Stemphylium revisited

Prevalence of FRAC Group 11 Fungicide Resistance in Stemphylium vesicarium Isolates, but Not S. beticola Isolates, Causing Stemphylium Leaf Spot of Spinach (Spinacia oleracea)

Stemphylium leaf spot of spinach, caused by Stemphylium beticola and S. vesicarium, is a disease of economic importance in fresh market, processing, and seed production. There have been increasing reports of difficulty managing the disease in the southern United States using fungicides in Fungicide Resistance Action Committee (FRAC) group 11. Isolates of S. beticola and S. vesicarium obtained from spinach leaves and seed from 2001 to 2020 were screened for resistance to azoxystrobin and pyraclostrobin in vitro, in vivo, and using PCR assays to detect mutations in cytochrome b associated with resistance in other fungi (F129L, G137R, and G143A). EC50 values for mycelial growth and conidial germination of S. vesicarium isolates in vitro were significantly less (mean of 0.35 μg/ml) than that of S. vesicarium (mean of 14.17 μg/ml) with both fungicides. All isolates were slightly more sensitive to pyraclostrobin than azoxystrobin in both assays. In vivo assays of plants inoculated with the isolates of S. vesicarium demonstrated poor efficacy of fungicides with each of the two active ingredients. Only the G143A mutation was detected in all spinach isolates of S. vesicarium, including an isolate of S. vesicarium collected in 2003 and 82.9% of isolates from spinach seed lots harvested from crops grown in or after 2017 in Europe, New Zealand, and the United States. The FRAC 11 mutations were not detected in any isolates of S. beticola. The in vitro, in vivo, and DNA mutation assays suggest FRAC group 11 fungicide resistance is widespread in spinach isolates of S. vesicarium but not S. beticola.

The Fungal Diversity and Potential Pathogens Associated with Postharvest Fruit Rot of 'Huangguan' Pear (Pyrus bretschneideri) in Hebei Province, China

Postharvest fruit rot caused by pathogens is a serious problem in the pear industry. This study investigated the fungal diversity and main pathogens and identified a new pathogen in the stored 'Huangguan' pear (Pyrus bretschneideri Rehd.), the dominant pear variety in northern China. We sampled 20 refrigeration houses from five main producing regions in Hebei Province and used Illumina sequencing technology to detect the fungal composition. Alternaria (56.3%) was the most abundant fungus, followed by Penicillium (9.2%) and Monilinia (6.2%). We also isolated and identified nine strains of Alternaria and four strains of Penicillium. Moreover, we observed a new postharvest fruit disease in 'Huangguan' pear caused by Stemphylium eturmiunum, which was confirmed by phylogenetic analysis by combining the sequences of three conserved genes, including internal transcribed spacer, gapdh, and calmodulin. This study marks the first documentation of S. eturmiunum causing fruit rot in 'Huangguan' pears, offering valuable insights for identifying and controlling this newly identified postharvest disease.

Causal agents of Stemphylium-induced foliar diseases of tomatoes and other Solanaceae hosts in Brazil

AIM

An extensive survey was done to clarify the prevalent Stemphylium species on Solanaceae plants across Brazil, and their host ranges.

METHODS AND RESULTS

Eighty nine (89) Stemphylium isolates were obtained from naturally infected tomatoes as well as S. paniculatum, potato, eggplant, scarlet eggplant (Solanum aethiopicum var. gilo), Physalis angulata, and Capsicum species. Phylogenetic analyses encompassing the ITS-5.8S rDNA and glyceraldehyde-3-phosphate dehydrogenase genomic regions placed the isolates into two distinct groupings with either Stemphylium lycopersici or S. solani. Isolates of S. lycopersici (n = 81) were obtained infecting tomato, potato, eggplant, S. paniculatum, and P. angulata. Isolates of S. solani (n = 8) were detected in natural association with scarlet eggplant and tomato. Two isolates of S. lycopersici displayed a wide experimental host range in greenhouse bioassays, infecting accessions of 12 out of 18 species. Ocimum basilicum (Lamiaceae) was the only experimental host outside the Solanaceae family.

Morphological characteristics and phylogenetic evidence reveal two new species and the first report of Comoclathris (Pleosporaceae, Pleosporales) on dicotyledonous plants from China

Two novel Comoclathris species were identified from dicotyledonous plants (Clematis sp. and Xanthocerassorbifolium) in China. The results were supported by morphological characters and Maximum Likelihood (ML) and Bayesian Inference (BI) analyses. Multi-gene phylogenetic analyses of the ITS, LSU, SSU and rpb2 sequences revealed two new species Comoclathrisclematidis and C.xanthoceratis, which are phylogenetically distinct. The new species are phylogenetically closely related to C.arrhenatheri. However, they are distinguishable from C.arrhenatheri by having comparatively larger asci and ascospores. This study improves our knowledge of Comoclathris as no species has been previously described from China. This suggests such taxa may be rare and it is likely that new taxa will be discovered from hosts and environments that have not yet been extensively investigated.

Enabling Population Biology Studies of Stemphylium vesicarium from Onion with Microsatellites

Stemphylium leaf blight (SLB), caused by the fungus Stemphylium vesicarium, is dominant within the foliar disease complex affecting onion production in New York (NY). The disease causes premature defoliation and significant reductions in bulb weight and quality. Foliar diseases of onion are usually managed by an intensive fungicide program, but SLB management is complicated by resistance to multiple single-site modes of action. The design of integrated disease management strategies is limited by incomplete knowledge surrounding the dominant sources of S. vesicarium inoculum. To facilitate genomic-based studies of S. vesicarium populations, nine microsatellite markers were developed. The markers were multiplexed into two PCR assays containing four and five fluorescently labeled microsatellite markers. Initial testing of the S. vesicarium isolates found the markers were highly polymorphic and reproducible with an average of 8.2 alleles per locus. The markers were used to characterize 54 S. vesicarium isolates from major NY onion production regions in 2016 (n = 27) and 2018 (n = 27). Fifty-two multilocus genotypes (MLGs) were identified between these populations. Genotypic and allelic diversities were high in both the 2016 and 2018 populations. A greater degree of genetic variation was observed within populations than between years. No distinct pattern of MLGs according to population was identified and some MLGs were closely related between 2016 and 2018. The lack of evidence for linkage among loci also was strongly suggestive of clonal populations with only minor differences between the two populations. These microsatellite markers will be a foundational resource for the testing of hypotheses surrounding the population biology of S. vesicarium and therefore informing disease management.

Two Species of Stemphylium, S. astragali and S. henanense sp. nov., Causing Leaf and Stem Spot Disease on Astragalus sinicus in China

Astragalus sinicus is a versatile legume crop, primarily utilized as a green manure in China. During 2020 and 2021, A. sinicus plants exhibiting dark brown or reddish-brown lesions or spots on leaves and stems were collected from fields in the Henan, Sichuan, and Guangxi provinces of China. Sixteen single-spore isolates were isolated from the infected leaf and stem tissue samples. Phylogenetic analyses based on the concatenated internal transcribed spacer, gapdh, and cmdA sequences indicated that 14 of them belong to Stemphylium astragali, whereas two isolates can be well separated from other known species in this genus. Based on the morphological characteristics and nucleotide polymorphisms with sister taxa, the two isolates were identified as a new species named S. henanense. Furthermore, pathogenicity assays showed that the S. astragali and S. henanense isolates caused leaf and stem spot symptoms on A. sinicus. Altogether, we describe a new species of Stemphylium (i.e., S. henanense sp. nov.) causing leaf spot disease of A. sinicus. In addition, this is the first report of S. astragali causing stem spot disease of A. sinicus.

Molecular Approaches for Detection of Trichoderma Green Mold Disease in Edible Mushroom Production

Due to the evident aggressive nature of green mold and the consequently huge economic damage it causes for producers of edible mushrooms, there is an urgent need for prevention and infection control measures, which should be based on the early detection of various Trichoderma spp. as green mold causative agents. The most promising current diagnostic tools are based on molecular methods, although additional optimization for real-time, in-field detection is still required. In the first part of this review, we briefly discuss cultivation-based methods and continue with the secondary metabolite-based methods. Furthermore, we present an overview of the commonly used molecular methods for Trichoderma species/strain detection. Additionally, we also comment on the potential of genomic approaches for green mold detection. In the last part, we discuss fast screening molecular methods for the early detection of Trichoderma infestation with the potential for in-field, point-of-need (PON) application, focusing on isothermal amplification methods. Finally, current challenges and future perspectives in Trichoderma diagnostics are summarized in the conclusions.

