Ana Rosa Peixoto

Hospedeiros Alternativos de Xanthomonas campestris pv. viticola

Xanthomonas campestris pv. viticola (Xcv), which causes the bacterial canker of grapevine, survives in infected plants as an epiphyte on aerial plant parts and may be carried in infected transplants and/or cuttings. This study was performed to investigate putative alternative hosts of the pathogen, aiming to find support for disease management. Bacteria similar to Xcv were isolated from the weeds Alternanthera tenella, Amaranthus sp., Glycine sp. and Senna obtusifolia showing canker-like symptoms and collected in vineyards of Juazeiro and Petrolina at the Submedio Sao Francisco. No bacteria were isolated from Commelina benghalensis and Azadirachta indica showing similar symptoms. The pathogenicity of the isolates was confirmed in plants of A. tenella, Amaranthus sp., Glycine sp., S. obtusifolia and grapevine cv. Red Globe, under greenhouse conditions. The weeds Chamaesyce hirta, Dactyloctenium aegyptium, Eragrostis pilosa and Pilea sp., artificially inoculated with strains Xcv1 and UnB1216, also developed typical symptoms of bacterial canker.

Meio semi-seletivo para isolamento de Xanthomonas campestris pv. viticola

Bacterial canker caused by Xanthomonas campestris pv. viticola is the most important bacterial disease of grapevine in Submedio Sao Francisco. The isolation of X. campestris pv. viticola of infected plant tissues is impaired by the presence of bacterial contaminants including Microbacterium barkeri. Aiming to formulate a semi-selective medium 22 X. campestris pv. viticola isolates were tested in relation to 30 antibiotics. The semi-selective NYDAM medium (meat extract 3, peptone 5, glucose 10, yeast extract 5, agar 18 and ampicilin 0.1 in gL -1 ) inhibited M. barkeri and plant pathogenic bacteria allowing X. campestris pv. viticola isolation from hosts naturally infected in the field.

Controle biológico da murcha bacteriana do tomateiro, por Pseudomonas spp. fluorescentes

This literature review has the objetive of evaluating the antagonism potential of species of florescem Pseudomonas to Pseudomonas solanacearum which is the causal agent of bacterial wilt on the tomato crop. Due to serious limitation in the ejficiency of conventional methods of contrai, other strategies have been siudied, such as the use o/beneficiai microrganisms. Rhizobacteria have shown to be a viable alternative in the contrai of some diseases of difficult managmenl. Among the mechanisms which have been suggestedfor microbian control of plantpathogens with fluorescent rhizobacteria, can be used antibiotic production, bacteriocin, uric emimes and competition for colonization and survival capacity on the host. The survival capacity is very important in the introduction and stablishment ofthe microrganisms in the rhizosphere. These bacteria can aiso increse the development and yield of the host and can be calledplant growth promete rhizobacteria.

Induction of resistance to Xanthomonas campestris pv. viticola in grapevine plants.

The objective of this work was to evaluate the effect of Saccharomyces cerevisiae (SC), Acibenzolar-S-Methyl (ASM), organic acids and polyphenols (OAP) and potassium silicate (SiK) on protecting grapevine plants (cv. Redglobe) from Xanthomonas campestris pv. viticola. Four application rates for each product (SC at 2.0, 2.50, 3.0, 3.50 and 4.0 mL 100 L-1; ASM and OAP at 2.50, 3.00, 3.50, 4.50 and 6.00 mL 100 L-1 and SiK at 5.00, 6.50, 7.50 and 8.50 mL 100 L-1) in different application times (0, 5, 10, and 15 days before inoculation), and the enzymatic activity of peroxidases, phenylalanine ammonia-lyase and ?-1,3 glucanases were evaluated. Plants were inoculated with a bacterial suspension of 5 x 108 CFU mL-1 by rubbing with gauze. The epidemiological variables incidence (INC), severity (SEV) and area under the disease progress curve (AUDPC) were assessed. The treatment with ASM had the lowest averages of INC (38%) and SEV (1.52%) from 3 g 100 L-1. The application of 4.5 mL 100 L-1 of OAP reduced the plant disease in 52% of INC and 2.45% of SEV. SiK and SC presented no significant reduction in these variables compared to control. The ASM applied 15 days before the inoculation (DBI) reduced the disease in 91.31% and the APO in 73.34%, while SC and SiK reduced the disease in 67.49 and 60.11%, respectively, with applications at 5 DBI. There was no increase of peroxidase activity in any of the treatments. There was a significant increase in activity of ?-1,3 glucanases and phenylalanine ammonia-lyase in plants treated with ASM at 15 DBI, indicating an influence on the induction of resistance of plants to this disease.ABSTRACT Peach is much appreciated by consumers and its popularity is mainly related with organoleptic characteristics. However, with emergence of concepts of functional foods (health promoters), there is high interest to study and to quantify the biochemical components of fruits. The aim of this work was to perform the biochemical characterization of peach genotypes, evaluating the genetic diversity and selecting those with desirable biochemical qualities for use as parents in future breeding programs. The experiment was carried out at the Laboratory of Plant Physiology UTFPR Campus of Dois Vizinhos, PR (Brazil), with fruits from 26 and 29 peach genotypes (Prunus persica) in the 2009/2010 and 2010/2011 crop years, respectively. The experimental design was entirely randomized, considering each genotype as treatment, using four replicates and four fruits per plot. Total and reducing sugars, total proteins, amino acids, total phenols, anthocyanins, flavonoids and phenylalanine ammonia-lyase enzyme activity (PAL) in fruits were evaluated. According to the results of two crop years, ‘Cascata 967’, ‘Conserva 985’, ‘Kampai’, ‘Tropic Snow’ and ‘Cascata 1055’ were selected as those with the highest levels of these compounds.O pessego e uma fruta muito apreciada, cuja popularidade e decorrente principalmente de seu sabor agradavel. Entretanto, com o surgimento dos conceitos de alimentos funcionais (com propriedades promotoras de saude), surgira interesse maior em estudar e quantificar os componentes bioquimicos das frutas. Os objetivos deste trabalho foram caracterizar bioquimicamente frutos de genotipos de pessegueiro, e selecionar aqueles com qualidades bioquimicas desejaveis para sua futura insercao como genitores em programas de melhoramento. O experimento foi conduzido no Laboratorio de Fisiologia Vegetal e Bioquimica da UTFPR - Campus Dois Vizinhos, com frutos de 26 e 29 genotipos de pessegueiro ( Prunus persica ), provenientes dos ciclos produtivos 2009/2010 e 2010/2011, respectivamente. O delineamento experimental foi inteiramente casualizado considerando-se cada genotipo como tratamento, utilizando-se quatro repeticoes de quatro frutos. Foram analisados os acucares totais e redutores, proteinas totais, aminoacidos, fenois totais, antocianinas, flavonoides e atividade da enzima fenilalanina amonia-liase (FAL) dos frutos. Os pessegos foram caracterizados bioquimicamente, selecionando-se como superiores, na media dos dois ciclos produtivos os genotipos ‘Cascata 967’, ‘Conserva 985’, ‘Kampai’, ‘Tropic Snow’, e ‘Cascata 1055’.

