Endophytic Colletotrichum Species from Aquatic Plants in Southwest China

Two new species of Nectriaceae (Hypocreales, Sordariomycetes) from Yunnan, China

Nectriaceae is a highly diverse family, and members have a worldwide distribution, particularly in warm temperate to tropical regions. During the survey of fungal diversity in different habitats in Yunnan province, China, two new species isolated from soil and air respectively, namely Atractiumyunnanense sp. nov. and Nalanthamalaxishuangbannaensis sp. nov., were proposed based on morphological comparisons and the multi-gene phylogenetic analyses of combined ITS, LSU, rpb2, and tub2 sequence data. Phylogenetically, both species clustered in a monophyletic clade within Nectriaceae with strong support. A.yunnanense is characterized by synnematous conidiophores, pale olivaceous-green, clavate to oblong-ellipsoidal, multi-septate conidia, and pale olivaceous-green chlamydospores. N.xishuangbannaensis has acremonium-like or penicillium-like conidiophores and either obovate or ellipsoidal, cylindrical or fusiform conidia. Full descriptions, illustrations, and a phylogenetic tree showing the phylogenetic position of the two new species were provided.

Endophytic species of Colletotrichum associated with cashew tree in northeastern Brazil

Anthracnose caused by Colletotrichum is the most severe and widely occurring cashew disease in Brazil. Colletotrichum species are commonly found as pathogens, endophytes and occasionally as saprophytes in a wide range of hosts. The endophytic species associated with cashew trees are poorly studied. In this study, we report the Colletotrichum endophytic species associated with cashew trees in two locations in the state of Pernambuco, their prevalence in different plant organs (leaves, veins, branches and inflorescences), and compare the species in terms of pathogenicity and aggressiveness using different inoculation methods (wounded × unwounded). Six species of Colletotrichum were identified according to multilocus phylogenetic analyses, including Colletotrichum asianum, Colletotrichum chrysophilum, Colletotrichum karsti, Colletotrichum siamense, Colletotrichum theobromicola, and Colletotrichum tropicale. There were differences in the percentage of isolation in relation to the prevalence of colonized tissues and collection locations. C. tropicale was the prevalent species in both geographic areas and plant tissues collected, with no pattern of distribution of species between areas and plant tissues. All isolates were pathogenic in injured tissues of cashew plants. The best method to test the pathogenicity of Colletotrichum species was utilizing the combination of leaves + presence of wounds + conidial suspension, as it better represents the natural infection process. C. siamense was the most aggressive species.

Diversity of Leaf Fungal Endophytes from Two Coffea arabica Varieties and Antagonism towards Coffee Leaf Rust

Coffee has immense value as a worldwide-appreciated commodity. However, its production faces the effects of climate change and the spread of severe diseases such as coffee leaf rust (CLR). The exploration of fungal endophytes associated with Coffea sp. has already found the existence of nearly 600 fungal species, but their role in the plants remains practically unknown. We have researched the diversity of leaf fungal endophytes in two Coffea arabica varieties: one susceptible and one resistant to CLR. Then, we conducted cross-infection essays with four common endophyte species (three Colletotrichum sp. and Xylaria sp. 1) and Hemileia vastatrix (CLR) in leaf discs, to investigate the interaction of the endophytes on CLR colonisation success and severity of infection. Two Colletotrichum sp., when inoculated 72 h before H. vastatrix, prevented the colonisation of the leaf disc by the latter. Moreover, the presence of endophytes prior to the arrival of H. vastatrix ameliorated the severity of CLR. Our work highlights both the importance of characterising the hidden biodiversity of endophytes and investigating their potential roles in the plant-endophyte interaction.

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

The Colletotrichum gloeosporioides species complex includes many phytopathogenic species, causing anthracnose disease on a wide range of host plants and appearing to be globally distributed. Seventy-one Colletotrichum isolates in the complex from different plants and geographic regions in Korea were preserved in the Korean Agricultural Culture Collection (KACC). Most of them had been identified based on hosts and morphological features, this could lead to inaccurate species names. Therefore, the KACC isolates were re-identified using DNA sequence analyses of six loci, comprising internal transcribed spacer, gapdh, chs-1, his3, act, and tub2 in this study. Based on the combined phylogenetic analysis, KACC strains were assigned to 12 known species and three new species candidates. The detected species are C. siamense (n = 20), C. fructicola (n = 19), C. gloeosporioides (n = 9), C. aenigma (n = 5), C. camelliae (n = 3), C. temperatum (n = 3), C. musae (n = 2), C. theobromicola (n = 2), C. viniferum (n = 2), C. alatae (n = 1), C. jiangxiense (n = 1), and C. yulongense (n = 1). Of these, C. jiangxiense, C. temperatum, C. theobromicola and C. yulongense are unrecorded species in Korea. Host plant comparisons showed that 27 fungus-host associations are newly reported in the country. However, plant-fungus interactions need to be investigated by pathogenicity tests.

