The Colletotrichum destructivum species complex - hemibiotrophic pathogens of forage and field crops

What are the 100 most cited fungal genera?

The global diversity of fungi has been estimated between 2 to 11 million species, of which only about 155 000 have been named. Most fungi are invisible to the unaided eye, but they represent a major component of biodiversity on our planet, and play essential ecological roles, supporting life as we know it. Although approximately 20 000 fungal genera are presently recognised, the ecology of most remains undetermined. Despite all this diversity, the mycological community actively researches some fungal genera more commonly than others. This poses an interesting question: why have some fungal genera impacted mycology and related fields more than others? To address this issue, we conducted a bibliometric analysis to identify the top 100 most cited fungal genera. A thorough database search of the Web of Science, Google Scholar, and PubMed was performed to establish which genera are most cited. The most cited 10 genera are Saccharomyces, Candida, Aspergillus, Fusarium, Penicillium, Trichoderma, Botrytis, Pichia, Cryptococcus and Alternaria. Case studies are presented for the 100 most cited genera with general background, notes on their ecology and economic significance and important research advances. This paper provides a historic overview of scientific research of these genera and the prospect for further research. Citation: Bhunjun CS, Chen YJ, Phukhamsakda C, Boekhout T, Groenewald JZ, McKenzie EHC, Francisco EC, Frisvad JC, Groenewald M, Hurdeal VG, Luangsa-ard J, Perrone G, Visagie CM, Bai FY, Błaszkowski J, Braun U, de Souza FA, de Queiroz MB, Dutta AK, Gonkhom D, Goto BT, Guarnaccia V, Hagen F, Houbraken J, Lachance MA, Li JJ, Luo KY, Magurno F, Mongkolsamrit S, Robert V, Roy N, Tibpromma S, Wanasinghe DN, Wang DQ, Wei DP, Zhao CL, Aiphuk W, Ajayi-Oyetunde O, Arantes TD, Araujo JC, Begerow D, Bakhshi M, Barbosa RN, Behrens FH, Bensch K, Bezerra JDP, Bilański P, Bradley CA, Bubner B, Burgess TI, Buyck B, Čadež N, Cai L, Calaça FJS, Campbell LJ, Chaverri P, Chen YY, Chethana KWT, Coetzee B, Costa MM, Chen Q, Custódio FA, Dai YC, Damm U, de Azevedo Santiago ALCM, De Miccolis Angelini RM, Dijksterhuis J, Dissanayake AJ, Doilom M, Dong W, Alvarez-Duarte E, Fischer M, Gajanayake AJ, Gené J, Gomdola D, Gomes AAM, Hausner G, He MQ, Hou L, Iturrieta-González I, Jami F, Jankowiak R, Jayawardena RS, Kandemir H, Kiss L, Kobmoo N, Kowalski T, Landi L, Lin CG, Liu JK, Liu XB, Loizides M, Luangharn T, Maharachchikumbura SSN, Makhathini Mkhwanazi GJ, Manawasinghe IS, Marin-Felix Y, McTaggart AR, Moreau PA, Morozova OV, Mostert L, Osiewacz HD, Pem D, Phookamsak R, Pollastro S, Pordel A, Poyntner C, Phillips AJL, Phonemany M, Promputtha I, Rathnayaka AR, Rodrigues AM, Romanazzi G, Rothmann L, Salgado-Salazar C, Sandoval-Denis M, Saupe SJ, Scholler M, Scott P, Shivas RG, Silar P, Souza-Motta CM, Silva-Filho AGS, Spies CFJ, Stchigel AM, Sterflinger K, Summerbell RC, Svetasheva TY, Takamatsu S, Theelen B, Theodoro RC, Thines M, Thongklang N, Torres R, Turchetti B, van den Brule T, Wang XW, Wartchow F, Welti S, Wijesinghe SN, Wu F, Xu R, Yang ZL, Yilmaz N, Yurkov A, Zhao L, Zhao RL, Zhou N, Hyde KD, Crous PW (2024). What are the 100 most cited fungal genera? Studies in Mycology 108: 1-411. doi: 10.3114/sim.2024.108.01.

A Biological Comparison of Three Colletotrichum Species Associated with Alfalfa Anthracnose in Northern China

Anthracnose caused by various species of Colletotrichum is one of the most prevalent diseases in alfalfa worldwide that not only reduces forage yields but also severely compromises forage quality. A comprehensive survey was conducted in 2020 in the main production regions of northern China. The survey results showed that alfalfa anthracnose is prevalent in northern China, with the disease incidence ranging from 9% to 45% and the disease index from 5 to 17 (maximum possible score: 100). In total, 24 isolates were collected and identified as three Colletotrichum species (C. trifolii, C. truncatum and C. americae-borealis) based on morphological characteristics and phylogenetic analysis (combined sequences ITS, HIS3, ACT and GAPDH). The three species displayed remarkable environmental adaptability, exhibiting a capacity for growth, sporulation and conidial germination in temperatures ranging from 4 to 35 °C and in different nutrient conditions. Pathogenicity assays showed that C. trifolii was more virulent than the other two species, although the growth vigor (in terms of colony diameter, sporulation and conidial germination) of C. truncatum was the greatest.

Identification and Characterization of Colletotrichum truncatum and C. destructivum Causing Stem Rot of White Clover in China

White clover (Trifolium repens L.) is an excellent quality forage legume species with superior planting efficiency, which reduces the cost of artificial weeding and nitrogen fertilizer inputs, and has feeding and economic value. However, from June to September 2022, severe stem rot affected the yield and quality of white clover crops in Harbin, Heilongjiang Province, China. The aim of this study was to identify the causative agents of the disease. Overall, Colletotrichum truncatum (6 isolates) and C. destructivum (10 isolates) were obtained from rotten white clover stems and identified based on morpho-molecular characteristics and phylogenetic analyses. Pathogenicity tests of the isolates revealed that C. destructivum had a higher pathogenicity to white clover than C. truncatum. In addition, all isolates were highly pathogenic to broad bean, fodder soybean, soybean, pak choi, and chickpea, were pathogenic to mint, and did not infect corn, wheat, or cilantro. C. destructivum and C. truncatum isolates were very sensitive to tebuconazole and pyraclostrobin, with EC50 values of 0.54 to 0.70 μg/ml and 0.42 to 0.62 μg/ml, respectively, efficacies ranging between 93.2 to 94.9% and 90.2 to 95.2% at 600 μg/ml and 450 μg/ml, respectively, and EC90 values of 1.88 to 13.36 μg/ml and 1.32 to 23.39 μg/ml, respectively. Therefore, intercropping of host and nonhost plants and chemicals can be considered to control stem rot in white clover. These results provide a basis for controlling C. destructivum and C. truncatum in white clover in China.

Identification and Genetic Diversity Analysis of the Pathogen of Anthracnose of Pepper in Guizhou

Anthracnose of pepper is a significant disease caused by Colletotrichum spp. In 2017 and 2021, 296 isolates were obtained from 69 disease samples. Through morphological analysis, pathogenicity detection, and polygenic phylogenetic analysis, the above strains were attributed to 10 species: C. scovillei, C. fructicola, C. karstii, C. truncatum, C. gloeosporioides, C. kahawae, C. boninense, C. nymphaeae, C. plurivorum, and C. nigrum. C. scovillei had the most strains (150), accounting for 51.02% of the total isolates; C. fructicola came in second (72 isolates), accounting for 24.49%. Regarding regional distribution, Zunyi City has the highest concentration of strains-92 strains total, or 34.18%-across seven species. Notably, this investigation showed that C. nymphaeae infected pepper fruit for the first time in China. Genetic diversity analysis showed that C. fructicola could be divided into seven haplotypes, and the population in each region had apparent genetic differentiation. However, the genetic distance between each population was not significantly related to geographical distance. Neutral detection and nucleotide mismatch analysis showed that C. fructicola might have undergone population expansion.

