of Fusarium spp. Associated with Chickpea Root Rot in Montana

Root rot caused by Fusarium spp. is a significant issue in the chickpea-growing regions of Montana. The specific Fusarium species responsible for the disease and their prevalence remain uncertain. A survey was conducted in 2020 and 2021 to identify Montana’s Fusarium species associated with chickpea. Four hundred and twenty-six Fusarium isolates were recovered from symptomatic chickpea roots across ten counties in the state. Isolates were identified by comparing translation elongation factor 1-α (TEF1-α) sequences in the FUSARIUM-ID database. Among the recovered isolates, Fusarium oxysporum was the most prevalent species (33%), followed by F. acuminatum (21%), F. avenaceum (15%), F. redolens (14%), F. culmorum (6%), F. sporotrichioides (6%), Neocosmospora solani (6%), F. equiseti (2%), F. torulosum (0.9%), F. gamsii (0.8%), F. proliferatum (0.2%), F. pseudograminearum (0.2%), and F. brachygibbosum (0.1%). The aggressiveness of a subset of 51 isolates representing various Fusarium spp. was tested on chickpea cv. ‘CDC Frontier’. A non-parametric variance analysis conducted on disease severity ranks indicated that F. avenaceum isolates were highly aggressive. This study reports for the first time that F. gamsii, F. proliferatum and F. brachygibbosum are causal agents of root rot in chickpea in the United States. This knowledge is invaluable for making informed decisions regarding crop rotation, disease management, and developing resistant chickpea varieties against economically significant Fusarium pathogens.

Comparative microbiome diversity in root-nodules of three Desmodium species used in push-pull cropping system.

Desmodium species used as intercrops in push-pull cropping systems are known to repel insect-pests, suppress Striga species weeds, and shift soil microbiome. However, the mechanisms through which Desmodium species impact the soil microbiome, either through its root exudates, changes in soil nutrition, or shading microbes from its nodules into the rhizosphere, are less understood. Here, we investigated the diversity of root-nodule microbial communities of three Desmodium species- Desmodium uncinatum (SLD), Desmodium intortum (GLD), and Desmodium incanum (AID) which are currently used in smallholder maize push-pull technology (PPT). Desmodium species root-nodule samples were collected from selected smallholder farms in western Kenya, and genomic DNA was extracted from the root-nodules. The amplicons underwent paired-end Illumina sequencing to assess bacterial and fungal populations. We found no significant differences in composition and relative abundance of bacterial and fungal species within the root-nodules of the three Desmodium species. While a more pronounced shift was observed for fungal community compositions compared to bacteria, no significant differences were observed in the general diversity (evenness and richness) of fungal and bacterial populations among the three Desmodium species. Similarly, beta diversity was not significantly different among the three Desmodium species. The root-nodule microbiome of the three Desmodium species was dominated by Bradyrhizobium and Fusarium species. Nevertheless, there were significant differences in the proportion of marker gene sequences responsible for energy and amino acid biosynthesis among the three Desmodium species, with higher sequence proportions observed in SLD. There is no significant difference in the microbial community of the three Desmodium species used in PPT. However, root-nodule microbiome of SLD had significantly higher marker gene sequences responsible for energy and amino acid biosynthesis. Therefore, it is likely that the root-nodules of the three Desmodium species host similar microbiomes and influence soil health, consequently impacting plant growth and agroecosystem functioning.

Lipopeptides from Bacillus tequilensis EA-CB0015 and cinnamon extract decrease the bioenergetic response of Fusarium oxysporum f. sp. cubense