Comparative Genomic Analysis of Colletotrichum lini Strains with Different Virulence on Flax

Colletotrichum lini is a flax fungal pathogen. The genus comprises differently virulent strains, leading to significant yield losses. However, there were no attempts to investigate the molecular mechanisms of C. lini pathogenicity from high-quality genome assemblies until this study. In this work, we sequenced the genomes of three C. lini strains of high (#390-1), medium (#757), and low (#771) virulence. We obtained more than 100× genome coverage with Oxford Nanopore Technologies reads (N50 = 12.1, 6.1, 5.0 kb) and more than 50× genome coverage with Illumina data (150 + 150 bp). Several assembly strategies were tested. The final assemblies were obtained using the Canu-Racon ×2-Medaka-Polca scheme. The assembled genomes had a size of 54.0-55.3 Mb, 26-32 contigs, N50 values > 5 Mb, and BUSCO completeness > 96%. A comparative genomic analysis showed high similarity among mitochondrial and nuclear genomes. However, a rearrangement event and the loss of a 0.7 Mb contig were revealed. After genome annotation with Funannotate, secreting proteins were selected using SignalP, and candidate effectors were predicted among them using EffectorP. The analysis of the InterPro annotations of predicted effectors revealed unique protein categories in each strain. The assembled genomes and the conducted comparative analysis extend the knowledge of the genetic diversity of C. lini and form the basis for establishing the molecular mechanisms of its pathogenicity.

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.

Steroid Components of Marine-Derived Fungal Strain Penicillium levitum N33.2 and Their Biological Activities

Genus Penicillium comprising the most important and extensively studied fungi has been well-known as a rich source of secondary metabolites. Our study aimed to analyze and investigate biological activities, including in vitro anti-cancer, anti-inflammatory and anti-diabetic properties, of metabolites from a marine-derived fungus belonging to P. levitum. The chemical compounds in the culture broth of P. levitum strain N33.2 were extracted with ethyl acetate. Followingly, chemical analysis of the extract leaded to the isolation of three ergostane-type steroid components, namely cerevisterol (1), ergosterol peroxide (2), and (3β,5α,22E)-ergosta-6,8(14),22-triene-3,5-diol (3). Among these, (3) was the most potent cytotoxic against human cancer cell lines Hep-G2, A549 and MCF-7 with IC50 values of 2.89, 18.51, and 16.47 µg/mL, respectively, while the compound (1) showed no significant effect against tested cancer cells. Anti-inflammatory properties of purified compounds were evaluated based on NO-production in LPS-induced murine RAW264.7 macrophages. As a result, tested compounds performed diverse inhibitory effects on NO production by the macrophages, with the most significant inhibition rate of 81.37 ± 1.35% at 25 µg/mL by the compound (2). Interestingly, compounds (2) and (3) exhibited inhibitory activities against pancreatic lipase and α-glucosidase enzymes in vitro assays. Our study brought out new data concerning the chemical properties and biological activities of isolated steroids from a P. levitum fungus.

Natural products from marine fungi as a source against agricultural pathogenic fungi

There are many kinds of agricultural pathogenic fungi, which may belong to pathogenic fungi in different species, such as Fusarium, Alternaria, Colletotrichum, Phytophthora, and other agricultural pathogens. Pathogenic fungi from different sources are widely distributed in agriculture, which threaten the lives of crops around the world and caused great damage to agricultural production and economic benefits. Due to the particularity of the marine environment, marine-derived fungi could produce natural compounds with unique structures, rich diversities, and significant bioactivities. Since marine natural products with different structural characteristics could inhibit different kinds of agricultural pathogenic fungi, secondary metabolites with antifungal activity could be used as lead compounds against agricultural pathogenic fungi. In order to summarize the structural characteristics of marine natural products against agricultural pathogenic fungi, this review systematically overview the activities against agricultural pathogenic fungi of 198 secondary metabolites from different marine fungal sources. A total of 92 references published from 1998 to 2022 were cited. KEY POINTS: • Pathogenic fungi, which could cause damage to agriculture, were classified. • Structurally diverse antifungal compounds from marine-derived fungi were summarized. • The sources and distributions of these bioactive metabolites were analyzed.

