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The spread and adaptation of fungal plant pathogens in agroecosystems are facilitated by environmental homogeneity. Metagenomic sequencing of infected tissues allowed us to monitor eco‐evolutionary dynamics and interactions between host, pathogen and plant microbiome. Exserohilum turcicum, the causal agent of northern corn leaf blight (NCLB) in maize, is distributed in multiple clonal lineages throughout Europe. To characterize regional pathogen diversity, we conducted metagenomic DNA sequencing on 241 infected leaf samples from the highly susceptible Swiss maize landrace Rheintaler Ribelmais, collected over 3 years (2016–2018) from an average of 14 agricultural farms within the Swiss Rhine Valley. All major European clonal lineages of E. turcicum were identified. Lineages differ by their mating types which indicates potential for sexual recombination and rapid evolution of new pathogen strains, although we found no evidence of recent recombination. The associated eukaryotic and prokaryotic leaf microbiome exhibited variation in taxonomic diversity between years and locations and is likely influenced by local weather conditions. A network analysis revealed distinct clusters of eukaryotic and prokaryotic taxa that correlates with the frequency of E. turcicum sequencing reads, suggesting causal interactions. Notably, the yeast genus Metschnikowia exhibited a strongly negative association with E. turcicum, supporting its known potential as biological control agent against fungal pathogens. Our findings show that metagenomic sequencing is a useful tool for analysing the role of environmental factors and potential pathogen–microbiome interactions in shaping pathogen dynamics and evolution, suggesting their potential for effective pathogen management strategies. [ABSTRACT FROM AUTHOR]

In 2023 in Aichi Prefecture, shiso plant growth in a deep flow technique (DFT) hydroponic system was delayed from mid-March to late April with roots showing evidence of rotting. An oomycete species was isolated from the roots and identified as Phytopythium helicoides based on morphological characteristics and DNA sequence homology. Identical symptoms appeared on shiso plants after inoculating seedlings with zoospores from the strain, and the same oomycete species was reisolated from the diseased plants. This study is the first report in the world of root rot caused by P. helicoides in shiso in a DFT hydroponic system. [ABSTRACT FROM AUTHOR]

The conjunctiva has immune-responsive properties to protect the eye from infections. Its innate immune system reacts against external pathogens, such as fungi. The complement factor C5a is an important contributor to the initial immune response. It is known that activation of transient-receptor-potential-vanilloid 1 (TRPV1) and TRP-melastatin 8 (TRPM8) channels is involved in different immune reactions and inflammation in the human body. The aim of this study was to determine if C5a and mucor racemosus e voluminae cellulae (MR) modulate Ca2+-signaling through changes in TRPs activity in human conjunctival epithelial cells (HCjECs). Furthermore, crosstalk was examined between C5a and MR in mediating calcium regulation. Intracellular Ca2+-concentration ([Ca2+]i) was measured by fluorescence calcium imaging, and whole-cell currents were recorded using the planar-patch-clamp technique. MR was used as a purified extract. Application of C5a (0.05–50 ng/mL) increased both [Ca2+]i and whole-cell currents, which were suppressed by either the TRPV1-blocker AMG 9810 or the TRPM8-blocker AMTB (both 20 µM). The N-terminal peptide C5L2p (20–50 ng/mL) blocked rises in [Ca2+]i induced by C5a. Moreover, the MR-induced rise in Ca2+-influx was suppressed by AMG 9810 and AMTB, as well as 0.05 ng/mL C5a. In conclusion, crosstalk between C5a and MR controls human conjunctival cell function through modulating interactions between TRPV1 and TRPM8 channel activity. [ABSTRACT FROM AUTHOR]

The plethora of genome sequences produced in the postgenomic age has not resolved many of our most pressing biological questions. Correlating gene expression with an interrogatable and easily observable characteristic such as the surrogate phenotype conferred by a reporter gene is a valuable approach to gaining insight into gene function. Many reporters including lacZ, amdS, and the fluorescent proteins mRuby3 and mNeonGreen have been used across all manners of organisms. Described here is an investigation into the creation of a robust, synthetic, fusion reporter system for Cryptococcus neoformans that combines some of the most useful fluorophores available in this system with the versatility of the counter-selectable nature of amdS. The reporters generated include multiple composition and orientation variants, all of which were investigated for differences in expression. Evaluation of known promoters from the TEF1 and GAL7 genes was undertaken, elucidating novel expression tendencies of these biologically relevant C. neoformans regulators of transcription. Smaller than lacZ but providing multiple useful surrogate phenotypes for interrogation, the fusion ORF serves as a superior whole-cell assay compared to traditional systems. Ultimately, the work described here bolsters the array of relevant genetic tools that may be employed in furthering manipulation and understanding of the WHO fungal priority group pathogen C. neoformans. [ABSTRACT FROM AUTHOR]

Candida albicans is a major fungal pathogen of humans that can cause serious systemic infections in vulnerable immunocompromised populations. One of its virulence attributes is its capacity to transition between yeast and filamentous morphologies, but our understanding of this process remains incomplete. Here, we analyzed data from a functional genomic screen performed with the C. albicans Gene Replacement And Conditional Expression collection to identify genes crucial for morphogenesis in host-relevant conditions. Through manual scoring of microscopy images coupled with analysis of each image using a deep learning-based method termed Candescence, we identified 307 genes important for filamentation in tissue culture medium at 37°C with 5% CO2. One such factor was orf19.5963 , which is predicted to encode the prenyltransferase Nus1 based on sequence homology to Saccharomyces cerevisiae. We further showed that Nus1 and its predicted interacting partner Rer2 are important for filamentation in multiple liquid filament-inducing conditions as well as for wrinkly colony formation on solid agar. Finally, we highlight that Nus1 and Rer2 likely govern C. albicans morphogenesis due to their importance in intracellular trafficking, as well as maintaining lipid homeostasis. Overall, this work identifies Nus1 and Rer2 as important regulators of C. albicans filamentation and highlights the power of functional genomic screens in advancing our understanding of gene function in human fungal pathogens. [ABSTRACT FROM AUTHOR]

Abstract Disease can act as a driving force in shaping genetic makeup across populations, even species, if the impacts influence a particularly sensitive part of their life cycles. White-nose disease is caused by a fungal pathogen infecting bats during hibernation. The mycosis has caused massive population declines of susceptible species in North America, particularly in the genus Myotis. However, Myotis bats appear to tolerate infection in Eurasia, where the fungal pathogen has co-evolved with its bat hosts for an extended period of time. Therefore, with susceptible and tolerant populations, the fungal disease provides a unique opportunity to tease apart factors contributing to tolerance at a genomic level to and gain an understanding of the evolution of non-harmful in host-parasite interactions. To investigate if the fungal disease has caused adaptation on a genomic level in Eurasian bat species, we adopted both whole-genome sequencing approaches and a literature search to compile a set of 300 genes from which to investigate signals of positive selection in genomes of 11 Eurasian bats at the codon-level. Our results indicate significant positive selection in 38 genes, many of which have a marked role in responses to infection. Our findings suggest that white-nose syndrome may have applied a significant selective pressure on Eurasian Myotis-bats in the past, which can contribute their survival in co-existence with the pathogen. Our findings provide an insight on the selective pressure pathogens afflict on their hosts using methodology that can be adapted to other host-pathogen study systems.

In 2020 and 2021, peach fruit with natural disease and decay were collected from orchards in Zhejiang Province. Then the fungal pathogens were isolated from the diseased spots and identified by morphological characteristics, molecular biological identification (rDNA-ITS sequence analysis) and pathogenicity detection. The antifungal effect of cinnamon essential oil on the fungal pathogens in vitro and in vivo were also investigated. The results showed that two fungal pathogens with strong pathogenicity were isolated, and identified as Monilinia fructicola and Rhizopus stolonifer, which caused brown rot and soft rot, respectively. Cinnamon essential oil inhibited the growth of M. fructicola and R. stolonifer, and the minimum inhibitory concentrations were 0.4 and 0.8 mL/L, respectively. M. fructicola was more sensitive to cinnamon essential oil. Cinnamon essential oil fumigation could reduce the disease incidence and lesion diameter of brown rot and soft rot of peach fruit caused by these two fungal pathogens. Therefore, cinnamon essential oil could be used as a natural fungicide to control fungal diseases of peach fruit.

The research aimed to determine the phenotypic characteristic, pathogenicity and molecular characterization of Hypomyces perniciosus isolates responsible for wet bubble disease of the white button mushroom Agaricus bisporus. Phenotypic characteristics such as colony appearance, mycelium texture, and pigmentation were studied on four different agar media, i.e., potato dextrose agar (PDA), malt extract agar (MEA), Czapek-Dox yeast agar (CYA), and Sabouraud dextrose agar (SDA), after eight days of incubation. Additionally, the growth rate of the tested isolates was studied depending on the pH of the medium. Fungal isolates showed the highest mycelial growth on MEA and SDA at pH 6.0. However, on CYA at pH 7.0, the mycelium exhibited the worst growth. Isolate identification and genetic relationship analysis were carried out using internal transcribed spacer region sequencing and the random amplified polymorphic DNA method. The research confirmed that all Polish isolates belong to the species H. perniciosus, and the genetic diversity is relatively low. Phylogenetic analyses revealed three subgroups of H. perniciosus isolates. The first group included three genetically distinct isolates with a similarity coefficient in the range of 0.76–0.85 to isolates CBS 815.73 and CBS 322.52. The second group was divided into two subgroups and included 16 isolates with a genetic similarity range of 0.91 to 1.0 to CBS 815.73 and CBS 322.52 isolates. Furthermore, the eight genetically similar isolates exhibited the greatest pathogenicity towards A. bisporus.

Paulownia spp. comes from South-East Asia, where there is a tradition of its cultivation. Social pressure, in favour of the use of renewable sources of energy and sustainable agriculture, is on the rise. In this context, agroforestry has become a significant topic of interest. Paulownia spp. could be one of the species utilized in this field. That is why, in 2014, the experimental agroforestry system, which was intended for the production of fodder for farm animals, and also for the production of saw timber, was established in one of the warmest areas of the Czech Republic. The aim of this research was to evaluate the production potential of Paulownia Bellissia®. The measuring of the heights and thicknesses, and the determination of the extent to which the plants were damaged, were conducted during 2017–2020. The plantation consisted of two plots, where the plants on the first plot (treated plants) were regularly irrigated and annually pruned and those on the second (reference plants) were not. The treated plants reached a mean annual increment of 1.6 m in height and 2.8 cm in diameter at breast height, but almost 80 % were sunscalded, whereas the reference plants reached only 1.1 m and 2.0 cm but remained undamaged. Most of the damaged plants were also infested with parasitic fungi Schizophyllum commune and Trametes hirsuta, while the occurrence of S. commune on plantations of Paulownia was found as one of the first discoveries in the Czech Republic.

We describe the detection of Paranannizziopsis sp. fungus in a wild population of vipers in Europe. Fungal infections were severe, and 1 animal likely died from infection. Surveillance efforts are needed to better understand the threat of this pathogen to snake conservation.

Dry rot disease is one of the main postharvest diseases caused by Fusarium species. Several pathogenic Fusarium species have the potential to be carried on imported citrus fruits. This study aims to detect, isolate, identify, and test the pathogenicity of Fusarium species from imported citrus fruits. Fusarium species were isolated using the Overnight Freezing Incubation technique (ONFIT) method by freezing citrus fruits at -- 20°C for 15 hours. Fusarium species were identified morphologically and molecularly. Morphological identification was conducted macroscopically and microscopically by observing the characteristics of the colony on PDA media and conidia. Molecular identification was carried out by the Polymerase Chain reaction (PCR) method using universal primers of ITS1 and ITS4. Pathogenicity was tested by injecting 100 µl of fungal conidia suspension with a density of 105 conidia/ml into healthy citrus fruits. The results showed that 3 Fusarium species were successfully isolated and identified as Fusarium equiseti, Fusarium lateritium, and Fusarium oxysporum. The pathogenicity test proved that all Fusarium species were pathogenic to citrus fruits. The disease incidence of all Fusarium species was 100%. The disease severity caused by F. equiseti, F. lateritium and F. oxysporum were 73.33, 93.33 and 84.44%, respectively. These results are a new report of 3 Fusarium species causing dry rot disease in citrus fruits. [ABSTRACT FROM AUTHOR]

In 2020 and 2021, peach fruit with natural disease and decay were collected from orchards in Zhejiang Province. Then the fungal pathogens were isolated from the diseased spots and identified by morphological characteristics, molecular biological identification (rDNA-ITS sequence analysis) and pathogenicity detection. The antifungal effect of cinnamon essential oil on the fungal pathogens in vitro and in vivo were also investigated. The results showed that two fungal pathogens with strong pathogenicity were isolated, and identified as Monilinia fructicola and Rhizopus stolonifer, which caused brown rot and soft rot, respectively. Cinnamon essential oil inhibited the growth of M. fructicola and R. stolonifer, and the minimum inhibitory concentrations were 0.4 and 0.8 mL/L, respectively. M. fructicola was more sensitive to cinnamon essential oil. Cinnamon essential oil fumigation could reduce the disease incidence and lesion diameter of brown rot and soft rot of peach fruit caused by these two fungal pathogens. Therefore, cinnamon essential oil could be used as a natural fungicide to control fungal diseases of peach fruit. [ABSTRACT FROM AUTHOR]

Terpenoids are defense metabolites that are induced upon infection or wounding. However, their role in systemic‐induced resistance (SIR) is not known. Here, we explored the role of terpenoids in this phenomenon at a very early stage in the interaction between Austrian pine and the tip blight and canker pathogen Diplodia pinea. We induced Austrian pine saplings by either wounding or inoculating the lower stems with D. pinea. The seedlings were then challenged after 12 h, 72 h, or 10 days with D. pinea on the stem 15 cm above the induction. Lesion lengths and terpenoids were quantified at both induction and challenge locations. Key terpenoids were assayed for antifungal activity in in vitro bioassays. SIR increased with time and was correlated with the inducibility of several compounds. α‐Pinene and a cluster of β‐pinene, limonene, benzaldehyde, dodecanol, and n‐dodecyl acrylate were positively correlated with SIR and were fungistatic in vitro, while other compounds were negatively correlated with SIR and appeared to serve as a carbon source for D. pinea. This study shows that, overall, terpenoids are involved in SIR in this system, but their role is nuanced, depending on the type of induction and time of incubation. We hypothesize that some, such as α‐pinene, could serve in SIR signaling. Summary statement: Trees can resist recurring pathogenic attacks using memory of successful prior encounters with pest or pathogens. Here we show that pathogenic induction results in systemic and selective accumulation of certain terpenoids and other non‐terpenoids in trees conferring higher resistance against newer infection. [ABSTRACT FROM AUTHOR]

Eucalyptus scab and shoot malformation is an emerging disease and a serious threat to the global plantation forestry industry. The disease appeared in North Sumatra (Indonesia) in the early 2010s and the causal agent was recently described as a novel species, Elsinoe necatrix. Nothing is known regarding its possible origin or why it emerged rapidly to cause a serious local epidemic. To investigate its population biology, we developed 15 polymorphic microsatellite markers as well as mating‐type markers using genome sequences for two E. necatrix isolates. Isolates of the pathogen were collected from different host varieties at four locations in the Lake Toba region of North Sumatra and characterized using these markers. A high level of genotypic diversity was observed for all populations with little to no genetic differentiation between sampling areas. Discriminant analysis of principal components, genotype networks and analysis of molecular variance all showed a lack of population structure and a high level of gene flow among sampling regions. Mating‐type ratios and linkage disequilibrium analyses suggest that sexual recombination is likely to be occurring, although a sexual state has not been found for the pathogen. The results of this study highlight the fact that new genotypes of E. necatrix, probably arising from cryptic sexual recombination, will challenge efforts to manage the disease, and that breeding and selection for tolerance will require substantial host genetic diversity. [ABSTRACT FROM AUTHOR]

Vomocytosis, also known as nonlytic exocytosis, is a process whereby fully phagocytosed microbes are expelled from phagocytes without discernible damage to either the phagocyte or microbe. Although this phenomenon was first described in the opportunistic fungal pathogen Cryptococcus neoformans in 2006, to date, mechanistic studies have been hampered by an inability to reliably stimulate or inhibit vomocytosis. Here we present the fortuitous discovery that macrophages lacking the scavenger receptor MAcrophage Receptor with COllagenous domain (MARCO), exhibit near‐total vomocytosis of internalised cryptococci within a few hours of infection. Marco−/− macrophages also showed elevated vomocytosis of a yeast‐locked C. albicans strain, suggesting this to be a broadly relevant observation. We go on to show that MARCO's role in modulating vomocytosis is independent of its role as a phagocytic receptor, suggesting that this protein may play an important and hitherto unrecognised role in modulating macrophage behaviour. [ABSTRACT FROM AUTHOR]

Fungi inflict a great deal of damage to crops in fields and in storage facilities, causing issues such as leaf spot, wilt, rust, dieback and rot, as well as releasing mycotoxins that taint vegetation. In the current study, 25 de novo fungal isolates were taken from infected plant tissue (leaf, root and fruit), at pre- and post-harvest stages. Isolates were identified using molecular markers; 8 genera and 15 species were determined. The most common species was Penicillium spp. (40%), Aspergillus spp. (20%), Fusarium spp. (16%) and Alternaria alternata species (8%). The remaining 16% was comprised of various types of fungi, including Geotrichum candidum, Neofusicoccum parvum, Rhizopus stolonifera and Mucor fragilis. Many of these genera are known to cause significant crop damage and are notorious mycotoxin producers. An evaluation of the optimal growth temperature revealed the ideal temperatures were 30 °C for 56% of isolates, 25 °C for 28% of isolates and 20 °C for 16% of isolates. An assessment of water activity showed that 60% of isolates belonged to Penicillium and Aspergillus spp. and were mesophilic and xerophilic. Another 28% of isolates were Fusarium spp., Geotrichum candidum, Neofusicoccum parvum and Mucor fragilis, and hydrophilic. The remaining 12%, representing Alternaria alternata and Rhizopus stolonifera, were mesophilic. The current study provides accurate eco-physiological response data and molecular information for each isolate. The findings can assist the development of novel approaches to control the expansion of invasive fungal infections and minimise their deleterious consequences. [ABSTRACT FROM AUTHOR]

Invasive fungal infections are a growing threat to human health. Secreted effector proteins are a ubiquitous strategy used by diverse microbial pathogens to manipulate host biology and enable pathogen replication. Recent work has revealed secreted protein effectors produced by human fungal pathogens. Secreted fungal effectors target apoptosis, myeloid cell polarization, Toll-like receptor signaling, and phagosome action. Despite lacking specialized secretion systems, fungi have evolved secreted effectors that subvert many host pathways targeted by highly host-adapted bacteria and parasites. Invasive fungal infections pose a major threat to human health. Bacterial and protozoan pathogens secrete protein effectors that overcome innate immune barriers to promote microbial colonization, yet few such molecules have been identified in human fungal pathogens. Recent studies have begun to reveal these long-sought effectors and have illuminated how they subvert key cellular pathways, including apoptosis, myeloid cell polarization, Toll-like receptor signaling, and phagosome action. Thus, despite lacking the specialized secretion systems of bacteria and parasites, it is increasingly clear that fungi independently evolved effectors targeting pathways often subverted by other classes of pathogens. These findings demonstrate the remarkable power of convergent evolution to enable diverse microbes to infect humans while also setting the stage for detailed dissection of fungal disease mechanisms. [ABSTRACT FROM AUTHOR]

Starting in the fall of 2019, mortality, blight symptoms, and signs of white fungal mycelia were observed on external host tissues of non-native landscape trees as well as numerous native trees, understory shrubs, and vines throughout northern and central Florida, USA. We determined that the fungus is an undescribed species of Basidiomycota based on morphological characteristics and DNA sequence analysis. Phylogenetic analyses of the internal transcribed spacer (ITS), large subunit (LSU), and translation elongation factor 1-alpha (tef1) regions revealed that this novel plant pathogen is an undescribed taxon of the genus Parvodontia (Cystostereaceae, Agaricales). We propose the name Parvodontia relampaga sp. nov. which describes its unique morphological features and phylogenetic placement. We confirmed the pathogenicity of P. relampaga in greenhouse inoculations on host plants from which strains of this novel pathogen were isolated, including the non-native gymnosperm Afrocarpus falcatus , the non-native and commercially important Ligustrum japonicum , and the native tree Quercus hemisphaerica. P. relampaga was also detected on a total of 27 different species of woody host plants, including such economically and ecologically important hosts as Fraxinus, Ilex, Magnolia, Persea, Prunus, Salix, Vitis , and Vaccinium. For this new plant disease, we propose the name "relampago blight," which refers to the lightning-like rhizomorph growth (relámpago means 'lightning' in Spanish). This study presents a newly discovered fungal taxon with a wide host range on both angiosperms and gymnosperms that may be an emerging pathogen of concern in Florida and the Gulf Coast region. • A novel thread blight pathogen is formally described as Parvodontia relampaga. • " Relampago blight" is the common name of the disease cause by P. relampaga. • This is the first report of any thread blight pathogen in continental USA. • Relampago blight was detected in plant seedlings in central and north Florida. [ABSTRACT FROM AUTHOR]

Social insects are prone to pathogen infection because of high exposure rates from social interactions. However, it remains unclear whether queens have enhanced pathogen resistance, because reproduction is largely confined to queens. Here, we used a natural host–pathogen system, the subterranean termite Reticulitermes chinensis and the entomopathogenic fungus Metarhizium anisopliae, to investigate the differences in allogrooming, locomotion, and immune gene expression between queens and workers against pathogen infection. We found that fungal infection significantly reduced survival in both queens and workers. Infected queens received significantly more grooming time from sanitary nestmates than infected workers, but they returned much less grooming time to sanitary nestmates than infected workers. Infection resulted in a reduction in the average locomotion speed and distance of queens but had no effect on worker locomotion. Infection resulted in upregulated expression of two immune genes (termicin and transferrin), two antioxidant genes (CAT and SOD), and phosphate genes CYP450 in queens but not in workers. Our results indicated that eusocial termites evolved strategies that prioritize the reproductive castes' welfare in defending against the pathogen infection to ensure continued reproduction and colony persistence. [ABSTRACT FROM AUTHOR]

Abstract The objective of this work was to verify if D-limonene in vitro presents inhibitory action on the mycelial growth of Colletotrichum spp. and antimicrobial activity against Enterococcus faecium and Escherichia coli, as well as to evaluate the effect of its concentrations on papaya disinfestation in the post-harvest process. For the in vitro tests, fungi were isolated from papaya fruit infected with anthracnose. For this, fruit fragments were disinfected and transferred to Petri dishes. Another test was carried out in vitro, to evaluate bactericidal activity, by for adding D-limonene to the suspension of the tested bacteria. Fruit physicochemical quality and disease incidence were evaluated. The application of D-limonene inhibited the mycelial growth of Colletotrichum spp. in vitro, with an increasing effect at increasing concentrations and a decreasing effect with time of product application. D-limonene was effective in inhibiting E. faecium and E. coli. There was no significant interaction between D-limonene rates and storage time for fruit quality or for disease incidence in ex vitro studies. D-limonene can be applied to papaya at postharvest, as it does not affect fruit quality and controls the growth of phytopathogens in vitro.

