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The antagonistic activities of three potential biocontrol agents (BCAs), Clonostachys miodochialis, C. rosea, and Minimedusa polyspora, were tested in vitro against the target fungi Fusarium acuminatum, F. avenaceum, F. equiseti, F. graminearum, and Cochliobolus sativus. In vitro dual-culture assay revealed that the BCAs were able to inhibit the mycelial growth of most of the target fungi, with the most common mode of action being mycoparasitism. After 5 d of incubation, depending on the host-parasite interface, biotrophic mycoparasitism was observed via attachment structures on F. avenaceum, F. equiseti, and C. sativus. Haustoria and appressoria were formed by C. miodochialis and M. polyspora on F. avenaceum and C. sativus, respectively. Clamp-like structures were also produced by both BCAs, depending on the host fungus. Clonostachys rosea formed only contact points on its hosts. Coiling structure was observed with C. rosea and M. polyspora occasionally in pure culture but more abundantly in the dual-culture assay. After an additional 3 to 5 d of incubation, the BCAs started damaging their host cells. Asexual fruiting bodies of the BCAs spread necrotrophically on F. acuminatum and F. graminearum and began destroying their mycelia after the initial 5 d of incubation. Furthermore, mycelial dissolution of F. acuminatum by an excreted substance was observed at a distance before direct contact with C. miodochialis. The diffuse metabolite assay revealed that the highest inhibition of the three BCAs was on C. sativus and their least effectiveness was observed on F. graminearum. Overall, these results provide evidence that C. miodochialis, C. rosea, and M. polyspora are potential candidates for biological control of the tested target fungi. This constitutes the first report that these three BCAs are able to establish an initial biotrophic relationship followed by a necrotrophic lifestyle. In addition, C. miodochialis has not previously been reported as a BCA. [ABSTRACT FROM AUTHOR]

Many Trichoderma species are cosmopolitan and widespread free-living fungi in various ecological environment, and many are economically important in the fields of agriculture and industry. However, carbon metabolism profiles of Trichoderma species have not been characterized in detail. In this study, Biolog FF MicroPlates were used to contrast carbon utilization and the differences among five Trichoderma species, each representing a unique phenotype. Their metabolic abilities varied greatly. Species producing cellulases and chitinases and with phosphate-solubilizing activities exhibited high efficiency of substrate utilization, whereas low efficiency was shown by saline-alkaline-tolerant species that metabolized simple carbon sources. Species producing cellulases at high levels may be specified to decompose and assimilate cellulose and hemicellulose in woody substrates, and those producing chitinases may have mycoparasitic roles. Species with plant growth–promoting traits are good at uptake of exudates from plant roots. Overall, metabolic models reflect nutritional adaptation of Trichoderma to diverse niches in nature. [ABSTRACT FROM AUTHOR]

The Piptocephalidaceae (Zoopagales, Zoopagomycota) contains three genera of mycoparasitic, haustoria-forming fungi: Kuzuhaea, Piptocephalis, and Syncephalis. Although the species in this family are diverse and ubiquitous in soil and dung, they are among the least studied fungi. Co-cultures of Piptocephalis and their hosts are relatively easy to isolate from soil and dung samples across the globe, making them a good model taxon for the order Zoopagales. This study focuses on the systematics of the genus Piptocephalis. Despite the fact that there are approximately 40 described Piptocephalis species, there are no modern taxonomic or molecular phylogenetic treatments of this group. Minimal sequence data are available, and relatively little is known about the true diversity or biogeography of the genus. Our study addresses two aspects: Piptocephalis systematics and analyses of the length and inter- and infraspecific variation of the nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) region. First, we generated a large subunit (28S) nuc rDNA phylogeny and evaluated several morphological characters by testing their correlation with the phylogeny using Bayesian Tip-association Significance testing (BaTS). We found monophyly of Piptocephalis species identified based on morphological traits, but morphological character states were not conserved across clades, suggesting that there have been multiple gains and losses of morphological characters. We also found that Kuzhuaea is nested within Piptocephalis. Second, we amplified the ITS from many Piptocephalis isolates, created a sequence alignment, and measured the lengths using the software ITSx. Piptocephalis species had ITS regions that were longer than the average for most Dikarya but were similar in length to those of the related genus Syncephalis. [ABSTRACT FROM AUTHOR]

