Abstract Effector proteins in Phakopsora pachyrhizi (Pp), the causative agent of Asian Soybean rust, are involved in the infection process. A previous study identified a rust effector Egh16-like family based expression profile during the interaction with soybean. Herein, we scrutinized available the Pp genomes to validate the predicted Egh16-like family of Pp and identify new family members. We described 22 members of the Egh16-like gene family in the Pp MT2006 genome and 18 in the UFV02 and K8108 genomes, highlighting a family expansion. Family members have a small signal peptide, conserved cysteine-rich R/Y/FxC motifs in the C-terminal region, and a virulence-related Egh16-like domain and were able to suppress PTI related responses in Benthamiana. Phylogenetic analysis placed the family members into eight clusters, with members induced during the early stages of rust infection. Members of clusters VI and VII are present in different copy numbers in Pp genomes and suppressed PAMP-related responses. Pp, , (Pp) process Egh16like Eghlike Egh16 like Egh soybean Herein 2 MT MT200 1 UFV UFV0 K K810 expansion peptide cysteinerich cysteine rich RYFxC R Y FxC Cterminal C terminal region virulencerelated virulence Benthamiana PAMPrelated PAMP (Pp Egh1 MT20 K81 MT2 K8

ABSTRACT. Bacterial leaf streak caused by Xanthomonas vasicola pv. vasculorum is an emerging disease for corn production around the world. However, information on management of this disease is still limited. This study aimed to determine the in vitro sensibility of X. vasicola pv. vasculorum to different chemicals and to evaluate the control of bacterial leaf streak on corn under greenhouse conditions. In vitro tests were carried out with kasugamycin, copper sulfate, copper oxychloride, copper hydroxide, cuprous oxide, bioactive copper, mancozeb, chlorothalonil, methyl thiophanate, and tebuconazole at the dosages of 1, 5, 10, 20, 50, 100, 200, and 400 μg mL−1. Four strains of X. vasicola pv. vasculorum were included in the study. The minimal inhibitory concentration for kasugamycin ranged from 50 to 200 μg mL-1, whereas to the inorganic copper compounds varied from 5 to 50 μg mL-1 and to the bioactive copper was 100 μg mL-1. Further, mancozeb and tebuconazole inhibited the bacterial growth at the dosage ranging from 5 to 20 μg mL-1 and 50 to 400 μg mL-1, respectively, depending on the X. vasicola pv. vasculorum strain. Chlorothalonil and methyl thiophanate did not inhibit the growth of the bacterium at any tested concentration. The control of bacterial leaf streak under greenhouse conditions was investigated on corn plants of the cultivar IPR 164 at the V3 phenological vegetative stage, sprayed with kasugamycin (3 mL L-1), copper oxychloride (1.5 mL L-1), bioactive copper (1 mL L-1), mancozeb (2 g L-1), tebuconazole (1 mL L-1), and chlorothalonil (2 mL L-1). The corn plants were inoculated with a 108 CFU mL-1 suspension of the RL1 strain of X. vasicola pv. vasculorum. Only copper oxychloride significantly reduced disease severity. However, this copper compound caused phytotoxicity to the corn plants at the tested concentration.

RESUMO A pústula bacteriana, causada pela bactéria Xanthomonas axonopodis pv. glycines, é considerada uma das mais sérias doenças bacterianas na cultura da soja. O objetivo deste trabalho foi desenvolver e validar uma escala diagramática para a avaliação da severidade da pústula bacteriana em soja. Para a elaboração da escala, foram coletados folíolos de soja com diferentes níveis de severidade, determinando assim os valores máximos e mínimos de quantidade de doença, e os níveis intermediários de severidade da escala foram estabelecidos de acordo com a lei do estímulo visual de Weber-Fechner. Os valores propostos para a escala foram: 1,4%; 3%; 6%; 9%; 20% e 29,5%. Para validação da escala, oito avaliadores, sem experiência na avaliação da doença, avaliaram 39 fotos com diferentes níveis de severidade, sem e com o auxílio da escala. Os resultados das severidades estimadas pelos avaliadores foram relacionados com os valores das severidades reais (determinadas com o software Assess 2.0 a partir de imagens digitais das folhas com sintomas) e submetidos a regressões lineares simples para avaliar a acurácia dos avaliadores. A precisão dos avaliadores foi determinada através dos coeficientes de determinação e da variância dos erros absolutos. As estimativas com o uso da escala diagramática proposta determinaram um aumento significativo do coeficiente de determinação e uma menor variância dos erros absolutos, proporcionando maior precisão e acurácia das avaliações, podendo ser adotada para a avaliação da severidade da pústula bacteriana em soja.