Deficiency of ChPks and ChThr1 Inhibited DHN-Melanin Biosynthesis, Disrupted Cell Wall Integrity and Attenuated Pathogenicity in Colletotrichum higginsianum

Colletotrichum higginsianum is a major pathogen causing anthracnose in Chinese flowering cabbage (Brassica parachinensis), posing a significant threat to the Chinese flowering cabbage industry. The conidia of C. higginsianum germinate and form melanized infection structures called appressoria, which enable penetration of the host plant's epidermal cells. However, the molecular mechanism underlying melanin biosynthesis in C. higginsianum remains poorly understood. In this study, we identified two enzymes related to DHN-melanin biosynthesis in C. higginsianum: ChPks and ChThr1. Our results demonstrate that the expression levels of genes ChPKS and ChTHR1 were significantly up-regulated during hyphal and appressorial melanization processes. Furthermore, knockout of the gene ChPKS resulted in a blocked DHN-melanin biosynthetic pathway in hyphae and appressoria, leading to increased sensitivity of the ChpksΔ mutant to cell-wall-interfering agents as well as decreased turgor pressure and pathogenicity. It should be noted that although the Chthr1Δ mutant still exhibited melanin accumulation in colonies and appressoria, its sensitivity to cell-wall-interfering agents and turgor pressure decreased compared to wild-type strains; however, complete loss of pathogenicity was not observed. In conclusion, our results indicate that DHN-melanin plays an essential role in both pathogenicity and cell wall integrity in C. higginsianum. Specifically, ChPks is crucial for DHN-melanin biosynthesis while deficiency of ChThr1 does not completely blocked melanin production.

Plant immune receptors interact with hemibiotrophic pathogens to activate plant immunity

Phytopathogens pose a devastating threat to the productivity and yield of crops by causing destructive plant diseases in natural and agricultural environments. Hemibiotrophic pathogens have a variable-length biotrophic phase before turning to necrosis and are among the most invasive plant pathogens. Plant resistance to hemibiotrophic pathogens relies mainly on the activation of innate immune responses. These responses are typically initiated after the plant plasma membrane and various plant immune receptors detect immunogenic signals associated with pathogen infection. Hemibiotrophic pathogens evade pathogen-triggered immunity by masking themselves in an arms race while also enhancing or manipulating other receptors to promote virulence. However, our understanding of plant immune defenses against hemibiotrophic pathogens is highly limited due to the intricate infection mechanisms. In this review, we summarize the strategies that different hemibiotrophic pathogens interact with host immune receptors to activate plant immunity. We also discuss the significant role of the plasma membrane in plant immune responses, as well as the current obstacles and potential future research directions in this field. This will enable a more comprehensive understanding of the pathogenicity of hemibiotrophic pathogens and how distinct plant immune receptors oppose them, delivering valuable data for the prevention and management of plant diseases.

Characterization of Colletotrichum Causing Anthracnose on Rubber Trees in Yunnan: Two New Records and Two New Species from China

Among the most damaging diseases of rubber trees is anthracnose caused by the genus Colletotrichum, which leads to significant economic losses. Nonetheless, the specific Colletotrichum spp. that infect rubber trees in Yunnan Province, an important natural rubber base in China, have not been extensively investigated. Here, we isolated 118 Colletotrichum strains from rubber tree leaves exhibiting anthracnose symptoms in multiple plantations in Yunnan. Based on comparisons of their phenotypic characteristics and internal transcribed spacer ribosomal DNA sequences, 80 representative strains were chosen for additional phylogenetic analysis based on eight loci (act, ApMat, cal, CHS-1, GAPDH, GS, his3, and tub2), and nine species were identified. Colletotrichum fructicola, C. siamense, and C. wanningense were found to be the dominant pathogens causing rubber tree anthracnose in Yunnan. C. karstii was common, whereas C. bannaense, C. brevisporum, C. jinpingense, C. mengdingense, and C. plurivorum were rare. Among these nine species, C. brevisporum and C. plurivorum are reported for the first time in China, and two species are new to the world: C. mengdingense sp. nov. in the C. acutatum species complex and C. jinpingense sp. nov. in the C. gloeosporioides species complex. Their pathogenicity was confirmed with Koch's postulates by inoculating each species in vivo on rubber tree leaves. This study clarifies the geographic distribution of Colletotrichum spp. associated with anthracnose on rubber trees in representative locations of Yunnan, which is crucial for the implementation of quarantine measures.

Two new species of Colletotrichum (Glomerellaceae, Glomerellales) causing walnut anthracnose in Beijing

Colletotrichum species are plant pathogens, saprobes and endophytes on various plant hosts. It is regarded as one of the 10 most important genera of plant pathogens in the world. Walnut anthracnose is one of the most severe diseases affecting walnut productivity and quality in China. In this study, 162 isolates were obtained from 30 fruits and 65 leaf samples of walnut collected in Beijing, China. Based on morphological characteristics and DNA sequence analyses of the concatenated loci, namely internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), chitin synthase 1 (CHS-1) and beta-tubulin (TUB2), these isolates were identified as two novel species of Colletotrichum, i.e. C.juglandicola and C.peakense. Koch's postulates indicated that both C.juglandicola and C.peakense could cause anthracnose in walnut.

The evolution of mini-chromosomes in the fungal genus Colletotrichum

Anthracnose diseases caused by Colletotrichum species are among the most common fungal diseases. These symptoms typically manifest as dark, sunken lesions on leaves, stems, and fruit. In China, mango anthracnose seriously affects fruit yield and quality. Genome sequencing of several species shows the presence of mini-chromosomes. These are thought to contribute to virulence, but their formation and activity remain to be fully elucidated. Here, we assembled 17 Colletotrichum genomes (16 isolated from mango plus one from persimmon) through PacBio long-read sequencing. Half of the assembled scaffolds had telomeric repeats at both ends indicating full-length chromosomes. Based on comparative genomics analysis at interspecies and intraspecies levels, we identified extensive chromosomal rearrangements events. We analyzed mini-chromosomes of Colletotrichum spp. and found large variation among close relatives. In C. fructicola, homology between core chromosomes and mini-chromosomes suggested that some mini-chromosomes were generated by recombination of core chromosomes. In C. musae GZ23-3, we found 26 horizontally transferred genes arranged in clusters on mini-chromosomes. In C. asianum FJ11-1, several potential pathogenesis-related genes on mini-chromosomes were upregulated, especially in strains with highly pathogenic phenotypes. Mutants of these upregulated genes showed obvious defects in virulence. Our findings provide insights into the evolution and potential relationships to virulence associated with mini-chromosomes. IMPORTANCE Colletotrichum is a cosmopolitan fungal genus that seriously affects fruit yield and quality of many plant species. Mini-chromosomes have been found to be related to virulence in Colletotrichum. Further examination of mini-chromosomes can help us elucidate some pathogenic mechanisms of Colletotrichum. In this study, we generated novel assemblies of several Colletotrichum strains. Comparative genomic analyses within and between Colletotrichum species were conducted. We then identified mini-chromosomes in our sequenced strains systematically. The characteristics and generation of mini-chromosomes were investigated. Transcriptome analysis and gene knockout revealed pathogenesis-related genes located on mini-chromosomes of C. asianum FJ11-1. This study represents the most comprehensive investigation of chromosome evolution and potential pathogenicity of mini-chromosomes in the Colletotrichum genus.

Re-identification of Colletotrichum acutatum Species Complex in Korea and Their Host Plants

Colletotrichum acutatum species complex is one of the most important groups in the genus Colletotrichum with a high species diversity and a wide range of host plants. C. acutatum and related species have been collected from different plants and locations in Korea and deposited into the Korean Agricultural Culture Collection (KACC), National Institute of Agricultural Sciences since the 1990s. These fungal isolates were previously identified based mainly on morphological characteristics, and a limitation of molecular data was provided. To confirm the identification of species, 64 C. acutatum species complex isolates in KACC were used in this study for DNA sequence analyses of six loci: nuclear ribosomal internal transcribed spacers (ITS), betatubulin 2 (TUB2), histone-3 (HIS3), glyceraldehyde3-phosphate dehydrogenase (GAPDH), chitin synthase 1 (CHS-1), and actin (ACT). The molecular analysis revealed that they were identified in six different species of C. fioriniae (24 isolates), C. nymphaeae (21 isolates), C. scovillei (12 isolates), C. chrysanthemi (three isolates), C. lupini (two isolates), and C. godetiae (one isolate), and a novel species candidate. We compared the hosts of KACC isolates with "The List of Plant Diseases in Korea", previous reports in Korea and global reports and found that 23 combinations between hosts and pathogens could be newly reported in Korea after pathogenicity tests, and 12 of these have not been recorded in the world.

