Fitopatologia - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741
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Item Mycobiota of the weed Tradescantia fluminensis in its native range in Brazil with particular reference to classical biological control(Australasian Plant Pathology, 2016-02) Macedo, D. M.; Pereira, O. L.; Hora Júnior, B. T.; Weir, B. S.; Barreto, R. W.Tradescantia fluminensis [Commelinaceae] (common name wandering Jew or trad), is a native Brazilian herbaceous plant, which has been introduced to be used as an ornamental in many warm areas of the world. In New Zealand and other countries it has become an aggressive invader of natural ecosystems, causing serious environmental disturbances and threatening biodiversity. Surveys of pathogen and insect natural enemies of T. fluminensis were conducted over several years in Brazil to identify potential candidates for use as classical biological control agents in New Zealand. The surveys found seven pathogenic fungi associated with T. fluminensis and related Tradescantia species: Cercospora apii (leaf spot), Rhizoctonia solani (leaf blight), Sclerotium rolfsii (crown rot) and Uromyces commelinae (rust), and three novel species described in this paper: Ceratobasidium tradescantiae sp. nov. (web blight), Colletotrichum riograndense sp. nov. (anthracnose) and Kordyana brasiliensis sp. nov. (white smut-like disease). Observations of damage in the field and expected host-range suggest that K. brasiliensis and U. commelinae have the highest potential for use as classical biological control agents.Item Colletotrichum dracaenophilum causes anthracnose on Dracaena braunii in Brazil(Australasian Plant Disease Notes, 2016-12) Macedo, D. M.; Barreto, R. W.Dracaena braunii (lucky bamboo) is a plant of West Africa widely used as an ornamental. Recently individuals bearing anthracnose symptoms were found in Viçosa (state of Minas Gerais, Brazil). Morphology was typical of Colletotrichum dracaenophilum and sequence analyses indicated a high homology to the internal transcribed spacer region and Beta tubulin with the ex-type sequences of this species. This is the first record in Brazil.Item Multilocus phylogeny of Clonostachys subgenus Bionectria from Brazil and description of Clonostachys chloroleuca sp. nov.(Mycological Progress, 2016-10) Abreu, Lucas M.; Moreira, Gláucia M.; Carvalho, Vívian G.; Schroers, Hans-Josef; Pfenning, Ludwig H.Phylogenetic analyses based on protein-encoding gene exons and introns of ATP citrate lyase (ACL1), beta tubulin (TUB), the largest subunit of RNA polymerase II (RPB1), and translation elongation factor 1-α (TEF1) are used for inferring the existence of a new Clonostachys species from the Cerrado biome in Brazil, described here as C. chloroleuca. The species produces dimorphic, primary, and secondary conidiophores that form consistently greenish conidial masses on artificial media. It resembles therefore C. rosea f. catenulata although it differs from this species by less adpressed branches in the secondary conidiophores. The new species is also phylogenetically related to C. byssicola and C. rhizophaga. Our inventory suggests that C. byssicola, C. chloroleuca, C. pseudochroleuca, C. rhizophaga, C. rogersoniana, and C. rosea commonly occur in native and agriculturally used soils of the Cerrado and Amazon Forest. Using sequences available from two genome-sequenced strains employed as biological control agents, we confirm the identity of the European strain IK726 as C. rosea and identify strain 67-1 from China as C. chloroleuca.Item The faces of fungi database: fungal names linked with morphology, phylogeny and human impacts(Fungal Diversity, 2015-11-03) Pereira, Olinto L.; Jayasiri, Subashini C.; Hyde, Kevin D.; Ariyawansa, Hiran A.; Bhat, Jayarama; Buyck, Bart; Cai, Lei; Dai, Yu-Cheng; Abd-Elsalam, Kamel A.; Ertz, Damien; Hidayat, Iman; Jeewon, Rajesh; Jones, E. B. Gareth; Bahkali, Ali H.; Karunarathna, Samantha C.; Liu, Jian-Kui; Luangsa-ard, J. Jennifer; et al.Taxonomic names are key links between various databases that store information on different organisms. Several global fungal nomenclural and taxonomic databases (notably Index Fungorum, Species Fungorum and MycoBank) can be sourced to find taxonomic details about fungi, while DNA sequence data can be sourced from NCBI, EBI and UNITE databases. Although the sequence data may be linked to a name, the quality of the metadata is variable and generally there is no corresponding link to images, descriptions or herbarium material. There is generally no way to establish the accuracy of the names in these genomic databases, other than whether the submission is from a reputable source. To tackle this problem, a new database (FacesofFungi), accessible at www.facesoffungi.org (FoF) has been established. This fungal database allows deposition of taxonomic data, phenotypic details and other useful data, which will enhance our current taxonomic understanding and ultimately enable mycologists to gain better and updated insights into the current fungal classification system. In addition, the database will also allow access to comprehensive metadata including descriptions of voucher and type specimens. This database is user-friendly, providing links and easy access between taxonomic ranks, with the classification system based primarily on molecular data (from the literature and via updated web-based phylogenetic trees), and to a lesser extent on morphological data when molecular data are unavailable. In FoF species are not only linked to the closest phylogenetic representatives, but also relevant data is provided, wherever available, on various applied aspects, such as ecological, industrial, quarantine and chemical uses. The data include the three main fungal groups (Ascomycota, Basidiomycota, Basal fungi) and fungus-like organisms. The FoF webpage is an output funded by the Mushroom Research Foundation which is an NGO with seven directors with mycological expertise. The webpage has 76 curators, and with the help of these specialists, FoF will provide an updated natural classification of the fungi, with illustrated accounts of species linked to molecular data. The present paper introduces the FoF database to the scientific community and briefly reviews some of the problems associated with classification and identification of the main fungal groups. The structure and use of the database is then explained. We would like to invite all mycologists to contribute to these web pages.Item Improving ITS sequence data for identification of plant pathogenic fungi(Fungal Diversity, 2014-05-15) Pereira, Olinto Liparini; Pinho, Danilo Batista; Nilsson, R. Henrik; Hyde, Kevin D.; Pawłowska, Julia; Ryberg, Martin; Tedersoo, Leho; Aas, Anders Bjørnsgard; Alias, Siti A.; Alves, Artur; Anderson, Cajsa Lisa; Antonelli, Alexandre; Arnold, A. Elizabeth; Bahnmann, Barbara; Bahram, Mohammad; Bengtsson-Palme, Johan; Berlin, Anna; et al.Plant pathogenic fungi are a large and diverse assemblage of eukaryotes with substantial impacts on natural ecosystems and human endeavours. These taxa often have complex and poorly understood life cycles, lack observable, discriminatory morphological characters, and may not be amenable to in vitro culturing. As a result, species identification is frequently difficult. Molecular (DNA sequence) data have emerged as crucial information for the taxonomic identification of plant pathogenic fungi, with the nuclear ribosomal internal transcribed spacer (ITS) region being the most popular marker. However, international nucleotide sequence databases are accumulating numerous sequences of compromised or low-resolution taxonomic annotations and substandard technical quality, making their use in the molecular identification of plant pathogenic fungi problematic. Here we report on a concerted effort to identify high-quality reference sequences for various plant pathogenic fungi and to re-annotate incorrectly or insufficiently annotated public ITS sequences from these fungal lineages. A third objective was to enrich the sequences with geographical and ecological metadata. The results – a total of 31,954 changes – are incorporated in and made available through the UNITE database for molecular identification of fungi (http://unite.ut.ee), including standalone FASTA files of sequence data for local BLAST searches, use in the next-generation sequencing analysis platforms QIIME and mothur, and related applications. The present initiative is