ABSTRACT Bacterial pustule, caused by the bacterium Xanthomonas axonopodis pv. glycines, is considered one of the most important bacterial diseases affecting soybean. The aim of this study was to develop and validate a diagrammatic scale for assessing the severity of soybean bacterial pustule. To elaborate the scale, soybean leaflets with different severity levels were collected to determine the maximum and minimum values of disease severity, while intermediate levels were established according to Weber-Fechner law of visual stimulus. The values proposed for the scale were 1.4%, 3%, 6%, 9%, 20% and 29.5%. To validate the scale, eight evaluators, with no experience in bacterial pustule evaluation, assessed 39 photos of leaflets with different severity levels, without and with the aid of the scale. The results of severity estimated by the evaluators were related to the actual severity values (determined with Assess 2.0 software from digital images of leaves with symptoms) and analyzed with simple linear regressions to assess the accuracy of evaluators. The precision of evaluators was determined based on the coefficients of determination and the variance in absolute errors. Estimates using the proposed diagrammatic scale indicated a significant increase in the coefficient of determination and lower variance in absolute errors, providing greater precision and accuracy of evaluations, which could be adopted to assess the severity of soybean bacterial pustule.

RESUMO O fungo Corynespora cassiicola, agente causal da mancha-alvo na soja, apresenta baixa esporulação em meios de cultura artificiais, o que dificulta a produção de esporos em condições de laboratório. O objetivo deste estudo foi avaliar a esporulação e o crescimento micelial radial de 21 isolados de C. cassiicola, obtidos de folhas de soja coletadas nas principais regiões produtoras do Brasil e submetidos a diferentes regimes de iluminação e estresse. Os isolados foram submetidos a três regimes de iluminação: luz contínua, 12 h/12 h de luz-escuro e escuro contínuo e duas condições de estresse mecânico: raspagem superficial da colônia ou ausência de estresse. A produção de esporos dos isolados foi quantificada utilizando um hemacitômetro, enquanto o crescimento micelial radial foi realizado pela média de dois diâmetros perpendiculares da colônia. A esporulação e o crescimento micelial radial sob diferentes regimes de iluminação e estresse, apresentaram comportamentos específicos para cada isolado. Não foi observada correlação significativa entre o crescimento micelial e a produção de esporos.

ABSTRACT The fungus Corynespora cassiicola, the causal agent of soybean target spot, presents low sporulation in artificial culture media, which makes difficult the production of spores under laboratory conditions. The objective of this study was to evaluate the sporulation and the mycelium radial growth of 21 C. cassiicola isolates obtained from soybean leaves collected from the main soybean growing regions in Brazil and subjected to different light and stress regimes. The isolates were subjected to three light regimes: continuous light, 12 h / 12 h light-dark and continuous dark, and two mechanical stress conditions: superficial scraping of the colony or absence of stress. The spore production of isolates was quantified by using a hemacytometer, while the radial mycelium growth was determined based on the average of two perpendicular diameters of the colony. Sporulation and mycelium radial growth under different light and stress regimes presented specific behaviors for each isolate. There was no significant correlation between mycelial growth and spore production.

