Antagonistic effect of Trichoderma isolates and its metabolites against Fusarium solani and F. oxysporum in chickpea / Efeito antagonista de isolados de Trichoderma e seus metabólitos contra Fusarium solani e F. oxysporum em grão-de-bico

The aim of this work was to study and select Trichoderma sp. strains with biocontrol potential against Fusarium solani and F. oxysporum, the causal agents of root rot and wilt in chickpea. Antagonism against pathogenic isolates of F. solani and F. oxysporum of twenty-one isolates of Trichoderma sp. obtained from the rhizosphere of chickpea plants were evaluated in vitro through competition in dual culture tests as well as the production of volatile and non-volatile organic compounds exhibiting fungicidal and/or fungistatic activity. In the in vivo experiment, four isolates of Trichoderma sp. were selected and their antagonism was evaluated separately and combined with a commercial product based on T. asperellum under greenhouse conditions. Trichoderma sp. isolates were efficient competitors and produced metabolites capable of inhibiting mycelial growth of both species of Fusarium. Our results show the great versatility of the mechanisms of action from Trichoderma isolates, mainly associated with the production of volatile organic compounds. Despite the antagonistic effect of Trichoderma isolates observed in vitro, these isolates did not control Fusarium neither promote chickpea growth in in vivo conditions.

Patogenicidade de Fusarium spp. a grão-de-bico e controle biológico com Trichoderma sp.

Exportado OPUSMade available in DSpace on 2019-08-13T22:39:22Z (GMT). No. of bitstreams: 1 daiana.pdf: 1785052 bytes, checksum: c6cb1347fbcc59ad8af204e8b8edb378 (MD5) Previous issue date: 24O grão-de-bico (Cicer arietinum L.) é uma leguminosa de grande importância mundial devido ao seu alto teor de proteína, ferro, vitaminas e fibra. A produção dessa leguminosa é limitada pela ocorrência de doenças causadas por Fusarium, o que tem dificultado a implantação da cultura em Montes Claros-MG e demais regiões brasileiras. Fungos do gênero Trichoderma são amplamente conhecidos por atuarem como antagonistas a diversos patógenos. Objetivou-se, com esse estudo, obter, identificar e avaliar a patogenicidade de Fusarium sp. associados a grão-de-bico e avaliar o potencial antagonista de isolados de Trichoderma no controle in vitro e in vivo a Fusarium spp. Isolados de Fusarium obtidos de plantas de grão-de-bico com aparentes sintomas de fusariose foram caracterizados por meio de parâmetros morfológicos e filogenéticos. Dentre as características micromorfológicas foram avaliadas: o tamanho, o formato e a septação de microconídios e macroconídios; a produção de conídios em falsas cabeças; a presença e a coloração de esporodóquios e tipo e tamanho de fiálides e clamidósporos. A análise filogenética foi realizada com base em comparação de sequências parciais do gene que codifica o Fator de elongação EF-1 com sequências do Complexo de espécies Fusarium oxysporum (FOSC) e do complexo de espécies Fusarium solani (FSSC) disponíveis no GenBank-NCBI. Foram conduzidos dois testes de patogenicidade em casa de vegetação. Isolados de Trichoderma foram obtidos da rizosfera de plantas de grão-de-bico e foram avaliados in vitro quanto ao antagonismo a isolados patogênicos de F. solani e F. oxysporum, por meio da competição em culturas pareadas e da produção de compostos orgânicos voláteis e não voláteis com atividade fungicida e/ou fungistática. Em casa de vegetação, quatro isolados de Trichoderma selecionados foram avaliados isoladamente e combinados em comparação ao produto comercial Quality®. Dos 14 isolados de Fusarium obtidos e caracterizados, 11 apresentaram marcadores morfológicos típicos de F. oxysporum e três de F. solani. De acordo com a análise filogenética, três isolados agruparam junto à linhagem 3+4 do FSSC, enquanto os outros 11 isolados agruparam no complexo FOSC, em clado distinto de F. oxysporum f. sp. ciceris. Todos os isolados foram patogênicos, causando sintomas de amarelecimento, murcha e podridão radicular. Os isolados FCA 27 e FCA 12 foram os mais agressivos, dentre os isolados de F. oxysporum e de F. solani avaliados, respectivamente. Os isolados de Trichoderma sp. foram eficientes competidores e produziram metabólitos voláteis capazes de inibir o crescimento micelial das duas espécies de Fusarium avaliadas. Já os metabólitos não voláteis produzidos pelos isolados de Trichoderma apresentaram baixa atividade inibitória a F. solani e F. oxysporum e variaram quanto à sua ação. Na avaliação em casa de vegetação, não foi obsevado o efeito dos tratamentos com isolados de Trichoderma sobre o controle de F. oxysporum e F. solani. Neste trabalho, demonstramos pela primeira vez, a posição filogenética de isolados de Fusarium associados ao grão-de-bico em área cultivada no Brasil.The chickpea (Cicer arietinum L.) is a leguminous of great importance worldwide due to its high content of protein, iron, vitamins and fiber. The production of this leguminous is limited by the occurrence of diseases caused by Fusarium, which has hindered the deployment of the culture in Montes Claros and other Brazilians regions. Fungi of the Trichoderma gender are widely known to act as antagonists to various pathogens. The objective of this study was to obtain, identify and evaluate the pathogenicity of Fusarium sp. associated with chickpea and evaluate the potential antagonist Trichoderma isolates in vitro and in vivo control to the Fusarium spp. Fusarium isolates obtained from chickpea plants with apparent fusarium symptoms caused by Fusarium were characterized by morphological and phylogenetic parameters. Among the micromorphological characteristics were evaluated the size, shape and septation of microconidia and macroconidia; conidia production in false heads; presence and coloring sporodochia and type and size of phialides and chlamydospores. The phylogenetic analysis was performed based on comparison of partial sequences of the gene encoding elongation factor EF-1 species with sequences of the Fusarium oxysporum (FOSC) species complex and Fusarium solani species complex (FSSC) available in GenBank-NCBI. Two pathogenicity tests were conducted in a greenhouse. Trichoderma isolates were obtained from the rhizosphere of chickpea plants and were evaluated in vitro as to antagonism to pathogenic isolates of F. solani and F. oxysporum through competition in paired cultures and the production of volatile organic compounds and non-volatile with fungicidal and/or fungistatic activity. In greenhouse four selected Trichoderma isolates were evaluated separately and combined as compared to the commercial product Quality®. Of the 14 isolates of Fusarium obtained and characterized, 11 showed typical morphological markers of F. oxysporum and three of F. solani. According to the phylogenetic analysis, three isolates clustered along the line 3 + 4 of FSSC, while the other 11 isolates clustered in FOSC complex, in a distinct clade of F. oxysporum f. sp. ciceris. All isolates were pathogenic, causing symptoms of yellowing, wilting and root rot. The isolated FCA 12 and FCA 27 were the most aggressive among the isolates of F. oxysporum and F. solani evaluated, respectively. The Trichoderma sp. isolates were efficient competitors and produced volatile metabolites capable of inhibiting the mycelial growth of the two species of Fusarium evaluated. Already the non-volatile metabolites produced by Trichoderma isolates showed low inhibitory activity to F. solani and F. oxysporum and varied as its action. In the evaluation in greenhouse was not observed the effect of treatment with Trichoderma isolated over control of F. oxysporum and F. solani. In this work we demonstrate for the first time phylogenetic position of Fusarium isolates associated with chickpea in cultivated area in Brazil