ABSTRACT At human body temperature, the fungal pathogen Candida albicans can transition from yeast to filamentous morphologies in response to host-relevant cues. Additionally, elevated temperatures encountered during febrile episodes can independently induce C. albicans filamentation. However, the underlying genetic pathways governing this developmental transition in response to elevated temperatures remain largely unexplored. Here, we conducted a functional genomic screen to unravel the genetic mechanisms orchestrating C. albicans filamentation specifically in response to elevated temperature, implicating 45% of genes associated with the spliceosome or pre-mRNA splicing in this process. Employing RNA-Seq to elucidate the relationship between mRNA splicing and filamentation, we identified greater levels of intron retention in filaments compared to yeast, which correlated with reduced expression of the affected genes. Intriguingly, homozygous deletion of a gene encoding a spliceosome component important for filamentation (PRP19) caused even greater levels of intron retention compared with wild type and displayed globally dysregulated gene expression. This suggests that intron retention is a mechanism for fine-tuning gene expression during filamentation, with perturbations of the spliceosome exacerbating this process and blocking filamentation. Overall, this study unveils a novel biological process governing C. albicans filamentation, providing new insights into the complex regulation of this key virulence trait.IMPORTANCEFungal pathogens such as Candida albicans can cause serious infections with high mortality rates in immunocompromised individuals. When C. albicans is grown at temperatures encountered during human febrile episodes, yeast cells undergo a transition to filamentous cells, and this process is key to its virulence. Here, we expanded our understanding of how C. albicans undergoes filamentation in response to elevated temperature and identified many genes involved in mRNA splicing that positively regulate filamentation. Through transcriptome analyses, we found that intron retention is a mechanism for fine-tuning gene expression in filaments, and perturbation of the spliceosome exacerbates intron retention and alters gene expression substantially, causing a block in filamentation. This work adds to the growing body of knowledge on the role of introns in fungi and provides new insights into the cellular processes that regulate a key virulence trait in C. albicans.

Abstract Puccinia abrupta var. partheniicola, the so-called winter rust of parthenium weed (Parthenium hysterophorus), an invasive alien weed in India, was rediscovered at an epiphytotic scale in February 2023 following a prolonged period of presumed absence in the field. Disease incidence was 80–90% in large tracts of P. hysterophorus stands along the roadsides in an area of 5 km2 near Attibele–Sarjapura road (948A) in Anekal taluk of Bengaluru Urban district in Karnataka. Pycnial, aecial or telial stages of the rust were not found. The morphological parameters of uredinia and urediniospores completely matched those originally described, thus confirming the fungal identity. The significance of this rust epiphytotic to P. hysterophorus biocontrol in India is discussed together with the planned follow-up activities.

Abstract Background Response to oxidative stress is universal in almost all organisms and the mitochondrial membrane protein, BbOhmm, negatively affects oxidative stress responses and virulence in the insect fungal pathogen, Beauveria bassiana. Nothing further, however, is known concerning how BbOhmm and this phenomenon is regulated. Results Three oxidative stress response regulating Zn2Cys6 transcription factors (BbOsrR1, 2, and 3) were identified and verified via chromatin immunoprecipitation (ChIP)-qPCR analysis as binding to the BbOhmm promoter region, with BbOsrR2 showing the strongest binding. Targeted gene knockout of BbOsrR1 or BbOsrR3 led to decreased BbOhmm expression and consequently increased tolerances to free radical generating compounds (H2O2 and menadione), whereas the ΔBbOsrR2 strain showed increased BbOhmm expression with concomitant decreased tolerances to these compounds. RNA and ChIP sequencing analysis revealed that BbOsrR1 directly regulated a wide range of antioxidation and transcription-associated genes, negatively affecting the expression of the BbClp1 cyclin and BbOsrR2. BbClp1 was shown to localize to the cell nucleus and negatively mediate oxidative stress responses. BbOsrR2 and BbOsrR3 were shown to feed into the Fus3-MAPK pathway in addition to regulating antioxidation and detoxification genes. Binding motifs for the three transcription factors were found to partially overlap in the promoter region of BbOhmm and other target genes. Whereas BbOsrR1 appeared to function independently, co-immunoprecipitation revealed complex formation between BbClp1, BbOsrR2, and BbOsrR3, with BbClp1 partially regulating BbOsrR2 phosphorylation. Conclusions These findings reveal a regulatory network mediated by BbOsrR1 and the formation of a BbClp1-BbOsrR2-BbOsrR3 complex that orchestrates fungal oxidative stress responses.

The experiments were carried out on 5 different bioproducts for control of Verticillium longisporum in oilseed rape. For in vitro trials, greenhouse trials and field trials, the bioproducts used were based on bacteria (Bacillus amyloliquefaciens, Pseudomonas veronii) and fungi (Pythium oligandrum, Trichoderma asperellum, Coniothyrium minitans). In in vitro trials, some products (based on Trichoderma asperellum) showed a 100% inhibition effect on the pathogen for a whole trial period of 45 days. The greenhouse trial showed significant differences in bioproducts effectiveness (P < 0.00723) compared to control. Three bioproducts (based on Coniothyrium minitans, Trichoderma asperellum and Pseudomonas veronii) showed a 100% inhibition effect against the pathogen. In field trials conducted in 3 locations, there were some differences in yield, which can be important for growers and practice use. The highest yield (19.1% higher than the control) was achieved with a bioproduct based on Trichoderma asperellum. In trials, it is possible to see that there are promising results that can be used for further testing.

Background: Response to oxidative stress is universal in almost all organisms and the mitochondrial membrane protein, BbOhmm, negatively affects oxidative stress responses and virulence in the insect fungal pathogen, Beauveria bassiana. Nothing further, however, is known concerning how BbOhmm and this phenomenon is regulated. Results: Three oxidative stress response regulating Zn2Cys6 transcription factors (BbOsrR1, 2, and 3) were identified and verified via chromatin immunoprecipitation (ChIP)-qPCR analysis as binding to the BbOhmm promoter region, with BbOsrR2 showing the strongest binding. Targeted gene knockout of BbOsrR1 or BbOsrR3 led to decreased BbOhmm expression and consequently increased tolerances to free radical generating compounds (H2O2 and menadione), whereas the ΔBbOsrR2 strain showed increased BbOhmm expression with concomitant decreased tolerances to these compounds. RNA and ChIP sequencing analysis revealed that BbOsrR1 directly regulated a wide range of antioxidation and transcription-associated genes, negatively affecting the expression of the BbClp1 cyclin and BbOsrR2. BbClp1 was shown to localize to the cell nucleus and negatively mediate oxidative stress responses. BbOsrR2 and BbOsrR3 were shown to feed into the Fus3-MAPK pathway in addition to regulating antioxidation and detoxification genes. Binding motifs for the three transcription factors were found to partially overlap in the promoter region of BbOhmm and other target genes. Whereas BbOsrR1 appeared to function independently, co-immunoprecipitation revealed complex formation between BbClp1, BbOsrR2, and BbOsrR3, with BbClp1 partially regulating BbOsrR2 phosphorylation. Conclusions: These findings reveal a regulatory network mediated by BbOsrR1 and the formation of a BbClp1-BbOsrR2-BbOsrR3 complex that orchestrates fungal oxidative stress responses. [ABSTRACT FROM AUTHOR]

