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Background Public health officials are responding to an outbreak of fungal meningitis among patients who received procedures under epidural anesthesia at 2 clinics (River Side Surgical Center and Clinica K-3) in Matamoros, Mexico, during 1 January to 13 May 2023. This report describes outbreak epidemiology and outlines interim diagnostic and treatment recommendations. Methods Interim recommendations for diagnosis and management were developed by the Mycoses Study Group Research Education and Consortium (MSGERC) based on the clinical experience of clinicians caring for patients during the current outbreak or during previous outbreaks of healthcare-associated fungal meningitis in Durango, Mexico, and the United States. Results As of 7 July 2023, the situation has evolved into a multistate and multinational fungal meningitis outbreak. A total of 185 residents in 22 US states and jurisdictions have been identified who might be at risk of fungal meningitis because they received epidural anesthesia at the clinics of interest in 2023. Among these patients, 11 suspected, 10 probable, and 10 confirmed US cases have been diagnosed, with severe vascular complications and 8 deaths occurring. Fusarium solani species complex has been identified as the causative agent, with antifungal susceptibility testing of a single isolate demonstrating poor in vitro activity for most available antifungals. Currently, triple therapy with intravenous voriconazole, liposomal amphotericin B, and fosmanogepix is recommended. Conclusions Efforts to understand the source of this outbreak and optimal treatment approaches are ongoing, but infectious diseases physicians should be aware of available treatment recommendations. New information will be available on the Centers for Disease Control and Prevention's (CDC's) website. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB) or scab is a devastating disease of barley that severely reduces the yield and quality of the grain. Additionally, mycotoxins produced by the causal Fusarium species can contaminate harvested grain, resulting in food safety concerns and further economic losses. In the Upper Midwest region of the United States, Fusarium graminearum is the primary causal agent, and deoxynivalenol (DON) is the main mycotoxin associated with Fusarium infection. Deployment of resistant cultivars is an important component of an integrated strategy to manage this disease. Unfortunately, few good sources of FHB resistance have been identified from the evaluation of large collections of Hordeum germplasm. Over the past 25 years, many barley mapping populations have been developed with selected resistance sources to identify the number, chromosomal position and allelic effect of quantitative trait loci (QTL) contributing to FHB resistance and DON accumulation. To consolidate the genetic data generated from 14 mapping studies that included 22 bi‐ or tri‐parental mapping populations and three genome‐wide association (GWAS) mapping panels, a consensus map was constructed that includes 4145 SNP, SSR, RFLP and AFLP markers. A meta‐analysis based on this consensus map revealed 96 QTL for FHB resistance and 57 for DON accumulation scattered across the barley genome. Many of the QTL explained a low percentage (<10%) of variation for the traits and were often found significant in only one or a few environments in multi‐year/multi‐location field trials. Moreover, many of the FHB/DON QTL mapped to chromosomal positions coincided with various agro‐morphological traits that could influence the level of disease (e.g. heading date, height, spike density, and spike angle), raising the important question of whether the former are true resistance factors or are simply the result of pleiotropy with the latter. Considering the magnitude of effect, consistency of detection across environments and independence from agro‐morphological traits, only three of 96 QTL for FHB and five of 57 QTL for DON were considered priority targets for marker‐assisted selection (MAS). In spite of the challenge for having a limited number of useful QTL for breeding, genomic selection holds promise for increasing the efficiency of developing FHB‐resistant barley cultivars, an essential component of the overall management strategy for the disease. [ABSTRACT FROM AUTHOR]

Tremendous progress has been made in variety development and host plant resistance to mitigate the impact of Fusarium head blight (FHB) since the disease manifested in the southeastern United States in the early 2000s. Much of this improvement was made possible through the establishment of and recurring support from the US Wheat & Barley Scab Initiative (USWBSI). Since its inception in 1997, the USWBSI has enabled land‐grant institutions to make advances in reducing the annual threat of devastating FHB epidemics. A coordinated field phenotyping effort for annual germplasm screening has become a staple tool for selection in public and private soft red winter wheat (SRWW) breeding programmes. Dedicated efforts of many SRWW breeders to identify and utilize resistance genes from both native and exotic sources provided a strong foundation for improvement. In recent years, implementation of genomics‐enabled breeding has further accelerated genetic gains in FHB resistance. This article reflects on the improvement of FHB resistance in southern SRWW and contextualizes the monumental progress made by collaborative, persistent, and good old‐fashioned cultivar development. [ABSTRACT FROM AUTHOR]

Constructing models that accurately predict Fusarium head blight (FHB) epidemics and are also amenable to large-scale deployment is a challenging task. In the United States, the emphasis has been on simple logistic regression (LR) models, which are easy to implement but may suffer from lower accuracies when compared with more complicated, harder-to-deploy (over large geographies) model frameworks such as functional or boosted regressions. This article examined the plausibility of random forests (RFs) for the binary prediction of FHB epidemics as a possible mediation between model simplicity and complexity without sacrificing accuracy. A minimalist set of predictors was also desirable rather than having the RF model use all 90 candidate variables as predictors. The input predictor set was filtered with the aid of three RF variable selection algorithms (Boruta, varSelRF, and VSURF), using resampling techniques to quantify the variability and stability of selected variable sets. Postselection filtering produced 58 competitive RF models with no more than 14 predictors each. One variable representing temperature stability in the 20 days before anthesis was the most frequently selected predictor. This was a departure from the prominence of relative humidity-based variables previously reported in LR models for FHB. The RF models had overall superior predictive performance over the LR models and may be suitable candidates for use by the Fusarium Head Blight Prediction Center. [ABSTRACT FROM AUTHOR]

The soil-borne pathogens, particularly Fusarium oxysporum f. sp. niveum (FON) and southern root-knot nematode (RKN, Meloidogyne incognita) are the major threats to watermelon production in the southeastern United States. The role of soil micronutrients on induced resistance (IR) to plant diseases is well-documented in soil-based media. However, soil-based media do not allow us to determine the contribution of individual micronutrients in the induction of IR. In this manuscript, we utilized hydroponics-medium to assess the effect of controlled application of micronutrients, including iron (Fe), manganese (Mn), and zinc (Zn) on the expression of important IR genes (PR1, PR5, and NPR1 from salicylic acid (SA) pathway, and VSP, PDF, and LOX genes from jasmonic acid (JA) pathway) in watermelon seedlings upon inoculation with either FON or RKN or both. A subset of micronutrient-treated plants was inoculated (on the eighth day of micronutrient application) with FON and RKN (single or mixed inoculation). The expression of the IR genes in treated and control samples was evaluated using qRT-PCR. Although, significant phenotypic differences were not observed with respect to the severity of wilt symptoms or RKN galling with any of the micronutrient treatments within the 30-day experimental period, differences in the induction of IR genes were considerably noticeable. However, the level of gene expression varied with sampling period, type and concentration of micronutrients applied, and pathogen inoculation. In the absence of pathogens, micronutrient applications on the seventh day, in general, downregulated the expression of the majority of the IR genes. However, pathogen inoculation preferentially either up- or down-regulated the expression levels of the IR genes at three days post-inoculation depending on the type and concentration of micronutrients. The results demonstrated here indicate that micronutrients in watermelon may potentially make watermelon plants susceptible to infection by FON and RKN. However, upon infection the IR genes are significantly up-regulated that they may potentially aid the prevention of further infection via SA- and JA-pathways. This is the first demonstration of the impact of micronutrients affecting IR in watermelon against FON and RKN infection. [ABSTRACT FROM AUTHOR]

The present study analyses the clinical characteristics of patients diagnosed with cutaneous fusarium through a systematic review of cases reported in literature. A total of 39 cases were included, of which 53% were men, 30% were women, and in 17% the sex was not specified. The age ranged from 5 to 85 years. Most cases were reported in Brazil, followed by Japan and United States of America. The most common agent was Fusarium solani, in 37.5% of the patients. Most of the affected individuals had acute myeloid leukaemia and some of the predisposing factors, which included induction chemotherapy, febrile neutropenia, and bone marrow transplantation. The clinical topography of the lesions was located in 27.5% and disseminated in 72.5%, with the most observed clinical feature outstanding the presence of papules and nodules with central necrosis in 47% of the cases. Longer survival was demonstrated in those treated with more than three antifungals. It is concluded that cutaneous fusarium is a complex and challenging clinical entity, infection in patients with leukaemias underscores the need for thorough care to decrease morbidity and mortality., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