Infection by Xanthomonas campestris pv.viticola under temperature increase and carbon dioxide concentrations.

The experiments were carried out under controlled conditions to evaluate the impact of increased temperature and concentration of carbon dioxide on infection of Xanthomonas campestris pv viticola, the causal agent of bacterial canker in Vine seedlings. It proceeded the evaluation of the following epidemiological components: incubation period (PI), severity (SEV) and using that data were calculated the area under the disease progress curve (AUDPC). It used grape seedlings (Italia, Crimson Seedless, Sugraone and Selection 8) inoculated with bacterial suspension (108 CFU mL-1). The experimental design was completely randomized, factorial arrangement 4x4 (cultivar x temperature) and 4x2 (cultivar x carbon dioxide concentration) which was carried out twice. The data were subjected to variance analysis. Increasing temperature reduced bacterium’s incubation period with significant differences between genotypes. For Selection 8 and Crimson temperature increase caused enhancement on severity and AUDPC. For Selecao 8 the incubation period (PI) was extended from 7.93 to 30.18 days when the concentration changed from 390 to 770 µmol/mol. The increased CO2 concentration reduced AACPSD and SEV for Sugraone and Selection 8. The results show that the temperature and carbon dioxide (CO2) concentration of the air may have different effects on bacterial canker of grapevine.

Estudos dos constituintes químicos e atividade antibacteriana do óleo essencial de Lippia gracilis a Xanthomonas campestris pv. viticola "in vitro"

Este trabalho foi realizado com o objetivo de estudar a eficacia de oleos essenciais de Lippia gracilis, no crescimento in vitro de Xcv. Foram utilizados oito oleos extraidos de L. gracilis, obtidos de diferentes manejos de cultivo, em tres dosagens diferentes (200; 250 e 300 µL.L-1), testemunha com o oxicloreto de cobre (controle padrao) e a testemunha absoluta. A suscetibilidade do isolado Xcv3 aos oleos testados foi avaliada na primeira etapa pela presenca e ausencia do crescimento bacteriano e, na segunda etapa, pela porcentagem de inibicao do crescimento bacteriano. A analise da composicao quimica dos oleos essenciais extraidos de L. gracilis, mostrou, o carvacrol (73,9 a 77%) como composto majoritario e o timol (4,9 a 10,3%). Os oleos referentes aos tratamentos 01, 06 e 07 foram os que proporcionaram maiores porcentagens de inibicao no crescimento bacteriano de Xcv: 94,75%, 96,50% e 94,02%, respectivamente, sendo superiores ao oxicloreto de cobre (49,6%).

Identificação de potenciais plantas hospedeiras alternativas de Xanthomonas campestris pv. viticola

Este estudo teve como objetivo identificar possiveis hospedeiras alternativas de Xanthomonas campestris pv. viticola (Xcv), visando a fornecer subsidios para o manejo do cancro bacteriano da videira. Vinte e seis especies vegetais foram inoculadas artificialmente com o isolado Xcv3 e mantidas em condicoes de casa de vegetacao, sendo avaliada a evolucao sintomatologica da doenca, como manchas necroticas angulares e lesoes nas nervuras. O Xcv3 foi reisolado a partir de cada hospedeiro alternativo com sintomas, sendo identificado por PCR (Polymerase Chain Reaction), com iniciadores especificos. As especies inoculadas que apresentaram os sintomas tipicos da doenca foram Glycine sp., Senna obtusifolia, Desmodium discolor, Amaranthus deflexus, Azadirachta indica, Solanum lycopersicum e Vigna unguiculata. As especies da familia Poaceae, Bidens pilosa, Emilia fosbergii, Praxelis pauciflora, Macroptilium lathyroides e Portulaca oleracea nao apresentaram sintomas durante o periodo da avaliacao.