Navegando por Autor "Maffia, Luiz Antonio"
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Item Erasing the past: A new identity for the damoclean pathogen causing south american leaf blight of rubber(Plos One, 2014-08-15) Hora Júnior, Braz Tavares da; Macedo, Davi Mesquita de; Barreto, Robert Weingart; Evans, Harry C.; Mattos, Carlos Raimundo Reis; Maffia, Luiz Antonio; Mizubuti, Eduardo S. G.South American leaf blight (SALB) of rubber has been the main constraint to production in its neotropical centre of origin since commercial plantations were first established. The fungal causal agent was identified and described more than a century ago but its precise placement within the Ascomycota still remains uncertain. Indeed, such is the ambiguity surrounding the pathogen that each of the spore morphs would, according to their present classification, be placed in different ascomycete families: the Microcyclus sexual morph in the Planistromellaceae and the two purported asexual morphs - Fusicladium and Aposphaeria – in the Venturiaceae and Lophiostomataceae, respectively. Given the historical importance of the fungus and the ever-menacing threat that it poses to rubber production in the Palaeotropics – and, thus to the rubber industry and to the global economy – its phylogeny, as well as its biology, should be resolved as a matter of urgency. Here, six genomic regions (LSU rRNA, mtSSU, MCM7, EF-1α, Act and ITS) were used for reconstructing the molecular phylogeny of the SALB fungus based on material collected throughout Brazil. The analyses support the classification of the fungus in the family Mycosphaerellaceae s. str. (Capnodiales, Dothideomycetes) and place it firmly within the clade Pseudocercospora s. str., now accepted as one of the distinct genera within Mycosphaerellaceae. The new combination Pseudocercospora ulei is proposed and the life cycle of the fungus is confirmed, based on both experimental and phylogenetic evidence, with the Aposphaeria morph shown to have a spermatial rather than an infective-dispersal function. Because the phylogeny of the SALB fungus has now been clarified, new insights of its epidemiology and genomics can be gained following comparison with closely-related, better-researched crop pathogens.Item Key factors to inoculate Botrytis cinerea in tomato plants(Summa Phytopathologica, 2014-07-28) Borges, Álefe Vitorino; Saraiva, Rodrigo Moreira; Maffia, Luiz AntonioStudies addressing the biological control of Botrytis cinerea have been unsuccessful because of fails in inoculating tomato plants with the pathogen. With the aim of establishing a methodology for inoculation into stems, experiments were designed to assess: i. the aggressiveness of pathogen isolates; ii. the age at which tomato plants should be inoculated; iii. the susceptibility of tissues at different stem heights; iv. the need for a moist chamber after inoculation; and v. the effectiveness of gelatin regarding inoculum adhesion. Infection with an isolate from tomato plants that was previously inoculated into petioles and then re-isolated was successful. An isolate from strawberry plants was also aggressive, although less than that from tomato plants. Tomato plants close to flowering, at 65 days after sowing, and younger, middle and apical stem portions were more susceptible. There was positive correlation between lesion length and sporulation and between lesion length and broken stems. Lesion length and the percentage of sporulation sites were reduced by using a moist chamber and were not affected by adding gelatin to the inoculum suspension. This methodology has been adopted in studies of B. cinerea in tomato plants showing reproducible results. The obtained results may assist researchers who study the gray mold.Item Methods for Cercospora coffeicola protoplast isolation and genetic transformation with the green fluorescent protein(European Journal of Plant Pathology, 2014-06) Souza, André Gomes Coelho; Herrero, Sonia; Maffia, Luiz Antonio; Daub, Margaret ElizabethCercospora coffeicola is the causal agent of brown eye spot on coffee leaves. Although the disease has significant importance, few molecular studies have been done with C. coffeicola. Here we report a protocol for isolating protoplasts as well as development of a genetic transformation system using Green Fluorescent Protein. High yields of protoplasts (≈108/ml) were obtained from mycelial cultures from five isolates of C. coffeicola. One isolate was transformed with a vector encoding hygromycin resistance and Green Fluorescent Protein. Out of 43 hygromycin-resistant transformants obtained, Green Fluorescent Protein was highly expressed in one (2.3 %).Item Uso e perspectiva de Clonostachys rosea como agente de biocontrole(Revista de Ciências Agrícolas, 2014-06-10) Saraiva, Rodrigo Moreira; França de M., Paulo Eduardo; Borges, Álefe Vitorino; Maffia, Luiz AntonioO uso de métodos de controle de doenças de plantas mais sustentáveis é uma necessidade na agricultura atual. Nessa perspectiva, o controle biológico de doenças de plantas surge como uma alternativa eficaz e viável no contexto de manejo integrado. Dentre os vários agentes de biocontrole estudados, ênfase vem sendo dada ao fungo Clonostach y s rosea por seu potencial de uso na agricultura. O fungo pode ser encontrado em diferentes regiões, colonizando todas as partes de diferentes espécies vegetais e, ainda, possui a capacidade de permanecer endofiticamente em algumas plantas. No que diz respeito ao controle biológico, C. rosea é comprovadamente eficiente no controle de diversos patógenos em uma ampla gama de hospedeiro. Além disso, há relatos do antagonista como promotor de crescimento e indutor de resistência em algumas espécies vegetais, e como fungo entomopatogênico. Pela eficiência e versatilidade do antagonista C. rosea, buscamos nessa revisão fornecer uma visão global sobre as perspectivas de uso do antagonista no contexto do controle biológico.