Potential for transmission of Stenocarpella macrospora from inoculated seeds to maize plants grown under controlled conditions

Siqueira, Carolina da Silva; Machado, José da Cruz; Barrocas, Ellen Noly; Almeida, Mirella Figueiró de

doi:10.1590/2317-1545v32n2904

Cited by 8 publications

(11 citation statements)

References 14 publications

(5 reference statements)

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“…The osmotic conditioning technique used to inoculate seed, in this paper, ensured its infection at varying levels, as has been demonstrated for some pathosystems Siqueira et al, 2014;Machado et al, 2004) and can be used as a tool that may help to validate techniques used for detecting pathogens in seeds. Therefore, it´s recommended to use the seeds inoculated with that technique, as a first study on the detection sensitivity seed borne pathogens.…”

Section: Inoculation Of S Sclerotiorum In Soybean Seeds and Sensitivmentioning

confidence: 76%

“…As reported in literature, other primers have been described as successful for the detection of S. sclerotiorum for ascospores and in plant tissues infected by the pathogen (Yanni et al, 2009;Kim and Knudsen, 2008;Rogers et al, 2009). In this work these primers were tested in soybeans seeds inoculated with S. sclerotiorum but without success.…”

Section: Specificity Of the Primersmentioning

confidence: 95%

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Detection of Sclerotinia sclerotiorum in soybean seeds by conventional and quantitative PCR techniques

Botelho

Barrocas²,

Machado

et al. 2015

J. Seed Sci.

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-Sclerotinia sclerotiorum, the etiological agent of the "white mould" in soybean, is responsible for severe losses in this crop and soil contamination. The introduction and dissemination of the disease can made through the use of seed lots contaminated with sclerotia and by seeds infected by mycelium. Therefore, seed health quality is one aspect to be monitored by means of health testing before to sowing time. In this study conventional and quantitative PCR techniques were used to assess their viability to detect S. sclerotiorum in artificially and naturally infected soybean seed samples. For that, seeds were inoculated by osmotic conditioning technique for 0, 24, 48 and 72 hours of contact of the seed with the fungal colony and mixed with healthy seeds generating incidence levels of 1, 2, 10, 20 and 100% for each incubation time. The cPCR was sensitive to detect S. sclerotiorum in samples with at least incidence 1% inoculated for 72 hours while the qPCR detected the pathogen in all incidence/inoculum potential combinations. The conventional PCR was able to detect 0.25% of the incidence of S. sclerotiorum in soybean seed lots naturally infected added a preincubation step.Index terms: seed healthy, molecular detection, seed borne pathogen, white mould.Detecção de Sclerotinia sclerotiorum em sementes de soja pelas técnicas de PCR convencional e quantitativo RESUMO -Sclerotinia sclerotiorum causador do "mofo branco" na cultura da soja, é responsável por redução da produção e contaminação do solo. A introdução e disseminação da doença podem se dar pelo uso de sementes contaminadas com escleródios e por sementes infectadas pelo micélio. A qualidade das sementes deve ser monitorada por testes de sanidade antes da semeadura. Neste estudo foram utilizadas técnicas de PCR convencional e quantitativo para avaliar a viabilidade de uso das mesmas para a detecção de S. sclerotiorum em amostras de sementes de soja artificialmente e naturalmente infectadas. Para isso, as sementes foram inoculadas usando a técnica do condicionamento osmótico por 0, 24, 48 e 72 horas de contato das sementes com a colônia do fungo e misturadas à sementes sadias gerando incidência de 1, 2, 10, 20 e 100% para cada tempo de incubação. A técnica de cPCR foi sensível para detectar S. sclerotiorum em amostras com, no mínimo, incidência de 1% inoculadas por 72 horas, enquanto que com o qPCR foi possível detectar o patógeno em todas as combinações incidência/potencial de inóculo. A PCR convencional foi capaz de detectar 0,25% de incidência de S. sclerotiorum em lotes de sementes de soja naturalmente infectados adicionando-se uma etapa de pré-incubação das sementes.Termos para indexação: sanidade de sementes, detecção molecular, patógeno de sementes, mofo branco.

