Primary Pathogenic Fungi Research Articles

Isolation and Identification of Postharvest Rot Pathogens in Citrus × tangelo and Their Potential Inhibition with Acidic Electrolyzed Water.

This study focused on the identification of rot-causing fungi in Citrus × tangelo (tangelo) with a particular emphasis on investigating the inhibitory effects of acidic electrolyzed water on the identified pathogens. The dominant strains responsible for postharvest decay were isolated from infected tangelo fruits and characterized through morphological observation, molecular identification, and pathogenicity detection. Two strains were isolated from postharvest diseased tangelo fruits, cultured and morphologically characterized, and had their gene fragments amplified using primers ITS1 and ITS4. The results revealed the rDNA-ITS sequence of two dominant pathogens were 100% homologous with those of Penicillium citrinum and Aspergillus sydowii. These isolated fungi were confirmed to induce tangelo disease, and subsequent re-isolation validated their consistency with the inoculum. Antifungal tests demonstrated that acidic electrolyzed water (AEW) exhibited a potent inhibitory effect on P. citrinum and A. sydowii, with EC50 values of 85.4μg/mL and 60.12μg/mL, respectively. The inhibition zones of 150μg/mL AEW to 2 kinds of pathogenic fungi were over 75mm in diameter. Furthermore, treatment with AEW resulted in morphological changes such as bending and shrinking of the fungal hyphae surface. In addition, extracellular pH, conductivity, and absorbance at 260nm of the fungi hypha significantly increased post-treatment with AEW. Pathogenic morphology and IST sequencing analysis confirmed P. citrinum and A. sydowii as the primary pathogenic fungi, with their growth effectively inhibited by AEW.

Carboxymethyl cellulose/Tween 80/Litsea cubeba essential oil nanoemulsion inhibits the growth of Penicillium digitatum and extends the shelf-life of ‘Shatangju’ mandarin

Penicillium digitatum (P. digitatum) is the primary pathogenic fungus responsible for postharvest citrus green mold, leading to a deterioration in fruit quality and significant economic losses. Litsea cubeba essential oil (LCEO) has gained widespread attention as a natural antifungal substance due to its high safety profile, non-resistance traits, and broad-spectrum antifungal activity. In this study, we prepared Litsea cubeba essential oil nanoemulsion (LCEO-NE) using Tween 80 and carboxymethyl cellulose (CMC) as emulsifiers through ultrasonic emulsification. The investigation delved into their stability, rheology, inhibitory activity against P. digitatum, and efficacy in preserving ‘Shatangju’ mandarin during storage. The results showed that the droplet size, polydispersity index, and zeta potential were 18.69 nm, 0.116, and −29.72 mV, respectively. LCEO-NE added with CMC and Tween 80 synergistically (LCEO-NE-CMC) have exhibited higher pH stability, ionic strength stability, thermal stability, storage stability, and centrifugal stability compared to LCEO-NE with Tween 80. In vitro fungistatic tests revealed that the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of LCEO-NE-CMC against P. digitatum were 1 μL mL−1 and 2 μL mL−1, respectively. LCEO-NE-CMC effectively inhibited mycelium growth, spore germination, and elongation of germ tubes. Scanning electron microscopy results demonstrated that LCEO-NE-CMC caused wrinkling and twisting of P. digitatum mycelium. Transmission electron microscopy results further revealed severe damage to the cell membrane, cytoplasm, and organelles, hindering mycelial growth. Furthermore, LCEO-NE-CMC treatment of ‘Shatangju’ mandarin significantly reduced weight loss and decay rate and delayed the decline in hardness and total soluble solids. In summary, LCEO-NE-CMC has been validated as a potent antifungal agent capable of extending the shelf life of ‘Shatangju’ mandarin.