RESUMO A seleção a campo de materiais resistentes à podridão negra da raiz, além de ter alto custo, apresenta alta variabilidade, uma vez que muitos fatores externos podem afetar o comportamento das plantas e, inclusive, do fungo, de local para local e de ano para ano. Seleção de variedades com resistência à podridão causada por Macrophomina phaseolina em casa de vegetação apresenta maior uniformidade e estabilidade dos resultados, uma vez que as condições são controladas. No entanto, é recomendado que os resultados obtidos em ambiente protegido, para serem adotados como protocolo de screening, apresentem boa correlação com resultados obtidos em campo. Assim, este trabalho teve por objetivo comparar a eficiência de métodos de screening em casa de vegetação e verificar suas correlações com o comportamento de variedades de soja em ensaio de campo. Os métodos de screening avaliados foram disco de micélio sobre haste cortada; punção da haste com palito colonizado; solo infestado por inóculo produzido em arroz (1g, 5g e 10g por kg de solo); e rega com suspensão de microescleródios (3 x 104 e 6 x 104 UFC/mL) sobre raízes de plântulas. O ensaio de campo foi montado em área com histórico de ocorrência da doença, e o solo foi infestado com sementes de sorgo colonizadas por M. phaseolina, no sulco de semeadura. Plantas inoculadas na haste, em casa de vegetação, foram submetidas a duas condições de umidade: câmara úmida por três dias após a inoculação, e ausência de câmara úmida. A severidade da doença foi avaliada através do comprimento da lesão no método do disco de micélio sobre haste cortada, e, para os métodos da punção da haste com palito colonizado, suspensão de microescleródios e inoculação por infestação do solo, por escala de notas referente à lesão na raiz. Para o último, avaliou-se ainda a altura das plantas. Os métodos do corte da haste e do palito colonizado apresentaram melhores resultados para discriminar os genótipos, e a ausência de câmara úmida proporcionou maior severidade da doença. De maneira geral, BMX Apolo foi mais suscetível à doença, enquanto GDM15I029 e BMX Elite apresentaram maior resistência. Houve redução na altura das plantas inoculadas por infestação do solo, principalmente para a maior concentração do inóculo. A inoculação por suspensão de inóculo foi eficiente somente no maior nível de inóculo, e foi possível diferenciar dois genótipos quanto à severidade, sendo BMX Tornado mais suscetível que GDM15I029. Verificou-se correlação significativa com os dados de campo somente para o método do disco de micélio sobre a haste cortada, com (rs = 0,84) e sem câmara úmida (rs = 0,80). Os resultados sugerem que a seleção de cultivares em casa de vegetação para resistência a podridão negra da raiz realizado pelo método da haste cortada é eficiente e representativa do comportamento dos genótipos de soja em condições de campo.

ABSTRACT The screening of genotypes resistant to black root rot in the field has high cost and high variability, since a large number of external factors can affect the behavior of plants and even of the fungus, according to the place and the year of cultivation. Screening of varieties resistant to the rot caused by Macrophomina phaseolina at greenhouse presents greater uniformity and stability of results once the conditions are controlled. However, it is recommended that the results obtained in a protected environment present good correlation to the results obtained in the field in order to be adopted as a screening protocol. Thus, this study aimed to compare the efficiency of screening methods at greenhouse and check their correlation with the behavior of soybean varieties in a field test. The evaluated screening methods were mycelium disc on cut stem; stem puncture with colonized toothpick; soil infested by inoculum produced in rice grains (1g, 5g and 10g per kg of soil); and irrigation with suspension of microsclerotia (3x104 and 6x104 CFU/mL) onto seedling roots. The field trial was set in an area with history of the disease occurrence, and the soil was infested with sorghum seeds colonized with M. phaseolina in the sowing groove. Plants inoculated on the stem, at greenhouse, were subjected to two humidity conditions: humid chamber for three days after inoculation and absence of humid chamber. The disease severity was determined based on the length of the lesion, for the method of mycelium disc on cut stem, and on a scale of notes referring to the root lesion, for the methods of stem puncture with colonized toothpick, suspension of microsclerotia and soil infested by inoculum. For the latter, the height of plants was also evaluated. The methods of stem cut and colonized toothpick were the best to discriminate genotypes, while the absence of humid chamber provided greater severity of the disease. In general, BMX Apolo was more susceptible to the disease, while GDM15I029 and BMX Elite showed more resistance. There was a reduction in the height of plants inoculated by soil infestation, especially for the higher inoculum concentration. Inoculation with inoculum suspension was efficient only at the highest inoculum level, and allowed to differentiate genotypes for severity, showing that BMX Tornado was more susceptible than GDM15I029. There was a significant correlation with the field data only for the method of mycelium disc on cut stem, with (rs = 0.84) and without humid chamber (rs = 0.80). The results suggest that screening for resistance to black root rot at greenhouse using the method of cut stem is efficient and representative of the behavior of soybean genotypes under field conditions.

RESUMOA incidência e os níveis de dano do mofo branco da soja (causado pelo fungo Sclerotinia sclerotiorum) têm aumentado nas áreas de maior altitude do cerrado e da região sul do Brasil, causando reduções de produtividade de até 60%. O trabalho objetivou selecionar fungos sapróbios com potencial de controle do mofo-branco da soja. Primeiramente, realizou-se teste de antagonismo in vitro onde testaram-se oito espécies de fungos sapróbios em confrontação com S. sclerotiorum. A avaliação do crescimento micelial de S. sclerotiorum foi realizada aos quatro e sete dias após a repicagem. O isolado de maior efeito antagônico em todos os ensaios/avaliações foi Myrothecium sp. Realizou-se ensaio em casa de vegetação e fitotron onde plantas tratadas com oito fungos sapróbios foram artificialmente inoculadas com S. sclerotiorum. Como controle foram utilizados o meio de cultura dos fungos (batata-dextrose) e o indutor comercial de resistência Acibenzolar-S-metílico. No teste in vivo, a severidade do mofo branco foi avaliada aos 8, 14 e 21 dias após a inoculação. A maior porcentagem de redução do comprimento da lesão foi observada para o tratamento com Myrothecium sp. (70%); o qual apresenta o maior potencial de utilização como biocontrolador de S. sclerotiorumnas condições do experimento.