The Influence of Cone Age and Urbanisation on the Diversity and Community Composition of Culturable Seed Fungal Endophytes within Native Australian Banksia ericifolia L.f. subsp. ericifolia

Seed fungal endophytes play a crucial role in assisting the overall health and success of their host plant; however, little is known about the factors that influence the diversity and composition of these endophytes, particularly with respect to how they change over time and within urban environments. Using culturing techniques, morphological analyses, and Sanger sequencing, we identified the culturable seed fungal endophytes of Banksia ericifolia at two urban and two natural sites in Sydney, New South Wales, Australia. A total of 27 Operational Taxonomic Units were obtained from 1200 seeds. Older cones were found to contain, on average, more colonised endophytes than younger cones. Species richness was also significantly influenced by cone age, with older cones being more speciose. Between urban and natural sites, the overall community composition did not change, although species richness and diversity were greatest at urban sites. Understanding how these endophytes vary in time and space may help provide an insight into the transmission pathways used and the potential role they play within the development and survival of the seed. This knowledge may also be crucial for restoration purposes, especially regarding the need to consider endophyte viability in ex situ seed collection and storage in seed-banking practices.

A real-time PCR for detection of pathogens of anthracnose on Chinese fir using TaqMan probe targeting ApMat gene

BACKGROUND

Anthracnose is one of the most widespread and destructive diseases on Chinese fir. Colletotrichum cangyuanense, Colletotrichum fructicola, Colletotrichum gloeosporioides, and Colletotrichum siamense are the causal agents of anthracnose on Chinese fir. A rapid and accurate diagnosis of different pathogens is critical for the disease management.

RESULTS

Phylogenetic tree and sequence similarity analysis showed that the single-locus ApMat provides superior phylogenetic information and is an appropriate target to distinguish C. cangyuanense, C. fructicola, C. gloeosporioides, and C. siamense. The real-time PCR assays with the primer sets of MQ-F/R, 1#C-F/R, YK-F/R, and WZ-F/R, and corresponding TaqMan probes of MQ-P, 1#C-P, YK-P, and WZ-P were specific for C. cangyuanense, C. fructicola, C. gloeosporioides, and C. siamense, respectively. The sensitivity tests showed that the lowest amount of gDNA that the PCRs can detect was 1 ng of genomic DNA. The validity of the assays was confirmed by directly detecting the pathogens from both the fungal culture and infected Chinese fir.

CONCLUSION

These results demonstrated the potential of the TaqMan real-time PCR targeting the ApMat gene to provide rapid, specific, and reliable molecular detection of C. fructicola, C. gloeosporioides, C. siamense, and C. cangyuanense, respectively. The data also provided a reference solution for the identification of species within Colletotrichum gloeosporioides species complex (CGSC), which share similar morphological characteristics. © 2022 Society of Chemical Industry.

Fungal diversity notes 1512-1610: taxonomic and phylogenetic contributions on genera and species of fungal taxa