Fusarium wilt of cotton (Gossypium spp.) is caused by a soil‐ and seed‐borne fungal pathogen Fusarium oxysporum f. sp. vasinfectum (FOV). Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4) is a significant threat to cotton production in the United States. The effect of temperature and soil on disease symptoms in cultivars with a range of susceptibility to FOV4 was examined in growth chamber trials. Three upland (G. hirsutum L.) and three pima (G. barbadense L.) cultivars were planted in three types of soils (potting mix and farm soils with and without FOV4 preinfestation) and maintained at four constant temperature regimes (20, 23, 26, and 29 °C). After seedling emergence, each pot was inoculated with conidial suspensions of FOV4 and scored for resistance based on disease incidence (DI), foliar disease severity rating (DSR), and mortality rate (MR) at 7, 14, 21, and 28 d post‐inoculation (dpi). The area under the disease progress curve (AUDPC) based on DSR across the four evaluation dpi was also analyzed. Among the six cultivars tested, Pima PHY 841 RF, Pima S‐6, and the uplands Acala 1517‐08 and FM 2334GLT were the most resistant, whereas upland PHY 725 RF and Pima S‐7 were the most susceptible. The genotypic responses to FOV4 were not significantly (P >.05) affected by differences in temperature regime or soil type. Cotton seedlings manifested more severe symptoms and higher mortality when maintained at 23 °C, followed by 20/26 °C and 29 °C in descending order. The mycelial growth rate was greater at 23/26 °C, whereas plants grew slower at 20/23 °C. There were no differences (P >.05) in DI, DSR, MR, and AUDPC between the inoculated farm soil (with no FOV4 preinfestation) and the inoculated FOV4‐preinfested farm soil, suggesting the unnecessity of using the latter in artificial inoculations. However, the potting soil produced higher (P <.05) DI and DSR at 7 and 14 dpi but lower (P <.05) AUDPC. This growth chamber study demonstrated that 23 °C produced the highest DI, severity, and plant death, providing an important piece of information for screening cotton for FOV4 resistance in breeding and FOV4 disease management in cotton production. [ABSTRACT FROM AUTHOR]

Although the maritime Pacific Northwest (PNW) is the only region of the United States suitable climatically for spinach seed production, the acidic soils are highly conducive to spinach Fusarium wilt caused by Fusarium oxysporum f. sp. spinaciae. A soil bioassay developed to quantify the risk of spinach Fusarium wilt in fields has been offered to seed growers annually since 2010. Soil sampled from growers' fields each winter was planted with highly susceptible, moderately susceptible, and partially resistant spinach inbred lines, and the plants rated weekly to calculate a Fusarium wilt severity index (FWSI) and the area under the disease progress curve (AUDPC). Results for 147 soils tested from 2010 to 2013 have been published. This study examined results for an additional 248 soils tested from 2014 to 2019 with the bioassay modified to include an option of agricultural limestone amendment to the soils tested. FWSI and AUDPC were affected significantly (p <.001) by the main effects of soil and spinach inbred line, and the interaction of these factors. Correlation analyses showed a range in degree of association of FWSI and AUDPC with spinach seed crop rotation duration and soil properties, depending on the spinach inbred line (r = −.255 to –.267, n = 172 soils with characteristics suitable for correlation analyses). Stepwise regression models for 172 soils with relevant parameters for regression analyses identified spinach seed crop rotation interval, rate of agricultural limestone amendment, soil pH, and soil Fe, Mn, and Zn concentrations as most strongly associated with FWSI and AUDPC. However, the models accounted for ≤33.4% (R2) of the variability in Fusarium wilt risk. The soil bioassay remains a primary tool for spinach seed growers to select fields with low risk of Fusarium wilt. [ABSTRACT FROM AUTHOR]

The purpose of our study was to determine whether the application of quinone outside inhibitor (QoI) and pyrazole-carboxamide fungicides as a tank mix would impact the endophyte community of soybean seed. Field trials during 2018 in Iowa, South Dakota, and Wisconsin, U.S.A., investigated the impact of a single combination fungicide spray at early pod set in soybeans. The composition of culturable endophytic fungi in mature soybean seed was assessed on three cultivars per state, with maturity groups (MGs) ranging from 1.1 to 4.7. An unusually wet 2018 season delayed harvest, which led to a high level of fungal growth in grain. The survey included 1,080 asymptomatic seeds that were disinfested and individually placed on 5-cm-diameter Petri plates of acidified water agar. The survey yielded 721 fungal isolates belonging to 24 putative species in seven genera; taxa were grouped into genera based on a combination of morphological and molecular evidence. The dominant genera encountered in the survey were Alternaria , Diaporthe , and Fusarium . The study showed that the fungicide treatment reduced the incidence of Fusarium in Wisconsin seed, increased the incidence of Diaporthe in seed from all states, and had no impact on the incidence of Alternaria . This is one of the first attempts to characterize the diversity of seed endophytes in soybean and the first to characterize the impacts of fungicide spraying on these endophyte communities across three states. Our study provides evidence that the impact of a fungicide spray on soybean seed endophyte communities may be influenced by site, weather, and cultivar maturity group., Competing Interests: The author(s) declare no conflict of interest.

Background: Endophthalmitis is an uncommon yet devastating compilation of Fusarium keratitis. Cases of Fusarium keratitis are seen commonly in tropical regions of the world; however, they have been increasing in frequency in the United States.Case Report: We present the case of a 36-year-old man who experienced an ocular lens expulsion secondary to Fusarium endophthalmitis. Why Should an Emergency Physician Be Aware of This?:Fusarium keratitis is becoming more common and can progress to endophthalmitis without proper management. This infection can be difficult to recognize and treat, so early action by the emergency physician could be the difference between vision loss and vision-sparing care. [ABSTRACT FROM AUTHOR]

Objective: To determine minimum inhibitory concentrations (MICs) of four fungal species isolated from horses presented with equine fungal keratitis (EFK) in the southeastern United States to previously untested azole, echinocandin, and carboxamide antifungal drugs. Methods: In vitro assays were performed to determine the susceptibility of Aspergillus flavus, A. fumigatus, Fusarium falciforme, and F. keratoplasticum to five antifungal drugs representing three modes of action. Results: Luliconazole exhibited increased growth inhibition against both Aspergillus and Fusarium compared to commonly used, standard antifungal drugs. MIC values for luliconazole at 0.001‐0.002 µg/mL were at least 25‐fold lower than all other antifungal drugs tested, including voriconazole. Conclusions: The increased antifungal activity of luliconazole observed in this study warrants further investigation for its potential as an antifungal drug for equine fungal keratitis. [ABSTRACT FROM AUTHOR]

• Fusarium head blight (FHB) leads to mycotoxin contamination of grain. • Multiple disease management approaches are essential for effective control. • We review current and developing directions for FHB management. • Effective control will incorporate traditional and innovative strategies. Fusarium head blight (FHB) is one of the most devastating diseases of cereal crops, causing severe reduction in yield and quality of grain worldwide. In the United States, the major causal agent of FHB is the mycotoxigenic fungus, Fusarium graminearum. The contamination of grain with mycotoxins, including deoxynivalenol and zearalenone, is a particularly serious concern due to its impact on the health of humans and livestock. For the past few decades, multidisciplinary studies have been conducted on management strategies designed to reduce the losses caused by FHB. However, effective management is still challenging due to the emergence of fungicide-tolerant strains of F. graminearum and the lack of highly resistant wheat and barley cultivars. This review presents multidisciplinary approaches that incorporate advances in genomics, genetic-engineering, new fungicide chemistries, applied biocontrol, and consideration of the disease cycle for management of FHB. [ABSTRACT FROM AUTHOR]

