BACKGROUND: Zoonotic sporotrichosis caused by Sporothrix brasiliensis has become the main subcutaneous mycosis in Brazil. Minas Gerais (MG) is located in southeast Brazil and since 2015 has experienced an epidemic of zoonotic sporotrichosis.
OBJECTIVE: This study aimed to reconstruct the epidemiological scenario of sporotrichosis from S. brasiliensis in recent epizooty in the Metropolitan Region of Belo Horizonte (MRBH), MG.
METHODS: A total of 95 Sporothrix spp. isolates (Sporothirx brasiliensis n = 74, S. schenckii n = 11 and S. globosa n = 10) were subjected to Amplified Fragment Length Polymorphism (AFLP) genotyping and mating-type analysis to determine genetic diversity and population structure. Of these, 46 S. brasiliensis isolates were recovered from animals (cats n = 41 and dogs n = 5) from MRBH.
RESULTS: Our study describes the high interspecific differentiation power of AFLP-based genotyping between the main phylogenetic Sporothrix groups. S. brasiliensis presents high genetic variability and pronounced population structure with geographically focused outbreaks in Brazil. The genetic groups include older genotypes from the prolonged epidemic in Southeast (Rio de Janeiro and São Paulo), South (Rio Grande do Sul), Northeast (Pernambuco) and new genotypes from the MRBH. Furthermore, we provide evidence of heterothallism mating strategy in pathogenic Sporothrix species. Genotypes originating in Rio de Janeiro and Pernambuco carry the predominant MAT1-2 idiomorph as opposed to genotypes from Rio Grande do Sul, which have the MAT1-1 idiomorph. We observed an overwhelming occurrence of MAT1-1 among MRBH isolates.
CONCLUSIONS: Our study provides clear evidence of the predominance of a genetic group profile circulating in animals in Minas Gerais, independent of that disseminated from Rio de Janeiro. Our data can help us understand the genetic population processes that drive the evolution of this fungus in Minas Gerais and contribute to future mitigation actions for this ongoing epidemic.

Colletotrichum fructicola shows morphological and genetic differences in plus and minus strains. However, the mechanism of the differentiation between two types of strains is still largely unclear. Our early transcriptome analysis revealed that CfHMG expression differed in plus and minus strains. To define the functions of the CfHMG gene, we constructed gene deletion mutants by homologous recombination. We found that a CfHMG deletion mutant of the minus strain, CfHMG-M, could lead to a reduction in perithecium sizes and densities on media and sterile perithecium formation compared with the minus wild type (WT), whereas there was no effect for the plus mutant CfHMG-P. In co-cultures between CfHMG-P and minus WT, CfHMG-M and plus WT, or CfHMG-P and CfHMG-M, the quantities of perithecia were all reduced significantly. When conidial suspensions were inoculated on non-wounded apple fruit, it was found that the virulence of the minus mutant decreased significantly but not for the plus one. Further, we found that the virulence decrease in minus mutants was caused by a decrease in the conidium germination rate. Our results indicate that CfHMG of C. fructicola plays an important role in the mating line formation between the plus and minus strain for both strains and differentially regulates the perithecium size, density, fertilization, and virulence of the minus strain. The results are significant for further detecting the differentiated mechanisms between the plus and minus strains in Colletotrichum fungi.