Surveillance of Landraces' Seed Health in South Italy and New Evidence on Crop Diseases

During the last three years, more than 300 landraces belonging to different plant species have been the main focus of an Italian valorization research project (AgroBiodiversità Campana, ABC) aiming at analyzing, recovering, preserving, and collecting local biodiversity. In this context, phytosanitary investigation plays a key role in identifying potential threats to the preservation of healthy seeds in gene banks and the successful cultivation of landraces. The surveillance carried out in this study, in addition to highlighting the expected presence of common species-specific pathogens such as Ascochyta pisi in peas, Ascochyta fabae in broad beans, and Macrophomina phaseolina, Xanthomonas axonopodis pv. phaseoli, and Xanthomonas fuscans subsp. fuscans in beans, pointed to the presence of novel microorganisms never detected before in the seeds of some hosts (Apiospora arundinis in common beans or Sclerotinia sclerotiorum and Stemphylium vesicarium in broad beans). These novel seedborne pathogens were fully characterized by (i) studying their morphology, (ii) identifying them by molecular methods, and (iii) studying their impact on adult crop plants. For the first time, this study provides key information about three novel seedborne pathogens that can be used to correctly diagnose their presence in seed lots, helping prevent the outbreaks of new diseases in the field.

First Report of Stemphylium Leaf Blight Caused by Stemphylium eturmiunum on Welsh Onion in China

Welsh onion (Allium fistulosum L. ) is native to Southwest China (Tomoo and Shinji 2012), with a cultivated area of about 550,000 ha and a production of 20 million tons in 2020, and widely cultivated throughout the world as a condiment. During April 2020, a Stemphylium-like disease occurred on a three-hectare field in Nanchang County (28°33'N, 115°57'E) was first observed and then monitored in Ningdu (26°23'N, 115°59'E) and Leping (28°50'N, 117°18'E), Jiangxi Province, China. The disease incidence was estimated to be nearly 30% in a survey of 300 plants. Disease symptoms were oval or irregular lesions at the center of outer leaves. The lesions were light brown at the edges and black-violet in the middle. Previous studies reported that the disease was mainly caused by S. vesicarium (Misawa et al. 2012). Besides, S. botryosum (Misawa et al. 2011) and S. solani (Dumin et al. 2021) can also cause this disease. To investigate the causal agent of the disease in Jiangxi, pieces of tissue from the margins of the symptomatic leaves were surface sterilized with 75% ethanol for 15 s, rinsed in sterile water three times, and placed on Potato Dextrose Agar (PDA) followed by incubation at 25°C in the dark for 5 days. Colonies were initially yellowish-brown and gradually turned into reddish-brown after 2 weeks. Conidia were solitary, oblong or ellipsoid, mid to deep brown (22-45×14-25 μm) with transverse and longitudinal septa (Fig. S1). Morphological characteristics were consistent with S. eturmiunum reported by Simmons (Simmons 2001). For molecular identification, genomic DNA was extracted from two representative isolates. ITS and gapdh genes of the isolates were amplified with primers ITS1/ITS4 (White et al. 1990) and gdp1/gdp2 (Berbee et al. 1999). BLASTn analysis showed that ITS sequences (OM846570, OM846571) of the two isolates both > 99% identity with S. eturmiunum strain CBS 109845 (MH862841) (Vu et al. 2018); and also had 100% identity for gapdh gene sequences (OM867337, OM867338) with S. eturmiunum strain CBS 109845 (KU850689) (Woudenberg et al. 2017). Phylogenetic tree based on ITS and gapdh gene sequences were constructed using a maximum-likelihood method with 1000 bootstraps indicated that the two isolates were clustered with S. eturmiunum (Fig. S2). Based on morphological characteristics and molecular analysis, the fungus was identified as S. eturmiunum. A pathogenicity test was performed on healthy welsh onion leaves to fulfill Koch's postulates. Twenty leaves were inoculated with a spore suspension of 1×104 conidia/mL followed by incubation at 25℃ (relative humidity > 90%) in the greenhouse. Negative controls were inoculated with sterile water. The experiment was repeated three times. Purple brown lesions were observed on all inoculated leaves at 7 days post-inoculation that similar to those observed in the field, and control remained symptomless. S. eturmiunum was re-isolated from the diseased leaves. It has reported that S. eturmiunum can infect tomato, garlic, sweet cherry and many other crops and cause different diseases. To the best of our knowledge, this is the first report of S. eturmiunum can cause Stemphylium leaf blight on welsh onion in China. Appropriate strategies should be developed to manage this disease.

Screening for broad-spectrum antimicrobial endophytes from Rosa roxburghii and multi-omic analyses of biosynthetic capacity

Plants with certain medicinal values are a good source for isolating function-specific endophytes. Rosa roxburghii Tratt. has been reported to be a botanical source of antimicrobial compounds, which may represent a promising candidate for screening endophytic fungi with antimicrobial potential. In this study, 54 endophytes were isolated and molecularly identified from R. roxburghii. The preliminary screening using the plate confrontation method resulted in 15 different endophytic strains showing at least one strong inhibition or three or more moderate inhibition against the 12 tested strains. Further re-screening experiments based on the disc diffusion method demonstrated that Epicoccum latusicollum HGUP191049 and Setophoma terrestris HGUP190028 had excellent antagonistic activity. The minimum inhibitory concentration (MIC) test for extracellular metabolites finally indicated that HGUP191049 had lower MIC values and a broader antimicrobial spectrum, compared to HGUP190028. Genomic, non-target metabolomic, and comparative genomic studies were performed to understand the biosynthetic capacity of the screened-out endophytic fungus. Genome sequencing and annotation of HGUP191049 revealed a size of 33.24 megabase pairs (Mbp), with 24 biosynthetic gene clusters (BGCs), where the putative antimicrobial compounds, oxyjavanicin, patulin and squalestatin S1 were encoded by three different BGCs, respectively. In addition, the non-targeted metabolic results demonstrated that the strain contained approximately 120 antimicrobial secondary metabolites and was structurally diverse. Finally, comparative genomics revealed differences in pathogenicity, virulence, and carbohydrate-active enzymes in the genome of Epicoccum spp. Moreover, the results of the comparative analyses presumed that Epicoccum is a promising source of antimicrobial terpenes, while oxyjavanicin and squalestatin S1 are antimicrobial compounds shared by the genus. In conclusion, R. roxburghii and the endophytic HGUP191049 isolated from it are promising sources of broad-spectrum antimicrobial agents.

Dynamic Fluctuation and Niche Differentiation of Fungal Pathogens Infecting Bell Pepper Plants

The plant microbiome is shaped by plant development and microbial interaction. Fungal pathogens infecting bell pepper plants may fluctuate across the growing seasons. Dynamic fluctuation of the microbiome and fungal pathogens in bell pepper plants is poorly understood, and the origin of fungal pathogens causing fruit rot and leaf wilt has been barely investigated. In this study, we used amplicon sequencing (i.e., 16S rRNA and internal transcribed spacer [ITS] sequencing) to explore the compositional variations of the microbiome in bell pepper plants and studied the fluctuation of fungal pathogens across the growing seasons. Co-occurrence network analysis was applied to track the origin and dissemination route of fungal pathogens that infected bell pepper plants. ITS and 16S rRNA sequencing analyses demonstrated that fungal pathogens infecting fruits and leaves probably belonged to the Penicillium, Cladosporium, Fusarium, and unclassified_Sclerotiniaceae genera rather than one specific genus. The dominant fungal pathogens were different, along with the development of bell pepper plants. Both plant development and fungal pathogens shaped microbial communities in bell pepper plants across the growing seasons. Fungal pathogens decreased species richness and diversity of fungal communities in fungus-infected fruit and leaf tissues but not the uninfected stem tissues. Bacterial metabolic functions of xenobiotics increased in fungus-infected leaves at a mature developmental stage. Competitive interaction was present between fungal and bacterial communities in leaves. Co-occurrence network analysis revealed that the origins of fungal pathogens included the greenhouse, packing house, and storage room. Niche differentiation of microbes was discovered among these locations. IMPORTANCE Bell peppers are widely consumed worldwide. Fungal pathogen infections of bell peppers lead to enormous economic loss. To control fungal pathogens and increase economic benefit, it is essential to investigate the shifting patterns of the microbiome and fungal pathogens in bell pepper plants across the growing seasons. In this study, bell pepper plant diseases observed in fruits and leaves were caused by different fungal pathogens. Fungal pathogens originated from the greenhouse, packing house, and storage room, and niche differentiation existed among microbes. This study improves the understanding of dynamic fluctuation and source of fungal pathogens infecting bell pepper plants in the farming system. It also facilitates precise management of fungal pathogens in the greenhouse.

Two Novel Genera, Neostemphylium and Scleromyces (Pleosporaceae) from Freshwater Sediments and Their Global Biogeography

Although the Pleosporaceae is one of the species-richest families in the Pleosporales, research into less-explored substrates can contribute to widening the knowledge of its diversity. In our ongoing survey on culturable Ascomycota from freshwater sediments in Spain, several pleosporacean specimens of taxonomic interest were isolated. Phylogenetic analyses based on five gene markers (ITS, LSU, gapdh, rbp2, and tef1) revealed that these fungi represent so far undescribed lineages, which are proposed as two novel genera in the family, i.e., Neostemphylium typified by Neostemphylium polymorphum sp. nov., and Scleromyces to accommodate Scleromyces submersus sp. nov. Neostemphylium is characterized by the production of phaeodictyospores from apically swollen and darkened conidiogenous cells, the presence of a synanamorph that consists of cylindrical and brown phragmoconidia growing terminally or laterally on hyphae, and by the ability to produce secondary conidia by a microconidiation cycle. Scleromyces is placed phylogenetically distant to any genera in the family and only produces sclerotium-like structures in vitro. The geographic distribution and ecology of N. polymorphum and Sc. submersus were inferred from metabarcoding data using the GlobalFungi database. The results suggest that N. polymorphum is a globally distributed fungus represented by environmental sequences originating primarily from soil samples collected in Australia, Europe, and the USA, whereas Sc. submersus is a less common species that has only been found associated with one environmental sequence from an Australian soil sample. The phylogenetic analyses of the environmental ITS1 and ITS2 sequences revealed at least four dark taxa that might be related to Neostemphylium and Scleromyces. The phylogeny presented here allows us to resolve the taxonomy of the genus Asteromyces as a member of the Pleosporaceae.