Fusarium root rot is an important disease of field pea ( Pisum sativum var. sativum L.) that occurs everywhere pea is grown, causing yield loss of up to 75%. Fusarium root rot is caused by a complex of Fusarium species, most notably Fusarium solani in the Pacific Northwest of the United States and F. avenaceum in the northern Great Plains of the United States and Canada. F. oxysporum f. sp. pisi (Fop) was frequently isolated from peas exhibiting root rot symptoms in North Dakota during recent surveys. Fop causes wilt (races 1, 5, and 6) and near wilt (race 2) on pea. However, its contribution to pea root rot remains unclear. Fop race was determined for isolates from North Dakota pea root rot surveys. ND Fop isolates were evaluated for root rot pathogenicity and aggressiveness at standard and elevated temperatures. Results from greenhouse wilt assays indicated that all Fop races exist in North Dakota, with race 2 most prevalent among the 25 North Dakota isolates evaluated. Root rot evaluations conducted at 21/18°C and 25/19°C day/night temperatures demonstrated that most Fop isolates were as aggressive or more aggressive than F. solani and F. avenaceum under both temperature regimes. Aggressiveness of Fop isolates tended to increase at elevated assay temperatures. Results from these experiments indicate that Fop may be an important contributor to the root rot complex of field pea in North Dakota and should be considered in integrated pest management strategies, including pea breeding efforts to improve resistance to Fusarium root rot.[Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license., Competing Interests: The author(s) declare no conflict of interest.

Introduction: Fusariosis of the central nervous system (CNS) is extremely uncommon. Treatment and outcome data from previously published cases may provide some guidance in light of the ongoing fungal meningitis outbreak in 2023 involving Fusarium spp. in the United States and Mexico., Methods: We reviewed the published literature describing cases of invasive fusariosis of the (CNS) that included data on patient demographic characteristics, treatment, and outcome., Results: Twenty-six cases met inclusion criteria. The mean age was 36 years, 55% involved females, 60% had underlying hematologic malignancy, and another 16% were on immunosuppressants. The majority of infections were from Fusarium solani species complex. Overall 72% of patients died. The majority received monotherapy with amphotericin B, although some received voriconazole monotherapy or combination therapy with amphotericin B plus voriconazole with or without adjuvant surgery. Among the survivors, 3 received amphotericin B monotherapy, 2 voriconazole monotherapy, 1 combination therapy of both, and one surgery only., Conclusion: The overall mortality rate in published cases of fusariosis of the CNS was high, although-unlike during the current outbreak-the preponderance of patients were severely immunocompromised. While historically the majority were treated with amphotericin B monotherapy, some recent patients were treated with voriconazole monotherapy or combination therapy with amphotericin B plus voriconazole. Current guidelines recommend monotherapy with voriconazole or lipid formulations of amphotericin B or combination of both for the treatment of invasive fusariosis, which is in line with the findings from our literature review and should be considered during the ongoing 2023 outbreak., (© 2023. The Author(s).)

• Bacterial blight and Fusarium wilt of cotton are recurrent diseases in U.S. cotton. • SWEET sugar transporters function as a susceptibility factor of bacterial blight. • Cell surface and intracellular immune receptors mediate host Fusarium wilt response. • Environment–pathogen–cotton interactions underpin strategies for disease control. Bacterial blight of cotton, caused by Xanthomonas citri subsp. malvacearum , and Fusarium wilt of cotton, caused by Fusarium oxysporum f. sp. vasinfectum , contribute cotton losses worldwide. Resurgences of these diseases in the United States were reported in recent years. There is a pressing need to understand pathogenicity and host responses to the pathogens and develop effective strategies for disease prevention and management. Here, we discuss the current status of bacterial blight and Fusarium wilt of cotton in the field as well as the knowledge of cotton resistance and susceptibility to these pathogens. In addition, we aim to provide insights into how these diseases are recurring and possible methods to use current technologies for biological control of these pathogens. [ABSTRACT FROM AUTHOR]

Fusarium wilt of watermelon, caused by Fusarium oxysporum f. sp. niveum (FON), occurs worldwide and is responsible for substantial yield losses in watermelon-producing areas of the southeastern United States. Management of this disease largely relies on the use of integrated pest management (i.e., fungicides, resistant cultivars, crop rotation, etc.). Knowledge about race structure and genetic diversity of FON in the southeastern US is limited. To determine genetic diversity of the pathogen, FON isolates were collected from symptomatic watermelon plants in commercial fields in Georgia and Florida, USA, and identified based on morphological characteristics and PCR analysis using FON-specific primers. Discriminant analysis of principal components (DAPC) of 99 isolates genotyped with 15 simple sequence repeat (SSR) markers grouped the isolates in eight distinct clusters with two prominent clusters (clusters 1 and 8). Cluster 1 consisted of a total of 14 isolates, out of which 85.7% of the isolates were collected in Florida. However, most of the isolates (92.4%) in cluster 8 were collected in Georgia. Both DAPC and pairwise population differentiation analysis (ФPT) revealed that the genetic groups were closely associated with geographical locations of pathogen collection. Three races of FON (races 0, 2 and 3) were identified in the phenotypic analysis; with race 3 identified for the first time in Georgia. Overall, 5.1%, 38.9% and 55.9% of the isolates were identified as race 0, race 2 and race 3, respectively. The majority of the isolates in cluster 1 and cluster 8 belonged to either race 2 (35.6%) or race 3 (45.8%). Additionally, no relationship between genetic cluster assignment and races of the isolates was observed. The information obtained on genotypic and phenotypic diversity of FON in the southeastern US will help in development of effective disease management programs to combat Fusarium wilt. [ABSTRACT FROM AUTHOR]

Morphological characterization and multi-locus DNA sequence analysis of fungal isolates obtained from 32 clinical cases of equine fungal keratitis (FK) was performed to identify species and determine associations with antifungal susceptibility, response to therapy and clinical outcome. Two species of Aspergillus (A. flavus and A. fumigatus) and three species of Fusarium (F. falciforme, F. keratoplasticum, and F. proliferatum) were the most common fungi isolated and identified from FK horses. Most (91%) equine FK Fusarium nested within the Fusarium solani species complex (FSSC) with nine genetically diverse strains/lineages, while 83% of equine FK Aspergillus nested within the A. flavus clade with three genetically diverse lineages. Fungal species and evolutionary lineage were not associated with clinical outcome. However, species of equine FK Fusarium were more likely (p = 0.045) to be associated with stromal keratitis. Species of Aspergillus were more susceptible to voriconazole and terbinafine than species of Fusarium, while species of Fusarium were more susceptible to thiabendazole than species of Aspergillus. At the species level, A. fumigatus and A. flavus were more susceptible to voriconazole and terbinafine than F. falciforme. Natamycin susceptibility was higher for F. falciforme and A. fumigatus compared to A. flavus. Furthermore, F. falciforme was more susceptible to thiabendazole than A. flavus and A. fumigatus. These observed associations of antifungal sensitivity to natamycin, terbinafine, and thiabendazole demonstrate the importance of fungal identification to the species rather than genus level. The results of this study suggest that treatment of equine FK with antifungal agents requires accurate fungal species identification. [ABSTRACT FROM AUTHOR]

Mycotoxins pose a challenge to a safe food supply worldwide, and their threat is expected to worsen with our changing climate. The need for diligence is exemplified by the discovery of fumonisin B2 in wine, which joins ochratoxin A as a mycotoxin of concern in the grape-wine chain. To elucidate the mycotoxin risk in southeastern American wine, grape samples were collected from vineyards during harvest in 2013 and potentially mycotoxigenic fungi (Fusarium and Aspergillus) were isolated from the samples. Numerous Fusarium isolates were recovered and identified to the species level by comparison of translation elongation factor 1-gene sequences to verified strains. Fusarium fujikuroi was the most abundant species recovered (239 isolates), followed by F. proliferatum (52), F. incarnatum-equiseti (14), F. oxysporum (7), F. concentricum (1), and F. solani (1). In vitro assays quantified fumonisin production for representative isolates via liquid chromatography-tandem mass spectrometry. Surprisingly, nearly all F. fujikuroi isolates produced fumonisins B1, B2, and B3 at levels comparable to both the F. proliferatum isolates and the positive control, Fusarium verticillioides. Such capacity for fumonisin production refutes the generally accepted notion that F. fujikuroi produces undetectable or low levels of fumonisins and provides evidence to reconsider this species as a mycotoxigenic threat to economically significant crops. [ABSTRACT FROM AUTHOR]