Foeniculum vulgare essential oil nanoemulsion inhibits Fusarium oxysporum causing Panax notoginseng root-rot disease

BackgroundFusarium oxysporum (F. oxysporum) is the primary pathogenic fungus that causes Panax notoginseng (P. notoginseng) root rot disease. To control the disease, safe and efficient antifungal pesticides must currently be developed. MethodsIn this study, we prepared and characterized a nanoemulsion of Foeniculum vulgare essential oil (Ne-FvEO) using ultrasonic technology and evaluated its stability. Traditional Foeniculum vulgare essential oil (T-FvEO) was prepared simultaneously with 1/1000 Tween-80 and 20/1000 dimethyl sulfoxide (DMSO). The effects and inhibitory mechanism of Ne-FvEO and T-FvEO in F. oxysporum were investigated through combined transcriptome and metabolome analyses. ResultsResults showed that the minimum inhibitory concentration (MIC) of Ne-FvEO decreased from 3.65 mg/mL to 0.35 mg/mL, and its bioavailability increased by 10-fold. The results of gas chromatography/mass spectrometry (GC/MS) showed that T-FvEO did not contain a high content of estragole compared to Foeniculum vulgare essential oil (FvEO) and Ne-FvEO. Combined metabolome and transcriptome analysis showed that both emulsions inhibited the growth and development of F. oxysporum through the synthesis of the cell wall and cell membrane, energy metabolism, and genetic information of F. oxysporum mycelium. Ne-FvEO also inhibited the expression of 2-oxoglutarate dehydrogenase and isocitrate dehydrogenase and reduced the content of 2-oxoglutarate, which inhibited the germination of spores. ConclusionOur findings suggest that Ne-FvEO effectively inhibited the growth of F. oxysporum in P. notoginseng in vivo. The findings contribute to our comprehension of the antifungal mechanism of essential oils (EOs) and lay the groundwork for the creation of plant-derived antifungal medicines.

Carvacrol Treatment Reduces Decay and Maintains the Postharvest Quality of Red Grape Fruits (Vitis vinifera L.) Inoculated with Alternaria alternata.

In this study, we isolated and identified pathogenic fungi from the naturally occurring fruits of red grapes, studied their biological characteristics, screened fifteen essential oil components to find the best natural antibacterial agent with the strongest inhibitory effect, and then compared the incidence of postharvest diseases and storage potential of red grapes treated with two concentrations (0.5 EC50/EC50) of essential oil components (inoculated with pathogenic fungi) during storage for 12 d at room temperature. In our research, Alternaria alternata was the primary pathogenic fungus of red grapes. Specifically, red grapes became infected which caused diseases, regardless of whether they were inoculated with Alternaria alternata in an injured or uninjured state. Our findings demonstrated that the following conditions were ideal for Alternaria alternata mycelial development and spore germination: BSA medium, D-maltose, ammonium nitrate, 28 °C, pH 6, and exposure to light. For the best Alternaria alternata spore production, OA medium, mannitol, urea, 34 °C, pH 9, and dark conditions were advised. Furthermore, with an EC50 value of 36.71 μg/mL, carvacrol demonstrated the highest inhibitory impact on Alternaria alternata among the 15 components of essential oils. In the meantime, treatment with EC50 concentration of carvacrol was found to be more effective than 0.5 EC50 concentration for controlling Alternaria alternata-induced decay disease of red grapes. The fruits exhibited remarkable improvements in the activity of defense-related enzymes, preservation of the greatest hardness and total soluble solids content, reduction in membrane lipid peroxidation in the peel, and preservation of the structural integrity of peel cells. Consequently, carvacrol was able to prevent the Alternaria alternata infestation disease that affects red grapes, and its EC50 concentration produced the greatest outcomes.

Proteomic profile of Cryptococcus gattii biofilm: Metabolic shift and the potential activation of electron chain transport

Cryptococcus gattii is a primary pathogenic fungus that causes pneumonia. This species is also responsible for an outbreak in Vancouver, Canada, and spreading to the mainland and United States. The use of medical devices is often complicated by infections with biofilm-forming microbes with increased resistance to antimicrobial agents and host defense mechanisms. This study investigated the comparative proteome of C. gattii R265 (VGIIa) grown under planktonic and biofilm conditions. A brief comparison with C. neoformans H99 biofilm and the use of different culture medium and surface were also evaluated. Using Multidimensional Protein Identification Technology (MudPIT), 1819 proteins were identified for both conditions, where 150 (8.2%) were considered differentially regulated (up- or down-regulated and unique in biofilm cells). Overall, the proteomic approach suggests that C. gattii R265 biofilm cells are maintained by the induction of electron transport chain for reoxidation, and by alternative energy metabolites, such as succinate and acetate. SignificanceSince C. gattii is considered a primary pathogen and is one of the most virulent and less susceptible to antifungals, understanding how biofilms are maintained is fundamental to search for new targets to control this important mode of growth that is difficult to eradicate.