Lipopeptides (LPs) from B. tequilensis EA-CB0015 have antifungal activity against Fusarium species. Specifically, against F. oxysporum f. sp. cubense (Foc), the cause of Fusarium wilt of banana. Cinnamon (CN) extract is also known for its inhibitory activity against the Fusarium genus. The main goal of this research was to determine whether the effect of LPs and CN extract or their combination against a Foc isolate is related to an impairment of mitochondrial function. Our results show that biomass decreased by 74% (p < 0.0001) and 84% (p < 0.0001) when cultures were treated with 128 ppm LPs and 152.5 ppm CN extract, respectively. In parallel, we found a pronounced impairment of the bioenergetic response. That is, the routine oxygen consumption rate diminished by 55% (p = 0.0148) and 38% (p < 0.0001), respectively. Moreover, the ATP-linked respiratory rate decreased by 63% (p = 0.0461) and 44% (p = 0.0005), while the FCCP-simulated respiratory rate by 63% (p = 0.0255) and 45% (p = 0.0002). Therefore, our data suggest that the altered bioenergetic response observed in cultures of Foc treated with LPs or CN is mainly caused by an impairment of the activity of the respiratory complexes. On the other hand, biomass production was reduced by 80% (p < 0.0001) when cultures were treated with a mixture comprising only 10% LPs and 40% CN extract. Furthermore, ATP-linked and FCCP-stimulated respiratory rates decreased by 62% (p = 0.0024) and 68% (p < 0.0001), respectively under the same conditions. A potentially synergistic antifungal effect of cyclic LPs with a CN extract is suggested.Graphical

A two-dimensional correlation spectroscopy analysis-based approach for asymptomatic rot detection in stored potatoes using hyperspectral imaging

Fusarium dry rot (FDR), which is caused by several Fusarium species, is a major disease affecting potatoes during storage. The study aimed to identify the gleyic stage and monitor rot progression in stored potatoes using a hyperspectral imaging (HSI) system. We evaluated the susceptibility parameters and quality attributes during the infection process and monitored starch, soluble protein, malondialdehyde, and aerobic bacterial contents in all samples. To further characterize the infection process, we collected spectral data on different storage days and then mapped these data using two-dimensional correlation spectroscopy. The results revealed 20 peaks related to these component contents. Then, the quantitative analysis models of these indicators were established based on the 2D correlation synchronization spectrum. The optimal correlation coefficients of the validation set were 0.9273, 0.9634, 0.9470, and 0.9487 for these indicators. Visual analysis was implemented to these indicators, and the content distribution can be effectively observed on hyperspectral images.

Effect of Fungicides on &lt;i&gt;Fusarium&lt;/i&gt; Fungi Caused Potato Dry Rot

A laboratory assessment of the effect of 4 fungicides containing active substance (a. s.) of different chemical classes on the growth of strains of 2 dominant species of Fusarium fungi, pathogens of fusarium dry rot of potatoes, was carried out. The drug containing benomyl most effectively suppressed the growth of F. sambucinum and F. solani strains by an average of 76 ± 4% compared with the control. The drug containing azoxystrobin turned out to be the least effective ‒ inhibition of strain growth averaged 35 ± 5%. The significant influence of the factors “species affiliation” and “region of origin” of the strain and their interaction on the sensitivity of strains of both Fusarium species to each of the 4 fungicides has been shown. The risk of developing resistance in F. sambucinum to a. s. of different classes was noted.

Reshaping the root endophytic microbiota in plants to combat mercury-induced stress

Emerging evidence suggests that plants experiencing abiotic stress actively seek help from soil microbes. However, the empirical evidence supporting this strategy is limited, especially in response to heavy metal stress. We used integrated microbial community profiling and culture-based methods to investigate the interaction between mercury (Hg) stress, the entophytic root microbiome, and maize seedlings. The results of the pot experiment showed that soil Hg (20 mg/kg) strongly inhibited maize growth, indicating its strong phytotoxicity. Furthermore, Hg stress significantly altered the structure of the bacterial and fungal communities and enriched the potentially pathogenic Fusarium sp., suggesting that soil Hg stress may enhance the bio-stress induced by Fusarium species in maize. Additionally, soil Hg also led to the enrichment of beneficial bacterial members of Streptomyces, Lysobacter, and Sphingomonas (defined as differential species), which were also identified as keystone species in the Hg treatment by the analysis of co-occurrence networks. Therefore, it can be postulated that the members of Streptomyces, Lysobacter, and Sphingomonas function as stress-alleviating microbes. We successfully isolated the representatives of these stress-alleviating microbes. As expected, these strains mitigated the detrimental effects of Hg stess for the maize seedlings, suggesting that plants recruit the stress-alleviated microbiota to combat Hg stress. This study provides insights into the potential of manipulating the root microbiome to enhance plant growth in polluted environments.

An updated list of eumycetoma causative agents and their differences in grain formation and treatment response.

