Causal agents of Stemphylium-induced foliar diseases of tomatoes and other Solanaceae hosts in Brazil.

AIM: An extensive survey was done to clarify the prevalent Stemphylium species on Solanaceae plants across Brazil, and their host ranges. METHODS AND RESULTS: Eighty nine (89) Stemphylium isolates were obtained from naturally infected tomatoes as well as S. paniculatum, potato, eggplant, scarlet eggplant (Solanum aethiopicum var. gilo), Physalis angulata, and Capsicum species. Phylogenetic analyses encompassing the ITS-5.8S rDNA and glyceraldehyde-3-phosphate dehydrogenase genomic regions placed the isolates into two distinct groupings with either Stemphylium lycopersici or S. solani. Isolates of S. lycopersici (n = 81) were obtained infecting tomato, potato, eggplant, S. paniculatum, and P. angulata. Isolates of S. solani (n = 8) were detected in natural association with scarlet eggplant and tomato. Two isolates of S. lycopersici displayed a wide experimental host range in greenhouse bioassays, infecting accessions of 12 out of 18 species. Ocimum basilicum (Lamiaceae) was the only experimental host outside the Solanaceae family.

Diversity of Colletotrichum species associated with torch ginger anthracnose.

Anthracnose caused by Colletotrichum species is one of the most important diseases of torch ginger. The disease leads to loss of aesthetic and commercial value of torch ginger stems. This study aimed to characterize Colletotrichum species associated with torch ginger anthracnose in the production areas of Pernambuco and Ceará. A total of 48 Colletotrichum isolates were identified using molecular techniques. Pathogenicity tests were performed on torch ginger with representative isolates. Phylogenetic analyses based on seven loci-DNA lyase (APN2), intergenic spacer between DNA lyase and the mating-type locus MAT1-2-1 (APN2/MAT-IGS), calmodulin (CAL), intergenic spacer between glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and a hypothetical protein (GAP2-IGS), glutamine synthetase (GS), and ß-tubulin (TUB2)-revealed that they belong to five known Colletotrichum species, namely, C. chrysophilum, C. fructicola, C. siamense, C. theobromicola, and C. tropicale, and three newly discovered species, described here as C. atlanticum, C. floscerae, and C. zingibericola. Of these, C. atlanticum was the most dominant. Pathogenicity assays showed that all isolates were pathogenic to torch ginger bracts. All species are reported for the first time associated with torch ginger in Brazil. The present study contributes to the current understanding of the diversity of Colletotrichum species associated with anthracnose on torch ginger and demonstrates the importance of accurate species identification for effective disease management strategies.

Elucidating the Colletotrichum spp. diversity responsible for papaya anthracnose in Brazil.

Papaya (Carica papaya L.) is among the most important tropical fruits produced in Brazil and is grown in nearly every state. However, several diseases can affect papaya production. Anthracnose stands out among these diseases due to high postharvest yield losses. Previous studies identified Colletotrichum magna (invalid name) and Colletotrichum gloeosporioides causing anthracnose of papaya in Brazil, but species identification was inadequate due to reliance on nuclear ribosomal internal transcribed space (nrITS) and glutamine synthetase (GS) sequences. Thus, the diversity of Colletotrichum spp. causing papaya anthracnose in Brazil may be underestimated. The present study aims to identify the Colletotrichum species associated with papaya anthracnose in Brazil based on broad geographical sampling and multilocus phylogenetic analysis, as well as to assess the prevalence and aggressiveness of the species found. Here, we report C. chrysophilum, C. fructicola, C. gloeosporioides, C. karsti, C. okinawense, C. plurivorum, C. queenslandicum, C. siamense, C. theobromicola, Colletotrichum truncatum causing papaya anthracnose in Brazil. We are also synonymizing Colletotrichum corchorum-capsularis under C. truncatum. Colletotrichum okinawense was the most prevalent species in general and in most sampled locations, and with C. truncatum represents the most aggressive species.

Optimal markers for the identification of Colletotrichum species.

