Fitopatologia Brasileira最新文献

{"title":"Detection of the \"Candidatus Liberibacter americanus\" in phloem vessels of experimentally infected cataranthus roseus by scanning electron microscopy","authors":"F. Tanaka, H. Coletta-Filho, K. C. S. Alves, Myldred O. Spinelli, M. Machado, E. Kitajima","doi":"10.1590/S0100-41582007000600013","DOIUrl":"https://doi.org/10.1590/S0100-41582007000600013","url":null,"abstract":"Presence of Huanglongbing (HLB) disease in citrus orchards in the state of Sao Paulo has been known since 2004. Its identification was made by molecular techniques which revealed the presence of two forms of the bacteria “Candidatus Liberibacter”. One previously described in Asia as Ca. L. asiaticus and the other a novel type, Ca. L. americanus (Coletta-Fo et al., Plant Dis. 88:1382. 2004; Teixeira et al., Plant Dis. 89:107. 2005). Transmission electron microscopy confirmed the presence of characteristic bacteria in the phloem vessels of affected sweet orange leaves (Tanaka et al., Fitopatol. Bras. 31:99. 2006). Attempts to observe these bacteria by scanning electron microscopy (SEM) to understand their three dimensional morphology were hindered by the extremely low concentration at which they usually occur in citrus plants. On the other hand, Ca. L. americanus was successfully transferred to the ornamental periwinkle (Cataranthus roseus (L.) G. Don.) using dodder (Cuscuta sp.) as previously reported for other Ca. Liberibacter (Garnier & Bove, Proc. Conf. IOCV 12: 212. 1993). Infected plants developed chlorotic symptoms and contained higher concentrations of the bacterium as evaluated by molecular techniques and transmission electron microscopy. For in situ observations of Ca. L. americanus under SEM, midribs from symptomatic leaves and young stems were fixed with aldehyde, infiltrated with glycerol, immersed in liquid nitrogen and fractured with a scalpel, and the pieces post-fixed in 0.1% OsO4 for 24 h, dehydrated in acetone, dried at the critical point, gold coated by sputtering and examined in a LEO 435 VP scanning electron microscope. In the vascular region of the infected leaves and stems, exposed by the fracture of frozen tissues, many phloem vessels contained bacterial cells, interpreted as Ca. L. americanus, in varied numbers. Some vessels were obliterated by aggregated bacterial cells (Fig. 1 A). Bacteria were typically baciliform and elongated, 2-3 μm long with rounded ends, 200-300 nm wide and with a smooth outer surface (Fig. 1 B). These values match those obtained in sectioned bacterial cells. Such bacterial cells were absent in the phloem vessels of healthy, uninoculated periwinkle plants. This report is the first description of Candidatus Liberibacter by scanning electron microscopy. RESUMO Deteccao de Candidatus Liberibacter americanus em vasos de floema de Catharantus roseus infectados experimentalmente, utilizando microscopia eletronica de varredura “Candidatus Liberibacter americanus”, agente causal do Huanglongbing (HLB) foi visualizado pela primeira vez ao microscopio eletronico de varredura infectando vasos do floema de plantas de vinca (Catharantus roseus) experimentalmente infectadas utilizando-se Cuscuta sp. no Brasil.","PeriodicalId":211183,"journal":{"name":"Fitopatologia Brasileira","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123754686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Peroxidases ativadas por frações protéicas de extrato biológico eficaz na proteção do tomateiro contra a mancha bacteriana","authors":"F. R. Cavalcanti, M. Resende, J. A. Oliveira","doi":"10.1590/S0100-41582007000600010","DOIUrl":"https://doi.org/10.1590/S0100-41582007000600010","url":null,"abstract":"A crude formulation (VLAF) of an aqueous cold extract obtained from Solanum lycocarpum necrotic tissue infected by Crinipellis perniciosa was showed capable of reducing disease progress of tomato bacterial leaf spot, when previously sprayed on tomato plants. The fractions F0/30 and F30/60 were achieved by saline precipitation and they showed highest amounts of proteins from VLAF. The fractions were submitted to cationic exchange chromatography for protein scanning. Non-retained peaks from this first chromatography were submitted to an anionic exchange chromatography. Both retained and non-retained peaks from both ion exchanges were sampled and sprayed on cv. Santa Cruz Kada tomatoes. Contrasting peroxidase activities were observed 14 hours after sprayings. The samples that produced the highest peroxidase increases were the retained peak in cationic exchange from F0/30 (F0-30CMR) and the retained