SUMMARYIn 2023, the World Health Organization designated eumycetoma causative agents as high-priority pathogens on its list of fungal priority pathogens. Despite this recognition, a comprehensive understanding of these causative agents is lacking, and potential variations in clinical manifestations or therapeutic responses remain unclear. In this review, 12,379 eumycetoma cases were reviewed. In total, 69 different fungal species were identified as causative agents. However, some were only identified once, and there was no supporting evidence that they were indeed present in the grain. Madurella mycetomatis was by far the most commonly reported fungal causative agent. In most studies, identification of the fungus at the species level was based on culture or histology, which was prone to misidentifications. The newly used molecular identification tools identified new causative agents. Clinically, no differences were reported in the appearance of the lesion, but variations in mycetoma grain formation and antifungal susceptibility were observed. Although attempts were made to explore the differences in clinical outcomes based on antifungal susceptibility, the lack of large clinical trials and the inclusion of surgery as standard treatment posed challenges in drawing definitive conclusions. Limited case series suggested that eumycetoma cases caused by Fusarium species were less responsive to treatment than those caused by Madurella mycetomatis. However, further research is imperative for a comprehensive understanding.

Hyphal editing of the conserved premature stop codon in CHE1 is stimulated by oxidative stress in Fusarium graminearum

Although genome-wide A-to-I editing mediated by adenosine-deaminase-acting-on-tRNA (ADAT) occurs during sexual reproduction in the presence of stage-specific cofactors, RNA editing is not known to occur during vegetative growth in filamentous fungi. Here we identified 33 A-to-I RNA editing events in vegetative hyphae of Fusarium graminearum and functionally characterized one conserved hyphal-editing site. Similar to ADAT-mediated editing during sexual reproduction, majority of hyphal-editing sites are in coding sequences and nonsynonymous, and have strong preference for U at -1 position and hairpin loops. Editing at TA437G, one of the hyphal-specific editing sites, is a premature stop codon correction (PSC) event that enables CHE1 gene to encode a full-length zinc fingertranscription factor. Manual annotations showed that this PSC site is conserved in CHE1 orthologs from closely-related Fusarium species. Whereas the che1 deletion and CHE1TAA (G438 to A) mutants had no detectable phenotype, the CHE1TGG (A437 to G) mutant was defective in hyphal growth, conidiation, sexual reproduction, and plant infection. However, the CHE1TGG mutant was increased in tolerance against oxidative stress and editing of TA437G in CHE1 was stimulated by H2O2 treatment in F. graminearum. These results indicate that fixation of the premature stop codon in CHE1 has a fitness cost on normal hyphal growth and reproduction but provides a benefit to tolerance against oxidative stress. Taken together, A-to-I editing events, although rare (not genome-wide), occur during vegetative growth and editing in CHE1 plays a role in response to oxidative stress in F. graminearum and likely in other fungal pathogens.

Biocontrol of Fusarium head blight in rice using Bacillus velezensis JCK-7158.

Fusarium head blight (FHB) is a destructive disease caused by several species of Fusarium, such as Fusarium graminearum and F. asiaticum. FHB affects cereal crops, including wheat, barley, and rice, worldwide. Fusarium-infected kernels not only cause reduced yields but also cause quality loss by producing mycotoxins, such as trichothecenes and zearalenone, which are toxic to animals and humans. For decades, chemical fungicides have been used to control FHB because of their convenience and high control efficacy. However, the prolonged use of chemical fungicides has caused adverse effects, including the emergence of drug resistance to pathogens and environmental pollution. Biological control is considered one of the most promising alternatives to chemicals and can be used for integrated management of FHB due to the rare possibility of environment pollution and reduced health risks. In this study, Bacillus velezensis JCK-7158 isolated from rice was selected as an ecofriendly alternative to chemical fungicides for the management of FHB. JCK-7158 produced the extracellular enzymes protease, chitinase, gelatinase, and cellulase; the plant growth hormone indole-3-acetic acid; and the 2,3-butanediol precursor acetoin. Moreover, JCK-7158 exhibited broad antagonistic activity against various phytopathogenic fungi and produced iturin A, surfactin, and volatile substances as active antifungal compounds. It also enhanced the expression of PR1, a known induced resistance marker gene, in transgenic Arabidopsis plants expressing β-glucuronidase (GUS) fused with the PR1 promoter. Under greenhouse conditions, treatments with the culture broth and suspension concentrate formulation of JCK-7158 at a 1,000-fold dilution inhibited the development of FHB by 50 and 66%, respectively. In a field experiment, treatment with the suspension concentrate formulation of JCK-7158 at a 1,000-fold dilution effectively controlled the development of FHB with a control value of 55% and reduced the production of the mycotoxin nivalenol by 40%. Interestingly, treatment with JCK-7158 enhanced the expression of plant defense-related genes in salicylic acid, jasmonic acid, ethylene, and reactive oxygen species (ROS) signaling pathways before and after FHB pathogen inoculation. Taken together, our findings support that JCK-7158 has the potential to serve as a new biocontrol agent for the management of FHB.