Fusarium graminearum sensu stricto causes Fusarium head blight (FHB) in wheat and barley, and contaminates grains with several trichothecene mycotoxins, causing destructive yield losses and economic impact in the United States. Recently, a F. graminearum strain collected from Minnesota (MN) was determined to produce a novel trichothecene toxin, called NX-2. In order to determine the spatial and temporal dynamics of NX-2 producing strains in MN, North Dakota (ND) and South Dakota (SD), a total of 463 F. graminearum strains were collected from three sampling periods, 1999–2000, 2006–2007 and 2011–2013. A PCR-RFLP based diagnostic test was developed and validated for NX-2 producing strains based on polymorphisms in the Tri1 gene. Trichothecene biosynthesis gene ( Tri gene )-based polymerase chain reaction (PCR) assays and ten PCR-restriction fragment length polymorphism (RFLP) markers were used to genotype all strains. NX-2 strains were detected in each sampling period but with a very low overall frequency (2.8%) and were mainly collected near the borders of MN, ND and SD. Strains with the 3ADON chemotype were relatively infrequent in 1999–2000 (4.5%) but increased to 29.4% in 2006–2007 and 17.2% in 2011–2013. The distribution of 3ADON producing strains also expanded from a few border counties between ND and MN in 1999–2000, southward toward the border between SD and MN in 2006–2007 and westward in 2011–2013. Genetic differentiation between 2006–2007 and 2011–2013 populations (3%) was much lower than that between 1999–2000 and 2006–2007 (22%) or 1999–2000 and 2011–2013 (20%) suggesting that most change to population genetic structure of F. graminearum occurred between 1999–2000 and 2006–2007. This change was associated with the emergence of a new population consisting largely of individuals with a 3ADON chemotype. A Bayesian clustering analysis suggested that NX-2 chemotype strains are part of a previously described Upper Midwestern population. However, these analyses also suggest that the NX-2 isolates could represent a distinct population, but that interpretations of population assignment are influenced by the small number of NX-2 strains available for analysis. [ABSTRACT FROM AUTHOR]

This study characterized a novel sugar beet ( Beta vulgaris L.) pathogen from the Red River Valley in north central USA, which was formally named Fusarium secorum . Molecular phylogenetic analyses of three loci (translation elongation factor1α, calmodulin, mitochondrial small subunit) and phenotypic data strongly supported the inclusion of F. secorum in the Fusarium fujikuroi species complex (FFSC). Phylogenetic analyses identified F. secorum as a sister taxon of F. acutatum and a member of the African subclade of the FFSC. Fusarium secorum produced circinate hyphae sometimes bearing microconidia and abundant corkscrew-shaped hyphae in culture. To assess mycotoxin production potential, 45 typical secondary metabolites were tested in F. secorum rice cultures, but only beauvericin was produced in detectable amounts by each isolate. Results of pathogenicity experiments revealed that F. secorum isolates are able to induce half- and full-leaf yellowing foliar symptoms and vascular necrosis in roots and petioles of sugar beet. Inoculation with F. acutatum did not result in any disease symptoms. The sugar beet disease caused by F. secorum is named Fusarium yellowing decline. Since Fusarium yellowing decline incidence has been increasing in the Red River Valley, disease management options are discussed. [ABSTRACT FROM AUTHOR]

Watermelon (Citrullus lanatus var. lanatus) yield losses due to Fusarium wilt can be considerable and have been increasing in the United States, mainly due to the emergence of the new races of Fusarium oxysporum f. sp. niveum (FON). One of the potential management strategies to reduce Fusarium wilt is the use of fumigants and soil-applied fungicides. Field experiments were conducted in 2018 and 2020 to evaluate fumigant Pic-clor 60 (choloropicrin pre-mixed with 1,3 dicholoropropene) with post-plant soil-applied fungicides (prothioconazole and pydiflumetofen) for their effectiveness against Fusarium wilt. The field was fumigated 21 days before transplanting, and three applications of either fungicide were made at 14-day intervals via a drip irrigation system starting a day after transplanting. In 2018, based on the disease ratings at harvest maturity, all treatments significantly reduced final disease incidence compared to the non-treated control, and the highest reduction was observed when the fumigant was applied at 336.26 kg/ha along with either fungicides. The application of fumigant, together with either fungicides, had significantly higher reduction in disease incidence compared to the stand-alone application (fumigant or fungicides). Also, Pic-clor 60 at 336.26 kg/ha provided a higher reduction in disease incidence than Pic-clor 60 at 280.21 kg/ha. In 2020, results showed a similar trend to 2018, where Pic-clor 60 at 336.26 kg/ha in combination with either prothioconazole or pydiflumetofen had significantly lower final disease incidence. The reduction in disease incidence in Pic-clor 60 at 336.26 kg/ha was higher compared to a lower application rate of 280.21 kg/ha, either when applied alone or in combination with either fungicides. The results presented here are the first to demonstrate that the fumigant Pic-clor 60 along with soil-applied fungicides, pydiflumetofen or prothioconazole may provide an effective management option for Fusarium wilt of watermelon. [ABSTRACT FROM AUTHOR]

Sudden death syndrome, caused by Fusarium virguliforme, is an important disease of soybean in the United States. Fifteen species of crops, weeds, or prairie plants were evaluated for their potential as hosts of F. virguliforme. Root and foliar symptoms and plant biomass were assessed following greenhouse inoculation studies. Root colonization of F virguliforme was determined with isolations and with polymerase chain reaction assays. Soybean, alfalfa, pinto and navy bean, white and red clover, pea, and Canadian milk vetch developed root necrosis. Soybean, alfalfa, and red clover also developed foliar symptoms following inoculation. Sugar beet and canola did not develop symptoms but had significant reductions in biomass, suggesting that they are also hosts of F. virguliforme. Corn, wheat, ryegrass, pigweed, and lambsquarters did not develop symptoms. However, these species appeared to be asymptomatic hosts because quantities of pathogen DNA detected in inoculated roots were similar to quantities detected in inoculated soybean roots. These results suggest that the number and diversity of hosts for F. virguliforme are greater than previously reported. The likely broad host range limits the efficacy of crop rotation and indicates that crops other than soybean can be damaged by F virguliforme and maintain or increase inoculum in soil. [ABSTRACT FROM AUTHOR]

Fusarium crown rot (FCR), caused by Fusarium pseudograminearum and F. culmorum, reduces wheat ( Triticum aestivum L.) yields in the Pacific Northwest (PNW) of the US by as much as 35%. Resistance to FCR has not yet been discovered in currently grown PNW wheat cultivars. Several significant quantitative trait loci (QTL) for FCR resistance have been documented on chromosomes 1A, 1D, 2B, 3B, and 4B in resistant Australian cultivars. Our objective was to identify QTL and tightly linked SSR markers for FCR resistance in the partially resistant Australian spring wheat cultivar Sunco using PNW isolates of F. pseudograminerarum in greenhouse and field based screening nurseries. A second objective was to compare heritabilities of FCR resistance in multiple types of disease assaying environments (seedling, terrace, and field) using multiple disease rating methods. Two recombinant inbred line (RIL) mapping populations were derived from crosses between Sunco and PNW spring wheat cultivars Macon and Otis. The Sunco/Macon population comprised 219 F:F lines and the Sunco/Otis population comprised 151 F:F lines. Plants were inoculated with a single PNW F. pseudograminearum isolate (006-13) in growth room (seedling), outdoor terrace (adult) and field (adult) assays conducted from 2008 through 2010. Crown and lower stem tissues of seedling and adult plants were rated for disease severity on several different scales, but mainly on a numeric scale from 0 to 10 where 0 = no discoloration and 10 = severe disease. Significant QTL were identified on chromosomes 2B, 3B, 4B, 4D, and 7A with LOD scores ranging from 3 to 22. The most significant and consistent QTL across screening environments was located on chromosome 3BL, inherited from the PNW cultivars Macon and Otis, with maximum LOD scores of 22 and 9 explaining 36 and 23% of the variation, respectively for the Sunco/Macon and Sunco/Otis populations. The SSR markers Xgwm247 and Xgwm299 flank these QTL and are being validated for use in marker-assisted selection for FCR resistance. This is the first report of QTL associated with FCR resistance in the US [ABSTRACT FROM AUTHOR]