Current Insight into Traditional and Modern Methods in Fungal Diversity Estimates

Fungi are an important and diverse component in various ecosystems. The methods to identify different fungi are an important step in any mycological study. Classical methods of fungal identification, which rely mainly on morphological characteristics and modern use of DNA based molecular techniques, have proven to be very helpful to explore their taxonomic identity. In the present compilation, we provide detailed information on estimates of fungi provided by different mycologistsover time. Along with this, a comprehensive analysis of the importance of classical and molecular methods is also presented. In orderto understand the utility of genus and species specific markers in fungal identification, a polyphasic approach to investigate various fungi is also presented in this paper. An account of the study of various fungi based on culture-based and cultureindependent methods is also provided here to understand the development and significance of both approaches. The available information on classical and modern methods compiled in this study revealed that the DNA based molecular studies are still scant, and more studies are required to achieve the accurate estimation of fungi present on earth.

Stemphylium Leaf Blight: A Re-Emerging Threat to Onion Production in Eastern North America

Stemphylium leaf blight (SLB), caused by Stemphylium vesicarium, is a foliar disease of onion worldwide, and has recently become an important disease in the northeastern United States and Ontario, Canada. The symptoms begin as small, tan to brown lesions on the leaves that can progress to defoliate plants. Crop loss occurs through reduced photosynthetic area, resulting in smaller, lower-quality bulbs. Leaf necrosis caused by SLB also can compromise bulb storage, as green leaves are required for the uptake of sprout inhibitors applied prior to harvest. The pathogen can overwinter on infested onion residue and infected volunteer plants. Asymptomatic weedy hosts near onion fields may also be a source of inoculum. Production of ascospores of the teleomorph (Pleospora allii) peaks in early spring in northeastern North America, often before the crop is planted, and declines rapidly as daily mean air temperatures rise. Conidia are usually present throughout the growing season. Application of fungicides is a standard practice for management of the complex of fungi that can cause foliar diseases of onion in this region. Recent assessments have shown that populations of S. vesicarium in New York and Ontario are resistant to at least three single-site mode-of-action fungicides. Three disease prediction systems have been developed and evaluated that may enable growers to reduce the frequency and/or number of fungicide applications, but the loss of efficacious fungicides due to resistance development within S. vesicarium populations threatens sustainability. The lack of commercially acceptable onion cultivars with sufficient resistance to reduce the number of fungicides for SLB also limits the ability to manage SLB effectively. Integrated disease management strategies for SLB are essential to maintain profitable, sustainable onion production across eastern North America.

Stemphylium Leaf Blight of Welsh Onion (Allium fistulosum): An Emerging Disease in Sanxing, Taiwan

Welsh onion (Allium fistulosum L.) is one of the main and oldest vegetable crops grown in Taiwan. A severe epidemic of leaf blight in Welsh onion caused by a Stemphylium-like pathogen was found in Sanxing, Taiwan, from 2018 to 2020. However, correct species identification, biology, and control of Stemphylium leaf blight (SLB) of Welsh onion are not well-established. Therefore, the main objective of this study was to investigate the causal agent of SLB in Sanxing and evaluate the in vitro sensitivity of Stemphylium-like pathogen to commonly used fungicides. A phylogenetic analysis based on combining the internal transcribed spacer (ITS) region and glyceraldedyhe-3-phosphate dehydrogenase (gapdh) and calmodulin (cmdA) gene sequences together with morphological features identified that S. vesicarium is associated with SLB in Sanxing. When inoculated onto Welsh onion leaves, the isolates caused symptoms identical to those observed in the field; therefore, S. vesicarium was reisolated and Koch's postulates were confirmed. We observed a higher incidence of SLB symptoms on the oldest leaves compared with younger leaves. The maximum and minimum temperatures for in vitro mycelial growth and conidial germination (%) of S. vesicarium were 20 to 30°C and 5°C, respectively. Sixteen fungicides were tested for their effectiveness to reduce the mycelial growth and conidial germination of S. vesicarium in vitro. Boscalid plus pyraclostrobin, fluopyram, fluxapyroxad, and fluxapyroxad plus pyraclostrobin were highly effective at reducing mycelial growth and conidial germination in S. vesicarium. However, strobilurin fungicides (azoxystrobin and kresoxim-methyl) commonly used in Welsh onion production in Sanxing were ineffective. This study discusses the emergence of SLB caused by S. vesicarium in the foliar disease complex affecting Welsh onion and the management of the disease using fungicides with different modes of action in Taiwan. The research will support the sustainable management of SLB in Sanxing, Taiwan; however, further field assessments of the fungicides are warranted.

Biological Characteristics and Molecular Mechanism of Procymidone Resistance in Stemphylium eturmiunum From Garlic

Garlic leaf blight caused by Stemphylium eturmiunum was first reported in Jiangsu Province in China. The dicarboximide fungicide (DCF) procymidone is reported to possess broad-spectrum action in inhibiting filamentous fungi and is widely used to control leaf disease of various plants. Of 41 Stemphylium eturmiunum isolates collected in this study from commercial garlic farms in Pizhou and Dafeng counties of Jiangsu Province, eight isolates were resistant to procymidone. The following three phenotypes were categorized according to in vitro responses to DCFs: sensitive, low resistance to iprodione and procymidone, and high resistance to all iprodione and procymidone. The fitness of all resistant isolates was decreased in accordance with data on mycelial growth, conidiation, and virulence. After treatment with 10 µg/ml of procymidone for 4 h, mycelial intracellular glycerol concentrations of resistant isolates were significantly lower than those of sensitive isolates. Positive cross-resistance was observed between dicarboximides and phenylpyrroles, but there was no cross-resistance between dicarboximides and fluazinam or difenoconazole in the two resistant phenotypes. Nucleotide sequence alignment of two-component histidine kinase genes from sensitive and resistant isolates indicated that amino acid mutations were located at the histidine kinase, adenylyl cyclase, methyl-accepting chemotaxis protein and at the phosphatase domain of the N-terminal region and the response regulator domain of the C-terminal region. To our knowledge, this is the first report of DCF resistance in Stemphylium eturmiunum, and these findings will help establish a rational strategy to manage DCF-resistant populations of Stemphylium eturmiunum in the field.

Stemphylium lycopersici Causing Leaf Spot of Watermelon (Citrullus lanatus) in China