just a beginning to cover the wide spectrum of plant pathogenic fungi, and we invite all researchers with pertinent expertise to join the annotation effort.Item Phylogeny, identification and pathogenicity of the Botryosphaeriaceae associated with collar and root rot of the biofuel plant Jatropha curcas in Brazil, with a description of new species of Lasiodiplodia(Fungal Diversity, 2014-07) Machado, Alexandre Reis; Pinho, Danilo Batista; Pereira, Olinto LipariniThe global expansion of cultivation areas of Jatropha has contributed to the emergence of various diseases. Currently in Brazil, the occurrence of a new disease has been reported that not only reduces the productivity but also causes the death of Jatropha. This disease is associated with collar and root rot of plants. From morphological and phylogenetic studies (based on Internal Transcribed Spacers, β-tubulin and Translation Elongation Factor 1-α sequences), nine species of Botryosphaeriaceae were identified. These species include Lasiodiplodia egyptiacae, L. pseudotheobromae, L. theobromae, Macrophomina phaseolina, Neoscytalidium hyalinum and four Lasiodiplodia spp. that are proposed as new species (L. euphorbicola, L. jatrophicola, L.macrospora and L. subglobosa). All the species in this study, except M. phaseolina, are pathogenic. The results show that root rot of physic nut plants is caused by complex pathogens. This study provides new information for future studies of disease management, quarantine programs and, especially, the development of resistant varieties for collar and root rot disease in J. curcas.Item Revision of Begomovirus taxonomy based on pairwise sequence comparisons(Archives of Virology, 2015-04-18) Zerbini, F. Murilo; Brown, Judith K.; Navas-Castillo, Jesús; Moriones, Enrique; Ramos-Sobrinho, Roberto; Silva, José C. F.; Fiallo-Olivé, Elvira; Briddon, Rob W.; Hernández-Zepeda, Cecilia; Idris, Ali; Malathi, V. G.; Martin, Darren P.; Rivera-Bustamante, Rafael; Ueda, Shigenori; Varsani, ArvindViruses of the genus Begomovirus (family Geminiviridae) are emergent pathogens of crops throughout the tropical and subtropical regions of the world. By virtue of having a small DNA genome that is easily cloned, and due to the recent innovations in cloning and low-cost sequencing, there has been a dramatic increase in the number of available begomovirus genome sequences. Even so, most of the available sequences have been obtained from cultivated plants and are likely a small and phylogenetically unrepresentative sample of begomovirus diversity, a factor constraining taxonomic decisions such as the establishment of operationally useful species demarcation criteria. In addition, problems in assigning new viruses to established species have highlighted shortcomings in the previously recommended mechanism of species demarcation. Based on the analysis of 3,123 full-length begomovirus genome (or DNA-A component) sequences available in public databases as of December 2012, a set of revised guidelines for the classification and nomenclature of begomoviruses are proposed. The guidelines primarily consider a) genus-level biological characteristics and b) results obtained using a standardized classification tool, Sequence Demarcation Tool, which performs pairwise sequence alignments and identity calculations. These guidelines are consistent with the recently published recommendations for the genera Mastrevirus and Curtovirus of the family Geminiviridae. Genome-wide pairwise identities of 91 % and 94 % are proposed as the demarcation threshold for begomoviruses belonging to different species and strains, respectively. Procedures and guidelines are outlined for resolving conflicts that may arise when assigning species and strains to categories wherever the pairwise identity falls on or very near the demarcation threshold value.Item A new species of the lenticel fungal genus Claviradulomyces (Ostropales) from the Brazilian Atlantic forest tree Xylopia sericea (Annonaceae)(IMA Fungus, 2012-11-15) Barreto, Robert W.; Johnston, Peter R.; Crous, Pedro W.; Evans, Harry C.Claviradulomyces xylopiae sp. nov. is introduced for a fungus occurring in association with abnormal (enlarged, spongy) lenticels of Xylopia sericea (Annonaceae), a common