Host specialization is common among parasitic fungi; however, there are examples when transitions in host specificity between disparately related hosts have occurred. Here, we examine the interkingdom host jump from insect pathogenicity and mycoparasitism in Tolypocladium. Previous phylogenetic inferences made using only a few genes and with poor support reconstructed an ancestral character state of insect pathogenesis, a transition to mycoparasitism, and reversions to insect pathogenesis. To further explore the directionality and genes underlying the transitions in host, we sequenced two additional species of Tolypocladium (T. capitatum and T. paradoxum) and used phylogenomics to compare two insect pathogens and two mycoparasites. Our whole-genome-scale analysis suggests that the diversification of Tolypocladium species happened relatively quickly and that the truffle parasites form a monophyletic, derived lineage within the genus that is the result of a single ecological transition or host jump from insects to fungi. A significant amount of gene tree/species tree discordance occurs within the data set, and we infer this to be the product of both an historical hybridization event and incomplete lineage sorting that was likely because of the rapid diversification of the clade. Furthermore, comparative genomic analyses revealed a set of genes that are exclusive to the mycoparasitic species. These potentially mycoparasitic gene clusters were characterized by a reduced proportion of secreted proteins when compared with entomopathogen-enriched genes and involved the reshaping of the fungal secretome in the ecological context of mycoparasitism. [ABSTRACT FROM AUTHOR]

We examined phylogenetic relationships among species of the mycoparasite genusSyncephalisusing sequences from three nuclear ribsosomal DNA genes (18S, 5.8S, and 28S nuc rDNA) and a gene encoding the largest subunit of RNA polymerase II (RPB1). Our data set included 88Syncephalisisolates comprising 23 named species and several unnamed taxa. We also revived a culturing technique using beef liver and cellophane to grow severalSyncephalisisolates without their host fungi to obtain pure parasite DNA. Most isolates, however, were grown in co-cultures with their host fungi, so we designedSyncephalis-specific primers to obtain sequence data. Individual and combined data sets were analyzed by maximum likelihood (ML) and Bayesian methods. We recovered 20 well-supported lineages and 38 operational taxonomic units (OTUs). Most major clades contained isolates from distant localities on multiple continents. There were taxonomic and nomenclature issues within several clades, probably due to high phenotypic plasticity or species dimorphism. We also conducted an analysis ofSyncephalisnuc rDNA internal transcribed spacer (ITS) sequences for 31 phylogenetically diverse isolates, and we determined that mostSyncephalisspecies have long ITS sequences relative to other fungi. Although commonly employed eukaryotic and fungal primers are compatible with diverseSyncephalisspecies, the ITS sequences ofSyncepahlisare nonetheless rarely recovered in environmental molecular diversity surveys. [ABSTRACT FROM PUBLISHER]

More than 520 soil samples were surveyed for species of the mycoparasitic zygomycete genus Syncephalis using a culture-based approach. These fungi are relatively common in soil using the optimal conditions for growing both the host and parasite. Five species obtained in dual culture are unknown to science and are described here: (i) S. digitata with sporangiophores short, merosporangia separate at the apices, simple, 3-5 spored; (ii) S. floridana, which forms galls in the host and has sporangiophores up to 170 mm long with unbranched merosporangia that contain 2-4 spores; (iii) S. pseudoplumigaleta, with an abrupt apical bend in the sporophore; (iv) S. pyriformis with fertile vesicles that are long-pyriform; and (v) S. unispora with unispored merosporangia. To facilitate future molecular comparisons between species of Syncephalis and to allow identification of these fungi from environmental sampling datasets, we used Syncephalis-specific PCR primers to generate internal transcribed spacer (ITS) sequences for all five new species. [ABSTRACT FROM AUTHOR]

This study revises Uromyces (Pucciniales or Uredinales) on the economically important plant family Cucurbitaceae and presents descriptions, illustrations and a key to aid determination of the 17 recognized species and four varieties. Seven species are described as new: Uromyces aimeae, U. aquiriensis, U. cucumivorus, U. infarctus, U. naucinus, U. saulensis and U. superstomatalis. Uromyces novissimus occurs on a number of tribes of Cucurbitaceae and is broadly circumscribed as a variable species that comprises four varieties. Variety cissampelidis, var. hellerianus and var. pentastriatus, are new combinations for U. cissampelidis, U. hellerianus and U. penlastriatus that have been regarded so far either as synonyms of U. novissimus or distinct species. The new name U. ernesti-ulei is proposed to replace the illegitimate name U. cayaponiae that refers to a uredinial state. It has been synonymized with U. novissimus as well but is considered a distinct species. Uromyces reynoldsii is reduced to a synonym of U. yakushimensis and a lectotype is selected for U. guraniae. Uromyces aimeae, U. neotropicalis and U. superstomatalis differ from the remaining species in superstomatal uredinia and telia and appear to be the first Uromyces spp. in which such sori are reported. The chytrid Olpidium uredinis is reported from three species, U. ernesti-ulei, U. guraniae and U. novissimus var. hellerianus, which are new hosts of this mycoparasite. [ABSTRACT FROM AUTHOR]

Fungi in the genus Hypomyces are mycoparasites of various fungal groups. Studies within this genus have dealt primarily with taxonomic descriptions, and no studies have been published on the population biology of these fungi in natural ecosystems. In this study, genetic structure within and among six California (CA) bolete-infecting H. microspermus populations were analyzed with amplified fragment length polymorphism (AFLP). Four of the populations were collected south of the transverse mountain ranges of southern CA, whereas the other populations were from the central coast of CA (Pismo Beach) and from northern CA (Humboldt County). Thirty-nine genotypes were found among 68 isolates based on 30 AFLP markers. This was a higher degree of genotypic diversity than expected because no sexual fruiting bodies were observed in the field, suggesting that sexual reproduction occurs infrequently. These observations were also supported by multilocus disequilibrium analyses. Overall the populations were significantly differentiated (θ = 0.321, P < 0.001), and most population pairwise Fst values were also significantly different. The populations sampled also fit an isolation by distance model based on a Mantel test (P < 0.001). The overall results suggest that this pathogen has a primarily clonal population genetic structure and l(hat spore dispersal was restricted across the sampled populations. [ABSTRACT FROM AUTHOR]

Knowledge of mycoparasitism has been focused on how antagonists affect pathogens in relation to mechanisms, metabolites and gene expression. Just as microbial antagonists use a diverse arsenal of mechanisms to dominate interactions with hosts, hosts also have diverse responses to counteract antagonism. In this study differential gene expression of eight mycoparasitism-induced genes and eight host-response genes was monitored during in vivo interactions between the mycoparasite Stachybotrys elegans and hyphae and sclerotia of the host, Rhizoctonia solani over 5 d of interaction. Using real time reverse transcription polymerase chain reaction, comparative analyses demonstrated that hyphal and sclerotial structures triggered different expression patterns. These results indicated that multiple regulatory mechanisms might be involved. The high elevated expression of some genes belonging to the mycoparasite and the host suggest that these genes play an important role during the mycoparasitic process and host defense respectively. [ABSTRACT FROM AUTHOR]

Sphaerodes quadrangularis García, Stchigel & Guarro was shown to be a facultative contact biotrophic mycoparasite of Fusarium avenaceum (Fr.) Sacc. (teleomorph: Gibberella avenacea Cooke) that established an intimate relationship with its host by producing hook-shaped and clamp-like attachment structures that appeared to derive nutrients and other essential factors from living host cells. The contact cells of the mycoparasite surrounded and envelop host hyphae and, although they do not appear to penetrate the host, the parasitized hyphae were significantly smaller than unparasitized controls. Sphaerodes quadrangularis did not form specialized attachment structures when cultured together with strains representing F. oxysporum and F. graminearum, indicating some degree of host specificity in the parasite. [ABSTRACT FROM AUTHOR]