Diagnosis of Soybean Diseases Caused by Fungal and Oomycete Pathogens: Existing Methods and New Developments

Soybean (Glycine max) acreage is increasing dramatically, together with the use of soybean as a source of vegetable protein and oil. However, soybean production is affected by several diseases, especially diseases caused by fungal seed-borne pathogens. As infected seeds often appear symptomless, diagnosis by applying accurate detection techniques is essential to prevent propagation of pathogens. Seed incubation on culture media is the traditional method to detect such pathogens. This method is simple, but fungi have to develop axenically and expert mycologists are required for species identification. Even experts may not be able to provide reliable type level identification because of close similarities between species. Other pathogens are soil-borne. Here, traditional methods for detection and identification pose even greater problems. Recently, molecular methods, based on analyzing DNA, have been developed for sensitive and specific identification. Here, we provide an overview of available molecular assays to identify species of the genera Diaporthe, Sclerotinia, Colletotrichum, Fusarium, Cercospora, Septoria, Macrophomina, Phialophora, Rhizoctonia, Phakopsora, Phytophthora, and Pythium, causing soybean diseases. We also describe the basic steps in establishing PCR-based detection methods, and we discuss potentials and challenges in using such assays.

Colletotrichum Species Associated with Anthracnose in Salix babylonica in China

Salix babylonica L. is a popular ornamental tree species in China and widely cultivated in Asia, Europe, and North America. Anthracnose in S. babylonica poses a serious threat to its growth and reduces its medicinal properties. In 2021, a total of 55 Colletotrichum isolates were isolated from symptomatic leaves in three provinces in China. Phylogenetic analyses using six loci (ITS, ACT, CHS-1, TUB2, CAL, and GAPDH) and a morphological characterization of the 55 isolates showed that they belonged to four species of Colletotrichum, including C. aenigma, C. fructicola, C. gloeosporioides s.s., and C. siamense. Among them, C. siamense was the dominant species, and C. gloeosporioides s.s. was occasionally discovered from the host tissues. Pathogenicity tests revealed that all the isolates of the aforementioned species were pathogenic to the host, and there were significant differences in pathogenicity or virulence among these isolates. The information on the diversity of Colletotrichum spp. that causes S. babylonica anthracnose in China is new.

Development of a model for Colletotrichum diseases with calibration for phylogenetic clades on different host plants

Fungi in the genus Colletotrichum cause serious pre- and post-harvest losses to several agricultural crops worldwide. Through a systematic literature review, we retrieved the published information on Colletotrichum anthracnose diseases on different host plants and developed a mechanistic model incorporating the main stages of the pathogen's life cycle and the effect of weather. The model predicts anthracnose progress during the growing season on the aerial organs of different crops, and was parameterized for seven Colletotrichum clades (acutatum, dematium, destructivum, gloeosporioides, graminicola, and orbiculare) and the singleton species, C. coccodes. The model was evaluated for the anthracnose diseases caused by fungi belonging to five clades on six hosts by using data from 17 epidemics that occurred in Italy, the USA, Canada, and Japan. A comparison of observed versus predicted data showed a concordance correlation coefficient of 0.928 and an average distance between real data and the fitted line of 0.044. After further validation, the model could be used to support decision-making for crop protection.

Assembling Quality Genomes of Flax Fungal Pathogens from Oxford Nanopore Technologies Data

Flax (Linum usitatissimum L.) is attacked by numerous devastating fungal pathogens, including Colletotrichum lini, Aureobasidium pullulans, and Fusarium verticillioides (Fusarium moniliforme). The effective control of flax diseases follows the paradigm of extensive molecular research on pathogenicity. However, such studies require quality genome sequences of the studied organisms. This article reports on the approaches to assembling a high-quality fungal genome from the Oxford Nanopore Technologies data. We sequenced the genomes of C. lini, A. pullulans, and F. verticillioides (F. moniliforme) and received different volumes of sequencing data: 1.7 Gb, 3.9 Gb, and 11.1 Gb, respectively. To obtain the optimal genome sequences, we studied the effect of input data quality and genome coverage on assembly statistics and tested the performance of different assembling and polishing software. For C. lini, the most contiguous and complete assembly was obtained by the Flye assembler and the Homopolish polisher. The genome coverage had more effect than data quality on assembly statistics, likely due to the relatively low amount of sequencing data obtained for C. lini. The final assembly was 53.4 Mb long and 96.4% complete (according to the glomerellales_odb10 BUSCO dataset), consisted of 42 contigs, and had an N50 of 4.4 Mb. For A. pullulans and F. verticillioides (F. moniliforme), the best assemblies were produced by Canu–Medaka and Canu–Homopolish, respectively. The final assembly of A. pullulans had a length of 29.5 Mb, 99.4% completeness (dothideomycetes_odb10), an N50 of 2.4 Mb and consisted of 32 contigs. F. verticillioides (F. moniliforme) assembly was 44.1 Mb long, 97.8% complete (hypocreales_odb10), consisted of 54 contigs, and had an N50 of 4.4 Mb. The obtained results can serve as a guideline for assembling a de novo genome of a fungus. In addition, our data can be used in genomic studies of fungal pathogens or plant–pathogen interactions and assist in the management of flax diseases.

Dual Transcriptome Analysis Reveals That ChATG8 Is Required for Fungal Development, Melanization and Pathogenicity during the Interaction between Colletotrichum higginsianum and Arabidopsis thaliana

Anthracnose disease of cruciferous plants caused by Colletotrichum higginsianum is a serious fungal disease that affects cruciferous crops such as Chinese cabbage, Chinese flowering cabbage, broccoli, mustard plant, as well as the model plant Arabidopsis thaliana. Dual transcriptome analysis is commonly used to identify the potential mechanisms of interaction between host and pathogen. In order to identify differentially expressed genes (DEGs) in both the pathogen and host, the conidia of wild-type (ChWT) and Chatg8 mutant (Chatg8Δ) strains were inoculated onto leaves of A. thaliana, and the infected leaves of A. thaliana at 8, 22, 40, and 60 h post-inoculation (hpi) were subjected to dual RNA-seq analysis. The results showed that comparison of gene expression between the 'ChWT' and 'Chatg8Δ' samples detected 900 DEGs (306 upregulated and 594 down-regulated) at 8 hpi, 692 DEGs (283 upregulated and 409 down-regulated) at 22 hpi, 496 DEGs (220 upregulated and 276 down-regulated) at 40 hpi, and 3159 DEGs (1544 upregulated and 1615 down-regulated) at 60 hpi. GO and KEGG analyses found that the DEGs were mainly involved in fungal development, biosynthesis of secondary metabolites, plant-fungal interactions, and phytohormone signaling. The regulatory network of key genes annotated in the Pathogen-Host Interactions database (PHI-base) and Plant Resistance Genes database (PRGdb), as well as a number of key genes highly correlated with the 8, 22, 40, and 60 hpi, were identified during the infection. Among the key genes, the most significant enrichment was in the gene encoding the trihydroxynaphthalene reductase (THR1) in the melanin biosynthesis pathway. Both Chatg8Δ and Chthr1Δ strains showed varying degrees of reduction of melanin in appressoria and colonies. The pathogenicity of the Chthr1Δ strain was lost. In addition, six DEGs from C. higginsianum and six DEGs from A. thaliana were selected for real-time quantitative PCR (RT-qPCR) to confirm the RNA-seq results. The information gathered from this study enriches the resources available for research into the role of the gene ChATG8 during the infection of A. thaliana by C. higginsianum, such as potential links between melanin biosynthesis and autophagy, and the response of A. thaliana to different fungal strains, thereby providing a theoretical basis for the breeding of cruciferous green leaf vegetable cultivars with resistance to anthracnose disease.

First report of Colletotrichum shisoi causing anthracnose of Perilla frutescens in the United States

Perilla mint (Perilla frutescens (L.) Britt.) is an annual plant native to Asia and considered invasive in North America where it has escaped cultivation as an ornamental (Miller 1947; Swearingen et al. 2010). In August 2021, an anthracnose disease was observed on invasive perilla found along the disturbed margins of a forest in Frederick County, Maryland, United States. Symptoms included necrotic lesions with chlorotic halos, were concentrated in the lower canopy, and caused premature defoliation of lower leaves (Figure S1). Leaves from four plants were surface sterilized by rinsing for 30 s in 70% ethanol, 60 s in 0.8% NaClO, and 60 s in sterile water and then incubated on 2% water agar under ambient laboratory conditions to permit sporulation. After three days, spores that exuded from individual lesions were streaked onto acidified potato dextrose agar. Two single-conidium isolates were recovered from each plant. All eight isolates were identified to species using DNA sequences. A single isolate (21-067) was selected at random for morphological characterization and completion of Koch's postulates. Morphological features were recorded after seven days of growth on synthetic low-nutrient agar (SNA) and potato dextrose agar (PDA) incubated at 22°C under 12 hr UV-B and white fluorescent lighting. Measurements were based on a minimum of 20 observations per structure. Cultures on SNA were flat, hyaline to pale salmon, lacked sporodochia and grew at a rate of 1.3 mm day-1 (n = 3). Vegetative hyphal width was (minimum-maximum) 1.5-4.0 μm, (average ± standard deviation) 2.7 ± 0.9 μm. Conidiophores arose directly from hyphae, were hyaline, smooth, unbranched and measured 40.0-180.0 x 1.5-4.5 μm, 102.3 ± 33.9 x 2.7 ± 0.8 μm. Conidia were single celled, straight, hyaline, glabrous, rounded at both ends and measured 10.0-20.0 x 3.8-6.3 μm, 15.4 ± 2.5 x 4.9 ± 0.7 μm. Setae, observed only on PDA, were pale brown, 1-2 septate, straight, blunt tipped and measured 42.5-97.5 μm, 70.8 ± 13.4 μm. Appressoria formed on PDA were single-celled, pigmented, smooth, and obovoid with entire margins, measuring 5.2-7.7 x 8.6-13.8 μm, 6.8 ± 0.6 x 10.8 ± 1.4 μm. These characteristics were consistent with members of the Colletotrichum destructivum species complex. Partial DNA sequences from five loci were amplified following the procedures of Damm et al. 2014: internal transcribed spacer region of rDNA (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), chitin synthase 1 (CHS-1), actin (ACT), and beta-tubulin (TUB2). Pairwise sequence comparisons to references using the Blastn algorithm found 99.8% similarity between isolate 21-067 and ex-type C. shisoi isolate JCM 31818: MH660930 (ITS, 545/546 bp), MH660931 (GAPDH,192/192 bp), MH660929 (CHS-1, 278/280 bp), MH660928 (ACT, 262/262 bp), and MH660932 (TUB2, 511/511 bp) (Altschul et al. 1990; Gan et al. 2019). Subsequently, sequences from all eight isolates were aligned with Clustal Omega (Sievers and Higgins 2018), concatenated, and used in a Bayesian phylogenetic reconstruction (Huelsenbeck and Ronquist 2001) of the C. destructivum species complex (Figure S2), confirming the species identity as C. shisoi. Sequences were deposited in NCBI GenBank under accession numbers OM865277-OM865284 and OM885059-OM885090. Koch's postulates were fulfilled using perilla grown in a greenhouse until second true leaves emerged. Inoculum washed from two-week-old fungal cultures grown on potato dextrose agar was adjusted to 4 x 104 conidia mL-1 and applied to three replicate plants with an aspirator until runoff. Three plants were sprayed with sterile water as a negative control. Plants were covered with plastic bags for 72 hrs and maintained in a growth chamber at 20°C and 80% RH for 14 days. Inoculated plants displayed disease symptoms similar to those observed under field conditions, and control plants did not develop symptoms. Colletotrichum shisoi was reisolated from symptomatic tissue and reidentified based on morphology. The experiment was completed twice. To the authors' knowledge, this is the first report of C. shisoi on P. frutescens in the United States. Colletotrichum shisoi has not been reported as a pathogen on other plants in the United States and may have potential use as a biological control agent for invasive perilla.

Identification and characterization of Colletotrichum fioriniae and C. fructicola that cause anthracnose in pecan

Pecan (Carya illinoinensis Wang. K. Koch) is a deciduous tree of the Juglandaceae family with important economic value worldwide. Anthracnose of the pecan leaves and shuck is a devastating disease faced by pecan-growing areas in China. However, the causal species occurring on pecan remain largely unidentified. we collected samples of diseased pecan from the provinces of China, Leaves and fruits affected by anthracnose were sampled and subjected to fungus isolation, The morphological characters of all strains were observed and compared; Multi-locus phylogenetic analyses [Internally transcribed spacer (ITS), Actin (ACT), Calmodulin (CAL), Chitin synthase (CHS1), Glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and b-tubulin (TUB2)] were performed on selected representative strains; examine their pathogenicity on leaves of pecan.The results showed that: (1) resulting in a total of 11 Colletotrichum isolates, Two Colletotrichum species were identifified to be C. fioriniae and C. fructicola; (2) Pathogenicity tests revealed that both species caused black spots on pecan leaves and fruit, The virulence of the different isolates varied substantially, with C. fioriniae PCJD179 being the most virulent; (3) The susceptibility levels of pecan tree varieties, 'Mahan' and 'Kanza', were determined, No significant differences were observed in the lesion sizes produced by the various isolates in 'Kanza', while there were signifificant differences in 'Mahan'. This study is thefifirst to determine that C. fructicola and C. fioriniaecan cause anthracnose in pecan in China. It improves the understanding of the species that cause anthracnose in pecan and provides useful information for the effective control of this disease in China.

Colletotrichumchinense sp. nov. from Yuccagloriosa and C.quercicola sp. nov. from Quercusvariabilis in China

Colletotrichum is an important plant pathogenic genus causing anthracnose on a wide range of host plants. During 2019 and 2021, Colletotrichum isolates were obtained during surveys of anthracnose on garden plants in China. Multi-gene phylogenetic analyses of internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (gapdh), chitin synthase 1 (chs-1), actin (act) and beta-tubulin (tub2) sequences coupled with morphological evidence support the introduction of two novel species namely Colletotrichumchinense sp. nov. from Yuccagloriosa in Beijing and C.quercicola sp. nov. from Quercusvariabilis in Shaanxi Province. Phylogenetic inference revealed that two isolates of C.chinense belonged to the agaves species complex and were closely related to C.agaves, and differed from the other species within this species complex by shorter conidia and the host association. Molecular identification showed that two isolates of C.quercicola formed a highly supported lineage close to C.tanaceti in the destructivum species complex, which could be distinguished from C.tanaceti by straighter conidia. In pathogenicity tests, yellow spots and orange conidial masses displayed on the inoculated Y.gloriosa leaves and brown spots appeared on the inoculated Q.variabilis leaves. In addition, C.chinense and C.quercicola were re-isolated from spots of the tested leaves of Y.gloriosa and Q.variabilis.

Characterization of Colletotrichum Isolates from Strawberry and Other Hosts with Reference to Cross-Inoculation Potential

Colletotrichum is an important phytopathogenic fungus that causes anthracnose disease in diverse agronomically important tropical food crops. Accurate pathogen identification is critical for early diagnosis and efficient management of anthracnose. ITS is not a reliable marker for this fungal genus due to its failure to phylogenetically resolve cryptic species. In this study, 36 Colletotrichum isolates belonging to the Acutatum, Boninense and Gloeosporioides species complexes were characterized using multigene phylogenetic analyses, morphology and pathogenicity assays. Additionally, the cross-inoculation potential of a representative subset of isolates was evaluated revealing that cross-infection potential is possible among the isolates belonging to the same species complex.

