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Priscila Chaverri

Publications and source records attributed to Priscila Chaverri.

7 recordsLinked to original sources

Genomes of the ex-type strains of Elsinoë mangiferae and E. perseae, the causal agents of scab on mango and avocado.

Elsinoë species are slow-growing, hemibiotrophic to necrotrophic fungi that cause scab diseases on economically important fruit crops. Genome resources for many host-specific species remain limited. We report high-quality draft genome assemblies for the ex-type strains of Elsinoë mangiferae (CBS 226.50) and E. perseae (CBS 406.34), causal agents of mango and avocado scab, respectively. Among 5 approaches tested, a Nanopore-only NextDenovo assembly produced the most contiguous genomes, yielding 24.5 Mb (E. mangiferae) and 25.1 Mb (E. perseae) assemblies with 13 and 18 contigs, respectively, BUSCO completeness scores of ∼94%, and multiple putative telomere-to-telomere chromosomes. Gene prediction identified 9,134 and 9,243 genes, respectively. Functional annotation revealed enrichment of metabolic and regulatory pathways, including those involved in posttranslational modification, protein transport, and secondary metabolism. Carbohydrate-active enzyme repertoires were small but conserved, consistent with stealth pathogenicity strategies and low plant cell wall degradation. Both genomes encoded large secretomes (>850 proteins), diverse protease repertoires (>300 proteins), Ecp2-like effector proteins, and multiple biosynthetic gene clusters, including clusters with similarity to those associated with elsinochrome and ACT-toxin II biosynthesis, some of which may contribute to host-pathogen interactions and disease development. A large fraction of genes lacked functional characterization, suggesting incomplete databases and/or the presence of lineage-specific genes potentially involved in virulence or host adaptation. These genome resources fill critical gaps for underrepresented Elsinoë species and provide taxonomically anchored references essential for diagnostics, comparative genomics, and research into the molecular basis of host specificity and pathogenicity in scab-causing fungi.

Persea↗

A taxonomic revision of the insect biocontrol fungus Aschersonia aleyrodis, its allies with white stromata and their Hypocrella sexual states.

A revision of a monophyletic group of Hypocrella species and their Aschersonia anamorphs with white effuse stromata is presented. In addition to taxon descriptions, distributions, and nomenclature, a synoptic key and a molecular phylogenetic analysis are also provided. A new holomorph, Hypocrella rhombispora sp. nov., is described. This study presents a revisionary treatment of Aschersonia aleyrodis (teleomorph: Hypocrella libera) and its allies. These fungi parasitize whiteflies and are promising candidates for whitefly biological control. Four species of Aschersonia and their Hypocrella teleomorphs are treated in detail: Aschersonia aleyrodis/Hypocrella libera; A. andropogonis/H. andropogonis, A. placenta/H. raciborskii, and A. sp./H. rhombispora sp. nov. A synoptic key including these and six other morphologically similar species is presented to facilitate identification in the field and laboratory. Phylogenetic analyses of partial DNA sequences from three genes (LSU, mtSSU, and RPB2) suggest that Aschersonia species with effuse white stromata form a monophyletic group of whitefly pathogens. Phylogenetically informative characters in the group include the colour and shape of the stromata, the arrangement of tubercles containing perithecia, the arrangement of conidial masses on the stromata, and the shape of conidia and part spores.

Hypocreales↗

A new species of Hypocrella, H. macrostroma, and its phylogenetic relationships to other species with large stromata.

Two specimens of a new species of Hypocrella with large stromata were collected in Bolivia and Costa Rica. The morphology of the new species, H. macrostroma sp. nov., was compared with that of other species with large stromata, i.e. H. africana, H. gaertneriana, and H. schizostachyi. In addition, phylogenetic analyses of partial sequences from three genes, large subunit nuclear ribosomal DNA (LSU), translation elongation factor 1-alpha (EF1-alpha), and RNA polymerase II subunit 1 (RPB1), were conducted to determine the relationships of the new species to other species of Hypocrella/Aschersonia. Phylogenetic analyses show that H. macrostroma belongs to a strongly supported clade that includes H. africana, H. schizostachyi, and Aschersonia insperata, whereas other Hypocrella species belong to two sister clades. Hypocrella macrostroma is described and illustrated, and a lectotype is designated for H. gaertneriana.

Animals↗

Multilocus phylogenetic structure within the Trichoderma harzianum/Hypocrea lixii complex.

Trichoderma harzianum is a ubiquitous species in the environment and is effective in the biological control of plant-pathogenic fungi. T. harzianum has not been linked unequivocally to its sexual state nor has its phylogeny been studied in detail. It has been suggested that T. harzianum is a species complex based on the phenotypic and genotypic variability encountered. On the basis of morphological and cultural characters and DNA sequence data analysis of four genes (ITS rDNA, translation elongation factor 1-alpha, calmodulin, and alpha-actin), Hypocrea lixii was found to be the sexual state of T. harzianum. Both the asexual and sexual states of this species have wide geographic distributions. Phylogenetic analysis of four genes showed that T. harzianum/H. lixii is a cohesive group that is supported by bootstrap values higher than 95%. Principles of genealogical concordance indicated that T. harzianum/H. lixii is a complex of independent monophyletic lineages, but no diagnostic morphological distinctions were identified that justify formal taxonomic recognition for the different lineages.