This article is the 14th in the Fungal Diversity Notes series, wherein we report 98 taxa distributed in two phyla, seven classes, 26 orders and 50 families which are described and illustrated. Taxa in this study were collected from Australia, Brazil, Burkina Faso, Chile, China, Cyprus, Egypt, France, French Guiana, India, Indonesia, Italy, Laos, Mexico, Russia, Sri Lanka, Thailand, and Vietnam. There are 59 new taxa, 39 new hosts and new geographical distributions with one new combination. The 59 new species comprise Angustimassarina kunmingense, Asterina lopi, Asterina brigadeirensis, Bartalinia bidenticola, Bartalinia caryotae, Buellia pruinocalcarea, Coltricia insularis, Colletotrichum flexuosum, Colletotrichum thasutense, Coniochaeta caraganae, Coniothyrium yuccicola, Dematipyriforma aquatic, Dematipyriforma globispora, Dematipyriforma nilotica, Distoseptispora bambusicola, Fulvifomes jawadhuvensis, Fulvifomes malaiyanurensis, Fulvifomes thiruvannamalaiensis, Fusarium purpurea, Gerronema atrovirens, Gerronema flavum, Gerronema keralense, Gerronema kuruvense, Grammothele taiwanensis, Hongkongmyces changchunensis, Hypoxylon inaequale, Kirschsteiniothelia acutisporum, Kirschsteiniothelia crustaceum, Kirschsteiniothelia extensum, Kirschsteiniothelia septemseptatum, Kirschsteiniothelia spatiosum, Lecanora immersocalcarea, Lepiota subthailandica, Lindgomyces guizhouensis, Marthe asmius pallidoaurantiacus, Marasmius tangerinus, Neovaginatispora mangiferae, Pararamichloridium aquisubtropicum, Pestalotiopsis piraubensis, Phacidium chinaum, Phaeoisaria goiasensis, Phaeoseptum thailandicum, Pleurothecium aquisubtropicum, Pseudocercospora vernoniae, Pyrenophora verruculosa, Rhachomyces cruralis, Rhachomyces hyperommae, Rhachomyces magrinii, Rhachomyces platyprosophi, Rhizomarasmius cunninghamietorum, Skeletocutis cangshanensis, Skeletocutis subchrysella, Sporisorium anadelphiae-leptocomae, Tetraploa dashaoensis, Tomentella exiguelata, Tomentella fuscoaraneosa, Tricholomopsis lechatii, Vaginatispora flavispora and Wetmoreana blastidiocalcarea. The new combination is Torula sundara. The 39 new records on hosts and geographical distribution comprise Apiospora guiyangensis, Aplosporella artocarpi, Ascochyta medicaginicola, Astrocystis bambusicola, Athelia rolfsii, Bambusicola bambusae, Bipolaris luttrellii, Botryosphaeria dothidea, Chlorophyllum squamulosum, Colletotrichum aeschynomenes, Colletotrichum pandanicola, Coprinopsis cinerea, Corylicola italica, Curvularia alcornii, Curvularia senegalensis, Diaporthe foeniculina, Diaporthe longicolla, Diaporthe phaseolorum, Diatrypella quercina, Fusarium brachygibbosum, Helicoma aquaticum, Lepiota metulispora, Lepiota pongduadensis, Lepiota subvenenata, Melanconiella meridionalis, Monotosporella erecta, Nodulosphaeria digitalis, Palmiascoma gregariascomum, Periconia byssoides, Periconia cortaderiae, Pleopunctum ellipsoideum, Psilocybe keralensis, Scedosporium apiospermum, Scedosporium dehoogii, Scedosporium marina, Spegazzinia deightonii, Torula fici, Wiesneriomyces laurinus and Xylaria venosula. All these taxa are supported by morphological and multigene phylogenetic analyses. This article allows the researchers to publish fungal collections which are important for future studies. An updated, accurate and timely report of fungus-host and fungus-geography is important. We also provide an updated list of fungal taxa published in the previous fungal diversity notes. In this list, erroneous taxa and synonyms are marked and corrected accordingly.

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.

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.

Colletotrichum Species Associated with Peaches in China

Colletotrichum is regarded as one of the 10 most important genera of plant pathogens in the world. It causes diseases in a wide range of economically important plants, including peaches. China is the largest producer of peaches in the world but little is known about the Colletotrichum spp. affecting the crop. In 2017 and 2018, a total of 286 Colletotrichum isolates were isolated from symptomatic fruit and leaves in 11 peach production provinces of China. Based on multilocus phylogenetic analyses (ITS, ACT, CAL, CHS-1, GAPDH, TUB2, and HIS3) and morphological characterization, the isolates were identified to be C. nymphaeae, C. fioriniae, and C. godetiae of the C. acutatum species complex, C. fructicola and C. siamense of the C. gloeosporioides species complex, C. karsti of the C. boninense species complex, and one newly identified species, C. folicola sp. nov. This study is the first report of C. karsti and C. godetiae in peaches, and the first report of C. nymphaeae, C. fioriniae, C. fructicola, and C. siamense in peaches in China. C. nymphaeae is the most prevalent species of Colletotrichum in peaches in China, which may be the result of fungicide selection. Pathogenicity tests revealed that all species found in this study were pathogenic on both the leaves and fruit of peaches, except for C. folicola, which only infected the leaves. The present study substantially improves our understanding of the causal agents of anthracnose on peaches in China.

Fourteen New Species of Foliar Colletotrichum Associated with the Invasive Plant Ageratinaadenophora and Surrounding Crops

Ageratina adenophora is one of the most invasive weeds in China. Following an outbreak in Yunnan in the 1960s, A. adenophora has been spreading in Southwest China at tremendous speed. Previous research indicated A. adenophora contained many Colletotrichum species as endophytes. In this study, we investigated the diversity of Colletotrichum in healthy and diseased leaves of the invasive plant A. adenophora and several surrounding crops in Yunnan, Guangxi, and Guizhou provinces in China, and obtained over 1000 Colletotrichum strains. After preliminary delimitation using the internal transcribed spacer region (ITS) sequences, 44 representative strains were selected for further study. Their phylogenetic positions were determined by phylogenetic analyses using combined sequences of ITS, actin (ACT), chitin synthase (CHS-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and beta-tubulin (TUB2). Combined with morphological characteristics, 14 new Colletotrichum species were named as C. adenophorae, C. analogum, C. cangyuanense, C. dimorphum, C. gracile, C. nanhuaense, C. nullisetosum, C. oblongisporum, C. parvisporum, C. robustum, C. simulanticitri, C. speciosum, C. subhenanense, and C. yunajiangense.