Close-Range Thermography and Reflectance Spectroscopy Support In Vitro and In Vivo Characterization of Colletotrichum spp. Isolates from Mango Fruits

Colletotrichum causing anthracnose in mango is known for its variable virulence that may have an effect on disease development and efficacy of management strategies. In this study, we characterized Colletotrichum spp. isolated from mango fruits under in vitro and in vivo conditions using close-range thermography and reflectance spectroscopy. Twenty-six isolates were phylogenetically characterized to ascertain species using the internal transcribed spacer sequence. Virulence, spectral (in vivo and in vitro), and thermographic responses (in vivo) of these isolates were analyzed. Isolates were grouped into the Colletotrichum gloeosporioides species complex and classified into eight morphotypes. Mycelial growth, conidia production, sporulation abundance, and area under disease progress curve (AUDPC) varied largely among isolates. Disease symptoms were observed 4 days after inoculation (dai), and, for most morphotypes, changes in tissue temperature were registered at 11 dai, with the greatest decrease at 14 dai with pathogen sporulation. In vitro and in vivo morphotypes shared changes in the spectrum range, and main variations were found in the number of informative spectral bands. In vivo average gross reflectance was higher in disease-inoculated tissue than in healthy uninoculated tissue. Morphotype responses varied depending on AUDPC values and postinoculation time. Discriminant analysis of the spectral response using principal component analysis and partial least squares regression explained 94 to 96.3 and 98 to 99.9% of the variance from in vitro and in vivo tests, respectively. Spectral markers were obtained for four distinct morphotype groups. We found three (550 to 650, 650.1 to 790, and 1,300 to 1,400 nm) and two (520 to 830 and 1,100 to 1,450 nm) regions with highly (P < 0.05) discriminant spectral bands for diseased fruits and morphotype characterization.

Phylogeny and pathogenicity of Colletotrichum lindemuthianum causing anthracnose of Phaseolus vulgaris cv. Bhaderwah-Rajmash from northern Himalayas, India

With an annual loss of up to 100%, anthracnose caused by Colletotrichum is one of the most devastating diseases of common beans (Phaseolus vulgaris L.). Due to few distinctive morphological characters, Colletotrichum species are frequently misidentified. In India, several Colletotrichum species have been reported as pathogens of Phaseolus species, but none had previously been validated by means of molecular tools. In this study, we studied Colletotrichum strains from common beans cv. Bhaderwah-Rajmash from the northern Himalayas of India based on both morphological and DNA sequence data of six loci, namely ITS, gapdh, chs-1, his3, act, tub2. The strains were identified as C. lindemuthianum that belongs to the C. orbiculare species complex. Representative C. lindemuthianum strains tested on Phaseolus vulgaris cv. Bhaderwah-Rajmash were pathogenic and exhibited variation in symptomology and disease progression. By identifying the causal agent, we provided substantial information to develop the best control strategies for anthracnose of Phaseolus vulgaris from the northern Himalayas of India.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03216-0.

Colletotrichum Species Associated with Anthracnose Disease of Watermelon (Citrullus lanatus) in China

Colletotrichum species are important plant pathogens, causing anthracnose in virtually every crop grown throughout the world. However, little is known about the species that infect watermelon. A total of 526 strains were isolated from diseased watermelon samples of eight major watermelon growing provinces in China. Phylogenetic analyses using seven loci (ITS, gadph, chs-1, his3, act, tub2, and gs) coupled with morphology of 146 representative isolates showed that they belonged to 12 known species of Colletotrichum, including C. aenigma, C. chlorophyti, C. fructicola, C. jiangxiense, C. karstii, C. magnum, C. nymphaeae, C. nigrum, C. orbiculare, C. plurivorum, C. sojae, and C. truncatum and three new species, here described as C. citrulli, C. kaifengense, and C. qilinense. Colletotrichum orbiculare was the dominant species. Pathogenicity tests revealed that all isolates of the species described above were pathogenic, with C. magnum and C. kaifengense being the most aggressive to leaves and fruits, respectively. This is the first report of C. aenigma, C. chlorophyti, C. fructicola, C. jiangxiense, C. nymphaeae, C. nigrum, C. plurivorum, and C. sojae on watermelon. These findings shed light on the Colletotrichum spp. involved in watermelon anthracnose and provide useful information for implementing effective control of watermelon anthracnose in China.

Temperature requirements of Colletotrichum spp. belonging to different clades

The fungal genus Colletotrichum includes plant pathogens that cause substantial economic damage to horticultural, ornamental, and fruit tree crops worldwide. Here, we conducted a systematic literature review to retrieve and analyze the metadata on the influence of temperature on four biological processes: (i) mycelial growth, (ii) conidial germination, (iii) infection by conidia, and (iv) sporulation. The literature review considered 118 papers (selected from a total of 1,641 papers found with the literature search), 19 Colletotrichum species belonging to eight clades (acutatum, graminicola, destructivum, coccodes, dematium, gloeosporioides, and orbiculare), and 27 host plants (alfalfa, almond, apple, azalea, banana, barley, bathurst burr, blueberry, celery, chilli, coffee, corn, cotton, cowpea, grape, guava, jointvetch, lentil, lupin, olive, onion, snap bean, spinach, strawberry, tomato, watermelon, and white bean). We used the metadata to develop temperature-dependent equations representing the effect of temperature on the biological processes for the different clades and species. Inter- and intra-clades similarities and differences are analyzed and discussed. A multi-factor cluster analysis identified four groups of clades with similar temperature dependencies. The results should facilitate further research on the biology and epidemiology of Colletotrichum species and should also contribute to the development of models for the management of anthracnose diseases.

Publicly Available and Validated DNA Reference Sequences Are Critical to Fungal Identification and Global Plant Protection Efforts: A Use-Case in Colletotrichum

Publicly available and validated DNA reference sequences useful for phylogeny estimation and identification of fungal pathogens are an increasingly important resource in the efforts of plant protection organizations to facilitate safe international trade of agricultural commodities. Colletotrichum species are among the most frequently encountered and regulated plant pathogens at U.S. ports-of-entry. The RefSeq Targeted Loci (RTL) project at NCBI (BioProject no. PRJNA177353) contains a database of curated fungal internal transcribed spacer (ITS) sequences that interact extensively with NCBI Taxonomy, resulting in verified name-strain-sequence type associations for >12,000 species. We present a publicly available dataset of verified and curated name-type strain-sequence associations for all available Colletotrichum species. This includes an updated GenBank Taxonomy for 238 species associated with up to 11 protein coding loci and an updated RTL ITS dataset for 226 species. We demonstrate that several marker loci are well suited for phylogenetic inference and identification. We improve understanding of phylogenetic relationships among verified species, verify or improve phylogenetic circumscriptions of 14 species complexes, and reveal that determining relationships among these major clades will require additional data. We present detailed comparisons between phylogenetic and similarity-based approaches to species identification, revealing complex patterns among single marker loci that often lead to misidentification when based on single-locus similarity approaches. We also demonstrate that species-level identification is elusive for a subset of samples regardless of analytical approach, which may be explained by novel species diversity in our dataset and incomplete lineage sorting and lack of accumulated synapomorphies at these loci.

New species of Colletotrichum from wild Poaceae and Cyperaceae plants in Iran

Twenty-two Colletotrichum strains were isolated from anthracnose symptoms or leaf spots on leaves of various wild Poaceae and Cyperaceae plants collected in three provinces of Iran and tentatively identified as belonging to the Graminicola species complex based on morphology. All strains were studied via a polyphasic approach combining colony characteristics, morphology and phylogeny inferred from multi-locus sequences, including the nuc rDNA ITS1-5.8S-ITS2 (ITS), partial sequences of the β-tubulin (tub2), actin (act), manganese superoxide dismutase 2 (sod2), DNA lyase 2 (apn2) genes, a 200-bp intron of the glyceraldehyde-3-phosphate dehydrogenase (gapdh), and the intergenic spacer between the apn2 gene and the mat1 idiomorph (apn2/mat1). Six species were distinguished, including three new species, namely C. caspicum, C. persicum, and C. sacchari, and three previously described species, C. cereale, C. nicholsonii and C. sublineola. Comprehensive morphological descriptions and illustrations are provided for all species. Furthermore, this study provided new insights into the distribution and host range of known species.