A novel secreted protein FgHrip1 from Fusarium graminearum triggers immune responses in plants

Fusarium graminearum, the primary pathogenic fungus responsible for Fusarium head blight (FHB) in wheat, secretes abundant chemical compounds that interact with host plants. In this study, a secreted protein FgHrip1, isolated from the culture filtrate of F. graminearum, was found to induce typical cell death in tobacco. The FgHrip1 gene was then cloned and expressed in Escherichia coli. Further bioassay analysis showed that the recombinant FgHrip1 induced early defense induction events, such as reactive oxygen species (ROS) production, callose deposition, and up-regulation of defense-related genes in tobacco. Furthermore, FgHrip1 significantly enhanced immunity in tobacco seedlings against Pseudomonas syringae pv. tabaci 6605 (Pst. 6605) and tobacco mosaic virus (TMV). FgHrip1-treated wheat spikes also exhibited defense-related transcript accumulation and developed immunity against FHB infection. Whereas the expression of FgHrip1 was induced during the infection process, the deletion of the gene impaired the virulence of F. graminearum. Our results suggest that FgHrip1 triggers immunity and induces disease resistance in tobacco and wheat, thereby providing new insight into strategy for biocontrol of FHB.

First Report of Anthracnose Caused by Colletotrichum camelliae on Amorphophallus konjac in Hunan Province of China.

Amorphophallus konjac is a crop in the family Araceae, which is widely cultivated in Hunan, Yunnan, and Guizhou in China. A. konjac flour is highly valuable economically as a product for weight reduction. In June 2022, a new leaf disease was discovered in an understory A. konjac plantation in Xupu County, Hunan Province, China, where 2,000 hm2 of A. konjac had been planted. Approximately 40% of the total cultivated area exhibited symptoms. The disease outbreaks occurred during warm and wet weather (May to June). In the early stages of infection, small brown spots appeared on the leaves and then gradually spread into irregular lesions. There was a light yellow halo around the brown lesions. In severe cases, the whole plant gradually turned yellow and died. Six symptomatic leaf samples were collected from three different fields in Xupu County to isolate the causal agent. They were rinsed with sterile water, and the lesions were cut off. The lesions were rinsed in 3% hydrogen peroxide for 30 s followed by a 90 s treatment in 75% alcohol. They were then rinsed five times in sterile water, placed on water agar plates and incubated for 2-3 days at 28°C. After the mycelium had grown, they were transferred to potato dextrose agar (PDA) plates and incubated for 3-5 days at 28°C. In total, ten isolates were obtained, and seven of them were Colletotrichum (isolation frequency 70%). Three representative isolates (HY1, HY2, and HY3) were selected for further study. This fungus grew as circular white colonies, which then became grey. The older colonies looked like cotton and had dense aerial hyphae. The conidia were cylindrical, lacked a septum, and were thin-walled. They measured 14.04 to 21.58 × 5.89 to 10.40 μm (n=100). To further confirm its fungal identity, the fungus was amplified and sequenced using six genetic regions, including β-tubulin (TUB2), actin (ACT), the internal transcribed spacer (ITS), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), calmodulin (CAL) and chitin synthase (CHS). The universal primers BT2a/TUB2R, ACT512F/ACT783R, ITS4/ITS5, GDF/GDR, CL1C/CL2C, CHS79F/CHS345R were used for amplification (Weir et al. 2012), sequenced by the Sanger chain termination method, and submitted to GenBank (TUB2: OQ506549, OQ506544, OP604480; ACT: OQ506551, OQ506546, OP604482; ITS: OQ457036, OQ457498, OP458555; GAPDH: OQ506553, OQ506548, OP604484; CAL: OQ506552, OQ506547, OP604483; CHS: OQ506550, OQ506545, OP604481). An analysis of a joint phylogenetic tree that was constructed using the six genes showed that the three isolates clearly clustered with Colletotrichum camelliae (syn. Glomerella cingulata f. sp. camelliae) strain ICMP 10646 (GenBank: JX010437.1, JX009563.1, JX010225.1, JX009993.1, JX009629.1, JX009892.1) and HUN1A4 (GenBank: KU252173.1, KU251646.1, KU251565.1, KU252019.1, KU251838.1, KU251913.1). HY3 was used as a representative strain for the pathogenicity test on the leaves of A. konjac from the whole plant. PDA blocks that were 6 × 6 mm and had been cultured for 5 d were placed on the leaf surface, and sterile PDA blocks were used as the control group. The climate chamber was maintained at 28°C at all times, and 90% relative humidity was maintained. The pathogenic lesions appeared after 10 days of inoculation. The pathogen that was re-isolated from the diseased tissues had the same morphological characteristics as HY3. Thus, Koch's postulates were fulfilled. C. camelliae has been shown to be the primary pathogenic fungus responsible for anthracnose in tea (Ca. sinensis (L.) O. Kuntze) (Wang et al. 2016) and camellia oleifera (Ca. oleifera Abel.) (Li et al. 2016). Anthracnose caused by Colletotrichum gloeosporioides has been reported on A. konjac (Li. 2021). However, to our knowledge, this is the first report in China and worldwide that C. camelliae causes anthracnose on A. konjac. This research lays the foundation for future research to control this disease.