peak in anionic exchange chromatography from F30/60 (F30-60DEAER). Our results indicate the viability of searching for protein- or carbohydrate-derived molecules from VLAF aqueous extract.","PeriodicalId":211183,"journal":{"name":"Fitopatologia Brasileira","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122823298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Qualidade Sanitária e Fisiológica de Sementes de Milho Submetidas a Termoterapia e Condicionamento Fisiológico","authors":"W. Coutinho, Renata Silva-Mann, Maria das Graças Vieira, C. F. Machado, J. Machado","doi":"10.1590/S0100-41582007000600002","DOIUrl":"https://doi.org/10.1590/S0100-41582007000600002","url":null,"abstract":"Thermotherapy has been used for eliminating fungi on seeds. However, physiological and biochemical alterations, which may occur on seeds following this treatment, have not been thoroughly investigated. In this work, the efficacy of heat treatment (hot water) followed by osmopriming, in the control of fungi associated with maize seeds and its effects on physiological seed quality, was evaluated. The fungi associated with the seeds were detected by the deep-freezing blotter method, and physiological quality was determined by germination, first-germination counting and electric conductivity tests in addition to determination of eletrophoretic patterns of the enzymes: esterase (EST), malate dehidrogenase (MDH) and alcohol dehidrogenase (ADH). The heat treatment used was hot water at 60°C for 5, 10 and 20 minutes. After treatment, a fraction of the seeds was submitted to osmopriming on roll paper soaked in PEG 6000 solution at -1.2 MPa. All heat treatments reduced or eliminated Acremonium strictum on maize seeds. Heat treatments for 10 and 20 minutes reduced significantly the percentage of Fusarium verticillioides. Increasing period of heat treatment raised the values of conductivity and reduced significantly seed germination rate and first-germination counting. Heat treatment for 20 minutes altered the eletrophoretic pattern of esterase and malate dehidrogenase enzymes. Osmopriming did not reverse damage caused by the heat treatments.","PeriodicalId":211183,"journal":{"name":"Fitopatologia Brasileira","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114835498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pseudocercospora holmskioldiae and Cercospora apii associated with foliar spots on Holmskioldia sanguinea in Brazil","authors":"E. M. Ferreira, D. J. Soares","doi":"10.1590/S0100-41582007000600012","DOIUrl":"https://doi.org/10.1590/S0100-41582007000600012","url":null,"abstract":"RESUMO Pseudocercospora holmskioldiae e Cercospora apii associadas a manchas foliares em Holmskioldia sanguinea no Brazil Durante os anos de 2004-2006, observou-se em plantas de Holmskioldia sanguinea (Verbenaceae), cultivadas no Campus da Universidade Federal de Viçosa (UFV) a ocorrência de manchas foliares. As estruturas fúngicas presentes nas lesões foram examinadas e corresponderam a Cercospora apii e Pseudocercospora holmskioldiae. Este é o primeiro relato destes fungos associados a H. sanguinea no Brasil.","PeriodicalId":211183,"journal":{"name":"Fitopatologia Brasileira","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127961793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Caracterização de isolados de Acidovorax avenae subsp. citrulli","authors":"J. C. Oliveira, E. B. D. Silveira, R. D. L. R. Mariano, Enildo Cardoso, Ivanise O. Viana","doi":"10.1590/S0100-41582007000600005","DOIUrl":"https://doi.org/10.1590/S0100-41582007000600005","url":null,"abstract":"Forty-one isolates of Acidovorax avenae subsp. citrulli were characterized based on physiological and biochemical aspects. All isolates induced typical symptoms of fruit blotch on seedlings, plants and fruits of melon (Cucumis melo) and watermelon (Citrullus lanatus).  The Scott-Knott test (P = 0.05) separated the isolates for disease index in 5 and 7 groups, respectively, for melon and watermelon seedlings, and 2 groups for plants of these two hosts.  In fruits, all isolates were separated in 3 and 10 groups for the variable diameter of extern lesion, and 2 and 9 groups for lesion depth, respectively, for melon and watermelon. All isolates induced hypersensitivity in tobacco (Nicotiana tabacum); utilized the composites asparagine, L-leucine and DL-acid lactic; produced enzymes lipolytic and phytohormone indoleacetic acid.  