Evidences of Colletotrichum fructicola Causing Anthracnose on Passiflora edulis Sims in China

Passion fruit (Passiflora edulis) is a tropical and subtropical plant that is widely cultivated in China due to its high nutritional value, unique flavor and medicinal properties. In August 2020, typical anthracnose symptoms with light brown and water-soaked lesions on Passiflora edulis Sims were observed, which result in severe economic losses. The incidence of this disease was approximately 30%. The pathogens from the infected fruit were isolated and purified by the method of tissue isolation. Morphological observations showed that the colony of isolate BXG-2 was gray to celadon and grew in concentric circles. The orange conidia appeared in the center after 14 days of incubation. The pathogenicity was verified by Koch’s postulates. The internal transcribed spacer (ITS), chitin synthase (CHS-1), actin (ACT), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were amplified by relevant PCR programs. The multi-gene (ITS, GAPDH, ACT, CHS-1) phylogeny analysis confirmed that isolate BXG-2 belongs to Colletotrichum fructicola. The inhibitory effect of six synthetic fungicides on the mycelial growth of the pathogen was investigated, among which difenoconazole 10% WG showed the best inhibitory effect against C. fructicola with an EC₅₀ value of 0.5579 mg·L⁻¹. This is the first report of anthracnose on Passiflora edulis Sims caused by Colletotrichum fructicola in China.

Transcriptome Analysis of Colletotrichum fructicola Infecting Camellia oleifera Indicates That Two Distinct Geographical Fungi Groups Have Different Destructive Proliferation Capacities Related to Purine Metabolism

Anthracnose, caused by Colletotrichum spp., is a significant disease affecting oil tea (Camellia oleifera Abel.). Extensive molecular studies have demonstrated that Colletotrichum fructicola is the dominant pathogen of oil tea anthracnose in China. This study aims to investigate differences in molecular processes and regulatory genes at a late stage of infection of C. fructicola, to aid in understanding differences in pathogenic mechanisms of C. fructicola of different geographic populations. We compared the pathogenicity of C. fructicola from different populations (Wuzhishan, Hainan province, and Shaoyang, Hunan province) and gene expression of representative strains of the two populations before and after inoculation in oil tea using RNA sequencing. The results revealed that C. fructicola from Wuzhishan has a more vital ability to impact oil tea leaf tissue. Following infection with oil tea leaves, up-regulated genes in the strains from two geographic populations were associated with galactosidase activity, glutamine family amino acid metabolism, arginine, and proline metabolism. Additionally, up-regulated gene lists associated with infection by Wuzhishan strains were significantly enriched in purine metabolism pathways, while Shaoyang strains were not. These results indicate that more transcriptional and translational activity and the greater regulation of the purine metabolism pathway in the C. fructicola of the Wuzhishan strain might contribute to its stronger pathogenicity.

Identification of Copper-Containing Oxidoreductases in the Secretomes of Three Colletotrichum Species with a Focus on Copper Radical Oxidases for the Biocatalytic Production of Fatty Aldehydes

Copper radical alcohol oxidases (CRO-AlcOx), which have been recently discovered among fungal phytopathogens, are attractive for the production of fragrant fatty aldehydes. With the initial objective to investigate the secretion of CRO-AlcOx by natural fungal strains, we undertook time course analyses of the secretomes of three Colletotrichum species (C. graminicola, C. tabacum, and C. destructivum) using proteomics. The addition of a copper-manganese-ethanol mixture in the absence of any plant-biomass mimicking compounds to Colletotrichum cultures unexpectedly induced the secretion of up to 400 proteins, 29 to 52% of which were carbohydrate-active enzymes (CAZymes), including a wide diversity of copper-containing oxidoreductases from the auxiliary activities (AA) class (AA1, AA3, AA5, AA7, AA9, AA11, AA12, AA13, and AA16). Under these specific conditions, while a CRO-glyoxal oxidase from the AA5_1 subfamily was among the most abundantly secreted proteins, the targeted AA5_2 CRO-AlcOx were secreted at lower levels, suggesting heterologous expression as a more promising strategy for CRO-AlcOx production and utilization. C. tabacum and C. destructivum CRO-AlcOx were thus expressed in Pichia pastoris, and their preference toward both aromatic and aliphatic primary alcohols was assessed. The CRO-AlcOx from C. destructivum was further investigated in applied settings, revealing a full conversion of C₆ and C₈ alcohols into their corresponding fragrant aldehydes. IMPORTANCE In the context of the industrial shift toward greener processes, the biocatalytic production of aldehydes is of utmost interest owing to their importance for their use as flavor and fragrance ingredients. Copper radical alcohol oxidases (CRO-AlcOx) have the potential to become platform enzymes for the oxidation of alcohols to aldehydes. However, the secretion of CRO-AlcOx by natural fungal strains has never been explored, while the use of crude fungal secretomes is an appealing approach for industrial applications to alleviate various costs pertaining to biocatalyst production. While investigating this primary objective, the secretomics studies revealed unexpected results showing that under the oxidative stress conditions we probed, Colletotrichum species can secrete a broad diversity of copper-containing enzymes (laccases, sugar oxidoreductases, and lytic polysaccharide monooxygenases [LPMOs]) usually assigned to "plant cell wall degradation," despite the absence of any plant-biomass mimicking compound. However, in these conditions, only small amounts of CRO-AlcOx were secreted, pointing out recombinant expression as the most promising path for their biocatalytic application.

Identification of anthracnose race 1 resistance loci in lentil by integrating linkage mapping and genome-wide association study

Anthracnose, caused byColletotrichum lentis, is a devastating disease of lentil (Lens culinaris Medik.) in western Canada. Growing resistant lentil cultivars is the most cost-effective and environmentally friendly approach to prevent seed yield losses that can exceed 70%. To identify loci conferring resistance to anthracnose race 1 in lentil, biparental quantitative trait loci (QTL) mapping of two recombinant inbred line (RIL) populations was integrated with a genome-wide association study (GWAS) using 200 diverse lentil accessions from a lentil diversity panel. A major-effect QTL (qAnt1.Lc-3) conferring resistance to race 1 was mapped to lentil chromosome 3 and colocated on the lentil physical map for both RIL populations. Clusters of candidate nucleotide-binding leucine-rich repeat (NB-LRR) and other defense-related genes were uncovered within the QTL region. A GWAS detected 14 significant single nucleotide polymorphism (SNP) markers associated with race 1 resistance on chromosomes 3, 4, 5, and 6. The most significant GWAS SNPs on chromosome 3 supported qAnt1.Lc-3 and delineated a region of 1.6 Mb containing candidate resistance genes. The identified SNP markers can be directly applied in marker-assisted selection (MAS) to accelerate the introgression of race 1 resistance in lentil breeding.

Biocontrol Potential of Bacillus amyloliquefaciens LYZ69 Against Anthracnose of Alfalfa (Medicago sativa)

Anthracnose is a destructive disease of alfalfa (Medicago sativa) that causes severe yield losses. Biological control can be an effective and eco-friendly approach to control this alfalfa disease. In the present study, Bacillus amyloliquefaciens LYZ69, previously isolated from healthy alfalfa roots, showed a strong in vitro antifungal activity against Colletotrichum truncatum, an important causal agent of anthracnose of alfalfa. The strain LYZ69 protected alfalfa plants (biocontrol efficacy of 82.59%) from anthracnose under greenhouse conditions. The cell-free culture (CFC) of LYZ69 (20%, vol/vol) caused 60 and 100% inhibition of mycelial growth and conidial germination, respectively. High-performance liquid chromatography tandem mass spectrometry separated and identified cyclic lipopeptides (LPs) such as bacillomycin D and fengycin in the CFC of LYZ69. Light microscopy and scanning electron microscopy revealed that the mixture of cyclic LPs produced by LYZ69 caused drastic changes in mycelial morphology. Fluorescence microscopy showed that the LPs induced reactive oxygen species accumulation and caused apoptosis-like cell death in C. truncatum hyphae. In summary, our findings provide evidence to support B. amyloliquefaciens LYZ69 as a promising candidate for the biological control of anthracnose in alfalfa.