tree of the Atlantic forest and Cerrado ecosystems in Brazil. This is the second species described in the genus and, although it is morphologically distinct from the type species, C. dabeicola from West Africa, it possesses the same characteristics. Apothecial ascomata have periphysoids and paraphyses that are inflated apically (clavate), and ornamented with denticles (raduliform). Furthermore, similar to the type species, it also has long-cylindric or acerose, aseptate ascospores and conidia. An additional asexual morph was produced in culture and is described. Molecular studies of C. dabeicola and the new species confirmed a placement in Ostropales, although a relationship to Odontotremataceae was not supported. Both species were consistently in association with abnormal lenticular development on their woody hosts. It remains to be ascertained, however, if these are the causal agents of the bark disorders, or, simply, opportunistic colonisers. The finding of the second species in the genus Claviradulomyces on a plant from a distantly related family to that of the host of C. dabeicola (Erythroxylaceae) for the genus on a different continent suggests that fungi in this genus may be common on lenticels of other woody plants, and could even have a pantropical distribution. It is possible that fungi in the genus have remained unreported until now because lenticels have remained neglected as a habitat surveyed by mycologists.Item A new species of Calonectria causing leaf blight and cutting rot of three forest tree species in Brazil(Tropical Plant Pathology, 2013-08-13) Alfenas, Rafael F.; Pereira, Olinto L.; Jorge, Vanessa L.; Crous, Pedro W.; Alfenas, Acelino C.Several species of Calonectria cause diseases on a wide range of forest tree species that are propagated either via seedlings or rooted cuttings. In nurseries these fungi cause damping-off, cutting and root rots, stem lesions, and leaf blights. Recently a Calonectria sp. was isolated from rooted cuttings of Anadenanthera peregrina (Fabaceae), Piptadenia gonoacantha (Fabaceae), and Azadirachta indica (Meliaceae) exhibiting leaf blight and cutting rot in a forest nursery at the Universidade Federal de Viçosa, Brazil. Morphological comparisons and DNA sequences of three loci containing partial gene sequences of β-tubulin (TUB2), calmodulin (CAL), and elongation factor (TEF-1α) indicated that these isolates represent an unnamed species of Calonectria, described here as C. hodgesii sp. nov. Sprayinoculated plants of all three hosts with a suspension at 1x104 conidia mL-1 induced leaf lesions, cutting rot, and intense defoliation as observed under natural conditions. Calonectria hodgesii was re-isolated from infected tissue, which fulfilled Koch's postulates and confirmed its status as a pathogen with a wide host range.Item Diversity and potential impact of Calonectria species in Eucalyptus plantations in Brazil(Studies in Mycology, 2015-01-23) Alfenas, R.F.; Lombard, L.; Pereira, O.L.; Alfenas, A.C.; Crous, P.W.Species in the genus Calonectria (Hypocreales) represent an important group of plant pathogenic fungi that cause serious losses to plant crops in tropical and subtropical climates. Calonectria leaf blight is currently one of the main impediments to Eucalyptus cultivation in Brazil, and various species of Calonectria have been associated with this disease. Since most previous identifications were solely based on morphological characters, much of the published literature needs to be re-evaluated. The aim of this study was thus to identify and determine the phylogenetic relationships among species that occur in the Eucalyptus growing regions of Brazil by using partial sequences of the β-tubulin, calmodulin, translation elongation factor 1-α and histone H3 gene regions. Based on extensive collections from soil and infected eucalypt leaf samples from plantations, phylogenetic inference revealed the Ca. pteridis complex to be the most common species complex present in Eucalyptus plantations in Brazil. By elucidating taxa in the Ca. pteridis, Ca. cylindrospora and Ca. candelabra species complexes, 20 novel Calonectria species were identified, and a new name in Calonectria provided for Cylindrocladium macrosporum as Ca. pseudopteridis.