Actins↗

The genus Podocrella and its nematode-killing anamorph Harposporium.

Several genera are described in the literature as having morphology similar to the clavicipitaceous genus Podocrella, viz. Atricordyceps, Ophiocordyceps, Wakefieldiomyces and "Cordyceps" peltata. These genera have capitate-stipitate stromata that gradually expand into a horizontally flattened fertile head that is dark, has strongly protruding perithecia and asci containing eight multiseptate filiform ascospores. These ascospores disarticulate at the middle septum to form two lanceolate multiseptate part-as-cospores. In this study several specimens of the above-mentioned genera, including the types, were examined to determine whether they are congeneric with Podocrella. This study also reveals the connection of Podocrella to its anamorph genus, Harposporium, and its relationship to several other clavicipitaceous genera, based on cultural data and large subunit nuclear ribosomal DNA (LSU) sequences. Nematode predation of the Harposporium anamorph of P. peltata is demonstrated. The results show Podocrella and selected Harposporium LSU sequences form a monophyletic group and that this clade is closely related to Aschersonia. A new species of Podocrella from Costa Rica, P fusca, is described, new combinations made for P. peltata and P. harposporifera, and a key to the known species is presented.

Animals↗

Clarification of the host substrate of Ascopolyporus and description of Ascopolyporus philodendrus sp. nov.

During a recent collection trip to Barro Colorado Island, Panama, two species belonging to genus Ascopolyporus (Clavicipitaceae, Hypocreales) were collected. Species of Ascopolyporus are epibionts of their bamboo (Poaceae) host and long thought to be biotrophs of their plant hosts. However, based on morphological observations and phylogenetic evidence using large subunit ribosomal DNA data, we propose that genus Ascopolyporus is likely composed of pathogens of scale insects (Coccoideae, Homoptera). Phylogenetic analyses included Ascopolyporus spp. in a clade containing only entomopathogenic clavicipitaceous species (100% posterior probability), and the scale insect pathogen Hyperdermium bertonii was found to share the most recent common ancestor with the Ascopolyporus clade (98% posterior probability). In addition remnants of the scale insect were observed to be embedded within stromata during early stages of stroma development. Ascopolyporus philodendrus sp. nov. was described and distinguished from the type species of the genus, A. polychrous, based on perithecial size, ascus size, plant host substrate and phylogenetic evidence. Furthermore subfamily Clavicipitoideae (Clavicipitaceae) was included and well supported in a single clade (100% posterior probability).

Ascomycota↗

Regiocrella, a new entomopathogenic genus with a pycnidial anamorph and its phylogenetic placement in the Clavicipitaceae.

A new genus, Regiocrella, is described with two species, R. camerunensis and R. sinensis, based on specimens collected in Cameroon and China. Both species are parasitic on scale insects (Coccidae, Homoptera). Morphological and molecular evidence place the new genus in the Clavicipitaceae (Hypocreales), despite its combination of characters that are atypical of that family; Regiocrella is characterized by having perithecia partly immersed in a subiculum, noncapitate asci, unicellular fusiform ascospores and pycnidial-acervular conidiomata. The two new species, R. camerunensis and R. sinensis, are distinguished based on ascospore and perithecium size. Morphological characters were evaluated and compared to other genera in the Clavicipitaceae, especially those parasitic on scale insects or with pycnidial-acervular anamorphs or synanamorphs (i.e. Aschersonia, Ephelis or Sphacelia): Atkinsonella, Balansia, Claviceps, Epichlöe, Hypocrella, Myriogenospora and Neoclaviceps. The phylogenetic relationships of Regiocrella were examined with three gene loci: large subunit nuclear ribosomal DNA (LSU), translation elongation factor 1-alpha (TEF), and RNA polymerase II subunit 1 (RPB1). The results of this study confirm that Regiocrella is distinct from other genera in the Clavicipitaceae and that its two species form a monophyletic group. Regiocrella is shown to be closely related to the scale insect pathogen Hypocrella and the plant-associated genera Balansia, Claviceps, Epichlöe, Myriogenospora and Neoclaviceps. This study also provides insights into the evolution of pycnidial-acervular conidiomata and scale insect parasitism within the Clavicipitaceae. Plant-associated genera form a monophyletic group correlated with Clavicipitaceae subfamily Clavicipitoideae sensu Diehl. We also demonstrate that scale insect parasites have multiple evolutionary origins within the family and genera with pycnidial-acervular anamorphs or synanamorphs have a single origin.

Base Sequence↗