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.

First Report of Alfalfa Anthracnose Caused by Colletotrichum americae-borealis in Xinjiang, China

Alfalfa (Medicago sativa L.) is widely planted in the world as one of the most important leguminous forage crops, and it is also the first choice of forage crops for animal feed in Xinjiang. In June 2018, alfalfa plants with typical anthracnose symptoms were observed in 75% of alfalfa fields in Hutubi County, Xinjiang, China. The disease usually occurred in alfalfa fields that had been planted for more than 2 years and was distributed in patches in the field. The incidence rate ranged from 7.5% to 53%, and the fatality rate ranged from 0 to 3%. Greater incidence was observed in fields with older stands. At the early stage of disease, pale brown prismatic or oval sunken lesions with dark brown to black edges were observed at the base of the stem of alfalfa plants. As the symptoms progressed, lesions on stems turned necrotic, and the center of the lesion became gray-white with black dots. In severe cases, the lesion expanded around the stem, causing the upper part of the stem to break off, or wilt and die. Twenty plant stem sections with typical symptoms were sampled and surface-sterilized with 75% ethanol for 30 s and 1% NaClO for 1 min, rinsed in sterilized distilled water, dried on sterilized filter paper for 45 s, placed on potato dextrose agar (PDA), and incubated in the dark at 25°C for 7 days. A fungus was frequently isolated from the surface-sterilized segments, and the colonies of this fungus were white and flat at first, and later the center of colonies became pale brown with black microsclerotia (2.0~3.2 mm. n = 30) and white or brown acervuli (1.0~1.8 mm. n = 30). A large number of conidia and setae spread from ruptured microsclerotia under microscopy. Conidia (n = 40) were hyaline, smooth-walled, straight, aseptate, cylindrical to fusoid, both tips acute to round, 13.7 to 19.5×3.0 to 4.5 μm . Setae (n = 30) were dark brown to black, smooth-walled, 3~6 septate, straight or slightly curved, 66.9~185.1 μm long, tip round and base swollen, 3.9~5.2 μm width. Sometimes setae formed directly on hyphae or brown acervuli. Colony and conidia morphology were similar to the description of Colletotrichum americae-borealis (Damm et al. 2014; Lyu et al. 2020). DNA was extracted from fresh mycelia of three representative isolates (R11, R12 and R13) and the ITS, ACT, CHS-1 and HIS3 genes of three isolates were amplified and sequenced using the primers described previously by Damm et al. (2014). The sequences of three isolates were identical, and twelve aligned sequences from three representative isolates were deposited in GenBank (MT877442, MT877443 and MT877444 for ITS, MW854350, MW854351 and MW854352 for ACT, MW270930, MW270931 and MW270107 for CHS-1, MW854347, MW854348 and MW854349 for HIS3). Sequence analysis revealed that the ITS, ACT, CHS-1 and HIS3 sequences of three representative isolates were shared 99% (355/356 bp for HIS3) to 100% (550/550 bp for ITS, 261/261 bp for ACT, 221/221 bp for CHS-1) identities to each sequence of an American strain (CBS 136232) of C. americae-borealis from alfalfa in GenBank (NR160760 for ITS, KM105434 for ACT, KM105294 for CHS-1, KM105364 for HIS3). Four phylogenetic trees were constructed by the Mrbayes method (Damm et al. 2014), and the result showed that three representative isolates grouped with C. americae-borealis. Combined with morphological observation and molecular biological identification, the pathogen was identified as C. americae-borealis. Pathogenicity tests were executed twice on alfalfa seedlings in a greenhouse. Pots containing ten 40-day old seedlings (Xinjiang daye) were sprayed with a 100 ml of condial suspension (10^6 condia/ml) of R11. Control pots were sprayed with 100 ml of sterile distilled water. Two weeks after inoculation under greenhouse conditions (25 ± 2°C, 12-h photoperiod, 85% humidity), brown spots and necrotic lesions developed on the stem of inoculated alfalfa seedlings, which were similar to disease plants in fields, and C. americae-borealis was reisolated from symptomatic tissue. The control seedlings remained symptomless. Anthracnose caused by C. americae-borealis was reported on alfalfa in the north region of America and Iran (Damm et al. 2014; Alizadeh et al. 2015), as well as Gansu, Inner Mongolia, Yunnan and Heilongjiang Province of China ( Xu. 2019; zhang et al. 2020) . To our knowledge, this is the first report of Colletotrichum americae-borealis causing Alfalfa Anthracnose in Xinjiang, China. This finding can provide an important reference for understanding the distribution and control of this disease.

Molecular characterization of a novel single-stranded RNA virus, ChRV1, isolated from the plant-pathogenic fungus Colletotrichum higginsianum

In this study, a novel single-stranded RNA virus was isolated from the plant-pathogenic fungus Colletotrichum higginsianum strain HTC-5, and the virus was named "Colletotrichum higginsianum ssRNA virus 1" (ChRV1). The complete genome of ChRV1 is 3850 nucleotides in length with a GC content of 52% and contains two in-frame open reading frames (ORFs): ORF1 (smaller) and ORF2 (larger). ORF1 encodes a protein with the highest sequence similarity to proteins encoded by Phoma matteucciicola RNA virus 1 (PmRV1, 47.99% identity) and Periconia macrospinosa ambiguivirus 1 (PmAV1, 50.73% identity). ORF2 encodes a protein with a conserved RNA-dependent RNA polymerase (RdRp) domain with similarity to the RdRps of PmRV1 (61.41% identity) and PmAV1 (60.61% identity), which are recently reported unclassified (+) ssRNA mycoviruses. Phylogenetic analysis of the RdRp domain showed that ChRV1 grouped together with PmRV1, PmAV1, and other unclassified (+) ssRNA mycoviruses and had a distant relationship to invertebrate viruses and plant viruses of the family Tombusviridae. This is the first report of a novel (+) ssRNA virus infecting the phytopathogenic fungus C. higginsianum.

Conyza bonariensis as an alternative host for Colletotrichum species in Argentina

AIMS

This study investigated the diversity of Colletotrichum isolates recovered from Conyza bonariensis leaves through the use of morphological characteristics, growth rate, carbon sources utilization and phylogenetic analysis.

METHODS AND RESULTS

In all, 30 Colletotrichum isolates recovered from C. bonariensis leaves showing symptoms of disease were included in the present study. Based on the analysis of morphology and sequences, the isolates were distributed into six Colletotrichum species complexes. The concatenated alignment of GAPDH and ITS sequences showed that 20 out of 30 isolates were included in four species complexes which comprise the most important pathogens causing anthracnose in soybean or anthracnose and stalk rot in maize: C. truncatum, C. orchidearum, C. gloeosporioides and C. graminicola. The remaining 10 isolates were included in the C. boninense and C. destructivum species complexes or could not be assigned to any complex with the available information.

CONCLUSION

Weeds belonging to genus Conyza are host to soybean and maize potential pathogenic species of Colletotrichum and could have a role as inoculum reservoir for cross contamination in the agroecosystem.

SIGNIFICANCE AND IMPACT OF THE STUDY

The combined use of morphological, kinetics and physiological parameters of growth and phylogenetic analysis in Colletotrichum isolates from Conyza leaves allowed the detection of species complexes previously not identified in Argentina.