Watermelon (Citrullus lanatus) is an important cucurbit crop in China. During September 2020, an unknown leaf spot disease was observed on watermelon in two greenhouses (640m2 per greenhouse) of Sangzi town, Jizhou district, in Tianjin, China (117°10'E, 39°55'N), where approximately 10% of plants were infected. Disease symptoms began as small, circular, brown spots on leaves. As these spots increased in size, they developed confluent, irregular lesions surrounded by dark brown edges. Severely affected plants had many wilted leaves followed by defoliation. Ten symptomatic leaves were collected for pathogen isolation. Diseased tissues (3×3 mm) were cut from the margins of lesions and surface disinfected with 1% NaClO for 1 min, rinsed three times with sterile distilled water and then placed on potato dextrose agar (PDA) at 25±2°C with a 12-h photoperiod for 7 to 10 days. Seven morphologically similar isolates were obtained from the ten infected leaves and purified by single-spore culturing for further study. The initial growth of the isolates on PDA appeared grayish white in obverse and bright yellow pigmentation in reverse. Colony color gradually deepened to grayish brown in obverse and brownish red in reverse. Conidia (n=50) were solitary, light brown, oblong to long elliptic, pointed or obtusely rounded at the top, constricted at the transverse septum, with verrucous processes on the surface, 36.3 to 64.2×16.6 to 25.1 μm, and the L/W ratio of conidia was 1.5-2.5. All characteristics were consistent with the description of Stemphylium lycopersici (Ellis 1971; Woudenberg et al. 2017). Total genomic DNA was extracted from a representative isolate (XG2-2) using a Fungal DNA Kit (GBCBIO, Guangzhou, China). The internal transcribed spacer (ITS) and translation elongation factor 1-α (EF1-α) genes (Sun et al. 2015) were amplified and sequenced with the primer pairs ITS1/ITS4 (5'-TCCGTAGGTGAACCTGCGG-3'/5'-TCCTCCGCTTATTGATATGC-3') and EF-1α-F/EF-1α-R(5'-TCACTTGATCTACAAGTGCGGTGG-3'/5'-CGATCTTGTAGACATCCTGGAGG-3'), respectively. The two sequences of strain XG2-2 (GenBank Accession No. MW362344 and MW664941) showed 100% and 99% identity to S. lycopersici strain 01 and strain KuNBY1 (GenBank Accession No. KR911814 and AB828256) respectively. The phylogenetic analysis using MEGA7 based on the sequences of ITS and EF1-α regions showed that the isolate XG2-2 was clustered with S. lycopersici isolates (strain 01 and strain KuNBY1). For the pathogenicity test, a spore suspension (1×106 spores/ml) in sterile distilled water from a 7-day-old culture of the fungus grown on PDA and counted with a hemacytometer was sprayed on leaves and stems of five healthy watermelon plants, grown for 2 months in the greenhouse at 25 to 30 °C, with 85% relative humidity. Conditions remained the same for inoculation experiments. Negative controls were healthy plants inoculated with sterile distilled water. The experiment was repeated twice. Six days after inoculation, typical leaf spot symptoms were observed on inoculated leaves, whereas control leaves remained symptomless. To satisfy Koch's postulates, the causal fungus was re-isolated from the lesions of inoculated plants, with morphological and cultural characteristics identical with the original isolate. Stemphylium lycopersici is a common fungus with a relatively extensive host range (Kee et al. 2018). In recent years, new host plants infected by S. lycopersici have been reported in Asia including Physali (Yange et al. 2020), common bean (Li et al. 2019), and potato (Kee et al. 2018). To our knowledge, this is a new host record for S. lycopersici causing leaf spot on watermelon in China. Sangzi watermelon is a special local product in the Jizhou district of Tianjin. At present the cultivated area in 1000 ha including 667 ha in controlled conditions and 333 ha of field-grown plants with a total annual output of 45000 Mg. In this survey, we found the disease caused by S. lycopersici on watermelon only in these two greenhouses, but cannot rule out the possibility of large-scale spread in the future. Therefore, integrated management strategies for this fungus need to be developed to reduce economic losses in commercial cultivation.

New and Interesting Fungi. 4

An order, family and genus are validated, seven new genera, 35 new species, two new combinations, two epitypes, two lectotypes, and 17 interesting new host and / or geographical records are introduced in this study. Validated order, family and genus: Superstratomycetales and Superstratomycetaceae (based on Superstratomyces ). New genera: Haudseptoria (based on Haudseptoria typhae); Hogelandia (based on Hogelandia lambearum); Neoscirrhia (based on Neoscirrhia osmundae); Nothoanungitopsis (based on Nothoanungitopsis urophyllae); Nothomicrosphaeropsis (based on Nothomicrosphaeropsis welwitschiae); Populomyces (based on Populomyces zwinianus); Pseudoacrospermum (based on Pseudoacrospermum goniomae). New species: Apiospora sasae on dead culms of Sasa veitchii (Netherlands); Apiospora stipae on dead culms of Stipa gigantea (Spain); Bagadiella eucalyptorum on leaves of Eucalyptus sp. (Australia); Calonectria singaporensis from submerged leaf litter (Singapore); Castanediella neomalaysiana on leaves of Eucalyptus sp. (Malaysia); Colletotrichum pleopeltidis on leaves of Pleopeltis sp. (South Africa); Coniochaeta deborreae from soil (Netherlands); Diaporthe durionigena on branches of Durio zibethinus (Vietnam); Floricola juncicola on dead culm of Juncus sp. (France); Haudseptoria typhae on leaf sheath of Typha sp. (Germany); Hogelandia lambearum from soil (Netherlands); Lomentospora valparaisensis from soil (Chile); Neofusicoccum mystacidii on dead stems of Mystacidium capense (South Africa); Neomycosphaerella guibourtiae on leaves of Guibourtia sp. (Angola); Niesslia neoexosporioides on dead leaves of Carex paniculata (Germany); Nothoanungitopsis urophyllae on seed capsules of Eucalyptus urophylla (South Africa); Nothomicrosphaeropsis welwitschiae on dead leaves of Welwitschia mirabilis (Namibia); Paracremonium bendijkiorum from soil (Netherlands); Paraphoma ledniceana on dead wood of Buxus sempervirens (Czech Republic); Paraphoma salicis on leaves of Salix cf. alba (Ukraine); Parasarocladium wereldwijsianum from soil (Netherlands); Peziza ligni on masonry and plastering (France); Phyllosticta phoenicis on leaves of Phoenix reclinata (South Africa); Plectosphaerella slobbergiarum from soil (Netherlands); Populomyces zwinianus from soil (Netherlands); Pseudoacrospermum goniomae on leaves of Gonioma kamassi (South Africa); Pseudopyricularia festucae on leaves of Festuca californica (USA); Sarocladium sasijaorum from soil (Netherlands); Sporothrix hypoxyli in sporocarp of Hypoxylon petriniae on Fraxinus wood (Netherlands); Superstratomyces albomucosus on Pycnanthus angolensis (Netherlands); Superstratomyces atroviridis on Pinus sylvestris (Netherlands); Superstratomyces flavomucosus on leaf of Hakea multilinearis (Australia); Superstratomyces tardicrescens from human eye specimen (USA); Taeniolella platani on twig of Platanus hispanica (Germany), and Tympanis pini on twigs of Pinus sylvestris (Spain). Citation: Crous PW, Hernández-Restrepo M, Schumacher RK, Cowan DA, Maggs-Kölling G, Marais E, Wingfield MJ, Yilmaz N, Adan OCG, Akulov A, Álvarez Duarte E, Berraf-Tebbal A, Bulgakov TS, Carnegie AJ, de Beer ZW, Decock C, Dijksterhuis J, Duong TA, Eichmeier A, Hien LT, Houbraken JAMP, Khanh TN, Liem NV, Lombard L, Lutzoni FM, Miadlikowska JM, Nel WJ, Pascoe IG, Roets F, Roux J, Samson RA, Shen M, Spetik M, Thangavel R, Thanh HM, Thao LD, van Nieuwenhuijzen EJ, Zhang JQ, Zhang Y, Zhao LL, Groenewald JZ (2021). New and Interesting Fungi. 4. Fungal Systematics and Evolution 7: 255-343. doi: 10.3114/fuse.2021.07.13.

Marine endophytic fungi associated with Halopteris scoparia (Linnaeus) Sauvageau as producers of bioactive secondary metabolites with potential dermocosmetic application

Marine fungi and, particularly, endophytic species have been recognised as one of the most prolific sources of structurally new and diverse bioactive secondary metabolites with multiple biotechnological applications. Despite the increasing number of bioprospecting studies, very few have already evaluated the cosmeceutical potential of marine fungal compounds. Thus, this study focused on a frequent seaweed in the Portuguese coast, Halopteris scoparia, to identify the endophytic marine fungi associated with this host, and assess their ability to biosynthesise secondary metabolites with antioxidative, enzymatic inhibitory (hyaluronidase, collagenase, elastase and tyrosinase), anti-inflammatory, photoprotective, and antimicrobial (Cutibacterium acnes, Staphylococcus epidermidis and Malassezia furfur) activities. The results revealed eight fungal taxa included in the Ascomycota, and in the most representative taxonomic classes in marine ecosystems (Eurotiomycetes, Sordariomycetes and Dothideomycetes). These fungi were reported for the first time in Portugal and in association with H. scoparia, as far as it is known. The screening analyses showed that most of these endophytic fungi were producers of compounds with relevant biological activities, though those biosynthesised by Penicillium sect. Exilicaulis and Aspergillus chevalieri proved to be the most promising ones for being further exploited by dermocosmetic industry. The chemical analysis of the crude extract from an isolate of A. chevalieri revealed the presence of two bioactive compounds, echinulin and neoechinulin A, which might explain the high antioxidant and UV photoprotective capacities exhibited by the extract. These noteworthy results emphasised the importance of screening the secondary metabolites produced by these marine endophytic fungal strains for other potential bioactivities, and the relevance of investing more efforts in understanding the ecology of halo/osmotolerant fungi.