None of the isolates studied showed pectinolytic, amylolytic, cellulolytic or proteolytic activity, nor produced polysaccharide levan and toxin syringomycin; showed sensitivity to copper oxychloride (120 µg mL-1), cuprous oxide (120 µg mL-1), copper hydroxide (138.2 µg mL-1), streptomycin sulfate (25 µg mL-1) and Agrimaicin 500 (428 µg mL-1); and resistance to kasugamycin (87 µg mL-1), agrimicin (200 µg mL-1), erythromycin (15 µg), gentamicin (10 µg), amoxicilin (10 µg), neomycin (30 µg) streptomycin (10 µg), norfloxacin (10 µg) and rifampicin (5 µg). With regard to tetracycline (30 µg), variability was found among the 41 isolates, with 41.5% considered resistant, 46.3% moderately sensitive and 12.2% highly sensitive.","PeriodicalId":211183,"journal":{"name":"Fitopatologia Brasileira","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121726737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reação de genótipos de cacaueiros a isolados de Ceratocystis cacaofunesta","authors":"S. D. V. M. Silva, E. P. Mandarino, V. O. Damaceno, Lindolfo Pereira dos Santos Filho","doi":"10.1590/S0100-41582007000600009","DOIUrl":"https://doi.org/10.1590/S0100-41582007000600009","url":null,"abstract":"Seventeen genotypes of cocoa (Theobroma cacao) were tested for reaction to Ceratocystis wilt caused by Ceratocystis cacaofunesta, using the three most virulent isolates among five isolates tested. In greenhouse conditions, a suspension containing 3.0 x 104 CFU/mL of each isolate was inoculated on six-month-old seedlings. The assay was carried out using a randomized complete block with 17 treatments, three replications and five seedlings per experimental unit. Assessments were made at 60 days after the inoculation date, by counting the number of healthy seedlings per plot unit. The data were analyzed by SAS statistical procedure and treatment averages were tested by Dunnett test at 5% significance level, using the cultivar Theobahia as control. From the genotypes analyzed, VB 1159 showed high resistance to the pathotype. The genotypes MUC 43, FL 78, VB 681, FC 101, VB 184, LP 06, ICS1, VB 902, FA 13, NO 34, PS 5784 and Theobahia showed moderate resistance, while CA 1.4, VB 206, LCT 37A and SJ 02 were the most susceptible genotypes. The new resistance source to Ceratocystis wilt identified in this work may be used in cocoa breeding programs and as a source of rootstock selection by farmers.","PeriodicalId":211183,"journal":{"name":"Fitopatologia Brasileira","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134334916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efeito da cercosporiose no rendimento de híbridos comerciais de milho","authors":"A. H. Brito, R. G. V. Pinho, E. A. Pozza, J. Pereira, Edmir Marques Faria Filho","doi":"10.1590/S0100-41582007000600004","DOIUrl":"https://doi.org/10.1590/S0100-41582007000600004","url":null,"abstract":"Effect of Gray leaf spot on yield of Commercial Maize Hybrids With the objective of quantifying the effect of gray leaf spot (Cercospora zeae-maydis) on yield of 12 commercial maize hybrids and of correlating grain yield reduction with disease severity, two experiments were performed at two sowing dates (November 11 th and December 23 rd , 2005) in the experimental area of the Federal University of Lavras (UFLA), Lavras, MG, Brazil. Disease control in healthy plots of all hybrids was obtained through two applications of epoxiconazol + pyraclostrobin – 37.5 + 99.75 g i.a.ha -1 ) at a 15-day interval. In uncontrolled plots, epidemic development started from natural inoculum present in the area. Eight evaluations of disease severity based on visual symptoms were performed at seven-day intervals from the 60 th day after maize emergence, ranging from 1 (resistant) to 9 (susceptible). The area under the disease progress curve (AUDPC) was estimated and grain yield per plot was also obtained. Results of damage percentage and correlations between grain yield and damage percentage with the estimates of the AUDPC were supported by the data. Damage intensity varied according to sowing season and hybrid, with an average of 13.3%. Maize gray leaf spot reduces the corn grain yield, mainly in the late sowing season, and the use of resistant hybrids excludes the chemical control of the disease. Additional keywords: Zea mays, damage, disease evaluation, fungal disease.","PeriodicalId":211183,"journal":{"name":"Fitopatologia Brasileira","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132992708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Expression of Grapevine leafroll-associated virus 3 coat protein gene in Escherichia coli and production of polyclonal antibodies","authors":"T. Fajardo, D. Barros, O. Nickel, G. B. Kuhn, F. Zerbini","doi":"10.1590/S0100-41582007000600007","DOIUrl":"https://doi.org/10.1590/S0100-41582007000600007","url":null,"abstract":"Grapevine