ABSTRACTThe incidence and the levels of yield loss caused by the white mold of soybean (caused by the fungus Sclerotinia sclerotiorum) have increased in areas of higher altitude at Cerrado and Southern Brazil, causing yield losses of up to 60%. The aim of this study was to select saprobic fungi with the potential to control the white mold of soybean. First, in vitroantagonism screening was carried out to test eight saprobic fungi against S. sclerotiorum. Assessment of S. sclerotiorum mycelial growth was done at four and seven days after its placement on the culture medium. The isolate showing greatest antagonistic effect in all tests/assessments was Myrothecium sp. An in vivo experiment was conducted in a greenhouse and growth chamber, where plants previously treated with eight saprobic fungi were artificially inoculated with S. sclerotiorum. The fungal culture medium (potato-dextrose) and the commercial resistance inducer acibenzolar-S-methyl were used as controls. In the in vivotests, severity of the white mold was assessed at 8, 14 and 21 days after inoculation. The highest reduction percentage in the lesion length was observed for the treatment with Myrothecium sp. (70%), which has the greater potential to be used as biocontrol agent of soybean under the conditions of this experiment.

Plant extracts for the control of plant disease are emerging as promising alternatives to the use of synthetic fungicides. The objective of this work was to study the effect of plant extracts and essential oils on naturally infected apple fruits with Penicillium spp. causal agent of blue mold. Apple fruits were immersed in citric and Azadirachta indica extracts at concentrations of 0.5 and 1.0% (v/v), stored at room temperature (25 °C and 90% RH) and analyzed at 21 days after the application of the treatments. Evaluated also the effect of fumigation of apple fruits with essential oils of Thymus vulgaris, Origanum vulgaris, Mentha piperita and Melaleuca alternifolia. Treated fruits were stored at 25±2 °C and 90±5% relative humidity for 20 days. Treated fruit with distilled water constituted the group controls. The higher values of incidence (100%), severity (99.98%) and the lowest percentage of disease control (4.56%) were observed in apple fruits treated with distilled water (group control). All treatments exhibited inhibitory effect on Penicillium spp. in apple fruits, however, A. indica and citric extracts, at concentrations of 1.0%, had a disease control of98.33% and 99.57%, respectively. There were no significant differences between the oils applied; except between these and the control. However, the treatments with essential oils were that exhibited the least incidence, severity and control of the disease. The results showed that essential oils showed good results, above 98.1% of control of blue mold disease in postharvest. It was demonstrated that extracts the different concentration and essential oils have antifungal activities and that they have a potential use as an alternative control in relation to chemical methods.

El uso de los extractos vegetales con actividad antimicrobiana para controlar enfermedades en pre o poscosecha es una alternativa promisoria frente al uso de fungicidas sintéticos. El objetivo de este estudio fue evaluar el efecto de extractos vegetales y aceites esenciales en manzanas infectadas naturalmente con Penicillium spp., agente causal del moho azul. Se sumergieron manzanas en extractos de cítricos y de neem (Azadirachta indica) en concentraciones de 0,5 y 1,0% (v/v) y se almacenaron a 25 °C y 90% de humedad relativa. Después de 21 días se midió incidencia y severidad de la enfermedad. También se evaluó el efecto de los aceites esenciales de Thymus vulgaris, Origanum vulgaris, Mentha piperita y Melaleuca alternifolia por fumigación. La fruta se almacenó a 25±2 °C y 90±5% de humedad relativa durante 21 días. Frutos tratados con agua destilada estéril constituyeron el tratamiento control. Los frutos sin tratar presentaron los valores más altos de incidencia (100%) y severidad (99,98%) de moho azul, así como el menor porcentaje de control (4,56%). Todos los tratamientos mostraron efecto antifúngico de Penicillium spp, sin embargo, los extractos cítricos y de A. indica en la concentración de 1,0% proporcionaron los mayores niveles de control de la enfermedad (99,57% y 98,33%, respectivamente). Los frutos tratados con aceites esenciales mostraron menor incidencia, menor severidad y mayor control de la enfermedad. Se ha demostrado que el extracto y aceites esenciales estudiados tienen actividad antifúngica y potencial para uso en poscosecha como una alternativa al control químico.