Due to rapidly emerging resistance to single‐site fungicides in fungal pathogens of plants, there is a burgeoning need for safe and multisite fungicides. Plant antifungal peptides with multisite modes of action (MoA) have potential as bioinspired fungicides. Medicago truncatula defensin MtDef4 was previously reported to exhibit potent antifungal activity against fungal pathogens. Its MoA involves plasma membrane disruption and binding to intracellular targets. However, specific biochemical processes inhibited by this defensin and causing cell death have not been determined. Here, we show that MtDef4 exhibited potent antifungal activity against Botrytis cinerea. It induced severe plasma membrane and organelle irregularities in the germlings of this pathogen. It bound to fungal ribosomes and inhibited protein translation in vitro. A MtDef4 variant lacking antifungal activity exhibited greatly reduced protein translation inhibitory activity. A cation‐tolerant MtDef4 variant was generated that bound to β‐glucan of the fungal cell wall with higher affinity than MtDef4. It also conferred a greater reduction in the grey mould disease symptoms than MtDef4 when applied exogenously on Nicotiana benthamiana plants, tomato fruits and rose petals. Our findings revealed inhibition of protein synthesis as a likely target of MtDef4 and the potential of its cation‐tolerant variant as a peptide‐based fungicide. [ABSTRACT FROM AUTHOR]

Aim: The development of carbon quantum dots (C-QDs) as nanotrackers to understand drug–pathogen interactions, virulence and multidrug resistance. Methods: Microwave synthesis of C-QDs was performed using citric acid and polyethylene glycol. Further, in vitro toxicity was evaluated and imaging applications were demonstrated in Candida albicans isolates. Results: Well-dispersed, ultra small C-QDs exhibited no cyto/microbial/reactive oxygen species-mediated toxicity and internalized effectively in Candida yeast and hyphal cells. C-QDs were employed for confocal imaging of drug-sensitive and -resistant cells, and a study of the yeast-to-hyphal transition using atomic force microscopy in Candida was conducted for the first time. Conclusion: These biocompatible C-QDs have promising potential as next-generation nanotrackers for in vitro and in vivo targeted cellular and live imaging, after functionalization with biomolecules and drugs. Scientists have used radiolabeled drugs and radioactive tracking agents for the imaging and study of drug resistance in microbial pathogens. But, these radiolabeled drugs or radiotrackers pose health hazards and environmental risks. However, such limitations can be overcome by designing nontoxic, environment-friendly, nanotechnology-based fluorescent imaging agents. This study demonstrates the development and application of cost-effective, nontoxic carbon-based quantum dots for imaging of drug-sensitive and -resistant microbial strains and transition to different morphological forms (yeast-to-hyphae transition) in fungal pathogens. The results demonstrated the suitability of carbon quantum dots as next-generation nano-based bioimaging/tracking agents for cellular imaging. The availability of such nontoxic fluorescent tracking agents is likely to offer promising solutions in therapeutics and diagnostics by providing insight into various mechanisms and functional links related to drug resistance, virulence and pathogenicity. [ABSTRACT FROM AUTHOR]

Lytic polysaccharide monooxygenases (LPMOs) are monocopper enzymes that oxidatively degrade various polysaccharides, such as cellulose. Despite extensive research on this class of enzymes, the role played by their C-terminal regions predicted to be intrinsically disordered (dCTR) has been overlooked. Here, we investigated the function of the dCTR of an LPMO, called CoAA9A, up-regulated during plant infection by Colletotrichum orbiculare, the causative agent of anthracnose. After recombinant production of the full-length protein, we found that the dCTR mediates CoAA9A dimerization in vitro, via a disulfide bridge, a hitherto-never-reported property that positively affects both binding and activity on cellulose. Using SAXS experiments, we show that the homodimer is in an extended conformation. In vivo, we demonstrate that gene deletion impairs formation of the infection-specialized cell called appressorium and delays penetration of the plant. Using immunochemistry, we show that the protein is a dimer not only in vitro but also in vivo when secreted by the appressorium. As these peculiar LPMOs are also found in other plant pathogens, our findings open up broad avenues for crop protection. [ABSTRACT FROM AUTHOR]

Mitophagy is a selective autophagy for the degradation of damaged or excessive mitochondria to maintain intracellular homeostasis. In Magnaporthe oryzae, a filamentous ascomycetous fungus that causes rice blast, the most devastating disease of rice, mitophagy occurs in the invasive hyphae to promote infection. To date, only a few proteins are known to participate in mitophagy and the mechanisms of mitophagy are largely unknown in pathogenic fungi. Here, by a yeast two‐hybrid screen with the core autophagy‐related protein MoAtg8 as a bait, we obtained a MoAtg8 interactor MoAti1 (MoAtg8‐interacting protein 1). Fluorescent observations and protease digestion analyses revealed that MoAti1 is primarily localized to the peripheral mitochondrial outer membrane and is responsible for recruiting MoAtg8 to mitochondria under mitophagy induction conditions. MoAti1 is specifically required for mitophagy, but not for macroautophagy and pexophagy. Infection assays suggested that MoAti1 is required for mitophagy in invasive hyphae during pathogenesis. Notably, no homologues of MoAti1 were found in rice and human protein databases, indicating that MoAti1 may be used as a potential target to control rice blast. By the host‐induced gene silencing (HIGS) strategy, transgenic rice plants targeted to silencing MoATI1 showed enhanced resistance against M. oryzae with unchanged agronomic traits. Our results suggest that MoATI1 is required for mitophagy and pathogenicity in M. oryzae and can be used as a target for reducing rice blast. [ABSTRACT FROM AUTHOR]

Necroses on aerial parts of Hydrangea macrophylla were regularly observed in plant storage chamber at 2°C in Hortensia France company. A total of 34 Botrytis isolates were collected from Hydrangea plants and their environment. To develop biocontrol methods against Botrytis, eight Trichoderma isolates were collected from Hydrangea or the plant soil substrate in the same cold room. Two Trichoderma isolates (E10SM, E014) from this study and one reference isolate (M03) exhibited a high degree of in vitro parasitism against B. cinerea, by comparison with Trichoderma C04 reference isolate (no parasitism). Culture filtrates of isolates E014 and M03 also showed significant in vitro antibiotic properties against B. cinerea growth. A pathosystem H. macrophylla– B. cinerea was set up in the greenhouse, with the inoculation of leaves using mycelial explants selected as the best infection mode. Using this pathosystem, a biocontrol assay showed a significant effect of M03 isolate towards B. cinerea, using Trichoderma conidia applied to leaves 5 h prior pathogen inoculation. After elicitor addition (B. cinerea grinded mycelia) in Trichoderma cultures, antagonistic potentialities of isolate C04 towards the pathogen was highly enhanced, reaching the inhibition level assessed with isolate M03 grown without elicitor. Optimisation of Trichoderma culture filtrates for antagonistic abilities was investigated, and specific cultural conditions were selected for M03 (12 g L−1 PDB, pH 4.2, 22°C, 22 days) and C04 (2.4 g L−1 PDB, pH 6.2, 13°C, 7 days). Overall, our results suggest great properties of several Trichoderma isolates for future development as biocontrol products. [ABSTRACT FROM AUTHOR]