Colletotrichum is among the most important genera of fungal plant pathogens. Molecular phylogenetic studies over the last decade have resulted in a much better understanding of the evolutionary relationships and species boundaries within the genus. There are now approximately 200 species accepted, most of which are distributed among 13 species complexes. Given their prominence on agricultural crops around the world, rapid identification of a large collection of Colletotrichum isolates is routinely needed by plant pathologists, regulatory officials, and fungal biologists. However, there is no agreement on the best molecular markers to discriminate species in each species complex. Here we calculate the barcode gap distance and intra/inter-specific distance overlap to evaluate each of the most commonly applied molecular markers for their utility as a barcode for species identification. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), histone-3 (HIS3), DNA lyase (APN2), intergenic spacer between DNA lyase and the mating-type locus MAT1-2-1 (APN2/MAT-IGS), and intergenic spacer between GAPDH and a hypothetical protein (GAP2-IGS) have the properties of good barcodes, whereas sequences of actin (ACT), chitin synthase (CHS-1) and nuclear rDNA internal transcribed spacers (nrITS) are not able to distinguish most species. Finally, we assessed the utility of these markers for phylogenetic studies using phylogenetic informativeness profiling, the genealogical sorting index (GSI), and Bayesian concordance analyses (BCA). Although GAPDH, HIS3 and ß-tubulin (TUB2) were frequently among the best markers, there was not a single set of markers that were best for all species complexes. Eliminating markers with low phylogenetic signal tends to decrease uncertainty in the topology, regardless of species complex, and leads to a larger proportion of markers that support each lineage in the Bayesian concordance analyses. Finally, we reconstruct the phylogeny of each species complex using a minimal set of phylogenetic markers with the strongest phylogenetic signal and find the majority of species are strongly supported as monophyletic.

Análise microbiológica de banana "prata anã" produzida no norte de Minas Gerais / Microbiological analysis of the "prata anã"banana productive in the north of Minas Gerais

Este trabalho teve como objetivo avaliar a qualidade microbiológica dos frutos e da água utilizada na cadeia produtiva de banana na região Norte de Minas Gerais. Foram selecionadas quatro áreas comerciais de banana "Prata Anã", duas que usavam água do canal de irrigação e duas que usavam água de poço tubular. Durante quatro meses, mensalmente foram analisadas a casca e a polpa dos frutos das quatro áreas nas etapas de colheita e após a embalagem dos frutos. Nas amostras coletadas realizou-se a análise de Coliformes Totais (CT), Coliformes Termotolerantes (CTe) e de Salmonella. No mesmo período coletou-se amostras da água proveniente do canal de irrigação e do poço tubular, da água da irrigação e do tanque antes e depois da lavagem dos frutos. Nestas amostras foram realizadas as análises de CT, CTe, de Salmonella e análise qualitativa de Escherichia Coli. Os valores de Coliformes Totais e Coliformes Termotolerantes na casca e na polpa de banana apresentaram-se dentro dos limites permitidos. Foi encontrado colônia de Salmonella na casca de banana durante a colheita e após a embalagem. A água do canal de irrigação apresentou níveis inadequados de CT e CTe. Nas áreas que utilizam a água do canal de irrigação, para lavagem dos frutos, a água do tanque antes e depois da lavagem dos frutos apresentaram colônias de Salmonella. Nas áreas em que utilizam a água do poço tubular para lavagem dos frutos, foi detectada a presença de CT e CTe no tanque de lavagem, mesmo antes da lavagem dos frutos.

The purpose of this study was to evaluate the microbiologic quality of the fruit as well as the water used to cultivate this specie in the north of Minas Gerais. Hence, four productive areas of "Prata Anã" bananas were selected, two using water from the irrigation channel and two using water from a well.The pulp and the peel of the fruit of the four areas were analyzed monthly during the picking season and after packing the fruit. From the samples obtained, analyzes of Total Coliformes (TC), Thermotolerante Coliformes (ThC), and Salmonella were done. During the same period, samples of water from the irrigation channel and from the well, water from the irrigation and from the tank, before and after washing the fruit, were collected. Tests for TC, ThC and Salmonella were done as well as quality tests for Escherichia Coli .TC and ThC values in the peel and pulp of the fruit are within the permitted limits. A colony of Salmonella was found in the peel of the fruit during the picking and after the packing. The water from the channel presented inadequate levels of TC and ThC. In the areas where the water from the irrigation channel was used, the water from the tank, before and after the washing of the fruit, colonies of Salmonella were found. In the areas where water from the well was used, the presence TC and ThC were detected in the tank where the fruit was washed, even before the washing of the fruit.