Abstract: Fungal infections of the cornea are an important cause of blindness and visual impairment worldwide, with contact lens wear being the main risk factor in the USA and other industrialized countries, and traumatic injury being the main risk factor in developing countries. In this review, we highlight recent advances in the understanding of the host response to Aspergillus and Fusarium species in infected human corneal tissue and in mouse models of fungal keratitis. [Copyright &y& Elsevier]

Background. Filamentous fungi of the genera Aspergillus and Fusarium are major causes of corneal ulcers in the United States and in the developing world and result in significant visual impairment and blindness. Methods. RNA was extracted from 110 patients with corneal ulcers in southern India within 1 week of infection with either Fusarium solani or Aspergillus flavus, and gene expression was determined by quantitative polymerase chain reaction. Posttransplant corneas from later stage disease (>2 weeks after infection) were also examined. Results. Expression of Dectin-1, Toll-like receptor 2 (TLR2), TLR4, TLR9, and NOD-like receptor protein (NLRP)3 messenger RNA was elevated >1000-fold compared with uninfected donor corneas, whereas Dectin-2 was constitutively expressed in uninfected corneas. Furthermore, interleukin 1β (IL-1β) expression was elevated >1000-fold, whereas IL-1α expression was not increased. Expression of IL-8, IL-17, and tumor necrosis factor α was also elevated. CD3+and CD4+ T cells were detected in infected posttransplant corneas. Expression of IL-17 and interferon γ was elevated but not that of IL-4. There were no significant differences in the host response between Aspergillus- and Fusarium-infected corneas at any time point. Conclusions. There is a common innate and adaptive immune response to these filamentous fungi, which includes the generation of T-helper 1 and T-helper 17 cells. [ABSTRACT FROM AUTHOR]

A canker disease of Florida torreya (Torreya taxifolia) has been implicated in the decline of this critically endangered species in its native range of northern Florida and southeastern Georgia. In surveys of eight Florida torreya sites, cankers were present on all dead trees and 71 to 100% of living trees, suggesting that a fungal pathogen might be the causal agent. To identify the causal agent, nuclear ribosomal internal transcribed spacer region (ITS rDNA) sequences were determined for 115 fungi isolated from cankers on 46 symptomatic trees sampled at three sites in northern Florida. BLASTn searches of the GenBank nucleotide database, using the ITS rDNA sequences as the query, indicated that a novel Fusarium species designated Fsp-l might be the etiological agent. Molecular phylogenetic analyses of partial translation elongation factor 1-alpha (EF-1) and RNA polymerase second largest subunit (RPB2) gene sequences indicate that Fsp-l represents a novel species representing one of the earliest divergences within the Gibberella dade of Fusarium. Results of pathogenicity experiments established that the four isolates of Fsp-1 tested could induce canker symptoms on cultivated Florida torreya in a growth chamber. Koch's postulates were completed by the recovery and identification of Fsp-1 from cankers of the inoculated plants. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB), caused by Fusarium graminearum, of wheat (Triticum aestivum L.) is a disease that periodically strikes the mid-Atlantic region of the United States. Breeding for resistant wheat varieties is an effective method of disease control. The objective of this study was to evaluate the effects of exotic FHB resistance quantitative trait loci (QTL), singly and in combination, on FHB resistance in soft red winter wheat (SRWW). Three FHB resistance QTL on chromosomes 3BS (Fhbl), 2D, and 5A were introgressed from nonadapted Chinese cultivar Ning7840 into the adapted SRWW cultivar McCormick. Eight near-isogenic lines (NIL) were developed by marker-assisted backcrossing. The NIL that combined 3BS and 2DL expressed the highest resistance and lowest deoxynivalenol (DON) content in four environments that included three field and one greenhouse studies. These results indicate that the combination of just two QTL (3BS and 2DL) would be useful to breed for improved FHB resistance in SRWW in the mid-Atlantic region. [ABSTRACT FROM AUTHOR]

The phylogenecity of the four Fusarium mycotoxin gene (Fum 5) that has already been deposited in National Center for Biotechnology Information (NCBI) gene bank was studied with a comparative sequence alignment with other fungi like Aspergillus sps. Cochiliobolus sps. These results clearly indicated that the Fum 5 genes of Fusarium species were originated from Aspergillues fumigates and Cochliobolus heterostrophus. Fum 5 gene closer identity was also observed clearly with other fungal Fusarium species of Aspergillus and Gibberella species. [ABSTRACT FROM AUTHOR]

The trichothecene mycotoxin deoxynivalenol (DON) is a common contaminant of small grains, such as wheat and barley, in the United States. New strategies to mitigate the threat of DON need to be developed and implemented. TRI101 and TRI201 are trichothecene 3-O-acetyltransferases that are able to modify DON and reduce its toxicity. Recent work has highlighted differences in the activities of TRI101 from two different species of Fusarium (F. graminearum and F. sporotrichioides), but little is known about the relative activities of TRI101/TRI201 enzymes produced by other species of Fusarium. We cloned TRI101 or TRI201 genes from seven different species of Fusarium and found genetic identity between sequences ranging from 66% to 98%. In vitro feeding studies using transformed yeast showed that all of the TRI101/TRI201 enzymes tested were able to acetylate DON; conversion of DON to 3-acetyl-deoxynivalenol (3ADON) ranged from 50.5% to 100.0%, depending on the Fusarium species from which the gene originated. A time course assay showed that the rate of acetylation varied from species to species, with the gene from F. sporotrichioides having the lowest rate. Steady-state kinetic assays using seven purified enzymes produced catalytic efficiencies for DON acetylation ranging from 6.8 x 104 M-1·s-1 to 4.7 x 106 M·1·s-1. Thermostability measurements for the seven orthologs ranged from 37.1°C to 43.2°C. Extended sequence analysis of portions of TRI101/TRI201 from 31 species of Fusarium (including known trichothecene producers and nonproducers) suggested that other members of the genus may contain functional TRI101/TRI201 genes, some with the potential to outperform those evaluated in the present study. [ABSTRACT FROM AUTHOR]

Head blight of wheat in the United States is caused primarily by the deoxynivalenol (DON)-producing chemotype of Fusarium graminearum. However, the discovery of the nivalenol (NIV) chemotype of F graminearum in Louisiana and Arkansas necessitates having resistance in wheat to both chemotypes. The objectives of this research were to quantify resistance of selected winter wheat lines to initial infection and pathogen spread within spikes, to determine whether wheat lines selected for resistance to the DON chemotype also have resistance to the NIV chemotype, and to improve the methods for quantifying resistance to initial infection. A susceptible check (Coker 9835) and 15 winter wheat lines, which are adapted to the southeastern United States and possess diverse sources of head blight resistance, were evaluated for head blight resistance in a series of greenhouse and growthchamber experiments. Significant levels of resistance to both initial infection and spread within a spike were found among the lines, and lines with resistance to isolates of the DON chemotype had even higher levels of resistance to isolates of the NIV chemotype. Quantifying resistance to initial infection was improved by standardizing the inoculum and environmental conditions. Additional information related to resistance to spread within a spike was obtained by calculating the area under the disease progress curve from 7 to 21 days after inoculation. [ABSTRACT FROM AUTHOR]