The experiments were carried out on 5 different bioproducts for control of Verticillium longisporum in oilseed rape. For in vitro trials, greenhouse trials and field trials, the bioproducts used were based on bacteria (Bacillus amyloliquefaciens, Pseudomonas veronii) and fungi (Pythium oligandrum, Trichoderma asperellum, Coniothyrium minitans). In in vitro trials, some products (based on Trichoderma asperellum) showed a 100% inhibition effect on the pathogen for a whole trial period of 45 days. The greenhouse trial showed significant differences in bioproducts effectiveness (P < 0.00723) compared to control. Three bioproducts (based on Coniothyrium minitans, Trichoderma asperellum and Pseudomonas veronii) showed a 100% inhibition effect against the pathogen. In field trials conducted in 3 locations, there were some differences in yield, which can be important for growers and practice use. The highest yield (19.1% higher than the control) was achieved with a bioproduct based on Trichoderma asperellum. In trials, it is possible to see that there are promising results that can be used for further testing. [ABSTRACT FROM AUTHOR]

Candida auris poses a serious threat to infection control and patient care since it can produce invasive infections that have a high fatality rate, has been linked to outbreaks in hospital environments, and is typically resistant to several antifungal medications. Since its first description in 2009, six clades have been described. The emerging fungal pathogen possesses adhesins that allow it to adhere to host tissues and medical devices, can form biofilms, produces various hydrolytic enzymes, employs several strategies to evade host immune responses, and exhibits high genetic diversity, which may contribute to its ability to adapt to different environmental conditions and evade host defenses. C. auris is very resistant to various disinfectants and may be difficult to detect. [ABSTRACT FROM AUTHOR]

Several economically important pathogens, including species of Chrysoporthe, pose a threat to the rapidly expanding eucalypt plantation industry in Southeast Asia. During 2019 disease surveys in Riau and Kalimantan (Indonesia), cankers were observed on eucalypt trees and a collection of fungal isolates was obtained from them. The aim of this study was to confirm the identity of the isolates and to evaluate their relative pathogenicity on different eucalypt clones. Using the DNA sequence data based on the internal transcribed spacer (ITS) region of the ribosomal DNA and two regions of the β-tubulin gene (TUB1 and TUB2), 31 fungal isolates were identified as C. deuterocubensis. Pathogenicity trials showed that C. deuterocubensis isolates differed in their pathogenicity and that different eucalypt genotypes differed in their susceptibility to the pathogen. These results will provide valuable information to reduce the threat of stem canker to future eucalypt plantation development. [ABSTRACT FROM AUTHOR]

Antagonistic selection between pathogens and their hosts can drive rapid evolutionary change and leave distinct molecular footprints of past and ongoing selection in the genomes of the interacting species. Despite an increasing availability of tools able to identify signatures of selection, the genetic mechanisms underlying coevolutionary interactions and the specific genes involved are still poorly understood, especially in heterogeneous natural environments. We searched the genomes of two species of Epichloe plant pathogen for evidence of recent selection. The Epichloe genus includes highly host‐specific species that can sterilize their grass hosts. We performed selection scans using genome‐wide SNP data from seven natural populations of two co‐occurring Epichloe sibling species specialized on different hosts. We found evidence of recent (and ongoing) selective sweeps across the genome in both species. However, selective sweeps were more abundant in the species with a larger effective population size. Sweep regions often overlapped with highly polymorphic AT‐rich regions supporting the role of these genome compartments in adaptive evolution. Although most loci under selection were specific to individual populations, we could also identify several candidate genes targeted by selection in sweep regions shared among populations. The genes encoded small secreted proteins typical of fungal effectors and cell wall‐degrading enzymes. By investigating the genomic signatures of selection across multiple populations and species, this study contributes to our understanding of complex adaptive processes in natural plant pathogen systems. [ABSTRACT FROM AUTHOR]

The ubiquitin/26S proteasome system is a crucial regulatory mechanism that governs various cellular processes in plants, including signal transduction, transcriptional regulation, and responses to biotic and abiotic stressors. Our study shows that the RING-H2-type E3 ubiquitin ligase, Arabidopsis Tóxicos en Levadura 2 (ATL2), is involved in response to fungal pathogen infection. Under normal growth conditions, the expression of the ATL2 gene is low, but it is rapidly and significantly induced by exogenous chitin. Additionally, ATL2 protein stability is markedly increased via chitin treatment, and its degradation is prolonged when 26S proteasomal function is inhibited. We found that an atl2 null mutant exhibited higher susceptibility to Alternaria brassicicola, while plants overexpressing ATL2 displayed increased resistance. We also observed that the hyphae of A. brassicicola were strongly stained with trypan blue staining, and the expression of A. brassicicola Cutinase A (AbCutA) was dramatically increased in atl2. In contrast, the hyphae were weakly stained, and AbCutA expression was significantly reduced in ATL2-overexpressing plants. Using bioinformatics, live-cell confocal imaging, and cell fractionation analysis, we revealed that ATL2 is localized to the plasma membrane. Further, it is demonstrated that the ATL2 protein possesses E3 ubiquitin ligase activity and found that cysteine 138 residue is critical for its function. Moreover, ATL2 is necessary to successfully defend against the A. brassicicola fungal pathogen. Altogether, our data suggest that ATL2 is a plasma membrane-integrated protein with RING-H2-type E3 ubiquitin ligase activity and is essential for the defense response against fungal pathogens in Arabidopsis. [ABSTRACT FROM AUTHOR]

This study represents the molecular characterization of Basidiobolus sp., isolated from gastrointestinal basidiobolomycosis in rainbow trout, Oncorhynchus mykiss in India. Basidiobolus spp. is a zoonotic fungal pathogen that can cause gastrointestinal, cutaneous or subcutaneous, visceral and colonic basidiobolomycosis in immunocompetent individuals of all genders and ages. The strain was recovered from ascitic fluid of moribund rainbow trout, which upon necropsy exhibited liquefaction and swelling of internal organs, as well as red-yellow drainable and foul-smelling ascites (150.5 ± 15.9 mL). The ascitic fluid was subjected to microscopic analysis, which revealed the presence of irregular, spore-forming fungal hyphae characterized by large size and sparse septation, with a diameter of 25.6 ± 4.9 µm and thin walls. Additionally, thick-walled zygospores measuring 35.9 ± 7.9 µm in diameter, exhibiting a single outer beak-like projection on the spore surface, were also detected. Furthermore, examination of the 72-h-old fungal culture displayed a furrowed, waxy colony with a raised center and flat edges, indicative of its unique morphology. The isolate demonstrated β-hemolysis and the capability to degrade protein, nucleic acid, gelatin, urea, and lipid. The amplification of RNA internal transcribed spacer (ITS) for amplicon size of 680 bp, phylogenetic analysis, calculation of genetic distance similarity (%), and haplotype networking confirmed that the isolate was Basidiobolus sp. Ind SN1 (MW 928426). Basidiobolus sp. Ind SN1 shared 97.82%, 96.59%, and 92.32% sequence similarity with Basidiobolus meristosporus (MH857419), B. meristosporus (FJ786040), and B. heterosporus (EF392521), respectively. The disease caused by Basidiobolus sp. Ind SN1 was successfully reproduced in rainbow trout through experimental infection, satisfying Koch's postulate. Histopathological examination of the liver, kidney, and gill of the infected rainbow trout revealed hydropic degeneration of hepatocytes, necrotic kidney tubules, and lamellar hyperplasia, respectively. This study also identifies rainbow trout as a novel host for Basidiobolus sp., highlighting the emergence of a fungal pathogen that could potentially lead to fatal infections in fish farming systems. Thus, it is recommended that fish culturists, aquaculture entrepreneurs, and fish handlers should maintain proper sanitation and good animal husbandry practices to minimize the risk of basidiobolomycosis in aquaculture. [ABSTRACT FROM AUTHOR]