Sixty-six fungi isolated from cyclamen phylloplanes were identified and assessed in vitro for antagonism to B. cinerea on leaves, petals, petioles and peduncles. The estimation of pathogen conidial production was used as indicator of biocontrol ability of each of the strains. They were classified by cluster analysis resulting in four categories according to their behavior in the different organs. The most promising category included 34 isolates that significantly reduced pathogen inoculum in all the organs. Correspondence analysis showed association among leaf isolations, strains of Clonostachys rosea and Penicillium spp. and the best biocontrol performance. The statistical analysis was successful in dealing with this complex set of experimental data. Leaf fungal diversity was higher than those of petals and petiols, with Shannon values of 2.7, 0.9 and 0.5 respectively. Evidence for antibiosis and hyperparasitism was found for C. rosea. [ABSTRACT FROM AUTHOR]

Three new species of Laboulbenia occurring on endogean Carabidae are described. These are L. lucifuga, parasitic on Winklerites spp. from Greece, L. magrinii, parasitic on Typloreicheia spy. from Italy, Reicheia spp. from Italy and Corsica and L. vailatii, parasitic on Coecoparvus spp. from Greece. New characters of L. coiffatii and L. endogea are pointed out, and the genus Scalenomyces is synonymized with Laboulbenia. [ABSTRACT FROM AUTHOR]

Abstract: The genus Penicillium comprises species that mostly colonize plant matter. However early reports suggest that several species are capable of parasitizing Aspergillus and sporulating on the conidial heads of the host. More recently Eupenicillium ochrosalmoneum and E. cinnamopurpureum, both with Penicillium anamorphs, have been observed sporulating on the heads of Aspergillus species belonging to section Flavi during the colonization of peanut seeds. Little is known about the host specificity underlying these Aspergillus-Penicillium associations. In this study Aspergillus species representing nine taxonomic sections were paired in culture with E. ochrosalmoneum, E. cinnamopurpureum and two unnamed Penicillium species. Eupenicillium ochrosalmoneum, E. cinnamopurpureum and Penicillium sp. 1 sporulated predominantly on the heads of section Flavi species. In contrast Penicillium sp. 2 was restricted to the heads of section Nigri species. All species spread across Aspergillus colonies by means of aerial hyphae that grew from head to head. Additional studies are required to clarify whether Eupenicillium and Penicillium species are parasitic or simply epibiotic on their hosts. [ABSTRACT FROM AUTHOR]

Mycoparasitism of fungal plant pathogens by Trichoderma species is a complex process that involves the production and co-ordinated secretion of cell-wall degrading enzymes. Genes implicated in mycoparasitism by Trichoderma atroviride contain motifs in the promoter region, designated MYRE1-MYRE4, that are proposed to act as binding sites for a global inducer of the mycoparasitic response. The aim of our study was to establish whether these motifs also were present in Trichoderma hamatum and whether the presence of these motifs could predict co-expression when T. hamatum was confronted by a pathogem Using a combination of targeted, degenerate and inverse PCR, homologues of the mycoparasitism-related genes ech42 (chit42), prb1 and lam1.3 (xbg1.3-110), which encode an endochitinase, proteinase, and β-1,3-glucanase, respectively, were cloned and sequenced from T. hamatum. Alignment of the promoter regions of the three genes revealed identical regions in the chit42 and prb1 promoters, which were 6-9 base pairs in length and conserved in position. Specifically, the regulatory motifs MYRE1-MYRE4 were fully conserved, together with a fifth motif, identified by this research. A substrate assay designed to investigate the response of these genes from T. harzianum and T. hamatum to a simple carbon source (glycerol) showed that, in contrast to chit42 and prb1, xbgl.3-110 was not expressed. Further comparison of the expression patterns of these three genes between T. harzianum and T. hamatum using the glycerol substrate assay showed that no chit42 or prb1 expression could be detected in T. harzianum when it was grown under the same conditions as T. hamatum. This showed that the response of these genes to glycerol was species specific and that a single expression pattern for these genes was not common to all Trichoderma species. Confrontation assays were used to investigate the response of the three T. hamatum genes to the more complex substrate posed by the fungal... [ABSTRACT FROM AUTHOR]