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Section: Inoculation Of S Sclerotiorum In Soybean Seeds and Sensitivmentioning

confidence: 76%

Section: Specificity Of the Primersmentioning

confidence: 95%

Detection of Sclerotinia sclerotiorum in soybean seeds by conventional and quantitative PCR techniques

Botelho

Barrocas²,

Machado

et al. 2015

J. Seed Sci.

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“…For the CML698 isolate, the highest percentages for rate of transmission at potentials P3 and P4 were 90% and 89.5%, and for the MY2 isolate, 93% and 90.5% respectively, relating to the temperature of 20 °C and C1 (RB9308YG). In a study conducted by Siqueira et al (2014), evaluating Stenocarpella macrospora, the highest total rate of transmission observed was 85.8%, which occurred in plants from seeds inoculated for 96 hours and grown at a temperature of 20 °C. These results indicate that if the seed is infected, transmission will take place at least through symptomatic plants and/or asymptomatic plants, as also seen in a study with F. verticillioides in maize (WILKE et al, 2007).…”

Section: Resultsmentioning

confidence: 98%

Transmission ofStenocarpella maydisby maize seeds

Siqueira

Barrocas

Machado

et al. 2016

Revista Ciência Agronômica

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-Stenocarpella maydis is one of the main fungi associated with maize seeds, being a causative agent of stalk and ear rot, a disease which causes considerable losses for crop-producing regions in Brazil. The organism is considered to be a pest, subject to sanitary standardisation in current programs of seed certification in the country. The aim of this study was to evaluate the transmission rate of the fungus from infected maize seeds. Seeds were inoculated with two isolates using a method of physiological conditioning, in which the seeds are kept in contact with colonies of the fungus for 24 (P1), 48 (P2), 72 (P3) and 96 (P4) hours. Two cultivars were used, one susceptible (C1) and one moderately resistant (C2), and the trial carried out at two temperatures (20 °C and 25 °C). The inoculated seeds were distributed individually into plastic cups containing substrate. The plants were evaluated daily for stand and the appearance of post-emergent symptoms. Based on the number of dead seeds, transmission rates reached a maximum of 90.5% at the P4 inoculum potential, this rate being greater than transmission rates achieved for symptomatic and asymptomatic infection in emerged plants. For the total transmission rate, transmission of the pathogen was seen at all inoculum potentials; these values varying from 25% for cultivar C2 at potential P1 and a temperature of 20 °C, to 93% for cultivar C2 at potential P3 and a temperature of 25 °C. RESUMO -Stenocarpella maydis é um dos principais fungos que se associam às sementes de milho, sendo um dos agentes causais da podridão do colmo e da espiga, que ocasiona perdas consideráveis em regiões produtoras desta cultura no Brasil. O referido organismo tem sido enquadrado como uma praga sujeita a padronização sanitária em programas de certificação de sementes vigentes no país. O objetivo nesse trabalho foi avaliar a taxa de transmissão do referido fungo a partir de sementes de milho infectadas. As sementes foram inoculadas com dois isolados pelo método de condicionamento fisiológico no qual as sementes são mantidas em contato com colônias do fungo por 24 (P1), 48 (P2), 72 (P3) e 96 (P4) horas. Foram utilizadas duas cultivares, uma suscetível (C1) e outra moderadamente resistente (C2) e o ensaio conduzido em duas temperaturas (20 e 25 °C). As sementes inoculadas foram distribuídas individualmente em copos plásticos contendo substrato. As plantas foram avaliadas diariamente quanto ao estande e aparecimento de sintomas em pós-emergência. Com base em sementes mortas, as taxas de transmissão alcançaram o percentual máximo de 90,5% para o potencial de inóculo P4, sendo esta taxa mais alta do que as alcançadas pelas taxas de transmissão para infecção sintomática e assintomática em plantas emergidas. Em relação à taxa de transmissão total, observou-se a transmissão do patógeno em todos os potenciais de inóculo, variando estes valores entre 25% para C2 no potencial P1 sob temperatura de 20 °C e 93% para C2 no potencial P3 sob temperatura de 25 °C.Palavras-chave: Fitopatologia. Patol...