Blue cheeses, including renowned mold-ripened varieties such as Roquefort (France), Gorgonzola (Italy), Stilton (UK), Danablue (Denmark), and Cabrales (Spain), owe their distinct blue-green color and unique flavor to the fungal species Penicillium roqueforti. In Turkey, traditional cheeses similar to blue cheeses, namely mold-ripened Tulum and Civil, employ production techniques distinct from their European counterparts. Notably, mold-ripening in Turkish cheeses is spontaneous and does not involve starter cultures. Despite P. roqueforti being recognized for its distinct genetic populations sourced from various blue cheeses and non-cheese origins globally, the characteristics of the P. roqueforti population within Turkish cheeses remain unexplored. This study aimed to unravel the genetic characteristics and population structure of P. roqueforti from Turkish mold-ripened cheeses. Analysis of mold-ripened Civil (n = 22) and Tulum (n = 8) samples revealed 66 P. roqueforti isolates (76.6 % of total fungal isolates). Subsequently, these isolates (n = 66) and those from previous studies (Tulum n = 53, Golot n = 1) were used to assess genetic characteristics and mating genotypes. All 120 isolates harbored horizontal transfer regions (Wallaby and CheesyTer) and predominantly possessed the MAT1-2 mating genotype, similar to global blue cheese populations. However, most lacked the mpaC deletion associated with such populations. Analysis of the population with three polymorphic microsatellite markers revealed 36 haplotypes (HTs). Some cheeses contained isolates with different HTs or opposite mating genotypes, aligning with spontaneous fungal growth. Tulum and Civil isolates exhibited similar population diversity without forming distinct subgroups. Phylogenetic analysis of 20 selected isolates showed 75 % aligning with global blue cheese isolates, while 25 % formed unique clades. Overall, Turkish P. roqueforti isolates share genetic similarities with global populations but exhibit unique characteristics, suggesting potential new clades deserving further investigation. This research illuminates the characteristics of P. roqueforti isolates from Turkish cheeses, contributing to the knowledge of the global intraspecific diversity of the P. roqueforti species.

Phytophthora infestans is the causal agent of late blight in potato. The occurrence of P. infestans with both A1 and A2 mating types in the field may result in sexual reproduction and the generation of recombinant strains. Such strains with new combinations of traits can be highly aggressive, resistant to fungicides, and can make the disease difficult to control in the field. Metalaxyl-resistant isolates are now more prevalent in potato fields. Understanding the genetic structure and rapid identification of mating types and metalaxyl response of P. infestans in the field is a prerequisite for effective late blight disease monitoring and management. Molecular and phenotypic assays involving molecular and phenotypic markers such as mating types and metalaxyl response are typically conducted separately in the studies of the genotypic and phenotypic diversity of P. infestans. As a result, there is a pressing need to reduce the experimental workload and more efficiently assess the aggressiveness of different strains. We think that employing genetic markers to not only estimate genotypic diversity but also to identify the mating type and fungicide response using machine learning techniques can guide and speed up the decision-making process in late blight disease management, especially when the mating type and metalaxyl resistance data are not available. This technique can also be applied to determine these phenotypic traits for dead isolates. In this study, over 600 P. infestans isolates from different populations-Estonia, Pskov region, and Poland-were classified for mating types and metalaxyl response using machine learning techniques based on simple sequence repeat (SSR) markers. For both traits, random forest and the support vector machine demonstrated good accuracy of over 70%, compared to the decision tree and artificial neural network models whose accuracy was lower. There were also associations (p < 0.05) between the traits and some of the alleles detected, but machine learning prediction techniques based on multilocus SSR genotypes offered better prediction accuracy.

BACKGROUND: Populations of the plant pathogenic fungus Verticillium dahliae display a complex and rich genetic diversity, yet the existence of sexual reproduction in the fungus remains contested. As pivotal genes, MAT genes play a crucial role in regulating cell differentiation, morphological development, and mating of compatible cells. However, the functions of the two mating type genes in V. dahliae, VdMAT1-1-1, and VdMAT1-2-1, remain poorly understood.
RESULTS: In this study, we confirmed that the MAT loci in V. dahliae are highly conserved, including both VdMAT1-1-1 and VdMAT1-2-1 which share high collinearity. The conserved core transcription factor encoded by the two MAT loci may facilitate the regulation of pheromone precursor and pheromone receptor genes by directly binding to their promoter regions. Additionally, peptide activity assays demonstrated that the signal peptide of the pheromone VdPpg1 possessed secretory activity, while VdPpg2, lacked a predicted signal peptide. Chemotactic growth assays revealed that V. dahliae senses and grows towards the pheromones FO-a and FO-α of Fusarium oxysporum, as well as towards VdPpg2 of V. dahliae, but not in response to VdPpg1. The findings herein also revealed that VdMAT1-1-1 and VdMAT1-2-1 regulate vegetative growth, carbon source utilization, and resistance to stressors in V. dahliae, while negatively regulating virulence.
CONCLUSIONS: These findings underscore the potential roles of VdMAT1-1-1 and VdMAT1-2-1 in sexual reproduction and confirm their involvement in various asexual processes of V. dahliae, offering novel insights into the functions of mating type genes in this species.