Objective: Fungal keratitis is a serious ocular infection that is considered to be rare among contact lens wearers. The recent Fusarium keratitis outbreak raised questions regarding the background rate of Fusarium-related keratitis and other fungal keratitis in this population. Design: Retrospective, multicenter case series. Participants: Six hundred ninety-five cases of fungal keratitis cases who presented to 1 of 10 tertiary medical centers from 2001 to 2007. Methods: Ten tertiary care centers in the United States performed a retrospective review of culture-positive fungal keratitis cases at their centers between January 2001 and December 2007. Cases were identified using microbiology, pathology, and/or confocal microscopy records. Information was collected on contact lens status, method of diagnosis, and organism(s) identified. The quarterly number of cases by contact lens status was calculated and Poisson regression was used to evaluate presence of trends. The Johns Hopkins Medicine Institutional Review Board (IRB) and the IRBs at each participating center approved the research. Main Outcome Measures: Quarterly number of fungal keratitis cases and fungal species. Results: We identified 695 fungal keratitis cases; 283 involved the use of contact lenses. The quarterly number of Fusarium cases increased among contact lens wearers (CLWs) during the period that ReNu with MoistureLoc (Bausch & Lomb, Rochester, NY) was on the market, but returned to prior levels after withdrawal of the product from the market. The quarterly frequency of other filamentous fungi cases showed a statistically significant increase among CLWs comparing October 2004 through June 2006 with July 2006 through December 2007 with January 2001 through September 2004 (P<0.0001). Conclusions: The quarterly number of Fusarium fungal keratitis cases among CLWs returned to pre-Renu with Moistureloc levels after removal of the product from the market. However, the number of other filamentous fungal keratitis cases, although small, seems to have increased among refractive CLWs. Reasons for these apparent increases are unclear. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. [Copyright &y& Elsevier]

Boll rots of cotton ( Gossypium hirsutum L.) are common in the humid areas of the Southeastern US. One type of boll damage that may be differentiated from others is hardlock, with symptoms that include compression of the fibers within individual locules of mature, open cotton bolls without further obvious disintegration of the lint or damage to the carpel wall. The principal economic effect is that the boll’s lint is unharvestable by mechanical cotton pickers. This disease is endemic to the Southeast and can cause severe yield losses up to 70% in some fields. Scanning electron microscopy images of fibers from hardlocked bolls showed flattened and twisted tissue compared to fibers from healthy bolls. Fusarium verticillioides (Saccardo) Nirenberg was the fungus most commonly isolated from seeds of developing cotton bolls. Flowers inoculated with F. verticillioides on the day of bloom by spraying a spore suspension onto the flowers developed significantly ( P < 0.05) more hardlock symptoms compared to untreated controls. The infection process was analyzed using a F. verticillioides isolate tagged with green fluorescent protein (GFP). When it was applied to cotton flowers on the day of bloom, the GFP-tagged F. verticillioides strain was detected in the stigma and style by 2 days after bloom (DAB) and in developing seeds at 4, 6, 8, 10, 16, 20, 40, and 60 (open bolls) DAB. By 8 DAB, the GFP F. verticillioides was isolated from over 80% of developing seeds. [ABSTRACT FROM AUTHOR]

The presence of deoxynivalenol (DON) in cereal-based baby food, a primary source of the first solid food for infants, was studied in order to develop a method to detect its presence al low concentrations. DON. produced primarily by Fusarium graminearum, is commonly isolated from grains and feed around the world and affects both animal and human health, producing diarrhea, vomiting, gastrointestinal inflammation, trod immunomodulation. An aqueous extract of infant cereal was cleaned by means of an immunoaffinity chromatography column. After the eluate was evaporated and redissolved, DON was determined by high-pressure liquid chromatography-UV. The level of quantification for DON was 10 ppb for three types of infant cereal (mixed, barley, and oatmeal); the level of detection was 5 ppb. The protocol we have developed can measure DON between 10 to 500 ppb. An advisory level of 1 ppm for wheat products has been established by the U.S. Food and Drug Administration; however, the European Communities (EC) regulations have been set at 200 ppb for cereal-based foods for infants. Only 1 of 52 samples of barley-, mixed-, or oat-based infant cereal purchased in 2008 and 2009 in the United Stales exceeded the European standard. [ABSTRACT FROM AUTHOR]

Fusarium graminearum, a known producer of trichothecene mycotoxins in cereal hosts, has been recently documented as a cause of dry rot of potato tubers in the United States. Due to the uncertainty of trichothecene production in these tubers, a study was conducted to determine the accumulation and diffusion of trichothecenes in potato tubers affected with dry rot caused by F. graminearum. Potato tubers of cv. Russet Burbank were inoculated with 14 F. graminearum isolates from potato, sugar beet, and wheat and incubated at 10 to 12°C for 5 weeks to determine accumulation of trichothecenes in potato tubers during storage. Twelve of the isolates were classified as deoxynivalenol (DON) genotype and two isolates were as nivalenol (NIV) genotype. Trichothecenes were detected only in rotted tissue. DON was detected in all F. graminearum DON genotype isolates up to 39.68 µg/ml in rotted potato tissue. Similarly, both NIV genotype isolates accumulated NIV in rotted potato tissue up to 18.28 µg/ml. Interestingly, isolates classified as genotype DON accumulated both DON and NIV in the dry rot lesion. Potato tubers were then inoculated with two isolates of F. graminearum chemotype DON and incubated up to 7 weeks at 10 to 12°C and assayed for DON diffusion. F. graminearum was recovered from >53% of the isolations from inoculated tubers at 3 cm distal to the rotted tissue after 7 weeks of incubation but DON was not detected in the surrounding tissue. Based in this data, the accumulation of trichothecenes in the asymptomatic tissue surrounding dry rot lesions caused by F. graminearum is minimal in cv. Russet Burbank potato tubers stored for 7 weeks at customary processing storage temperatures. [ABSTRACT FROM AUTHOR]

Baseline sensitivity was determined using in vitro radial growth assay for Fusarium oxysporum, Fusarium graminearum, and a novel uncharacterized Fusarium sp. nov. from sugarbeet, and F. sambucinum from potato, to metconazole, triticonazole, and thiabendazole. All the isolates from sugarbeet and a thiabendazole-sensitive F. sambucinum isolate were sensitive to the tested fungicides. A thiabendazole-resistant isolate of F. sambucinum was resistant to thiabendazole but sensitive to the other two fungicides. The EC50 values of F. oxysporum, F. graminearum, and F. sp. nov. for triticonazole were 0.51 μg ml-1, 2.15 μg ml-1, and 0.04 μg ml-1, respectively. The EC50 values of F. oxysporum, F. graminearum, and F. sp. nov. for metconazole were 0.04 μg ml-1, 0.03 μg ml-1, and 0.02 μg ml-1, respectively. The EC50 values of F. oxysporum, F. graminearum, and F. sp. nov. for thiabendazole were 0.57 μg ml-1, 0.54 μg ml-1, and 0.64 μg ml-1, respectively. Generally, a higher concentration of triticonazole and thiabendazole compared to metconazole were required to reduce colony growth by 50%. The low EC50 values of metconazole, triticonazole, and thiabendazole for the Fusarium species tested suggest that they are potential candidates for control of Fusarium diseases of sugarbeet. Research is needed to determine the effectiveness of these fungicides for control of Fusarium diseases under field conditions. [ABSTRACT FROM AUTHOR]

Abstract: Mould growth and mycotoxin production are related to plant stress caused by environmental factors such as: extreme weather; insect damage; inadequate storage conditions and incorrect fertilization; these predispose plants to mycotoxin contamination in the field. Fusarium species infect wheat during the flowering period. In addition to losses of yield, these fungi can also synthesize toxic components (mycotoxins) in suitable environmental conditions, thus threatening animal and human health. Given the severe consequences and the fact that mycotoxins affect production throughout the world, the ability to predict Fusarium head blight (FHB) and deoxynivalenol (DON) and other mycotoxin contamination is important to reduce the year-to-year risk for producers. Owing to these dangerous consequences in Argentina, Belgium, Canada, Italy, the United States and in Europe, computer models, based on weather variables (temperature, rainfall and moisture level), have been developed to predict the occurrence of FHB and DON contamination in wheat. [Copyright &y& Elsevier]

The article reports on a study of the characteristics and distribution of the soybean sudden death syndrome (SDS) caused by Fusarium virguliforme in the northern United States. It used the polymerase chain reaction assay and DNA sequences to compare the SDS symptoms on soybean seedlings from Minnesota, Iowa, Missouri, and Illinois. It showed that SDS in Minnesota was caused by the establishment of a clonal US population of Fusarium virguliforme and increasing production risk in northern states.