LncRNAs have gained increasing attention owing to their important regulatory roles on growth and stress responses of plants. However, the mechanisms underlying the functions of lncRNAs in fruit‐pathogen interaction are still largely unknown. In this study, a total of 273 lncRNAs responding to Botrytis cinerea infection were identified in tomato fruit, among which a higher percentage of antisense lncRNAs were targeted to the genes enriched in hydrolase activity. To ascertain the roles of these lncRNAs, seven hydrolase‐related transcripts were transiently knocked‐down by virus‐induced gene silencing. Silencing of lncRNACXE20 reduced the expression level of a carboxylesterase gene, further enhancing the resistance of tomato to B. cinerea. In contrast, silencing of lncRNACHI, lncRNAMMP, lncRNASBT1.9 and lncRNAPME1.9 impaired the resistance to B. cinerea, respectively. Further RT‐qPCR assay and enzymatic activity detection displayed that the attenuated resistance of lncRNAMMP and lncRNASBT1.9‐silenced plants was associated with the inhibition on the expression of JA‐related genes, while the decreased resistance of lncRNACHI‐silenced plants resulted in reduced chitinase activity. Collectively, these results may provide references for deciphering the mechanisms underlying specific lncRNAs to interfere with B. cinerea infection by regulating the expression of defence‐related genes or affecting hydrolase activity. Summary Statement: To add more references to the mechanisms underlying the interaction between fruit—Botrytis cinerea interaction, the lncRNAs induced by B. cinerea in tomato fruit were identified and their roles were preliminarily investigated. The results revealed that specific lncRNAs are involved in fruit—B. cinerea interaction by regulating the expression of defence‐related genes or affecting hydrolase activity. [ABSTRACT FROM AUTHOR]

Cetaceans, which are integral to marine ecosystems, face escalating anthropogenic threats, including climate change and pollution, positioning them as critical sentinel species for ocean and human health. This review explores the neglected realm of non-Candida yeasts in cetaceans, addressing the gaps in the understanding of their prevalence, pathogenicity, and environmental impacts. By examining identified species such as Cryptococcus spp., Paracoccidioides spp., and several dimorphic fungi, this review emphasizes global prevalence, epidemiology and ecology, pathogenicity, and potential zoonotic implications. It also discusses the fine line between yeast commensalism and pathogenicity by considering environmental influences such as pollution, climate shifts, and immune suppression. Environmental impact discussions delve into how rising ocean temperatures and pollution can modify yeast mycobiota, potentially affecting marine host health and broader ecosystem dynamics. The cetacean's unique physiology and ecological niches are considered, highlighting potential impacts on behaviors, reproductive success, and survival rates. Identifying crucial knowledge gaps, the review calls for intensified research efforts, employing advanced molecular techniques to unravel the cetacean mycobiome. Systematic studies on yeast diversity, antifungal susceptibility, and their influence on environmental and ecosystem health are proposed, and the balance between commensal and pathogenic species emphasizes the significance of the One Health approach. In conclusion, as marine mammals face unprecedented challenges, unveiling non-Candida yeasts in cetaceans emerges as a critical endeavor with far-reaching implications for the conservation of marine ecosystems and for both animal and human public health. [ABSTRACT FROM AUTHOR]

Tra1 is an essential coactivator protein of the yeast SAGA and NuA4 acetyltransferase complexes that regulate gene expression through multiple mechanisms including the acetylation of histone proteins. Tra1 is a pseudokinase of the PIKK family characterized by a C-terminal PI3K domain with no known kinase activity. However, mutations of specific arginine residues to glutamine in the PI3K domains (an allele termed tra1Q3) result in reduced growth and increased sensitivity to multiple stresses. In the opportunistic fungal pathogen Candida albicans , the tra1Q3 allele reduces pathogenicity and increases sensitivity to the echinocandin antifungal drug caspofungin, which disrupts the fungal cell wall. Here, we found that compromised Tra1 function, in contrast to what is seen with caspofungin, increases tolerance to the azole class of antifungal drugs, which inhibits ergosterol synthesis. In C. albicans , tra1Q3 increases the expression of genes linked to azole resistance, such as ERG11 and CDR1. CDR1 encodes a multidrug ABC transporter associated with efflux of multiple xenobiotics, including azoles. Consequently, cells carrying tra1Q3 show reduced intracellular accumulation of fluconazole. In contrast, a tra1Q3 Saccharomyces cerevisiae strain displayed opposite phenotypes: decreased tolerance to azole, decreased expression of the efflux pump PDR5 , and increased intracellular accumulation of fluconazole. Therefore, our data provide evidence that Tra1 differentially regulates the antifungal response across yeast species. [ABSTRACT FROM AUTHOR]

To complete its parasitic lifecycle, Salmacisia buchloëana , a biotrophic fungus, manipulates reproductive organ development, meristem determinacy, and resource allocation in its dioecious plant host, buffalograss (Bouteloua dactyloides ; Poaceae). To gain insight into S. buchloëana's ability to manipulate its host, we sequenced and assembled the 20.1 Mb genome of S. buchloëana into 22 chromosome-level pseudomolecules. Phylogenetic analysis suggests that S. buchloëana is nested within the genus Tilletia and diverged from Tilletia caries and Tilletia walkeri ∼ 40 MYA. We find that S. buchloëana contains a novel chromosome arm with no syntenic relationship to other publicly available Tilletia genomes, and that genes on the novel arm are upregulated upon infection, suggesting that this unique chromosomal segment may have played a critical role in S. buchloëana's evolution and host specificity. Salmacisia buchloëana has one of the largest fractions of serine peptidases (1.53% of the proteome) and one of the highest GC contents (62.3%) in all classified fungi. Analysis of codon base composition indicated that GC content is controlled more by selective constraints than directional mutation, and that S. buchloëana has a unique bias for the serine codon UCG. Finally, we identify 3 inteins within the S. buchloëana genome, 2 of which are located in a gene often used in fungal taxonomy. The genomic and transcriptomic resources generated here will aid plant pathologists and breeders by providing insight into the extracellular components contributing to sex determination in dioecious grasses. [ABSTRACT FROM AUTHOR]

White-nose disease (WND), caused by the psychrophilic fungus Pseudogymnoascus destructans, represents one of the greatest threats for North American hibernating bats. Research on molecular data has significantly advanced our knowledge of various aspects of the disease, yet more studies are needed regarding patterns of P. destructans genetic diversity distribution. In the present study, we investigate three sites within the native range of the fungus in detail: two natural hibernacula (karst caves) in Bulgaria, south-eastern Europe and one artificial hibernaculum (disused cellar) in Germany, northern Europe, where we conducted intensive surveys between 2014 and 2019. Using 18 microsatellite and two mating type markers, we describe how P. destructans genetic diversity is distributed between and within sites, the latter including differentiation across years and seasons of sampling; across sampling locations within the site; and between bats and hibernaculum walls. We found significant genetic differentiation between hibernacula, but we could not detect any significant differentiation within hibernacula, based on the variables examined. This indicates that most of the pathogen's movement occurs within sites. Genotypic richness of P. destructans varied between sites within the same order of magnitude, being approximately two times higher in the natural caves (Bulgaria) compared to the disused cellar (Germany). Within all sites, the pathogen's genotypic richness was higher in samples collected from hibernaculum walls than in samples collected from bats, which corresponds with the hypothesis that hibernacula walls represent the environmental reservoir of the fungus. Multiple pathogen genotypes were commonly isolated from a single bat (i.e. from the same swab sample) in all study sites, which might be important to consider when studying disease progression. [ABSTRACT FROM AUTHOR]