leafroll-associated virus 3 (GLRaV-3), the main viral species of the grapevine leafroll complex, causes yield and quality reduction in grapes (Vitis spp.). The coat protein gene was RT-PCR-amplified from total RNA extracted from infected grapevine leaves and the amplified fragment was cloned and completely sequenced. The fragment was subsequently subcloned into the pRSET-C expression vector. The recombinant plasmid was used to transform Escherichia coli BL21:DE3 and express the capsid protein. The coat protein, fused to a 6 His-tag, was purified by affinity chromatography using an Ni-NTA resin. The identity of the purified protein was confirmed by SDS-PAGE and Western blot. The in vitro-expressed protein was quantified and used for rabbit immunizations. The antiserum was shown to be sensitive and specific for the detection of GLRaV-3 in grapevine extracts in Western blot and DAS-ELISA assays, with no unspecific or heterologous reactions against other non-serologically related viruses being observed.","PeriodicalId":211183,"journal":{"name":"Fitopatologia Brasileira","volume":"38 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130969442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Avaliação de danos causados pelo Barley yellow dwarf virus: PAV em cultivares de trigo no Brasil","authors":"Ariane C. Lanzarini, J. Schons, J. R. Salvadori, Alexandre Augusto Nienow, Fernanda Nicolini-Teixeira, Francini Binotto-Missiura, Elaine Deuner","doi":"10.1590/S0100-41582007000600011","DOIUrl":"https://doi.org/10.1590/S0100-41582007000600011","url":null,"abstract":"Assessment of damage caused by the Barley yellow dwarf virus in Brazilian wheat cultivars The aim of this study was to assess the damage caused by the Barley yellow dwarf virus (BYDV-PAV) in five wheat cultivars (BRS 177, BRS 179, BRS 194, BRS Camboata and BRS Angico) grown in a greenhouse at Embrapa (Empresa Brasileira de Pesquisa Agropecuaria), Passo Fundo, state of Rio Grande do Sul, Brazil, in 2005. The damage caused by the BDV-PAV was determined by the analysis of agronomic traits (plant height and dry matter) and yield (number of tillers, ears, and grains per plant; thousand-grain weight). The data were submitted to the analysis of variance and the means were determined by Tukey's test at 5%. The virus significantly affected all of the tested variables. Among the agronomic traits, dry matter was the most affected one, with rates between 26.1% (BRS 177) and 51.4% (BRS 179). Reductions in plant height ranged between 12.5% (BRS 177) and 15.5% (BRS Camboata). Total grain yield was greatly affected by the viral infection, with significant damage in all cultivars, with a reduction between 34.2% (BRS Camboata) and 60.8% (BRS 179). There was a reduction in the mean number of tillers per plant only in BRS Angico and BRS 179 cultivars, which amounted to 20 % and 26.6% respectively. The reduction in the mean number of grains varied between 26.1% (BRS Camboata) and 54.3% (BRS 179). Finally, the reduction in thousand-grain weight corresponded to 16.9% and 38.4% in BRS Camboata and BRS 194 cultivars, respectively. Additional keywords: Luteovirus, aphids, Triticum aestivum.","PeriodicalId":211183,"journal":{"name":"Fitopatologia Brasileira","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122021724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Is it necessary to soak rice grains to prepare Rhizoctonia solani AG-4 inoculum?","authors":"T. J. P. Júnior, R. F. Vieira, W. C. Júnior, B. Hau, H. Teixeira","doi":"10.1590/S0100-41582007000600008","DOIUrl":"https://doi.org/10.1590/S0100-41582007000600008","url":null,"abstract":"A study was conducted to evaluate the effects on the development of root rot on common bean, cv. 'Dufrix' after treatment with four volumes of water (0, 30%, 60%, and 90%, v/w) added to rice grains previously immersed in water for 24 hours before autoclaving and colonization of grains by Rhizoctoniasolani AG-4. Colonized rice grains and non-infested rice grains were mixed in pots with sterilized soil and sand (2:1), where beans were sown. Based on results of area under plant emergence curve, plant height, plant dry weight, and disease severity, we conclude that inoculum is more effective in causing disease when no water is added to the rice grains before autoclaving.","PeriodicalId":211183,"journal":{"name":"Fitopatologia Brasileira","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134598878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}