A collection of 712 Fusarium graimnearum sensu stricto (s.s.) strains, predominantly gathered between 1999 and 2000 from nine states within the United States, was examined for population structure and polymerase chain reaction-based trichothecene type. Most strains belonged to a cohesive genetic population characterized by a 15-acetyldeoxynivalenol (I5ADON) trichothecene type. However, using a Bayesian model-based clustering method, we also identified genetically divergent groups of strains in some sampled locations of Minnesota and North Dakota. Strains of the major group of divergent populations were of a 3ADON trichothecene type and formed a distinct cluster with a collection of previously gathered strains from Italy, which displayed all three trichothecene types (15ADON, 3ADON, and nivalenol). The co-existence of genetically divergent populations of F. graminearum s.s. in the Upper Midwest allows for the rejection of the hypothesis that F. graminearum s.s. in the United States consists of a single population. These results also suggest that recombination has been insufficiently frequent in this homothallic (selfing) fungal species to homogenize the divergent populations observed in the Upper Midwest. [ABSTRACT FROM AUTHOR]

Isolates of two biologically and phylogenetically distinct species, referred to as Fusarium solani f. sp. cucurbitae race (Fsc-1 = Nectria haematococca mating population I [MPI]) and F. solani f. sp. cucurbitae race 2 (Fsc-2 = N. haematococca mating population V [MPV]), were suspected of causing an outbreak of Fusarium foot and fruit rot of pumpkin during 2001 to 2003 in Connecticut, New York, Ohio, and Missouri. Both species affect the fruit, but Fsc-1 also affects the crown and causes a stem rot. In this study, 156 isolates from affected plants and from soil under diseased fruit that tentatively were identified morphologically as members of the F. solani species complex were assayed for pathogenicity on pumpkin seedlings and mature fruit. Results of the pathogenicity assay indicated that 81 of the isolates were Fsc-1. The remaining 74 isolates were either nonpathogenic or only weakly pathogenic on the fruit. A subset of 53 test isolates from soil and plants, plus reference isolates of Fsc-1 and Fsc-2 and an isolate from wheat reported to cause a seedling rot on cucurbits, were characterized phylogenetically by sequencing a portion of the translation elongation factor 1-α gene. A BLAST query of the FUSARIUM-ID database at Pennsylvania State University indicated that 42 of the 53 test isolates were Fsc-1, whereas none were typed as Fsc-2. A polymerase chain reaction assay for mating-type (MAT) idiomorph revealed that all of the Fsc-1 isolates were MAT-1-2, suggesting that the pathogen may be strictly clonal in the affected fields. These findings provide convincing evidence that the Fusarium foot and fruit rot outbreaks were incited by Fsc-1. [ABSTRACT FROM AUTHOR]

Commercially distributed garlic ( Allium sativum) seed cloves from six states of the United States and mainland China were surveyed for the presence of fungi recorded as pathogenic to garlic in the literature. Aspergillus niger, A. ochraceus, Botrytis porri, Embellisia allii, Fusarium oxysporum f. sp. cepae, F. proliferatum and Penicillium hirsutum, were each recovered from one or more of these commercial sources, as was F. verticillioides, not previously reported as pathogenic to garlic, but here demonstrated to be a pathogen. Seed garlic distributed from public germplasm collections may also contain fungal pathogens: E. allii, F. oxysporum f. sp. cepae and/or F. proliferatum caused severe losses in 2002–2003 and 2005–2006 during germplasm regeneration and storage for the National Plant Germplasm System in Pullman, Washington. Use of fludioxonil, thiophanate methyl and/or benomyl (the latter withdrawn from the market, but used here as a standard) at label rates against E. allii and Fusarium species promoted plant health, but not when infections were located deep within tissues nor under some situations involving high disease pressure. [ABSTRACT FROM AUTHOR]

Pitch canker disease (Fusarium circinatum Nirenberg & O''Donnell) causes serious shoot dieback, reduced growth and mortality in pines found in the southern and western USA, and has been linked to nutrient imbalances. Poultry houses with forced-air ventilation systems produce nitrogen (N) emissions. This study analyzed spatial correlations between pitch canker disease and foliar, forest floor, soil, and throughfall N in a slash pine (Pinus elliottii var. Elliottii Engelm. ) plantation adjacent to a poultry operation in north Florida, USA. Tissue and throughfall N concentrations were highest near the poultry houses and remained elevated for 400m. Disease incidence ranged from 57–71% near the poultry houses and was spatially correlated with N levels. Similarly, stem mortality ranged from 41–53% in the most heavily impacted area, and declined to 0–9% at distances greater than 400m. These results suggest that nutritional processes exacerbate changes in disease susceptibility and expression in slash pine. [Copyright &y& Elsevier]

Zearalenone, a secondary metabolite produced by several plant-pathogenic fungi of the genus Fusarium, has high estrogenic activity in vertebrates. We developed a Saccharomyces cerevisiae bioassay strain that we used to identify plant genes encoding UDP-glucosyltransferases that can convert zearalenone into zearalenone-4-O-glucoside (ZON-4-O-Glc). Attachment of the glucose moiety to zearalenone prevented the interaction of the mycotoxin with the human estrogen receptor. We found that two of six clustered, similar UGT73C genes of Arabidopsis thaliana encode glucosyltransferases that can inactivate zearalenone in the yeast bioassay. The formation of glucose conjugates seems to be an important plant mechanism for coping with zearalenone but may result in significant amounts of ‘masked’ zearalenone in Fusarium-infected plant products. Due to the unavailability of an analytical standard, the ZON-4-O-Glc is not measured in routine analytical procedures, even though it can be converted back to active zearalenone in the digestive tracts of animals. Zearalenone added to yeast transformed with UGT73C6 was converted rapidly and efficiently to ZON-4-O-Glc, suggesting that the cloned UDP-glucosyltransferase could be used to produce reference glucosides of zearalenone and its derivatives. [ABSTRACT FROM AUTHOR]

In limited previous studies of the Ascomycete fungus Gibberella zeae in North America, the populations examined were genetically and phenotypically diverse and could be viewed as subsamples of a larger population. Our objective in this study was to test the hypothesis that a homogeneous, randomly mating population of G. zeae is contiguous throughout the central and eastern United States across a span of several years. We analysed presence/absence alleles based on amplified fragment length polymorphisms (AFLPs) at 30 loci, 24 of which are defined genetically on a linkage map of G. zeae, from > 500 isolates in eight field populations from seven states collected during the 1998, 1999 and 2000 cropping seasons. All these strains had AFLP profiles similar to those of standard isolates of G. zeae phylogenetic lineage 7. All the populations are genetically similar, have high genotypic diversity and little or no detectable genetic disequilibrium, and show evidence of extensive interpopulation genetic exchange. Allele frequencies in some of the populations examined are not statistically different from one another, but others are. Thus, the populations examined are not mere subsamples from a single, large, randomly mating population. Geographic distance and genetic distance between populations are correlated significantly. The observed differences are relatively small, however, indicating that while genetic isolation by distance may occur, genetic exchange has occurred at a relatively high frequency among US populations of G. zeae. We think that these differences reflect the time required for the alleles to diffuse across the distances that separate them, because relatively little linkage disequilibrium is detected either in the population as a whole or in any of the individual subpopulations. [ABSTRACT FROM AUTHOR]