Data from: Zika virus in the Americas: early epidemiological and genetic findings

Brazil has experienced an unprecedented epidemic of Zika virus (ZIKV), with ~30,000 cases reported to date. ZIKV was first detected in Brazil in May 2015 and cases of microcephaly potentially associated with ZIKV infection were identified in November 2015. Using next generation sequencing we generated seven Brazilian ZIKV genomes, sampled from four self-limited cases, one blood donor, one fatal adult case, and one newborn with microcephaly and congenital malformations. Phylogenetic and molecular clock analyses show a single introduction of ZIKV into the Americas, estimated to have occurred between May-Dec 2013, more than 12 months prior to the detection of ZIKV in Brazil. The estimated date of origin coincides with an increase in air passengers to Brazil from ZIKV endemic areas, and with reported outbreaks in Pacific Islands. ZIKV genomes from Brazil are phylogenetically interspersed with those from other South American and Caribbean countries. Mapping mutations onto existing structural models revealed the context of viral amino acid changes present in the outbreak lineage; however no shared amino acid changes were found among the three currently available virus genomes from microcephaly cases. Municipality-level incidence data indicate that reports of suspected microcephaly in Brazil best correlate with ZIKV incidence around week 17 of pregnancy, although this does not demonstrate causation. Our genetic description and analysis of ZIKV isolates in Brazil provide a baseline for future studies of the evolution and molecular epidemiology in the Americas of this emerging virus

Epidemiological Data: Numbers of suspected ZIKV cases and suspected microcephaly cases per state and per epidemiological week.

Contains 1) CSV file with number suspected ZIKV cases from January 2015 to the end of December 2015; 2) CSV file with number of suspected microcephaly cases from January 2015 to the first week of January 2016. Numbers correspond to suspected microcephaly cases at week 20 of pregnancy; 3) CSV file with codes of state of residence and municipality of residence in Brazil; and 4) R scripts for correlation analysis described in SI Section 1.5

Sequence data details and alignments for dataset A and B.

Contains (1) table with accession numbers, isolate names, cell passage history, publication details, country/location of sampling, sampling dates and (2) Fasta format sequence alignments of datasets A and B

BEAST XML input file used for genetic analysis.

BEAST XML input file used to generate Figure 3 under a strict clock model, a Bayesian skyline coalescent prior and a CTMC prior on the clock rate

Núcleos de Ensino da Unesp: artigos 2007

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq