Fitopatologia - Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11741
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Item Silicon improves the emergence and sanity of rice seedlings obtained from seeds infected with Bipolaris oryzae(Tropical Plant Pathology, 2013-11) Rodrigues, Fabrício A.; Mielli, Matheus V. B.; Dallagnol, Leandro J.This study investigated the importance of silicon (Si) in rice grain husk in association with fungicide treatment for preventing Bipolaris oryzae transmission from seed to seedling and the improvement in seedling emergence. Plants from cv. Oochikara and its mutant (lsi1 mutant) defective in active Si uptake were grown in nutrient solution without (-Si) or with (+Si) Si and their panicles were inoculated with B. oryzae. Seeds were evaluated for brown spot severity (BSS) and husk Si concentration. The Si concentration in the husks of cv. Oochikara plants was up to four times higher than the lsi1 mutant plants. BSS was significantly reduced in the husks of the seeds obtained from +Si plants, particularly for cv. Oochikara. A higher percentage of seedling emergence occurred for +Si plant seeds, particularly for cv. Oochikara, and a lower percentage of infected seedlings was observed for the +Si cv. Oochikara treatment, particularly for the fungicide treated seeds. Fungicide was not efficient in preventing seedling infection by B. oryzae for seeds with BSS greater than 50%. High Si concentration in the husk resulted in lower BSS and the fungicide efficiency was greater with a low BSS on seeds from +Si plants, particularly for cv. Oochikara.Item Rice grain resistance to brown spot and yield are increased by silicon(Tropical Plant Pathology, 2014-01) Rodrigues, Fabricio A.; Dallagnol, Leandro J.; Mielli, Mateus V. B.; Ma, Jian F.Brown spot, caused by Bipolaris oryzae, is one of the most important diseases of rice and can cause a reduction in yield and grain quality. The effect of silicon (Si) on the resistance of rice grains to brown spot was investigated. Plants from cv. Oochikara and its mutant, defective in the Lsi1 transporter (lsi1 mutant), were grown in hydroponic culture either with Si (+Si; 2 mM) or without Si (-Si). Panicle inoculation with B. oryzae was carried out at the beginning of the milk-grain stage. Panicles were harvested at physiological grain maturity. The supply of Si significantly increased Si concentration in husks compared to -Si plants. Si concentration in husks from cv. Oochikara was up to three times greater than the lsi1 mutant. In the presence of Si, brown spot severity was reduced by 88% in grains from cv. Oochikara and by 53% in grains from lsi1 mutant. Brown spot severity was 77% lower for grains of cv. Oochikara than for the lsi1 mutant, both plant types were grown in the presence of Si. Panicle inoculation reduced significantly the following yield components: number of grains per panicle, the weight of 1000 grains and the percentage of filled grains. Si significantly increased these yield components, especially for inoculated panicles. Considering kernel quality, the panicle inoculation with B. oryzae significantly reduced the yield of husked kernel, yield of whole kernel and kernel diameter, especially for grains from -Si plants. For panicles from +Si plants, the kernel quality was improved under inoculation, compared to -Si plants. Results from this study show that Si improved rice yield and kernel quality in panicles inoculated with B. oryzae. Furthermore the functional Lsi1 gene contributed significantly for increasing the yield of whole kernel and kernel diameter, possibly due to the increasing Si concentration in husks.Item Induction of resistance to Pyricularia oryzae in wheat by acibenzolar-S-methyl, ethylene and jasmonic acid(Tropical Plant Pathology, 2014-05) Rios, Jonas Alberto; Rodrigues, Fabrício Ávila; Debona, Daniel; Resende, Renata Sousa; Moreira, Wiler Ribas; Andrade, Camila Cristina LageThis study investigated the effects of acibenzolar-S-methyl (ASM), ethylene (ET) and jasmonic acid (JA) on the resistance of two wheat cultivars (BRS-229 and BR-18) to infection by Pyricularia oryzae. The treatments included spraying plants with ASM (300 mg L-1), ET (0.5 mM), JA (0.1 mM) and distilled water (control) 48 h before inoculation with P. oryzae. Malondialdehyde concentration, an indicative of oxidative damage to the lipids in the leaf cells, was significantly higher for plants sprayed with ASM compared to plants sprayed with JA and ET. Plants sprayed with JA and ET showed reduced values for the number of lesions per cm2 of leaf area and area under blast progress curve, but these hormones had no effect on the incubation period and lesion size (in mm). Plants sprayed with JA and ET showed reduce blast symptoms in comparison to plants sprayed with ASM due to greater