First Report of Stemphylium eturmiunum causing postharvest rot on tomato (Solanum lycopersicum) in Italy

Italy is the largest tomato (Solanum lycopersicum)-producing country in Europe with a cultivated area of 97,092 ha and a production of 5,798,103 tons/year in 2018 (FAOSTAT, 2020). During July 2020, a postharvest rot occurred in fresh tomatoes 'Piccadilly' cultivated in Sicily (Pachino, RG) and commercialized in Northern Italy (Torino, TO). Affected fruit showed circular black rot on the blossom end. The rot had an average incidence of 7% of the fruits, in three batches of 100 tomatoes each. Isolation was carried out by cutting pieces of symptomatic rotten fruits. The fragments were surface-disinfected with 1% sodium hypochlorite for 30 s, rinsed in sterile water and air-dried. Five fragments were cut and plated onto Potato Dextrose Agar (PDA) supplemented with streptomycin, and incubated at 24±1°C in the dark for 5 days. Representative colonies were transferred onto PCA and morphological observations were performed as described by Woudenberg et al. (2017) after 7 and 14 days. Colonies were olive-green, flat with regular margins, while conidia were mid to deep brown, solitary, ovoid or ellipsoid (17.39 µm ± 2.04 × 10.59 ± 3.30 µm) with transverse and longitudinal septa. Based on morphological observations the isolates were identified as Stemphylium eturmiunum (Simmons, 2001). Species identification was confirmed by sequencing rDNA internal transcribed spacer (ITS) using primers ITS1/ITS4 (White et al. 1990), cmdA gene region using primers CALDF1/CALDR2 (Lawrence et al. 2013) and gapdh gene region with primers gpd1/gpd2 (Berbee et al. 1999). Six amplified sequences per region (ANos. from MW158387 to MW158398 and from MW159746 to MW159751) were BLAST-searched in GenBank, obtaining >99 % identity with ex-type strain of S. eturmiunum strain CBS 109845 (AN° KU850541) for ITS, and 100% identity (ANos. KU850831 and KU850689) for cmdA and gapdh, respectively. To confirm the species, DNA sequences were aligned with CLUSTAL W with closely related species of Stemphylium reported in the last revision of the genus (Woudenberg et al., 2017), and a phylogenetic analysis with the Neighbor Joining method based on Tamura Nei model + Gamma distribution (bootstrap 1,000) was performed. The phylogenetic tree confirmed the identity of the isolates as S. eturmiunum (Suppl. Fig. 1). To fulfil Koch's postulates, pathogenicity tests were conducted on S. lycopersicum cv. Piccadilly fruits. Tomatoes were surface sterilized with 1% sodium hypochlorite and air-dried. Fruits (5 fruits per isolates) were wounded (two injuries of 3 mm each) and inoculated with a spore suspension of 1x105 cell/mL obtained from 15 days-old PCA cultures, as in Spadoni et al. (2020. Negative controls were wounded and inoculated with sterile deionized water. Symptoms occurred on all fruits inoculated after 12 days at 24±1°C and S. eturmiunum was re-isolated from inoculated fruits on PCA (Suppl. Fig. 2), control remained symptomless. Re-isolated colonies were molecularly identified as S. eturmiunum. In Italy a different species, S. vesicarium, was reported on tomato (Porta-Puglia, 1981), while S. eturmiunum was described as a postharvest pathogen of tomato in China, Greece, New Zealand and the United States (Woudenberg et al., 2017; Vaghefi et al., 2020), and from fruits commercialized in Danish and Spanish markets (Andersen and Frisvad, 2004). To the best of our knowledge, this is the first report of S. eturmiunum causing postharvest rot on tomato in Italy. The occurrence of this pathogen further stresses the importance of careful handling to prevent fruit crackings and of preharvest control strategies.

First report of leaf spot disease caused by Stemphylium eturmiunum on American sweetgum (Liquidambar styraciflua L.) in China

American sweetgum (Liquidambar styraciflua L.) is an important tree for landscaping and wood processing. In recent years, leaf spots on American sweetgum with disease incidence of about 53% were observed in about 1200 full grown plants in a field (about 8 ha) located in Pizhou, Jiangsu Province, China. Initially, dense reddish-brown spots appeared on both old and new leaves. Later, the spots expanded into dark brown lesions with yellow halos. Symptomatic leaf samples from different trees were collected and processed in the laboratory. For pathogen isolation, leaf sections (4×4mm) removed from the lesion margin were surface sterilized with 75% ethanol for 20s and then sterilized in 2% NaOCl for 30s, rinsed three times in sterile distilled water, incubated on potato dextrose agar (PDA) at 25 °C in the darkness. After 5 days of cultivation, the pure culture was obtained by single spore separation. 6 isolate samples from different leaves named FXA1 to FXA6 shared nearly identical morphological features. The isolate FXA1 (codes CFCC 54675) was deposited in the China Center for Type Culture Collection. On the PDA, the colonies were light yellow with dense mycelium, rough margin, and reverse brownish yellow. Conidiophores (23-35 × 6-10 µm) (n=60) were solitary, straight to flexuous. Conidia (19-34 × 10-21 µm) (n=60) were single, muriform, oblong, mid to deep brown, with 1 to 6 transverse septa. These morphological characteristics resemble Stemphylium eturmiunum (Simmons 2001). Genomic DNA was extracted from mycelium following the CTAB method. The ITS region, gapdh, and cmdA genes were amplified and sequenced with the primers ITS5/ITS4 (Woudenberg et al. 2017), gpd1/gpd2 (Berbee et al. 1999), and CALDF1/CALDR2 (Lawrence et al. 2013), respectively. A maximum likelihood phylogenetic analysis based on ITS, gapdh and cmdA (accession nos. MT898502-MT898507, MT902342-MT902347, MT902336-MT902341) sequences using MEGA 7.0 revealed that the isolates were placed in the same clade as S. eturmiunum with 98% bootstrap support. All seedlings for pathogenicity tests were enclosed in plastic transparent incubators to maintain high relative humidity (90%-100%) and incubated in a greenhouse at 25°C with a 12-h photoperiod. For pathogenicity, the conidial suspension (105 spores/ml) of each isolate was sprayed respectively onto healthy leaves of L. styraciflua potted seedlings (2-year-old, 3 replicate plants per isolate). As a control, 3 seedlings were sprayed with sterile distilled water. After 7 days, dense reddish-brown spots were observed on all inoculated leaves. In another set of tests, healthy plants (3 leaves per plant, 3 replicate plants per isolate) were wound-inoculated with mycelial plugs (4×4mm) and inoculated with sterile PDA plugs as a control. After 7 days, brown lesions with light yellow halo were observed on all inoculation sites with the mycelial plugs. Controls remained asymptomatic in the entire experiment. The pathogen was reisolated from symptomatic tissues and identified as S. eturmiunum but was not recovered from the control. The experiment was repeated twice with the similar results, fulfilling Koch's postulates. S. eturmiunum had been reported on tomato (Andersen et al. 2004), wheat (Poursafar et al. 2016), garlic (L. Fu et al. 2019) but not on woody plant leaves. To our knowledge, this is the first report of S. eturmiunum causing leaf spot on L. styraciflua in the world. This disease poses a potential threat to American sweetgum and wheat in Pizhou.

Fungal Planet description sheets: 1112-1181

Novel species of fungi described in this study include those from various countries as follows: Australia, Austroboletus asper on soil, Cylindromonium alloxyli on leaves of Alloxylon pinnatum, Davidhawksworthia quintiniae on leaves of Quintinia sieberi, Exophiala prostantherae on leaves of Prostanthera sp., Lactifluus lactiglaucus on soil, Linteromyces quintiniae (incl. Linteromyces gen. nov.) on leaves of Quintinia sieberi, Lophotrichus medusoides from stem tissue of Citrus garrawayi, Mycena pulchra on soil, Neocalonectria tristaniopsidis (incl. Neocalonectria gen. nov.) and Xyladictyochaeta tristaniopsidis on leaves of Tristaniopsis collina, Parasarocladium tasmanniae on leaves of Tasmannia insipida, Phytophthora aquae-cooljarloo from pond water, Serendipita whamiae as endophyte from roots of Eriochilus cucullatus, Veloboletus limbatus (incl. Veloboletus gen. nov.) on soil. Austria, Cortinarius glaucoelotus on soil. Bulgaria, Suhomyces rilaensis from the gut of Bolitophagus interruptus found on a Polyporus sp. Canada, Cantharellus betularum among leaf litter of Betula, Penicillium saanichii from house dust. Chile, Circinella lampensis on soil, Exophiala embothrii from rhizosphere of Embothrium coccineum.China, Colletotrichum cycadis on leaves of Cycas revoluta.Croatia, Phialocephala melitaea on fallen branch of Pinus halepensis. Czech Republic, Geoglossum jirinae on soil, Pyrenochaetopsis rajhradensis from dead wood of Buxus sempervirens.Dominican Republic, Amanita domingensis on litter of deciduous wood, Melanoleuca dominicana on forest litter. France, Crinipellis nigrolamellata (Martinique) on leaves of Pisonia fragrans, Talaromyces pulveris from bore dust of Xestobium rufovillosum infesting floorboards. French Guiana, Hypoxylon hepaticolor on dead corticated branch. Great Britain, Inocybe ionolepis on soil. India, Cortinarius indopurpurascens among leaf litter of Quercus leucotrichophora.Iran, Pseudopyricularia javanii on infected leaves of Cyperus sp., Xenomonodictys iranica (incl. Xenomonodictys gen. nov.) on wood of Fagus orientalis.Italy, Penicillium vallebormidaense from compost. Namibia, Alternaria mirabibensis on plant litter, Curvularia moringae and Moringomyces phantasmae (incl. Moringomyces gen. nov.) on leaves and flowers of Moringa ovalifolia, Gobabebomyces vachelliae (incl. Gobabebomyces gen. nov.) on leaves of Vachellia erioloba, Preussia procaviae on dung of Procavia capensis.Pakistan, Russula shawarensis from soil on forest floor. Russia, Cyberlindnera dauci from Daucus carota. South Africa, Acremonium behniae on leaves of Behnia reticulata, Dothiora aloidendri and Hantamomyces aloidendri (incl. Hantamomyces gen. nov.) on leaves of Aloidendron dichotomum, Endoconidioma euphorbiae on leaves of Euphorbia mauritanica, Eucasphaeria proteae on leaves of Protea neriifolia, Exophiala mali from inner fruit tissue of Malus sp., Graminopassalora geissorhizae on leaves of Geissorhiza splendidissima, Neocamarosporium leipoldtiae on leaves of Leipoldtia schultzii, Neocladosporium osteospermi on leaf spots of Osteospermum moniliferum, Neometulocladosporiella seifertii on leaves of Combretum caffrum, Paramyrothecium pituitipietianum on stems of Grielum humifusum, Phytopythium paucipapillatum from roots of Vitis sp., Stemphylium carpobroti and Verrucocladosporium carpobroti on leaves of Carpobrotus quadrifolius, Suttonomyces cephalophylli on leaves of Cephalophyllum pilansii. Sweden, Coprinopsis rubra on cow dung, Elaphomyces nemoreus from deciduous woodlands. Spain, Polyscytalum pini-canariensis on needles of Pinus canariensis, Pseudosubramaniomyces septatus from stream sediment, Tuber lusitanicum on soil under Quercus suber.Thailand, Tolypocladium flavonigrum on Elaphomyces sp. USA, Chaetothyrina spondiadis on fruits of Spondias mombin, Gymnascella minnisii from bat guano, Juncomyces patwiniorum on culms of Juncus effusus, Moelleriella puertoricoensis on scale insect, Neodothiora populina (incl. Neodothiora gen. nov.) on stem cankers of Populus tremuloides, Pseudogymnoascus palmeri from cave sediment. Vietnam, Cyphellophora vietnamensis on leaf litter, Tylopilus subotsuensis on soil in montane evergreen broadleaf forest. Morphological and culture characteristics are supported by DNA barcodes.

First report of Stemphylium leaf spot caused by Stemphylium vesicarium on alfalfa (Medicago sativa) in Peru

Alfalfa (Medicago sativa) is the most cultivated fodder crop in Peru with 172,000 ha cultivated (MINAM 2019), and Arequipa is the top producing region with 40% of the national production in 2015 (Santamaría et al. 2016). In January-April 2019 (av. 20°C and 70% RH), most alfalfa fields in Majes-Pedregal, Arequipa were affected by an unidentified foliar disease. One of the fields was located at the farm of the Universidad Nacional de San Agustín de Arequipa (16°19'29.6" S, 72°12'59.9" W). Symptoms appeared as elliptical light brown spots witdark brown borders (Fig. S1a and b). The field (~60 × 60 m) was divided into ~30 × 12 m sections and two plants in each section were collected (20 plants total). Plants were digitized and the leaflet diseased area was calculated with ImageJ 1.53a, from which an incidence of 100% and a severity of 38.7 ± 4.4 % were estimated. Microscopical observations at the leaflet spots revealed consistently the presence of oblong multiseptated conidia (23.6-42.8 × 16.5-25.2 µm; av. 33.3 × 20.9 µm; n = 40) of the genus Stemphylium (Simmons 1969; Woudenberg et al. 2017) (Fig. S1c). We obtained 10 pure cultures by placing conidia from the spots directly onto potato dextrose agar medium with the aid of stereoscope and sterile forceps. Two isolates (UNSA-StemV01 and UNSA-StemV02) were incubated further until ascospore production at room temperature with no special light stimulus. After 45 days of growth, globose pseudothecia and ellipsoidal ascospores (25.4-38.7 × 11.2-16.6 µm; av. 31.9 × 13.7 µm; n = 30) formation occurred (Fig. S1d and e). We extracted the DNA from these two isolates using Wizard® Purification Kit (Promega Corp., Madison, WI) and sequenced the internal transcribed spacer 1 and 2 intervening 5.8S rDNA subunit (GenBank accessions: MT371236-37), and the glyceraldehyde-3-phosphate dehydrogenase (MT375513-14) and the calmodulin (MT375515-16) genes, highly resolutive markers to identify Stemphylium species, following Woudenberg et al. (2017). We retrieved sequence data available from 43 isolates of nine Stemphylium species (Han et al. 2019; Woudenberg et al. 2017), and built a mid-point rooted phylogeny with the three-loci concatenated data set (Fig. S2). We identified our isolates as S. vesicarium (Fig. S2). Koch's postulates were fulfilled by spray-inoculation with conidia from isolate UNSA-StemV01 suspended in sterile water (1×104 / mL) to two healthy 50-day old alfalfa plants growing on pots in the university greenhouse (av. 25°C and 70% RH). Two plants sprayed with sterile water without conidia served as control. Symptoms appeared after 21 days of inoculation, and when conidia were re-isolated, they were the same as originally obtained. No symptoms developed in the control plants. This confirmed that S. vesicarium is the causal agent of the alfalfa disease in Majes-Pedregal, identified as Stemphylium leaf spot. revious studies documented S. vesicarium on asparagus and onion in Peru (Castillo Valiente 2018; Vásquez Salas 2018; Vásquez Sangay 2013), but molecular characterization has only been applied to S. lycopersici from potatoes (Woudenberg et al. 2017). Stemphylium vesicarium has been documented in various crops, including alfalfa, and countries in Europe, North America, Africa, Asia and in Australia and New Zealand (Han et al. 2019; Woudenberg et al. 2017). This occurrence is the first report of S. vesicarium on alfalfa in Peru. The disease compromises the quality of this fodder crop, so actions need to be taken in Arequipa.

Reconsideration of species boundaries and proposed DNA barcodes for Calonectria

Calonectria represents a genus of phytopathogenic ascomycetous fungi with a worldwide distribution. In recent years, there has been an increase in the number of taxonomic studies on these fungi. Currently, there are 169 described species of Calonectria based on comparisons of DNA sequence data, combined with morphological characteristics. However, for some of these species, the sequence data utilised at the time of their description were relatively limited. This has justified an urgent need to reconsider the species boundaries for Calonectria based on robust genus-wide phylogenetic analyses. In this study, we utilised 240 available isolates including the ex-types of 128 Calonectria species, and re-sequenced eight gene regions (act, cmdA, his3, ITS, LSU, rpb2, tef1 and tub2) for them. Sequences for 44 Calonectria species, for which cultures could not be obtained, were downloaded from GenBank. DNA sequence data of all the 169 Calonectria species were then used to determine their phylogenetic relationships. As a consequence, 51 species were reduced to synonymy, two new species were identified, and the name Ca. lauri was validated. This resulted in the acceptance of 120 clearly defined Calonectria spp. The overall data revealed that the genus includes 11 species complexes, distributed across the Prolate and Sphaero-Naviculate Groups known to divide Calonectria. The results also made it possible to develop a robust set of DNA barcodes for Calonectria spp. To accomplish this goal, we evaluated the outcomes of each of the eight candidate DNA barcodes for the genus, as well as for each of the 11 species complexes. No single gene region provided a clear identity for all Calonectria species. Sequences of the tef1 and tub2 genes were the most reliable markers; those for the cmdA, his3, rpb2 and act gene regions also provided a relatively effective resolution for Calonectria spp., while the ITS and LSU failed to produce useful barcodes for species discrimination. At the species complex level, results showed that the most informative barcodes were inconsistent, but that a combination of six candidate barcodes (tef1, tub2, cmdA, his3, rpb2 and act) provided stable and reliable resolution for all 11 species complexes. A six-gene combined phylogeny resolved all 120 Calonectria species, and revealed that tef1, tub2, cmdA, his3, rpb2 and act gene regions are effective DNA barcodes for Calonectria.

One stop shop IV: taxonomic update with molecular phylogeny for important phytopathogenic genera: 76–100 (2020)

This is a continuation of a series focused on providing a stable platform for the taxonomy of phytopathogenic fungi and fungus-like organisms. This paper focuses on one family: Erysiphaceae and 24 phytopathogenic genera: Armillaria, Barriopsis, Cercospora, Cladosporium, Clinoconidium, Colletotrichum, Cylindrocladiella, Dothidotthia,, Fomitopsis, Ganoderma, Golovinomyces, Heterobasidium, Meliola, Mucor, Neoerysiphe, Nothophoma, Phellinus, Phytophthora, Pseudoseptoria, Pythium, Rhizopus, Stemphylium, Thyrostroma and Wojnowiciella. Each genus is provided with a taxonomic background, distribution, hosts, disease symptoms, and updated backbone trees. Species confirmed with pathogenicity studies are denoted when data are available. Six of the genera are updated from previous entries as many new species have been described.