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“…The variability is related mostly to the environment and to inherent characteristics of the pathogen and of the host (Machado, 1988;Garcia Junior et al, 2008;Siqueira et al, 2016), such as the inoculum potential of the pathogen and the degree of resistance of the host. Physical and biological factors, the position of the pathogen inside the seed and its intensity are responsible for the great variability in transmission of the pathogen by seed (Siqueira et al, 2014).…”

Section: Resultsmentioning

confidence: 99%

Potential of transmission of Pyricularia graminis-tritici from plant to seed and from seed to seedling in wheat genotypes with different degrees of blast resistance

Gomes

Rocha

et al. 2018

J. Seed Sci.

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Transmission studies of Pyricularia graminis-tritici by wheat seed can help establishing pathogen tolerance standards in crops. Four genotypes, each one with different responses to blast, were inoculated with five volumes of fungal suspension (1,5x10 5 spores.mL -1 ), in order to obtain 0, 5, 10, 20 and 30% of plants inoculated in the experimental unit. The potential of transmission of P. graminis-tritici from plant to seed was evaluated by the incidence of the fungus in the seeds produced. Under controlled conditions, the transmission rate of the fungus from seed to seedling was evaluated. Blast incidence in field allowed a high incidence of P. graminis-tritici in the seeds, especially in the genotypes considered susceptible. The transmission of fungus from the seeds to seedlings occurred 7, 14 and 21 days after sowing, at low rates. There was a relationship between the presence of blast in field and the incidence of P. graminis-tritici in seeds produced by the genotypes BRS 264, VI 98053, CD 116 and CD 104. Inoculation of 5, 10, 20 and 30% of plants with fungus can generate a high incidence of the pathogen in field and in the seeds produced, but it doesn`t guarantee a high transmission rate from seed to seedling, which is low under controlled conditions. Potencial de transmissão de Pyricularia graminis-tritici planta-semente e sementeplântula em genótipos de trigo com graus diferentes de resistência a brusone RESUMO -Estudos da transmissão de Pyricularia graminis-tritici pela semente de trigo podem auxiliar no estabelecimento de padrões de tolerância do patógeno na cultura. Quatro genótipos diferentes quanto à reação à brusone foram inoculados com cinco volumes da suspensão fúngica (1,5x10 5 esporos.mL -1 ), de modo a obter 0, 5, 10, 20 e 30% de plantas inoculadas na unidade experimental. O potencial de transmissão de P. graminis-tritici planta-semente foi avaliado pela incidência do fungo nas sementes produzidas. Em condições controladas, avaliou-se a taxa de transmissão do fungo da semente à plântula. A incidência da brusone no campo possibilitou elevada incidência de P. graminis-tritici nas sementes, principalmente nos genótipos considerados suscetíveis. Ocorreu transmissão do fungo da semente para plântula aos 7, 14 e 21 dias após a semeadura e as taxas foram baixas. Existe relação entre a presença da brusone no campo e a incidência de P. graminis-tritici nas sementes produzidas pelos genótipos BRS 264, VI 98053, CD 116 e CD 104. A inoculação de 5, 10, 20 e 30% de plantas com o fungo pode gerar alta incidência do patógeno no campo e nas sementes produzidas, mas não garante elevada taxa de transmissão da semente para a plântula, que é baixa em condições controladas.Termos para indexação: Triticum aestivum, patologia de sementes, transmissibilidade, condições controladas, padrões de tolerância.

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Potential for transmission of Stenocarpella macrospora from inoculated seeds to maize plants grown under controlled conditions

Cited by 8 publications

References 14 publications

Detection of Sclerotinia sclerotiorum in soybean seeds by conventional and quantitative PCR techniques

Detection of Sclerotinia sclerotiorum in soybean seeds by conventional and quantitative PCR techniques

Transmission ofStenocarpella maydisby maize seeds

Potential of transmission of Pyricularia graminis-tritici from plant to seed and from seed to seedling in wheat genotypes with different degrees of blast resistance

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