Pyrenophora teres f. teres (Ptt) is a severe pathogen to spring barley in Northern Europe. Ptt with relevant mutations in fungicide target proteins, sterol 14α-demethylase (CYP51A), cytochrome b (Cyt b), and succinate dehydrogenase (SDH) would put efficient disease control at risk. In the growing seasons of 2021 and 2022, 193 Ptt isolates from Estonia were analysed. In this study, mutation detection and in vitro fungicide sensitivity assays of single-spore isolates were carried out. Reduced sensitivity phenotype to mefentrifluconazole was evident in Ptt isolates with a F489L mutation in CYP51A or with 129 bp insert in the Cyp51A gene-promoter region. However, sensitivity to a prothioconazole-desthio remained high regardless of these molecular changes. The Ptt population was mostly sensitive to bixafen, fluxapyroxad, pyraclostrobin, and azoxystrobin. The sensitivity of fluxapyroxad and bixafen has been affected by two mutations, C-S135R and D-H134R, found in SDH subunits. The F129L mutation in Cyt b influenced azoxystrobin but not pyraclostrobin sensitivity. In total, 30 isolates from five fields had relevant mutations in three target protein genes simultaneously. Most of these isolates had a reduced sensitivity phenotype to mefentrifluconazole, fluxapyroxad, and azoxystrobin, while sensitivity to other tested fungicides remained high. Furthermore, possible sexual reproduction may enhance the pathogen\'s fitness and help it adapt to fungicides.

Thielaviopsis paradoxa sensu lato is a soilborne fungal pathogen that causes Thielaviopsis trunk rot and heart rot in palms. The loss of structural integrity resulting from trunk rot can cause the palm trunk to collapse suddenly and poses a serious threat to life and property. Even though rudimentary knowledge about the Thielaviopsis infection process in palms is available, nothing is known about the T. paradoxa species complex in the US. The aim of this study was to characterize T. paradoxa s. lat. isolates collected from diseased palms grown in Florida. Multi-locus phylogeny using three genes, ITS, β-tubulin, and tef1-α, revealed that the isolates separate into two distinct clades with high bootstrap support. The majority of the isolates clustered with the species T. ethacetica, while two isolates formed a separate clade, distinct from T. musarum, and might represent an undescribed Thielaviopsis species. One representative isolate from each clade, when grown on three distinct media and at four different temperatures, showed differences in gross colony morphology, as well as growth rates. The T. ethacetica isolate TP5448 and the Thielaviopsis sp. isolate PLM300 grew better at opposite ends of the temperature spectrum tested in this study, i.e., 35 °C and 10 °C, respectively. In pathogenicity assays on whole plants, the T. ethacetica isolate proved to be more aggressive than Thielaviopsis sp. isolate PLM300, as it produced larger lesions when inoculated on wounded leaflets. An unequal distribution was observed for the mating-type locus of T. ethacetica, as 12 isolates carried the MAT1-1-1 allele, while the status for four isolates remained undefined. Variation in mycelial growth in response to different fungicides was also observed between the two clades. These results demonstrate the existence of two Thielaviopsis clades that can infect palms in Florida and underscore the need for targeted sampling to help uncover the diversity of Thielaviopsis species across palm-growing regions in the US.

