Diversity, Prevalence, and Virulence of Colletotrichum Species Associated with Lima Bean in Brazil.

Anthracnose is one of the most important diseases of lima bean in Brazil. Previously, the disease was attributed exclusively to Colletotrichum truncatum. Therefore, this work aimed to characterize the diversity, prevalence, and virulence of Colletotrichum spp. associated with anthracnose in lima bean in Brazil. Here, we report the species C. truncatum, C. brevisporum, C. lobatum, C. plurivorum, and C. musicola in association with anthracnose of lima bean. All species were pathogenic to lima bean. In addition, several strains were found that represent novel lineages, presented here as Colletotrichum lineages 1 to 5. C. truncatum is the prevailing species and more virulent than all other species studied.

Diversity, Prevalence and Virulence of Colletotrichum Species Causing Anthracnose on Cassava Leaves in the Northern Region of Brazil.

Cassava (Manihot esculenta Crantz) is a staple crop widely cultivated by small farmers in tropical countries. However, despite the low level of technology required for its management, it can be affected by several diseases, with anthracnose as the main threat. There is little information about the main species of Colletotrichum that infect cassava in Brazil. Thus, the objective of this work was to study the diversity, prevalence and virulence of Colletotrichum species that cause anthracnose in cassava leaves in northern Brazil. Twenty municipalities of the Pará and Tocantins states were selected, and leaves with symptoms were collected in those locations. Pure cultures were isolated in the laboratory. Species were identified using phylogenetic analyses of multiple loci, and their pathogenicity, aggressivity and virulence levels were assessed. Our results showed the greatest diversity of Colletotrichum associated with anthracnose in cassava plants of the "Formosa" cultivar in the Tocantins and Pará states. We determined the presence of Colletotrichum chrysophilum, C. truncatum, C. siamense, C. fructicola, C. plurivorum, C. musicola and C. karsti, with C. chrysophilum as the most aggressive and virulent. Our findings provide accurate identifications of species of Colletotrichum causing anthracnose in cassava crops, which are of great relevance for cassava breeding programs (e.g., the search for genotypes with polygenic resistance since the pathogen is so diverse) and for developing anthracnose management strategies that can work efficiently against species complexes of Colletotrichum.

Why species delimitation matters for fungal ecology: Colletotrichum diversity on wild and cultivated cashew in Brazil.

Anthracnose is one of the most important plant diseases globally, occurring on a wide range of cultivated and wild host species. This study aimed to identify the Colletotrichum species associated with cashew anthracnose in Brazil, determine their phylogenetic relationships and geographical distribution, and provide some insight into the factors that may be influencing community composition. Colletotrichum isolates collected from symptomatic leaves, stems, inflorescences, and fruit of cultivated and wild cashew, across four Brazilian biomes, were identified as Colletotrichum chrysophilum, Colletotrichum fragariae, Colletotrichum fructicola, Colletotrichum gloeosporioides sensu stricto, Colletotrichum queenslandicum, Colletotrichum siamense and Colletotrichum tropicale. Colletotrichum siamense was the most dominant species. The greatest species richness was associated with cultivated cashew; leaves harbored more species than the other organs; the Atlantic Forest encompassed more species than the other biomes; and Pernambuco was the most species-rich location. However, accounting for the relative abundance of Colletotrichum species and differences in sample size across strata, the interpretation of which community is most diverse depends on how species are delimited. The present study provides valuable information about the Colletotrichum/cashew pathosystem, sheds light on the causal agents identification,and highlights the impact that species delimitation can have on ecological studies of fungi.

The impact of phenotypic and molecular data on the inference of Colletotrichum diversity associated with Musa.

Developing a comprehensive and reliable taxonomy for the Colletotrichum gloeosporioides species complex will require adopting data standards on the basis of an understanding of how methodological choices impact morphological evaluations and phylogenetic inference. We explored the impact of methodological choices in a morphological and molecular evaluation of Colletotrichum species associated with banana in Brazil. The choice of alignment filtering algorithm has a significant impact on topological inference and the retention of phylogenetically informative sites. Similarly, the choice of phylogenetic marker affects the delimitation of species boundaries, particularly if low phylogenetic signal is confounded with strong discordance, and inference of the species tree from multiple-gene trees. According to both phylogenetic informativeness profiling and Bayesian concordance analyses, the most informative loci are DNA lyase (APN2), intergenic spacer (IGS) between DNA lyase and the mating-type locus MAT1-2-1 (APN2/MAT-IGS), calmodulin (CAL), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glutamine synthetase (GS), ß-tubulin (TUB2), and a new marker, the intergenic spacer between GAPDH and an hypothetical protein (GAP2-IGS). Cornmeal agar minimizes the variance in conidial dimensions compared with potato dextrose agar and synthetic nutrient-poor agar, such that species are more readily distinguishable based on phenotypic differences. We apply these insights to investigate the diversity of Colletotrichum species associated with banana anthracnose in Brazil and report C. musae, C. tropicale, C. theobromicola, and C. siamense in association with banana anthracnose. One lineage did not cluster with any previously described species and is described here as C. chrysophilum.

Analysis of phylogeny, distribution, and pathogenicity of Botryosphaeriaceae species associated with gummosis of Anacardium in Brazil, with a new species of Lasiodiplodia.

Netto, M. S. B., Lima, W. G., Correia, K. C., da Silva, C. F. B., Thon, M., Martins, R. B., Miller, R. N. G., Michereff, S. J., and Câmara, M. P. S. 2016. Analysis of phylogeny, distribution, and pathogenicity of Botryosphaeriaceae species associated with gummosis of Anacardium in Brazil, with a new species of Lasiodiplodia. We identified Botryosphaeriaceae species associated with gummosis on Anacardium in Brazil. Isolates were sampled and identified on the basis morphology and phylogeny, through analysis of a partial translation elongation factor 1-α sequence, ribosomal DNA internal transcribed spacers, and ß-tubulin gene sequence. Ten taxa were identified, namely, Lasiodiplodia brasiliense, L. euphorbicola, L. gonubiensis, L. iraniensis, L. jatrophicola, L. gravistriata sp. nov., L. pseudotheobromae, L. theobromae, Neofusicoccum batangarum, and Pseudofusicoccum stromaticum. Lasiodiplodia theobromae has been previously reported in cashew and is the most prevalent species observed. All the other species are reported here for the first time on this host. All species of Botryosphaeriaceae were pathogenic on detached green cashew shoots. Differences in aggressiveness were observed among the species, with N. batangarum, L. iraniensis, L. jatrophicola, and L. gravistriata characterized as the most aggressive species, whilst L. euphorbicola and L. pseudotheobromae were identified as the least aggressive.

Phylogeny of Stemphylium spp. based on ITS and glyceraldehyde-3-phosphate dehydrogenase gene sequences.

The phylogenetic relationships among 44 isolates representing 16 species of Stemphylium were inferred from ITS and glyceraldehyde-3-phosphate dehydrogenase (gpd) sequence data. The results generally agree with morphological species concepts. There was strong support for monophyly of the genus Stemphylium. Analysis of the gpd fragment in particular was useful for establishing well-supported relationships among the species and isolates of Stemphylium. Species of Stemphylium that appear to have lost the ability to produce a sexual state are scattered among the species with the ability to reproduce sexually (Pleospora spp.). Species that are pathogenic to alfalfa are resolved into two groups. Stemphylium botryosum and two isolates with morphological characters similar to S. globuliferum had identical sequences at both loci. These two loci in S. vesicarium, S. alfalfae and S. herbarum are nearly identical but differ from S. botryosum. The separation of S. vesicarium, S. herbarum and S. alfalfae into separate species by morphometric evidence was not supported by the molecular data. Morphological and developmental characters such as size and shape of conidia, conidiophores, and ascospores, and size and time of maturation of pseudothecia are useful for diagnosing species. However, other morphological characters such as septum development and small variations in conidial wall ornamentation are not as useful.

Molecular phylogeny of Leptosphaeria and Phaeosphaeria.

The objectives of this study were to determine the phylogenetic relationships of species of Leptosphaeria and Phaeosphaeria and evaluate the phylogenetic significance of morphological characters of the teleomorph, anamorph, and host. Sequences of the entire ITS region, including the 5.8S rDNA, of 59 isolates representing 54 species were analyzed and the phylogeny inferred using parsimony and distance analyses. Isolates grouped into three well-supported clades. The results of this study support the separation of Phaeosphaeria from Leptosphaeria sensu stricto. Leptosphaeria bicolor and the morphologically similar Leptosphaeria taiwanensis formed a separate, well-supported clade. We conclude that peridial wall morphology, anamorph characteristics, and to a lesser extent host, are phylogenetically significant at the generic level. Ascospore and conidial morphology are taxonomically useful at the species level.

Neophaeosphaeria and Phaeosphaeriopsis, segregates of Paraphaeosphaeria.

Two new genera, Neophaeosphaeria and Phaeosphaeriopsis, are described to accommodate species of Paraphaeosphaeria that are not congeneric based on morphological characters and results of 18S rDNA sequence analyses. Paraphaeosphaeria s. str. is restricted to species with two-septate ascospores and anamorphs that produce non-septate, smooth, pale brown conidia enteroblastically from phialides which have some periclinal thickening. Species in Neophaeosphaeria have 3-4-septate ascospores and anamorphs that produce ovoid to ellipsoid, non-septate, brown, verrucose or punctate conidia from percurrently proliferating conidiogenous cells. Paraphaeosphaeria barrii, P. conglomerata, P. filamentosa and P. quadriseptata are transferred to Neophaeosphaeria. At present all species in Neophaeosphaeria occur on Yucca (Agavaceae). Phaeosphaeriopsis is described for species that produce 4-5-septate ascospores. Known anamorphs produce cylindrical, 0-3-septate, brown, punctate conidia from percurrently proliferating conidiogenous cells or bacillar conidia from simple phialides. P. agavensis, P. glauco-punctata, P. nolinae and P. obtusispora are transferred to Phaeosphaeriopsis. P. amblyspora is described as a new species.