Identification and Fungicide Sensitivity of Fusarium spp. Associated with Root Rot of Scutellaria baicalensis in Shanxi Province, China.

Fusarium root rot is usually classified as an extremely destructive soilborne disease. From 2020 to 2021, Fusarium root rot was observed in production areas and seriously affected the yield and quality of Scutellaria baicalensis in Shanxi Province, China. Based on morphological characteristics and combined analysis of the internal transcribed spacer region of ribosomal DNA and translation elongation factor 1-alpha sequences, 68 Fusarium isolates obtained in this work were identified as F. oxysporum (52.94%), F. acuminatum (20.59%), F. solani (16.17%), F. proliferatum (5.88%), F. incarnatum (2.94%), and F. brachygibbosum (1.47%). In the pathogenicity tests, all Fusarium isolates could infect S. baicalensis roots, presenting different pathogenic ability. Among these isolates, F. oxysporum was found to have the highest virulence on S. baicalensis roots, followed by F. acuminatum, F. solani, F.proliferatum, F. brachygibbosum, and F.incarnatum. According to fungicide sensitivity tests, Fusarium isolates were more sensitive to fludioxonil and difenoconazole, followed by carbendazim, thiophanate-methyl, and hymexazol. In brief, this is the first report of Fusarium species (F. oxysporum, F. acuminatum, F. solani, F. proliferatum, F. incarnatum, and F. brachygibbosum) as causal agents of root rot of S.baicalensis in Shanxi Province, China. The fungicide sensitivity results will be helpful for formulating management strategies of S. baicalensis root rot.

Efficacy of Beta vulgaris Essential Oils Against Potato Dry Rot Disease and Deoxynivalenol (DON) Mycotoxin

AbstractPotato dry rot is a global problem caused by Fusarium species. Symptoms of dry rot include wrinkled brown to black patches of tissue. Fusarium spp. infection in potato tubers results in the formation of mycotoxins. Fungi that cause dry rot are commonly Fusarium sambucinum and Fusarium solani. This article was made to determine the effect of the essential oils of the Beta vulagaris plant on Fusarium species, which is the causative agent of dry rot in potatoes. In the study, Beta vulgaris plant essential oil content was determined by Gas Chromatography (GC–MC). In addition, the amount of deoxynivalenol (DON) mycotoxin produced by Fusarium species was determined by enzyme-linked immunosorbent assay (ELISA) analyses. Inhibition rates of these essential oils (1, 5, 10, 20, 50, 100, 250, 500, 1000 µl) on Fusarium sambicunum (1.3, 3.0, 5.2, 7.3, 9.1, 12.7, 22.3, 27.1, 29.1%) were found. Similarly, inhibition rates on Fusarium solani (1.1, 2.8, 4.3, 6.7, 8.8, 10.5, 19.4, 24.7, 27.3%) were found. In addition, the results showed that the amount of deoxynivalenol DON in 25 potato tubers ranged from 44.1–172.6 ppb. Infections of potato tubers caused by certain Fusarium species are typically accompanied by mycotoxin production, thus posing a potential risk to human health and food safety. In this study, it was determined that the essential oils of Beta vulgaris plant were effective against Fusarium spp., which are the cause of dry rot disease that may occur in potatoes.