peroxidase, polyphenoloxidase, chitinase and β-1,3-glucanase activities.Item Indutores de resistência no controle da pinta bacteriana do tomateiro e na atividade de enzimas de defesa(Tropical Plant Pathology, 2013-01) Resende, Renata S.; Rodrigues, Fabrício A.; Silveira, Patrícia R.; Rios, Jonas A.; Oliveira, José R.; Mariano, Rosa L. R.; Andrade, Camila C. L.Em três experimentos, avaliou-se o efeito de pulverizações de ácido jasmônico (AJ), etefon (ET) e acibenzolar-S-metil (Bion®) (ASM) a 0,1 mM, 0,5 mM e 0,3 g L-1, respectivamente, nos componentes de resistência do tomateiro (cv. Santa Clara) à pinta bacteriana, causada por Pseudomonas syringae pv. tomato e na atividade de peroxidases (POX), polifenoloxidases (PFO), β-1,3-glucanases (GLU) e lipoxigenases (LOX). Apenas no experimento 3, o período de incubação aumentou significativamente em um dia nas plantas pulverizadas com ASM, em comparação com as plantas pulverizadas com água (controle). O número de lesões por planta foi significativamente reduzido por AJ, ET e ASM nos três experimentos. Para algumas épocas de avaliação, a atividade de POX, PFO e GLU foram maiores para o AJ; de PFO, GLU e LOX, para o ASM; e de GLU e LOX, para o ET em comparação com o controle. Conclui-se que na presença de AJ, ET e ASM, os sintomas da pinta bacteriana foram reduzidos e a atividade das enzimas POX, PFO, GLU e LOX foram maiores.Item Regional and varietal differences in prevalence and incidence levels of Bipolaris species in Brazilian rice seedlots(Tropical Plant Pathology, 2014-09) Del Ponte, Emerson Medeiros; Funck, Gustavo Daltrozzo; Deibler, Alexandre Nunes; Schwanck, André Aguiar; Caniela, Ana Rita de Almeida; Farias, Cândida Renata Jacobsen de; Meneses, Priscila RossattoA total of 722 rice seed lots were collected at six production regions of Rio Grande do Sul state during three consecutive seasons (2009/10 to 2011/12). For each seed lot, 200 seeds were assessed for the presence of Bipolaris spp. using a standard seed health blotter test. Results showed that B. oryzae and B. cynodontis were found in 62.5% and 10.4% of the seed lots, respectively. Overall mean incidence of B. oryzae and B. cynodontis were 0.5% and 0.06%, respectively. For the two most sampled varieties (75% of the seed lots), IRGA 424 and Puitá INTA CL, mean incidence levels were highest and lowest, respectively. Among regions, infection risk was highest in the southeastern and lowest in the western regions of the state, especially the Fronteira Oeste. The prevalence and the incidence levels of Bipolaris oryzae reported in this study were lower than previous reports in the same region - eighty percent of the seed lots showed incidence levels below the recommended 5% inoculum threshold. In conclusion, rice seeds produced by IRGA-certified growers showed an overall good health quality with regards to B. oryzae infection, which is the main Bipolaris species associated with rice seeds in southern Brazil.Item Photosynthetic gas exchange and antioxidative system in common bean plants infected by Colletotrichum lindemuthianum and supplied with silicon(Tropical Plant Pathology, 2014-01) Polanco, Leonora R.; Rodrigues, Fabrício A.; Nascimento, Kelly J. T.; Cruz, Maria F. A.; Curvelo, Carmen R. S.; Vale, Francisco X. R.This study investigated the effects of silicon (Si) on the resistance of common bean plants to anthracnose caused by Colletotrichum lindemuthianum. The plants were grown in a nutrient solution containing 0 (control) or 2 mM Si (+Si) and both photosynthesis and antioxidative metabolism levels were evaluated. The Si concentrations in the leaf tissues of +Si plants increased by 33% in comparison to those of control plants. Anthracnose severity was reduced by 34% in +Si plants in comparison to control plants. The net carbon assimilation rate, stomatal conductance to water vapor and transpiration rate values were significantly higher in +Si plants than in control plants. The activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) tended to be higher in +Si plants than in control plants. The hydrogen peroxide concentration was significantly lower in +Si plants than in control plants. In conclusion, the Si supply was associated with lower anthracnose severity and up-regulation of antioxidant enzymes, which in turn might be associated with better gas exchange in +Si plants. The impaired photosynthetic performance in +Si plants was associated with stomatal limitations, whereas in control plants those impairments likely reflected dysfunctions at the level of biochemical reactions involved in CO2 fixation.Item Reappraisal of the black mildews (Meliolales) on Hevea brasiliensis(Tropical Plant Pathology, 2014-01) Pinho, Danilo B.; Honorato Junior, Jaime; Firmino, André L.; Hora Junior, Braz T.; Mizubuti, Eduardo S. G.; Pereira, Olinto