Characterization of the CAZy Repertoire from the Marine-Derived Fungus Stemphylium lucomagnoense in Relation to Saline Conditions

Even if the ocean represents a large part of Earth's surface, only a few studies describe marine-derived fungi compared to their terrestrial homologues. In this ecosystem, marine-derived fungi have had to adapt to the salinity and to the plant biomass composition. This articles studies the growth of five marine isolates and the tuning of lignocellulolytic activities under different conditions, including the salinity. A de novo transcriptome sequencing and assembly were used in combination with a proteomic approach to characterize the Carbohydrate Active Enzymes (CAZy) repertoire of one of these strains. Following these approaches, Stemphylium lucomagnoense was selected for its adapted growth on xylan in saline conditions, its high xylanase activity, and its improved laccase activities in seagrass-containing cultures with salt. De novo transcriptome sequencing and assembly indicated the presence of 51 putative lignocellulolytic enzymes. Its secretome composition was studied in detail when the fungus was grown on either a terrestrial or a marine substrate, under saline and non-saline conditions. Proteomic analysis of the four S. lucomagnoense secretomes revealed a minimal suite of extracellular enzymes for plant biomass degradation and highlighted potential enzyme targets to be further studied for their adaptation to salts and for potential biotechnological applications.

Unambiguous identification of fungi: where do we stand and how accurate and precise is fungal DNA barcoding?

True fungi (Fungi) and fungus-like organisms (e.g. Mycetozoa, Oomycota) constitute the second largest group of organisms based on global richness estimates, with around 3 million predicted species. Compared to plants and animals, fungi have simple body plans with often morphologically and ecologically obscure structures. This poses challenges for accurate and precise identifications. Here we provide a conceptual framework for the identification of fungi, encouraging the approach of integrative (polyphasic) taxonomy for species delimitation, i.e. the combination of genealogy (phylogeny), phenotype (including autecology), and reproductive biology (when feasible). This allows objective evaluation of diagnostic characters, either phenotypic or molecular or both. Verification of identifications is crucial but often neglected. Because of clade-specific evolutionary histories, there is currently no single tool for the identification of fungi, although DNA barcoding using the internal transcribed spacer (ITS) remains a first diagnosis, particularly in metabarcoding studies. Secondary DNA barcodes are increasingly implemented for groups where ITS does not provide sufficient precision. Issues of pairwise sequence similarity-based identifications and OTU clustering are discussed, and multiple sequence alignment-based phylogenetic approaches with subsequent verification are recommended as more accurate alternatives. In metabarcoding approaches, the trade-off between speed and accuracy and precision of molecular identifications must be carefully considered. Intragenomic variation of the ITS and other barcoding markers should be properly documented, as phylotype diversity is not necessarily a proxy of species richness. Important strategies to improve molecular identification of fungi are: (1) broadly document intraspecific and intragenomic variation of barcoding markers; (2) substantially expand sequence repositories, focusing on undersampled clades and missing taxa; (3) improve curation of sequence labels in primary repositories and substantially increase the number of sequences based on verified material; (4) link sequence data to digital information of voucher specimens including imagery. In parallel, technological improvements to genome sequencing offer promising alternatives to DNA barcoding in the future. Despite the prevalence of DNA-based fungal taxonomy, phenotype-based approaches remain an important strategy to catalog the global diversity of fungi and establish initial species hypotheses.

Characterization of Leaf Spot Pathogens from Several Spinach Production Areas in the United States

Leaf spot diseases have become a major concern in spinach production in the United States. Determining the causal agents of leaf spots on spinach, their prevalence and pathogenicity, and fungicide efficacy against these pathogens is vital for effective disease management. Spinach leaves with leaf spots were collected from Texas, California, Arizona, and South Carolina from 2016 to 2018, incubated in a moist chamber, and plated on potato dextrose and tryptic soy agar media. Fungal and bacterial colonies recovered were identified based on morphology and sequence analysis of the internal transcribed spacer rDNA and 16S rRNA, respectively. Two predominant genera were isolated: (i) Colletotrichum spp., which were identified to species based on sequences of both introns of the glutamate synthetase (GS-I) and glyceraldehyde-3-phosphate dehydrogenase (gapdh-I) genes; and (ii) Stemphylium spp., identified to species based on sequences of the gapdh and calmodulin (cmdA) genes. Anthracnose (Colletotrichum spinaciae) and Stemphylium leaf spot (Stemphylium vesicarium and S. beticola) were the predominant diseases. Additional fungi recovered at very limited frequencies that were also pathogenic to spinach included Colletotrichum coccodes, C. truncatum, Cercospora beticola, and Myrothecium verrucaria. All of the bacterial isolates were not pathogenic on spinach. Pathogenicity tests showed that C. spinaciae, S. vesicarium, and S. beticola caused significant leaf damage. The fungicides Bravo WeatherStik (chlorothalonil), Dithane F-45 (mancozeb), Cabrio (pyraclostrobin), and Merivon (fluxapyroxad and pyraclostrobin) were highly effective at reducing leaf spot severity caused by an isolate of each of C. spinaciae and S. vesicarium, when inoculated individually and in combination.

Metagenomics analysis of fungal communities associated with postharvest diseases in pear fruits under the effect of management practices

An amplicon metagenomic approach based on the ITS1 region of fungal rDNA was employed to identify the composition of fungal communities associated with diseases of pear fruits during postharvest storage. The sampled fruits were harvested at an orchard using routine management practices involving treatments with various chemical fungicides and were transferred to a storage packinghouse. Effective tags of reading sequences clustered into 53 OTUs whereas Ascomycota was the dominant phylum (83.4%) followed by Basidiomycota (15.8%). Our results revealed that four genera, Penicillium, Rhodotorula, Alternaria and Cladosporium were the most abundant representing 59-95% of the relative abundance per sample. The interruption of chemical treatments during the last month before harvest altered the structure of the fungal community of fruits among untreated and treated samples, mainly in cases of relative abundance of Penicillium and Rhodotorula genera. We hypothesize that various antagonistic interactions might occur on fruit surfaces among the detected fungal genera whose relative abundances were affected by fungicide treatments. Interestingly, some common pre- and postharvest pear fungal pathogens were either less present (such as Moniliana), or undetected (such as Aspergillus, Venturia and Septoria) in untreated and treated samples.

Tenuazonic acid from Stemphylium loti inhibits the plant plasma membrane H+ -ATPase by a mechanism involving the C-terminal regulatory domain

Pathogenic fungi often target the plant plasma membrane (PM) H+ -ATPase during infection. To identify pathogenic compounds targeting plant H+ -ATPases, we screened extracts from 10 Stemphylium species for their effect on H+ -ATPase activity. We identified Stemphylium loti extracts as potential H+ -ATPase inhibitors, and through chemical separation and analysis, tenuazonic acid (TeA) as a potent H+ -ATPase inhibitor. By assaying ATP hydrolysis and H+ pumping, we confirmed TeA as a H+ -ATPase inhibitor both in vitro and in vivo. To visualize in planta inhibition of the H+ -ATPase, we treated pH-sensing Arabidopsis thaliana seedlings with TeA and quantified apoplastic alkalization. TeA affected both ATPase hydrolysis and H+ pumping, supporting a direct effect on the H+ -ATPase. We demonstrated apoplastic alkalization of A. thaliana seedlings after short-term TeA treatment, indicating that TeA effectively inhibits plant PM H+ -ATPase in planta. TeA-induced inhibition was highly dependent on the regulatory C-terminal domain of the plant H+ -ATPase. Stemphylium loti is a phytopathogenic fungus. Inhibiting the plant PM H+ -ATPase results in membrane potential depolarization and eventually necrosis. The corresponding fungal H+ -ATPase, PMA1, is less affected by TeA when comparing native preparations. Fungi are thus able to target an essential plant enzyme without causing self-toxicity.

Current Knowledge on Pathogenicity and Management of Stemphylium botryosum in Lentils (Lens culinaris ssp. culinaris Medik)

Stemphylium blight (SB) caused by Ascomycete, Stemphylium botryosum Wallr. has been a serious threat to lentil cultivation, mainly in Bangladesh, Nepal, India, and Canada since its first outbreak in Bangladesh in 1986. The genus Stemphylium Wallr., a dematiaceous hyphomycete, comprises up to 150 species, and is pathogenic on a wide range of plants infecting leguminous as well as nonleguminous crops. In recent years, studies indicated overlapping in morphological characters among the different species under the genus Stemphylium, making the identification and description of species difficult. This necessitates different molecular phylogenetic analysis in species delimitation. Therefore, a detailed understanding of spatial diversity and population structure of the pathogen is pertinent for producing source material for resistance breeding. The role of different weather variables as predisposing factors for the rapid spread of the pathogen necessitates devising a disease predictive model for the judicial application of fungicides. A dearth of information regarding spore biology, epidemiology, race diversity, host-pathogen interaction, and holistic disease management approach necessitates immediate attention towards more intensive research efforts. This is the first comprehensive review on the current state of knowledge and research efforts being made for a better understanding of the SB resistance through cognizing biology, ecology, and epidemiology of S. botryosum and effective disease management strategies to prevent widespread outbreaks of SB. The information regarding the biology and epidemiology of S. botryosum is also crucial for strengthening the "Integrated Disease Management" (IDM) programme. The need for a regional research network is advocated where the disease is becoming endemic.