Fungal diversity in ginger and effect of storage conditions on occurrence of Fusarium and its mycotoxins

This study investigated the fungal diversity in ginger from fields and storage and the effects of storage temperature and relative humidity (RH) on fungal and mycotoxin occurrence. A total of 909 isolates from ginger samples (30 from fields and 24 from storages) were identified using a molecular approach. Fusarium (23 species, 82.3%) was dominant in the ginger samples, followed by Aspergillus (16 species, 8.5%), and Penicillium (11 species, 2.1%). Among the Fusarium species, F. oxysporum (28.3%) was predominant, followed by F. asiaticum (14.9%) and F. solani (7.2%). Most isolates of F. oxysporum, F. graminearum, and F. fujikuroi species complex tested produced the respective mycotoxins: beauvericin (15.9–93.4 mg/kg), nivalenol (16.0–611.6 μg/kg), deoxynivalenol (31.3–1605.5 μg/kg), and fumonisins (0.1–101.4 mg/kg) on potato dextrose agar. During six months of ginger storage under three conditions, Fusarium species predominated (64.8%), followed by Aspergillus (3.8%) and Penicillium (0.1%). The frequency of F. oxysporum increased during storage, whereas mycotoxin occurrence varied significantly depending on storage conditions (p < 0.05). At 5 °C/73% RH, F. oxysporum frequency was the lowest (32.8%), while the average concentrations of enniatins were the highest (2030.0 μg/kg). At 14 °C/68% RH, F. oxysporum frequency (71.9%) and beauvericin (725.7 μg/kg) were the highest. At 13 °C/96% RH, F. oxysporum frequency (56.1%) was lower than at 14 °C/68% RH, and beauvericin (56.8 μg/kg) and enniatins (41.3 μg/kg) were the lowest. Aflatoxins and ochratoxin A were not detected in any of the stored samples. These results suggest that 13 °C/96% RH is the most suitable storage condition for ginger to minimize fungal growth and the production of mycotoxins.

Determination of In Vitro Biocontrol Efficacy of Trichoderma Harzianum Against Some Wheat Pathogen Fusarium Species

Recently, phytopathogenic problems have been increasing day by day in cereal production and have adverse effects on its production. One of the most common methods applied to control phytopathogens is the use of synthetic chemicals. The impacts of pesticides on the environment and food safety have made their use controversial. Therefore, developing and applying methods that can replace agricultural chemicals is an issue that needs to be emphasized. In this sense, biocontrol can be an alternative approach against agrochemicals in terms of sustainable agriculture. In the present study, it was aimed to examine the biocontrol efficiency of Trichoderma harzianum against Fusarium graminearum, Fusarium culmorum and Fusarium avenaceum, causing product losses in wheat by dual culture tests and double plate assays. Results showed that T. harzianum had remarkable inhibition of mycelial growth of all Fusarium species in dual culture assays. Moreover, no statistically crucial differences were found in the double plate tests.

Variation in symptoms and morphology of Fusarium spp. on shallot associated with basal plate rot disease in Brebes District, Central Java Province, Indonesia

Abstract. Marianah L, Nawangsih AA, Munif A, Giyanto, Tondok ET. 2024. Variation in symptoms and morphology of Fusarium spp. on shallot associated with basal plate rot disease in Brebes District, Central Java Province, Indonesia. Biodiversitas 25: 2198-2208. Basal plate rot disease is an important disease of shallots that causes losses in the field and storage. The disease is caused by Fusarium complex species, with different levels of virulence and host susceptibility. The six species of Fusarium spp. reported to cause basal plate rot disease of onion were F. oxysporum f.sp. cepae, F. proliferatum, F. redolens, F. solani, F. acutatum and F. tricinctum. Information about the variation in symptoms and morphology of fungi that cause basal plate rot disease on shallots, especially in Indonesia, is still very limited. Besides, the species that cause basal plate rot disease on shallots has not been molecularly confirmed using specific primers. The objective of this study was to isolate, identify, and study the variation in symptoms of the fungus associated with basal plate rot disease. The fungi were isolated from shallot plants symptomatic of basal plate rot disease collected from Brebes, Central Java Province. Eight isolates of Fusarium with different morphologies were successfully isolated and identified. Five isolates were identified as F. solani (isolate BC1, BC2, BC3, BBS1, and BBS4), two isolates as F. oxysporum f.sp. cepae (isolate BC4 and BBS6) and one isolate F. proliferatum (isolate BBS5). All eight isolates were pathogenic on shallots with different levels of virulence and symptom variations. BC4 isolate had the highest level of virulence, resulting in plant death, and was identified as F. oxysporum f.sp. cepae.