Measuring Pathogenic Soil Fungi That Cause Sclerotinia Rot of Panax ginseng Using Real-Time Fluorescence Quantitative PCR

Sclerotinia ginseng is the primary pathogenic fungus responsible for Sclerotinia rot of ginseng, which significantly reduces plant yield and quality. The density of sclerotia in the soil is closely associated with rot incidence and severity. Whole genome sequencing was conducted to obtain fungal frame maps. The specific primers, q2001F/q2001R, were screened out by pan-genomic analysis using the NCBI database. Recombinant plasmids containing amplicons obtained with this primer set were used as standard plasmids to construct a real-time fluorescence quantitative PCR system. The relationships between the cycle threshold (Ct) values and the soil sclerotium densities were determined by real-time PCR. Real-time PCR had a detection limit of 1.5 × 10−2 g·kg−1 soil for Sclerotinia rot causing fungal mycelium, and the relationship between the density of S. ginseng mycelium n (g·g−1 soil) and the Ct value was n = 10(40.048 − Ct)/6.9541. The detection limit of real-time PCR for measuring soil sclerotia was 3.8 × 10−5 g·g−1 soil, suggesting a sensitivity 100 times that of conventional PCR. The relationship between the sclerotium density n (g·g−1 soil) and the Ct value was n = 10(18.351 − Ct)/7.0914. Compared with the conventional PCR method, the fluorescent quantitative PCR method could detect the population of Sclerotinia spp. in soil more efficiently, accurately, and sensitively.

Candida albicans the main opportunistic pathogenic fungus in humans

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

Defense Mechanisms of Cotton Fusarium and Verticillium Wilt and Comparison of Pathogenic Response in Cotton and Humans.

Cotton is an important economic crop. Fusarium and Verticillium are the primary pathogenic fungi that threaten both the quality and sustainable production of cotton. As an opportunistic pathogen, Fusarium causes various human diseases, including fungal keratitis, which is the most common. Therefore, there is an urgent need to study and clarify the resistance mechanisms of cotton and humans toward Fusarium in order to mitigate, or eliminate, its harm. Herein, we first discuss the resistance and susceptibility mechanisms of cotton to Fusarium and Verticillium wilt and classify associated genes based on their functions. We then outline the characteristics and pathogenicity of Fusarium and describe the multiple roles of human neutrophils in limiting hyphal growth. Finally, we comprehensively compare the similarities and differences between animal and plant resistance to Fusarium and put forward new insights into novel strategies for cotton disease resistance breeding and treatment of Fusarium infection in humans.

Potential role of rhizobia to enhance chickpea-growth and yield in low fertility-soils of Tunisia.