A New Colletotrichum Species Associated with Brown Blight Disease on Camellia sinensis

Brown blight, as the most damaging and common foliar disease of the tea plant (Camellia sinensis) in China, has been recently reported to be caused by different species of the genus Colletotrichum. During the years 2016 to 2017, tea plants in commercial tea cultivation areas of Chongqing City that reported significant incidences of brown blight disease were investigated and then analyzed using both morphological characteristics and multilocus phylogenetic analysis. The results showed that at least five species of Colletotrichum were identified, including four well-known species (Colletotrichum gloeosporioides, C. camelliae, C. fioriniae, and C. karstii) and one novel species (C. chongqingense), indicating that there is remarkable species diversity in Colletotrichum spp. present as pathogens. Results of pathogenicity analyses confirmed that C. chongqingense was the causal agent of brown blight and different isolates differed in virulence. C. chongqingense, as a novel pathogen, has never been reported as being associated with brown blight disease in tea plants or anthracnose in other host plants anywhere in the world. Knowledge of the Colletotrichum populations will facilitate further studies addressing the relationships between Colletotrichum spp. and their host plant Camellia sinensis.

Diversity and Cross-Infection Potential of Colletotrichum Causing Fruit Rots in Mixed-Fruit Orchards in Kentucky

Fungi in the genus Colletotrichum cause apple, blueberry, and strawberry fruit rots, which can result in significant losses. Accurate identification is important because species differ in aggressiveness, fungicide sensitivity, and other factors affecting management. Multiple Colletotrichum species can cause similar symptoms on the same host, and more than one fruit type can be infected by a single Colletotrichum species. Mixed-fruit orchards may facilitate cross-infection, with significant management implications. Colletotrichum isolates from small fruits in Kentucky orchards were characterized and compared with apple isolates via a combination of morphotyping, sequencing of voucher loci and whole genomes, and cross-inoculation assays. Seven morphotypes representing two species complexes (C. acutatum and C. gloeosporioides) were identified. Morphotypes corresponded with phylogenetic species C. fioriniae, C. fructicola, C. nymphaeae, and C. siamense, identified by TUB2 or GAPDH barcodes. Phylogenetic trees built from nine single-gene sequences matched barcoding results with one exception, later determined to belong to an undescribed species. Comparison of single-gene trees with representative whole genome sequences revealed that CHS and ApMat were the most informative for diagnosis of fruit rot species and individual morphotypes within the C. acutatum or C. gloeosporioides complexes, respectively. All blueberry isolates belonged to C. fioriniae, and most strawberry isolates were C. nymphaeae, with a few C. siamense and C. fioriniae also recovered. All three species cause fruit rot on apples in Kentucky. Cross-inoculation assays on detached apple, blueberry, and strawberry fruits showed that all species were pathogenic on all three hosts but with species-specific differences in aggressiveness.

Soybean anthracnose caused by Colletotrichum species: Current status and future prospects

Soybean (Glycine max) is one of the most important cultivated plants worldwide as a source of protein-rich foods and animal feeds. Anthracnose, caused by different lineages of the hemibiotrophic fungus Colletotrichum, is one of the main limiting factors to soybean production. Losses due to anthracnose have been neglected, but their impact may threaten up to 50% of the grain production.

TAXONOMY

While C. truncatum is considered the main species associated with soybean anthracnose, recently other species have been reported as pathogenic on this host. Until now, it has not been clear whether the association of new Colletotrichum species with the disease is related to emerging species or whether it is due to the undergoing changes in the taxonomy of the genus.

DISEASE SYMPTOMS

Typical anthracnose symptoms are pre- and postemergence damping-off; dark, depressed, and irregular spots on cotyledons, stems, petioles, and pods; and necrotic laminar veins on leaves that can result in premature defoliation. Symptoms may evolve to pod rot, immature opening of pods, and premature germination of grains.

CHALLENGES

As accurate species identification of the causal agent is decisive for disease control and prevention, in this work we review the taxonomic designation of Colletotrichum isolated from soybean to understand which lineages are pathogenic on this host. We also present a comprehensive literature review of soybean anthracnose, focusing on distribution, symptomatology, epidemiology, disease management, identification, and diagnosis. We consider the knowledge emerging from population studies and comparative genomics of Colletotrichum spp. associated with soybean providing future perspectives in the identification of molecular factors involved in the pathogenicity process.

USEFUL WEBSITE

Updates on Colletotrichum can be found at http://www.colletotrichum.org/. All available Colletotrichum genomes on GenBank can be viewed at http://www.colletotrichum.org/genomics/.

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.

Colletotrichum cymbidiicola Causing Anthracnose on Cymbidium Orchids in Korea

A Colletotrichum species was isolated from leaves of Cymbidium exhibiting symptoms of anthracnose. In this study, the isolates obtained were identified based on recent taxonomic approaches for the genus Colletotrichum. The identity of the causal pathogen was confirmed using morphological data and phylogenetic analysis of combined multi-gene dataset (internal transcribed spacer, glyceraldehyde 3-phosphate dehydrogenase, chitin synthase-1, actin, histone3, beta-tubulin, and calmodulin). Pathogenicity testing revealed that the isolates were pathogenic to Cymbidium. Based on these results, the fungal pathogen occurring on Cymbidium orchids was identified as Colletotrichum cymbidiicola, which is a newly recorded species in Korea.

Anthracnose Disease of Carpetgrass (Axonopus compressus) Caused by Colletotrichum hainanense sp. nov

Carpetgrass (Axonopus compressus) is a creeping, stoloniferous, perennial warm-season grass that is adapted to humid tropical and subtropical climates. Recently, outbreaks of anthracnose disease of A. compressus caused by an unidentified Colletotrichum sp. were observed in the Hainan and Guangdong provinces in southern China. In late winter and early spring, the disease incidence reached 100% in some badly infected lawns. Under high-moisture conditions, the crowns and oldest leaf sheaths of the majority of the plants became necrotic, which led to whole lawns turning reddish brown. Pathogenicity was confirmed by inoculating uninfected A. compressus plants with a conidial suspension of the Colletotrichum sp. isolated from diseased Axonopus plants. Phylogenetic analyses of the combined internal transcribed spacer, Sod2, Apn2, and Apn2/Mat1 sequences revealed the pathogen to be a novel species of the Colletotrichum graminicola species complex. Microscopic examination showed that the species was also morphologically distinct from related Colletotrichum species. As a result of the phylogenetic, morphological, and pathogenicity analyses, we propose the name Colletotrichum hainanense for this pathogen of A. compressus in southern China.

Characterization of Colletotrichum ocimi Population Associated with Black Spot of Sweet Basil (Ocimum basilicum) in Northern Italy

Black spot is a major foliar disease of sweet basil (Ocimum basilicum) present in a typical cultivation area of northern Italy, including the Liguria and southern Piedmont regions, where this aromatic herb is an economically important crop. In this study, 15 Colletotrichum isolates obtained from sweet basil plants with symptoms of black spot sampled in this area were characterized morphologically and by nuclear DNA analysis using internal transcribed spacers (ITS) and intervening 5.8S nrDNA as well as part of the β-tubulin gene (TUB2) regions as barcode markers. Analysis revealed all but one isolate belonged to the recently described species C. ocimi of the C. destructivum species complex. Only one isolate was identified as C. destructivum sensu stricto (s.s.). In pathogenicity tests on sweet basil, both C. ocimi and C. destructivum s.s. isolates incited typical symptoms of black spot, showing that although C. ocimi prevails in this basil production area, it is not the sole causal agent of black spot in northern Italy. While no other hosts of C. ocimi are known worldwide, the close related species C. destructivum has a broad host range, suggesting a speciation process of C. ocimi within this species complex driven by adaptation to the host.

The Many Questions about Mini Chromosomes in Colletotrichum spp

Many fungal pathogens carry accessory regions in their genome, which are not required for vegetative fitness. Often, although not always, these regions occur as relatively small chromosomes in different species. Such mini chromosomes appear to be a typical feature of many filamentous plant pathogens. Since these regions often carry genes coding for effectors or toxin-producing enzymes, they may be directly related to virulence of the respective pathogen. In this review, we outline the situation of small accessory chromosomes in the genus Colletotrichum, which accounts for ecologically important plant diseases. We summarize which species carry accessory chromosomes, their gene content, and chromosomal makeup. We discuss the large variation in size and number even between different isolates of the same species, their potential roles in host range, and possible mechanisms for intra- and interspecies exchange of these interesting genetic elements.