Tuberculina species are mitosporic parasites of rust fungi. It was demonstrated recently that Tuberculina represents the asexual life stage of the plant-parasitic genus Helicobasidium. Here we reveal the host specificities of Tuberculina and Helicobasidium species on rust fungal hosts by means of infection experiments and molecular analyses. We inoculated species of the rust genera Chrysomyxa, Coleosporium, Cronartium, Gymnosporangium, Puccinia, Tranzschelia and Uromyces with conidia and with basidiospores of Helicobasidium longisporum and H. purpureum and with conidia of Tuberculina maxima, T. persicina and T. sbrozzii. In addition we analyzed base sequences from the nuclear ITS region of 51 Tuberculina and Helicobasidium specimens collected in the field together with the sequences from the Tuberculina infections obtained by infection experiments. The resulting data show that at least six monophyletic lineages are within the Tuberculina/Helicobasidium-group that can be unambiguously distinguished by combining molecular and morphological characters and by specific host spectra of the Tuberculina-stage. This diversity opens up new vistas on the evolution of this exceptional mycoparasitic-phytoparasitic fungal group. [ABSTRACT FROM AUTHOR]

Cellular interaction of the basidiomycete Tuberculina persicina with the haploid stages of two rusts Puccinia silvatica and Tranzschelia pruni-spinosae was analyzed by serial-section electron microscopy of chemically fixed samples and samples subjected to high-pressure freezing and freeze substitution. Tuberculina persicina is a contact parasite, forming neither haustoria nor other intracellular structures. However, at contact areas between T. persicina and its hosts, distinct interfungal interactions are present. At the beginning, a hyphal cell of T. persicina invades the host cell wall with a protuberance and the cell walls of both protuberance and host cell dissolve at the point of contact. Thus, the plasma membranes of the two organisms contact and fuse to form a pore that enlarges to a final diameter of approximately 1 µm. The membrane of the fusion pore is continuous with the plasma membranes of both cells, and Tuberculina nuclei and other organelles are transferred to the rust cells. Phylogenetic and functional aspects of this curious basidiomycetous interfungal interaction are discussed, and a hypothesis of the evolutionary derivation of the Tuberculina mycoparasitism from a sexual interaction is presented. [ABSTRACT FROM AUTHOR]

Molecular sequence data together with ultrastructural features were used to infer the phylogenetic position of Tuberculina species. Additional ultrastructural characteristics were used to determine their mode of nutrition. We investigated ultrastructural morphology of the type species Tuberculina persicina and determined base sequences from the D1/D2 region of the nuclear large-subunit ribosomal DNA of the three commonly distinguished Tuberculina species, T. maxima, T. persicina and T. sbrozzii. Analyses of sequence data by means of a Bayesian method of phylogenetic inference using a Markov Chain Monte Carlo technique reveal the basidiomycetous nature of Tuberculina. Within the Urediniomycetes, Tuberculina clusters as a sister group of Helicobasidium, closely related to the rusts (Uredinales). This phylogenetic position is supported by the uredinalean architecture of septal pores in Tuberculina. In addition, we present aspects of the ultrastructural morphology of the cellular interaction of Tuberculina and rusts showing a unique interaction with large fusion pores, revealing the mycoparasitic nature of Tuberculina on its close relatives, the rusts. [ABSTRACT FROM AUTHOR]

A new genus, Classicula, and a new species, Classicula fluitans, are described in the Urediniomycetes for the teleomorph of Naiadella fluitans. Classicula fluitans forms transversely septate basidia with subapically swollen sterigmata and long fusiform basidiospores. An integrated analysis of morphological, ultrastructural and molecular data indicates that Classicula fluitans is a member of the Urediniomycetes. Among the Urediniomycetes, Classicula fluitans shares the formation of simple septal pores associated with microbodies and tremelloid haustorial cells only with the hyphomycete Jaculispora submersa. In addition, in our molecular phylogenetic analyses with at least two representatives of all known urediniomycetous groups, Classicula fluitans appears together with Jaculispora submersa in a statistically well-supported cluster. Accordingly, the family Classiculaceae and the order Classiculales are proposed to accommodate these fungi in the Urediniomycetes. [ABSTRACT FROM AUTHOR]