Plant growth-promoting rhizobacteria are bacteria that improve plant growth and reduce plant pathogen damages. In this study, 100 nodule bacteria were isolated from chickpea, screened for their plant growth-promoting (PGP) traits and then characterised by PCR-RFLP of 16S rDNA. Results showed that most of the slow-growing isolates fixed nitrogen but those exhibiting fast-growth did not. Fourteen isolates solubilized inorganic phosphorus, 16 strains produced siderophores, and 17 strains produced indole acetic acid. Co-culture experiments identified three strains having an inhibitory effect against Fusarium oxysporum, the primary pathogenic fungus for chickpea in Tunisia. Rhizobia with PGP traits were assigned to Mesorhizobium ciceri, Mesorhizobium mediterraneum, Sinorhizobium meliloti and Agrobacterium tumefaciens. We noted that PGP activities were differentially distributed between M. ciceri and M. mediterraneum. The region of Mateur in northern Tunisia, with clay-silty soil, was the origin of 53% of PGP isolates. Interestingly, we found that S. meliloti and A. tumefaciens strains did not behave as parasitic nodule-bacteria but as PGP rhizobacteria useful for chickpea nutrition and health. In fact, S. meliloti strains could solubilize phosphorus, produce siderophore and auxin. The A. tumefaciens strains could perform the previous PGP traits and inhibit pathogen growth also. Finally, one candidate strain of M. ciceri (LL10)-selected for its highest symbiotic nitrogen fixation and phosphorus solubilization-was used for field experiment. The LL10 inoculation increased grain yield more than three-fold. These finding showed the potential role of rhizobia to be used as biofertilizers and biopesticides, representing low-cost and environment-friendly inputs for sustainable agriculture.

Antagonism Activity of Phosphate Solubilizing Bacteria Against Ganoderma philippii and Fusarium oxysporum of Acacia Plants

Ganoderma philippii and Fusarium oxysporum 0148c are the primary pathogenic fungi that causes root rot and damping-off in young acacia plants. The best treatment to date is the use of biological control agents. Phosphate solubilizing bacteria (PSB) isolated from acid soil is a bacterial isolate classified as plant growth-promoting bacteria (PGPB). PGPB has an indirect function as a biocontrol agent for fungal pathogens. This study aimed to determine the potential of PSB isolate EF.NAP 8 in inhibiting G. philippii and F. oxysporum 0148c from acacia plants. The method used is a dual culture antagonism test and observation of abnormal hyphae after the antagonism process. The results showed that the isolate EF.NAP 8 inhibited G. philippii by 34.44% and F. oxysporum 0148c by 33.33%. The abnormality of hyphae after antagonistic activity results in hyphal malformations such as hyphae lysis and hyphae coiling. The antagonistic activity of PSB EF.NAP 8 isolate is one of part of the ability of a bacterium classified as PGPB in the form of biocontrol activity against pathogenic fungi. This provides information regarding the opportunity to utilize EF.NAP 8 as a candidate agent for controlling fungal pathogens on acacia plants.

The role of cell wall polysaccharides disassembly in Lasiodiplodia theobromae-induced disease occurrence and softening of fresh longan fruit

Cell wall polysaccharides in fruits act a pivotal role in their resistance to fungal invasion. Lasiodiplodia theobromae (Pat.) Griff. & Maubl. is a primary pathogenic fungus causing the spoilage of fresh longan fruit. In this study, the influences of L. theobromae inoculation on the disassembly of cell wall polysaccharides in pericarp of fresh longans and its association with L. theobromae-induced disease and softening development were investigated. In contrast to the control, samples with L. theobromae infection showed more severe disease development, lower firmness, lower amounts of cell wall materials, covalent-soluble pectin, ionic-soluble pectin, cellulose and hemicellulose, whereas higher value of water-soluble pectin, higher activities of cell wall polysaccharide-disassembling enzymes (cellulase, β-galactosidase, polygalacturonase and pectinesterase). These findings revealed that cell wall polysaccharides disassembly induced by enzymatic manipulation was an essential pathway for L. theobromae to infect harvested longans, and thus led to the disease occurrence and fruit softening.

Innate Immune Receptors and Defense Against Primary Pathogenic Fungi.

The innate immune system is critical for natural resistance to all pathogenic microorganisms, including fungi. The innate response plays a vital role in resistance to infections before the antigen-specific immune response and also influences antigen-specific adaptive immunity. There are many different receptors for the innate immune response to fungi, and some receptors have been found to play a significant role in the response to human infections with opportunistic fungi. Most human infections are caused by opportunistic fungi, but a small number of organisms are capable of causing infections in normal hosts. The primary pathogenic fungi that cause invasive infections include Blastomyces spp., Cryptococcus gattii, Coccidioides spp., Histoplasma spp., and Paracoccidioides spp. In this review of innate immune receptors that play a role in infections caused by these organisms, we find that innate immunity differs between organisms.