Genera of phytopathogenic fungi: GOPHY 3

This paper represents the third contribution in the Genera of Phytopathogenic Fungi (GOPHY) series. The series provides morphological descriptions, information about the pathology, distribution, hosts and disease symptoms for the treated genera, as well as primary and secondary DNA barcodes for the currently accepted species included in these. This third paper in the GOPHY series treats 21 genera of phytopathogenic fungi and their relatives including: Allophoma, Alternaria, Brunneosphaerella, Elsinoe, Exserohilum, Neosetophoma, Neostagonospora, Nothophoma, Parastagonospora, Phaeosphaeriopsis, Pleiocarpon, Pyrenophora, Ramichloridium, Seifertia, Seiridium, Septoriella, Setophoma, Stagonosporopsis, Stemphylium, Tubakia and Zasmidium. This study includes three new genera, 42 new species, 23 new combinations, four new names, and three typifications of older names.

Floral and Foliar Source Affect the Bee Nest Microbial Community

Managed pollinators such as the alfalfa leafcutting bee, Megachile rotundata, are essential to the production of a wide variety of agricultural crops. These pollinators encounter a diverse array of microbes when foraging for food and nest-building materials on various plants. To test the hypothesis that food and nest-building source affects the composition of the bee-nest microbiome, we exposed M. rotundata adults to treatments that varied both floral and foliar source in a 2 × 2 factorial design. We used 16S rRNA gene and internal transcribed spacer (ITS) sequencing to capture the bacterial and fungal diversity of the bee nests. We found that nest microbial communities were significantly different between treatments, indicating that bee nests become inoculated with environmentally derived microbes. We did not find evidence of interactions between the fungi and bacteria within our samples. Furthermore, both the bacterial and fungal communities were quite diverse and contained numerous exact sequence variants (ESVs) of known plant and bee pathogens that differed based on treatment. Our research indicates that bees deposit plant-associated microbes into their nests, including multiple plant pathogens such as smut fungi and bacteria that cause blight and wilt. The presence of plant pathogens in larval pollen provisions highlights the potential for bee nests to act as disease reservoirs across seasons. We therefore suggest that future research should investigate the ability of bees to transmit pathogens from nest to host plant.

Plant Pathogenic Fungi Associated with Coraebus florentinus (Coleoptera: Buprestidae) Attacks in Declining Oak Forests

The black-banded oak borer, Coraebus florentinus, is an emerging pest of oak trees in the western Mediterranean region. Larvae of the insect are xylophagous and progressively excavate an annular gallery that interrupts sap flow, resulting in the death of the attacked branches. Until now, limited information has been available regarding the ecological interactions between C. florentinus and the main plant pathogenic fungi involved in the etiology of oak decline. Knowledge of these interactions is important in understanding their impact in natural ecosystems and developing appropriate management strategies. Therefore, in this study, we characterized the fungal communities occurring in the exoskeleton of adults and larvae of C. florentinus and associated with the necrotic wood tissues surrounding the branch galleries of declining oak trees. A total of 29 fungal species were identified based on DNA sequence data and morphological features, of which 14 were from symptomatic woody tissues, six from insect exoskeleton, and nine from both insects and symptomatic wood tissues. The most frequent fungal species, Cryphonectria naterciae (15.9% of isolates), Dothiorella iberica (11.3%), and Diplodia corticola (9.9%), were isolated from both insect and gallery systems. All three species are well-known oak pathogens and are reported here, for the first time, to be associated with C. florentinus. At the same time, 89.6% of the fungal taxa were isolated from one or two sites, highlighting the site-dependence of fungal community assemblages.

Re-evaluation of Mycoleptodiscus species and morphologically similar fungi

Mycoleptodiscus includes plant pathogens, animal opportunists, saprobic and endophytic fungi. The present study presents the first molecular phylogeny and revision of the genus based on four loci, including ITS, LSU, rpb2, and tef1. An extensive collection of Mycoleptodiscus cultures, including ex-type strains from the CBS, IMI, MUCL, BRIP, clinical isolates from the USA, and fresh isolates from Brazil and Spain, was studied morphologically and phylogenetically to resolve their taxonomy. The study showed that Mycoleptodiscus sensu lato is polyphyletic. Phylogenetic analysis places Mycoleptodiscus in Muyocopronales (Dothideomycetes), together with Arxiella, Leptodiscella, Muyocopron, Neocochlearomyces, and Paramycoleptodiscus. Mycoleptodiscus terrestris, the type species, and M. sphaericus are reduced to synonyms, and one new species is introduced, M. suttonii. Mycoleptodiscus atromaculans, M. coloratus, M. freycinetiae, M. geniculatus, M. indicus, M. lateralis (including M. unilateralis and M. variabilis as its synonyms) and M. taiwanensis belong to Muyocopron (Muyocopronales, Dothideomycetes), and M. affinis, and M. lunatus to Omnidemptus (Magnaporthales, Sordariomycetes). Based on phylogenetic analyses we propose Muyocopron alcornii sp. nov., a fungus associated with leaf spots on Epidendrum sp. (Orchidaceae) in Australia, Muyocopron zamiae sp. nov. associated with leaf spots on Zamia (Zamiaceae) in the USA, and Omnidemptus graminis sp. nov. isolated from a grass (Poaceae) in Spain. Furthermore, Neomycoleptodiscus venezuelense gen. & sp. nov. is introduced for a genus similar to Mycoleptodiscus in Muyocopronaceae.

A New Record and Characterization of Asparagus Purple Spot Caused by Stemphylium vesicarium in Korea

In 2017, small, elliptical, brownish purple spots on spears and ferns of asparagus were found in fields of Gangwon-do. The isolated fungal species was identified as an ascomycete Stemphylium vesicarium based on morphological characteristics and molecular phylogenic analyses including nucleotide sequences of the internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and cytochrome b (cytb). A pathogenicity test revealed that S. vesicarium was the causal agent of purple spot disease on asparagus. The occurrence of purple spots caused by S. vesicarium on asparagus is the first report in Korea.

Closing the Yield Gap of Sugar Beet in the Netherlands-A Joint Effort

The reform of the European Union's sugar regime caused potential decreasing beet prices. Therefore, the Speeding Up Sugar Yield (SUSY) project was initiated. At the start, a 3 × 15 target was formulated: in 2015 the national average sugar yield in the Netherlands equals 15 t/ha (60% of the sugar beet potential) and the total variable costs 15 euro/t sugar beet, aspiring a saving on total variable costs and a strong increase in sugar yield. Based on their average sugar yield in 2000-2004, 26 pairs of "type top" (high yielding) and "type average" (average yielding) growers were selected from all sugar beet growing regions in the Netherlands. On the fields of those farmers, all measures of sugar beet cultivation were investigated, including cost calculation and recording phytopathological, agronomical and soil characteristics in 2006 and 2007. Although there was no significant difference in total variable costs, the "type top" growers yielded significantly 20% more sugar in each year compared to the "type average" growers. Therefore, the most profitable strategy for the growers is maximizing sugar yield and optimizing costs. The difference in sugar yield between growers could be explained by pests and diseases (50%), weed control (30%), soil structure (25%) and sowing date (14%), all interacting with each other. The SUSY-project revealed the effect of the grower's management on sugar yield. As a follow up for the SUSY-project, a growers' guide "Suikerbietsignalen" was published, Best Practice study groups of growers were formed and trainings and workshops were given and field days organized. Further, the benchmarking and feedback on the crop management recordings and the extension on variety choice, sowing performance, foliar fungi control and harvest losses were intensified. On the research part, a resistance breaking strain of the Beet Necrotic Yellow Vein Virus (BNYVV) and a new foliar fungus, Stemphylium beticola, were identified and options for control were tested, and implemented in growers practices. The joint efforts of sugar industry, sugar beet research and growers resulted in a raise in sugar yield from 10.6 t/ha in 2002-2006 to 13.8 t/ha in 2012-2016.

Phylogenetic revision of Camarosporium (Pleosporineae, Dothideomycetes) and allied genera

A concatenated dataset of LSU, SSU, ITS and tef1 DNA sequence data was analysed to investigate the taxonomic position and phylogenetic relationships of the genus Camarosporium in Pleosporineae (Dothideomycetes). Newly generated sequences from camarosporium-like taxa collected from Europe (Italy) and Russia form a well-supported monophyletic clade within Pleosporineae. A new genus Camarosporidiella and a new family Camarosporidiellaceae are established to accommodate these taxa. Four new species, Neocamarosporium korfii, N. lamiacearum, N. salicorniicola and N. salsolae, constitute a strongly supported clade with several known taxa for which the new family, Neocamarosporiaceae, is introduced. The genus Staurosphaeria based on S. lycii is resurrected and epitypified, and shown to accommodate the recently introduced genus Hazslinszkyomyces in Coniothyriaceae with significant statistical support. Camarosporium quaternatum, the type species of Camarosporium and Camarosporomyces flavigena cluster together in a monophyletic clade with significant statistical support and sister to the Leptosphaeriaceae. To better resolve interfamilial/intergeneric level relationships and improve taxonomic understanding within Pleosporineae, we validate Camarosporiaceae to accommodate Camarosporium and Camarosporomyces. The latter taxa along with other species are described in this study.