In China, Fusarium pseudograminearum has emerged as a major pathogen causing Fusarium crown rot (FCR) and caused significant losses. Studies on the pathogen\'s properties, especially its mating type and trichothecene chemotypes, are critical with respect to disease epidemiology and food/feed safety. There are currently few available reports on these issues. This study investigated the species composition, mating type idiomorphs, and trichothecene genotypes of Fusarium spp. causing FCR in Henan, China. A significant shift in F. pseudograminearum-induced FCR was found in the present study. Of the 144 purified strains, 143 were F. pseudograminearum, whereas only 1 Fusarium graminearum was identified. Moreover, a significant trichothecene-producing capability of F. pseudograminearum strains from Henan was observed in this work. Among the 143 F. pseudograminearum strains identified, F. pseudograminearum with a 15ADON genotype was found to be predominant (133 isolates), accounting for 92.36% of all strains, followed by F. pseudograminearum with a 3ADON genotype, whereas only one NIV genotype strain was detected. Overall, a relatively well-balanced 1:1 ratio of the F. pseudograminearum population was found in Henan. To the best of our knowledge, this is the first study that has examined the Fusarium populations responsible for FCR across the Henan wheat-growing region.

Cordyceps militaris has been extensively cultivated as a model cordyceps species for commercial purposes. Nevertheless, the problems related to strain degeneration and breeding technologies remain unresolved. This study assessed the physiology and fertility traits of six C. militaris strains with distinct origins and characteristics, focusing on single mating-type strains. The results demonstrated that the three identified strains (CMDB01, CMSY01, and CMJB02) were single mating-type possessing only one mating-type gene (MAT1-1). In contrast, the other three strains (CMXF07, CMXF09, and CMMS05) were the dual mating type. The MAT1-1 strains sourced from CMDB01, CMSY01, and CMJB02 consistently produced sporocarps but failed to generate ascospores. However, when paired with MAT1-2 strains, the MAT1-1 strains with slender fruiting bodies and normal morphology were fertile. The hyphal growth rate of single mating-type strains (CMDB01, CMSY01, and CMJB02) typically surpassed that of dual mating-type strains (CMXF07, CMXF09, and CMMS05). The growth rates of MAT1-2 and MAT1-1 strains were proportional to their ratios, such that a single mating-type strain with a higher ratio exhibited an increased growth rate. As C. militaris matured, the adenosine content decreased. In summary, the C. militaris strains that consistently produce sporocarps and have a single mating type are highly promising for production and breeding.

Saccharomycopsis species are natural organic sulphur auxotrophs. Their genomes do not encode genes for the uptake and assimilation of sulphate and thus these species cannot grow on media lacking e.g. methionine. Due to the similarity between sulphate and selenate, uptake and assimilation of selenate occurs through the same pathway starting from sulphate transporters encoded by the homologs of the SUL1 and SUL2 genes in S. cerevisiae. Lack of these transporters renders Saccharomycopsis species resistant to selenate levels that are toxic to other microorganisms. We used this feature to enrich environmental samples for Saccharomycopsis species. This led to the isolation of S. schoenii, S. lassenensis and a hitherto undescribed Saccharomycopsis species with limited by-catch of other yeasts, mainly belonging to Metschnikowia and Hanseniaspora. We performed growth and predation assays to characterize the potential of these new isolates as predacious yeasts. Most Saccharomycopsis species are temperature sensitive and cannot grow at 37°C; with the exception of S. lassenensis strains. Predation assays with S. schoenii and S. cerevisiae as prey indicated that predation was enhanced at 20°C compared to 30°C. We crossed an American isolate of S. schoenii with our German isolate using marker directed breeding. Viable progeny indicated that both strains are interfertile and belong to the same biological species. S. lassenensis is heterothallic, while S. schoenii and the new Saccharomycopsis isolate, for which we suggest the name S. geisenheimensis sp. nov., are homothallic.