ABSTRACT Alternaria alternata is a ubiquitous soil-borne fungus capable of causing diseases in a variety of plants and occasionally in humans. While populations of A. alternata from infected plants have received significant attention, relatively little is known about its soil populations, including its population genetic structure and antifungal susceptibilities. In addition, over the last two decades, greenhouses have become increasingly important for food and ornamental plant production throughout the world, but how greenhouses might impact microbial pathogens such as A. alternata populations remains largely unknown. Different from open crop fields, greenhouses are often more intensively cultivated, with each greenhouse being a relatively small and isolated space where temperature and humidity are higher than surrounding environments. Previous studies have shown that greenhouse populations of two common molds, Aspergillus fumigatus and A. alternata, within a small community in southwestern China were variably differentiated. However, the relative contribution of physical separation among local greenhouses to the large-scale population structure remains unknown. Here, we isolated strains of A. alternata from seven greenhouses in Shijiazhuang, northeast China. Their genetic diversity and triazole susceptibilities were analyzed and compared with each other and with 242 isolates from nine greenhouses in Kunming, southwest China. Results showed that the isolation of greenhouses located

Abstract Social insects are prone to pathogen infection because of high exposure rates from social interactions. However, it remains unclear whether queens have enhanced pathogen resistance, because reproduction is largely confined to queens. Here, we used a natural host–pathogen system, the subterranean termite Reticulitermes chinensis and the entomopathogenic fungus Metarhizium anisopliae, to investigate the differences in allogrooming, locomotion, and immune gene expression between queens and workers against pathogen infection. We found that fungal infection significantly reduced survival in both queens and workers. Infected queens received significantly more grooming time from sanitary nestmates than infected workers, but they returned much less grooming time to sanitary nestmates than infected workers. Infection resulted in a reduction in the average locomotion speed and distance of queens but had no effect on worker locomotion. Infection resulted in upregulated expression of two immune genes (termicin and transferrin), two antioxidant genes (CAT and SOD), and phosphate genes CYP450 in queens but not in workers. Our results indicated that eusocial termites evolved strategies that prioritize the reproductive castes' welfare in defending against the pathogen infection to ensure continued reproduction and colony persistence.

Parastagonospora nodorum is a necrotrophic pathogen of wheat that is particularly destructive in major wheat-growing regions of the United States, northern Europe, Australia, and South America. P. nodorum secretes necrotrophic effectors that target wheat susceptibility genes to induce programmed cell death (PCD), resulting in increased colonization of host tissue and, ultimately, sporulation to complete its pathogenic life cycle. Intensive research over the last two decades has led to the functional characterization of five proteinaceous necrotrophic effectors, SnTox1, SnToxA, SnTox267, SnTox3, and SnTox5, and three wheat susceptibility genes, Tsn1, Snn1, and Snn3D-1. Functional characterization has revealed that these effectors, in addition to inducing PCD, have additional roles in pathogenesis, including chitin binding that results in protection from wheat chitinases, blocking defense response signaling, and facilitating plant colonization. There are still large gaps in our understanding of how this necrotrophic pathogen is successfully manipulating wheat defense to complete its life cycle. This review summarizes our current knowledge, identifies knowledge gaps, and provides a summary of well-developed tools and resources currently available to study the P. nodorum–wheat interaction, which has become a model for necrotrophic specialist interactions. Further functional characterization of the effectors involved in this interaction and work toward a complete understanding of how P. nodorum manipulates wheat defense will provide fundamental knowledge about this and other necrotrophic interactions. Additionally, a broader understanding of this interaction will contribute to the successful management of Septoria nodorum blotch disease on wheat. [Graphic: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

The SnTox1 effector is a virulence factor of the fungal pathogen Stagonospora nodorum (Berk.), which interacts with the host susceptibility gene Snn1 in a gene-for-gene manner and causes necrosis on the leaves of sensitive wheat genotypes. It is known that salicylic acid (SA), jasmonic acid (JA) and ethylene are the key phytohormones involved in plant immunity. To date, effectors of various pathogens have been discovered that can manipulate plant hormonal pathways and even use hormone crosstalk to promote disease development. However, the role of SnTox1 in manipulating hormonal pathways has not been studied in detail. We studied the redox status and the expression of twelve genes of hormonal pathways and two MAPK genes in six bread wheat cultivars sensitive and insensitive to SnTox1 with or without treatment by SA, JA and ethephon (ethylene-releasing agent) during infection with the SnTox1-producing isolate S. nodorum 1SP. The results showed that SnTox1 controls the antagonism between the SA and JA/ethylene signaling pathways. The SA pathway was involved in the development of susceptibility, and the JA/ethylene pathways were involved in the development of wheat plants resistance to the Sn1SP isolate in the presence of a SnTox1-Snn1 interaction. SnTox1 hijacked the SA pathway to suppress catalase activity, increase hydrogen peroxide content and induce necrosis formation; it simultaneously suppresses the JA and ethylene hormonal pathways by SA. To do this, SnTox1 reprogrammed the expression of the MAPK genes TaMRK3 and TaMRK6 and the TF genes TaWRKY13, TaEIN3 and TaWRKY53b. This study provides new data on the role of SnTox1 in manipulating hormonal pathways and on the role of SA, JA and ethylene in the pathosystem wheat S. nodorum.

The conjunctiva has immune-responsive properties to protect the eye from infections. Its innate immune system reacts against external pathogens, such as fungi. The complement factor C5a is an important contributor to the initial immune response. It is known that activation of transient-receptor-potential-vanilloid 1 (TRPV1) and TRP-melastatin 8 (TRPM8) channels is involved in different immune reactions and inflammation in the human body. The aim of this study was to determine if C5a and mucor racemosus e voluminae cellulae (MR) modulate Ca2+-signaling through changes in TRPs activity in human conjunctival epithelial cells (HCjECs). Furthermore, crosstalk was examined between C5a and MR in mediating calcium regulation. Intracellular Ca2+-concentration ([Ca2+]i) was measured by fluorescence calcium imaging, and whole-cell currents were recorded using the planar-patch-clamp technique. MR was used as a purified extract. Application of C5a (0.05–50 ng/mL) increased both [Ca2+]i and whole-cell currents, which were suppressed by either the TRPV1-blocker AMG 9810 or the TRPM8-blocker AMTB (both 20 µM). The N-terminal peptide C5L2p (20–50 ng/mL) blocked rises in [Ca2+]i induced by C5a. Moreover, the MR-induced rise in Ca2+-influx was suppressed by AMG 9810 and AMTB, as well as 0.05 ng/mL C5a. In conclusion, crosstalk between C5a and MR controls human conjunctival cell function through modulating interactions between TRPV1 and TRPM8 channel activity.

The plethora of genome sequences produced in the postgenomic age has not resolved many of our most pressing biological questions. Correlating gene expression with an interrogatable and easily observable characteristic such as the surrogate phenotype conferred by a reporter gene is a valuable approach to gaining insight into gene function. Many reporters including lacZ, amdS, and the fluorescent proteins mRuby3 and mNeonGreen have been used across all manners of organisms. Described here is an investigation into the creation of a robust, synthetic, fusion reporter system for Cryptococcus neoformans that combines some of the most useful fluorophores available in this system with the versatility of the counter-selectable nature of amdS. The reporters generated include multiple composition and orientation variants, all of which were investigated for differences in expression. Evaluation of known promoters from the TEF1 and GAL7 genes was undertaken, elucidating novel expression tendencies of these biologically relevant C. neoformans regulators of transcription. Smaller than lacZ but providing multiple useful surrogate phenotypes for interrogation, the fusion ORF serves as a superior whole-cell assay compared to traditional systems. Ultimately, the work described here bolsters the array of relevant genetic tools that may be employed in furthering manipulation and understanding of the WHO fungal priority group pathogen C. neoformans.