L.The rubber tree (Hevea brasiliensis) is host to several fungal species, including Irenopsis heveae as described by Hansford in 1961, which causes black mildew on leaves. One specimen of Irenopsis heveae from the state of Espírito Santo and two from the state of Pará were analyzed and showed some morphological differences. Some structures are similar to morphological characteristics as described and illustrated by Vincens in 1915 for Meliola heveae. Morphological comparisons with the type specimen of I. heveae and the alignment of the nucleotide sequences of the 28S rDNA region, however, indicate that the three samples belong to the same species. According to these data M. heveae and I. heveae are heterotypic synonyms with M. heveae being the older name. As the name I. heveae is already occupied by Hansford, Irenopsis vincensii is proposed as new name for the black mildew on H. brasiliensis. This is the first contribution of molecular sequence data for this species.Item Selection of fungi with biocontrol potential against the black spot disease of papaya(Pesquisa Agropecuária Tropical, 2017-10) Pereira, Olinto Liparini; Vivas, Janieli Maganha Silva; Silveira, Silvaldo Felipe da; Santos, Pedro Henrique Dias dos; Pinho, Danilo BatistaThe use of fungicides is the main control measure against the black-spot disease of papaya. The biological control is an alternative to that, being the selection of mycoparasitic fungi the first step in programs aiming at this kind of control. This study aimed to obtain and select fungi with potential to the biocontrol of the black spot disease of papaya. For this purpose, 24 isolates were collected from different regions and pathosystems, and then identified morphologically and by the ITS region sequencing. In order to evaluate the mycoparasite potential, two assessments, in a randomized block design, with three replications, were carried out in a shadehouse, being the obtained isolates inoculated on papaya leaves with black spot lesions. The average time for the appearance of mycoparasitism signs and the incidence of mycoparasitized black spot lesions were evaluated. Of the 24 isolates obtained, ten were from Hansfordia pulvinata, two from Lecanicillium lecaniium, two from Simplicillium lanossoniveum, one from Sarocladium implicatum and nine from Acremonium spp. A wide variability, concerning the mycoparasitism on black spot lesions, was observed, especially for the isolates H-611, H-613, H-614 and H-615, which showed the highest colonization averages. The results demonstrate that H. pulvinata has a great potential to be used as a biocontrol agent against Asperisporium caricae.Item Mycological Diversity Description II(Acta Botanica Brasilica, 2019-01) Pereira, Olinto L.; Silva, Rejane Maria Ferreira da; Soares, Adriene Mayra; Pádua, Ana Patrícia Sousa Lopes de; Firmino, André Luiz; Souza-Motta, Cristina Maria de; Silva, Gladstone Alves da; Plautz Jr, Helio Longoni; Bezerra, Jadson Diogo Pereira; Paiva, Laura Mesquita; Ryvarden, Leif; Oliani, Luisa Cunha; Mélo, Mayara Alice Correia de; Magalhães, Oliane Maria Correia; Oliveira, Rafael José Vilela de; Gibertoni, Tatiana Baptista; Oliveira, Thays Gabrielle Lins de; Svedese, Virginia Michelle; Fan, XinleiHere, Diaporthe myracrodruonis is introduced as new species from Brazil, isolated as endophyte from Myracrodruon urundeuva. Asterina mandaquiensis is epitypified and ilustrated for the first time. Serpula similis is reported as new to the Neotropics, while Perenniporia centrali-africana is reported for the first time as endophyte and Preussia africana as endophyte from Spondias tuberosa in Caatinga in Brazil.Item Larvicidal Activity of Beauveria bassiana extracts against Aedes aegypti and identification of beauvericins(Journal of the Brazilian Chemical Society, 2017-06) Abreu, Lucas M.; Daniel, Juliana F. S.; Silva, Andressa A.; Nakagawa, Danielle H.; Medeiros, Lívia S. de; Carvalho, Mário G.; Tavares, Lucineli J.; Rodrigues-Filho, EdsonBeauveria bassiana is an entomopathogenic fungus that has been well known for its capacity to act as biopesticide on various disease vectors. The analysis of organic extracts of strains CG71 and UNI40 led to identification of cyclodepsipeptides beauvericin, beauvericin A or F, beauvericin E and bassianolide by ultra-high pressure liquid chromatography-high resolution mass spectrometry in tandem mode (UHPLC-HRMS/MS). The larvicidal activity on 3rd instar of Aedes aegypti revealed LC50 0.9887 and 0.4653 ppm in 24 and 48 hours (CG71 methanolic extract), LC50 0.7834 ppm in 48 hours (CG71 ethyl acetate), LC50 0.7834 and 1.8149 ppm (UNI 40 for ethyl acetate and methanolic extracts, respectively) in 48 hours. These findings highlight the potential of B. bassiana metabolites for controlling the vector of Dengue and Zika diseases.