Fusarium ear rot and fumonisin contamination are serious problems for maize growers, particularly in the southeastern United States. The lack of maize genotypes highly resistant to infection by Fusarium verticillioides or to fumonisin contamination emphasizes the need for management strategies to prevent contamination by this mycotoxin. Information on the initial appearance of infection and fumonisin contamination of kernels and their increase over time is needed to determine if early harvest may be an appropriate control strategy. Maize ears from replicated studies at two locations in eastern North Carolina were harvested weekly, starting 2 weeks after pollination and continuing for 14 weeks. The percentage of kernels infected with F. verticillioides and the fumonisin contamination in the harvested samples were determined. Kernel infection by E verticillioides and fumonisin contamination appeared as kernels neared physiological maturity and increased up to the average harvest date for maize in North Carolina. Beyond this date, the concentrations of fumonisin fluctuated. Under years conducive for fumonisin contamination, early harvest (greater than 25% grain moisture) may help reduce the level of contamination. [ABSTRACT FROM AUTHOR]

Abstract Fusarium wilt is an economically important fungal disease of common bean and sugar beet in the Central High Plains (CHP) region of the USA, with yield losses approaching 30% under appropriate environmental conditions. The objective of this study was to characterize genetic diversity and pathogenicity of isolates of Fusarium oxysporum obtained from common bean and sugar beet plants in the CHP that exhibited Fusarium wilt symptoms. A total of 166 isolates of F. oxysporum isolated from diseased common bean plants were screened for pathogenicity on the universal susceptible common bean cultivar ‘UI 114’. Only four of 166 isolates were pathogenic and were designated F. oxysporum f.sp. phaseoli (Fop). A set of 34 isolates, including pathogenic Fop, F. oxysporum f.sp. betae (Fob) isolates pathogenic on sugar beet, and non-pathogenic (Fo) isolates, were selected for random-amplified polymorphic DNA (RAPD) analysis. A total of 12 RAPD primers, which generated 105 polymorphic bands, were used to construct an unweighted paired group method with arithmetic averages dendrogram based on Jaccard's coefficient of similarity. All CHP Fop isolates had identical RAPD banding patterns, suggesting low genetic diversity for Fop in this region. CHP Fob isolates showed a greater degree of diversity, but in general clustered together in a grouping distinct from Fop isolates. As RAPD markers revealed such a high level of genetic diversity across all isolates examined, we conclude that RAPD markers had only limited usefulness in correlating pathogenicity among the isolates and races in this study. [ABSTRACT FROM AUTHOR]

Studies the colonization of maize seedling roots and rhizosphere by Fusarium species in two soil types in Mississippi. Effects of planting date and days after planting on the frequency of isolation of Fusarium species from maize seedling roots; Effects of location, year of production, tillage system and sampling time on the population of Fusarium isolated from the rhizosphere.

Watermelon is an important commercial crop in the Southeastern United States and around the world. However, production is significantly limited by biotic factors including fusarium wilt caused by the hemibiotrophic fungus Fusarium oxysporum forma specialis niveum (Fon). Unfortunately, this disease has increased significantly in its presence over the last several decades as races have emerged which can overcome the available commercial resistance. Management strategies include rotation, improved crop resistance, and chemical control, but early and accurate diagnostics are required for appropriate management. Accurate diagnostics require molecular and genomic strategies due to the near identical genomic sequences of the various races. Bioassays exist for evaluating both the pathogenicity and virulence of an isolate but are limited by the time and resources required. Molecular strategies are still imperfect but greatly reduce the time to complete the diagnosis. This article presents the current state of the research surrounding races, both how races have been detected and diagnosed in the past and future prospects for improving the system of differentiation. Additionally, the available Fon genomes were analyzed using a strategy previously described in separate formae speciales avirulence gene association studies in Fusarium oxysporum races. [ABSTRACT FROM AUTHOR]

Mycotoxins contaminate crops worldwide and play a role in animal health and performance. Multiple mycotoxins may co-occur which may increase the impact on the animal. To assess the multiple mycotoxin profile of corn (Zea mays), we conducted a 7-year survey of new crop corn grain and silage in the United States. A total of 711 grain and 1117 silage samples were collected between 2013 and 2019 and analyzed for the simultaneous presence of 35 mycotoxins using ultra-performance liquid chromatography–tandem mass spectrometry. The measured mean number of mycotoxins per sample were 4.8 (grain) and 5.2 (silage), ranging from 0 to 13. Fusaric acid (FA) was most frequently detected in 78.1 and 93.8% of grains and silages, respectively, followed by deoxynivalenol (DON) in 75.7 and 88.2% of samples. Fumonisin B1 (FB1), fumonisin B2 and 15-acetyl-deoxynivalenol (15ADON) followed. The greatest (p < 0.05) co-occurrence was between FA and DON in 59.1% of grains and 82.7% of silages, followed by FA with FB1, DON with 15ADON, and FA with 15ADON. Although many samples had lower mycotoxin concentrations, 1.6% (grain) and 7.9% (silage) of tested samples had DON ≥ 5000 µg/kg. Fumonisins were detected ≥ 10,000 µg/kg in 9.6 and 3.9% of grain and silage samples, respectively. Concentrations in grain varied by year for eight mycotoxin groups (p < 0.05), while all 10 groups showed yearly variations in silage. Our survey suggest that multiple mycotoxins frequently co-occur in corn grain and silage in the United States, and some of the more prevalent mycotoxins are those that may not be routinely analyzed (i.e., FA and 15ADON). Assessment of multiple mycotoxins should be considered when developing management programs. [ABSTRACT FROM AUTHOR]

During a survey of root diseases of pea in Denmark a new genetic variant or Fusarium axysporum f.sp. pisi was isolated from vining peas in two widely separated geographical regions. In terms of pathogenicity on a set of differential pea lines, the Danish isolated closely resembled a race 6 isolate from the United States. DNA extracts of the isolates, restricted with the endonuclease hind Ill. then probed with a homologous repetitive genomic fragment from the plasmid pDG106 by the Southern hybridization technique, gave a unique 'fingerprint' pattern distinctly different from the American race 6 and all other known races. When probed with pDG312. containing a homologous ribosomal repeat unit. the pattern obtained for the Danish isolates was indistinguishable from races 1. 5 and 6 but distinctly different from 2A and 2B. The Danish isolates represent a separate vegetative compatibility group because they are compatible with each other but incompatible with the other known races. In pigmentation the new variant resembled races 1, 5 and 6 for the first 8-12 days, after which it began to secrete a dark purple pigment resembling that of race 2A and 28. Until an additional line in the host differentials can separate the new genetic variant it should be conssidered a subgroup of F. oxysporum f. sp. pisi race 6. [ABSTRACT FROM AUTHOR]

Background: As effects of global climate change intensify, the interaction of biotic and abiotic stresses increasingly threatens current agricultural practices. The secondary cell wall is a vanguard of resistance to these stresses. Fusarium thapsinum (Fusarium stalk rot) and Macrophomina phaseolina (charcoal rot) cause internal damage to the stalks of the drought tolerant C4 grass, sorghum (Sorghum bicolor (L.) Moench), resulting in reduced transpiration, reduced photosynthesis, and increased lodging, severely reducing yields. Drought can magnify these losses. Two null alleles in monolignol biosynthesis of sorghum (brown midrib 6-ref, bmr6-ref; cinnamyl alcohol dehydrogenase, CAD; and bmr12-ref; caffeic acid O-methyltransferase, COMT) were used to investigate the interaction of water limitation with F. thapsinum or M. phaseolina infection., Results: The bmr12 plants inoculated with either of these pathogens had increased levels of salicylic acid (SA) and jasmonic acid (JA) across both watering conditions and significantly reduced lesion sizes under water limitation compared to adequate watering, which suggested that drought may prime induction of pathogen resistance. RNA-Seq analysis revealed coexpressed genes associated with pathogen infection. The defense response included phytohormone signal transduction pathways, primary and secondary cell wall biosynthetic genes, and genes encoding components of the spliceosome and proteasome., Conclusion: Alterations in the composition of the secondary cell wall affect immunity by influencing phenolic composition and phytohormone signaling, leading to the action of defense pathways. Some of these pathways appear to be activated or enhanced by drought. Secondary metabolite biosynthesis and modification in SA and JA signal transduction may be involved in priming a stronger defense response in water-limited bmr12 plants., (© 2021. The Author(s).)