Laboratory exposure to Coccidioides: lessons learnt in a non-endemic country

Coccidioides is a primary pathogenic fungus, which infects humans through highly infectious arthroconidia, causing substantial morbidity including life-threatening disseminated infections. Due to the low infectious dose, laboratory personnel might become infected during diagnostic procedures. Accordingly, coccidioidomycosis is reported as the most frequent laboratory-acquired systemic mycosis worldwide. This risk is aggravated in non-endemic countries, where the diagnosis may not be suspected. We report on an inadvertent exposure of 44 persons to Coccidioides posadasii in a clinical microbiology laboratory in Chile, the measures of containment after rapid diagnosis with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and the lessons learnt in a non-endemic setting.

Analysis of Transposable Elements in Coccidioides Species.

Coccidioides immitis and C. posadasii are primary pathogenic fungi that cause disease in immunologically-normal animals and people. The organism is found exclusively in arid regions of the Southwestern United States, Mexico, and South America, but not in other parts of the world. This study is a detailed analysis of the transposable elements (TE) in Coccidioides spp. As is common in most fungi, Class I and Class II transposons were identified and the LTR Gypsy superfamily is the most common. The minority of Coccidioides Gypsy transposons contained regions highly homologous to polyprotein domains. Phylogenetic analysis of the integrase and reverse transcriptase sequences revealed that many, but not all, of the Gypsy reverse transcriptase and integrase domains clustered by species suggesting extensive transposition after speciation of the two Coccidiodies spp. The TEs were clustered and the distribution is enriched for the ends on contigs. Analysis of gene expression data from C. immitis found that protein-coding genes within 1 kB of hAT or Gypsy TEs were poorly expressed. The expression of C. posadasii genes within 1 kB of Gypsy TEs was also significantly lower compared to all genes but the difference in expression was smaller than C. immitis. C. posadasii orthologs of C. immitis Gyspsy-associated genes were also likely to be TE-associated. In both C. immitis and C. posadasii the TEs were preferentially associated with genes annotated with protein kinase gene ontology terms. These observations suggest that TE may play a role in influencing gene expression in Coccidioides spp. Our hope is that these bioinformatic studies of the potential TE influence on expression and evolution of Coccidioides will prompt the development of testable hypotheses to better understand the role of TEs in the biology and gene regulation of Coccidioides spp.

Effect of environmental factors on Fusarium population and associated trichothecenes in wheat grain grown in Jiangsu province, China

The present study was performed to identify prevailing Fusarium species and the environmental factors affecting their frequencies and the contamination of grain with major mycotoxins in Jiangsu province. The precipitation levels were 184.2mm, 156.4mm, and 245.8mm in the years 2013–2015, respectively, and the temperature fluctuated by an average of 10.6±7.2°C in 2013, 10.9±7.2°C in 2014, and 10.6±6.3°C in 2015. Co-occurrence of deoxynivalenol (DON), 3-acetyldeoxynivalenol (3ADON), and 15-acetyldeoxynivalenol (15ADON) were observed in wheat. The average concentrations of DON were 879.3±1127.8, 627.8±640.5, and 1628.6±2,168.0μg/kg in 2013–2015, respectively. The average concentrations of 3ADON were 43.5±59.0, 71.2±102.5, and 33.5±111.9μg/kg in 2013–2015, respectively. We found that the average concentration of DON in wheat was positively correlated with precipitation (r=0.998, p<0.01), and 3ADON was negatively correlated with precipitation (r=−0.887, p<0.05). However, there was no correlation between precipitation and 15ADON or nivalenol (NIV). The differences in temperature were not as significant as the differences in rainfall amount over a short time period. Therefore, there were no correlations between temperature and the concentrations of trichothecenes, excluding 3ADON (r=0.996, p<0.01). Our data indicated that Fusarium asiaticum is the primary pathogenic fungus prevalent in the Fusarium head blight disease nursery. The trichothecene chemotype composition differed between Fusarium graminearum sensu stricto (s. str.) and F. asiaticum isolates. The 3ADON chemotype was found only among strains of F. asiaticum. The NIV chemotype was not observed among strains of F. graminearum, while the 15ADON chemotype represented 100% of the F. graminearum strains collected. The results of this study indicated no correlations between environmental conditions and the species or genetic chemotype composition of pathogens in Jiangsu province in 2013–2015.

A retrospective analysis of the clinical characteristics, etiology and prognosis of fungal keratitis with diabetes mellitus

Background The incidence of fungal keratitis is increasing and it is one of the leading causes of infectious corneal blindness.Fungal keratitis with diabetes mellitus (DM)also has an increasing trend,but the study on the disease is still relatively scarce.Objective This study was to analyze the clinical characteristics,etiology and prognosis of fungal keratitis with DM.Methods The clinical data of 87 cases of fungal keratitis with DM and 40 cases of fungal keratitis without systemic disease were retrospectively reviewed,and the demographic characteristics,clinical symptoms,pathologic examination and the prognosis of the patients were analyzed and compared.Results Poor glycemic control and trauma were more likely precipitating factors of fungal keratitis with DM.The proportion of vegetable injury was 36.8％ in the fungal keratitis with DM group,and it was lower than 57.5％ in the fungal keratitis without systemic disease group(x2 =6.06,P＜0.05).The age at onset for fungal keratitis in the fungal keratitis with DM group was higher than that in the fungal keratitis without systemic disease group.The majority of patients in the fungal keratitis with DM group was farmers (34.5％)and physical workers (26.4％),with a mean history of DM for (13.0±4.9) years.Laboratory examination showed that Fusarium was the primary pathogenic fungi for the fungal keratitis with a proportion of 60.0％ and next was Aspergillus (20.0％) and Candida (20.0％).The proportion of Candida infection was higher in the fungal keratitis with DM group than that in the fungal keratitis without systemic disease group(20.0％ versus 10.0％) (x2 =3.92,P＜0.05).The cure rate for fungal keratitis with DM patients was 46.0％,and that for fungal keratitis without systemic disease patients was 62.5％,showing a significant difference between them (x2 =5.48,P＜0.05).In addition,the ineffective rate of treatment for fungal keratitis with DM patients was 14.9％,which was higher than that of fungal keratitis without systemic disease patients(5.0％) (x2 =5.47,P＜ 0.05).Conclusions Fungal keratitis with DM possesses its own characteristics.DM is an important risk factor of pathogenesis of fungal keratitis.Sustained high blood glucose levels might affect the demographic characteristics,clinical symptom,pathogenic types and prognosis of fungal keratitis patients. Key words: Eye infection, fungal; Keratitis; Diabetes complication; Retrospective study

Dectin-1 Is Required for Resistance to Coccidioidomycosis in Mice

ABSTRACTWe assessed the role of Dectin-1 in the immune response to the pathogenic fungus Coccidioides, both in vitro and in vivo, using mice with a targeted mutation in Clec7a. Elicited peritoneal macrophages responded to formalin-killed spherules (FKS) and alkali-treated FKS by secreting proinflammatory cytokines in a Dectin-1- and β-glucan-dependent manner. The responses of bone marrow-derived dendritic cells (BMDC) to the same stimulants were more complex; interleukin 1β (IL-1β) and tumor necrosis factor alpha (TNF-α) secretion was independent of Dectin-1, while IL-6, IL-10, and granulocyte-macrophage colony-stimulating factor (GM-CSF) were largely but not entirely dependent on Dectin-1. After intranasal infection, Dectin-1−/− mice had lower concentrations of IL-12p70, gamma interferon (IFN-γ), IL-1β, and the Th17 cytokines IL-22, IL-23, and 17A in the lung lavage fluid, which may explain why they were significantly more susceptible to pulmonary coccidioidomycosis two weeks after infection. The Dectin-1 mutation was even more deleterious in (B6 × DBA/2)F2 mice, which are more resistant to coccidioidomycosis than B6 mice by virtue of protective genes from DBA/2, a genetically resistant strain. We also found that two susceptible strains of mice (B6 and BALB/c) expressed much less Dectin-1 in their lungs than did resistant DBA/2 mice. We conclude that Dectin-1 is necessary for resistance to Coccidioides immitis, that Dectin-1 promotes both Th1 and Th17 protective immune responses to this infection, and that there is a correlation between expression of Dectin-1 by the inflammatory infiltrate and resistance to coccidioidomycosis.

Temperate Climate Niche forCryptococcus gattiiin Northern Europe

Temperate Climate Niche for<i>Cryptococcus gattii</i>in Northern Europe