I. M. G. Almeida

Nitrite as the major source of nitric oxide production by Arabidopsis thaliana in response to Pseudomonas syringae

The origin of nitric oxide (.NO) in plants is unclear and an .NO synthase (NOS)‐like enzyme and nitrate reductase (NR) are claimed as potential sources. Here we used wild‐type and NR‐defective double mutant plants to investigate .NO production in Arabidopsis thaliana in response to Pseudomonas syringae pv maculicola. NOS activity increased substantially in leaves inoculated with P. syringae. However, electron paramagnetic resonance experiments showed a much higher .NO formation that was dependent on nitrite and mitochondrial electron transport rather than on arginine or nitrate. Overall, these results indicate that NOS, NR and a mitochondrial‐dependent nitrite‐reducing activity cooperate to produce .NO during A. thaliana–P. syringae interaction.

Differentiation of Xanthomonas species Pathogenic to Sugarcane by PCR-RFLP Analysis

The PCR-RFLP of the 16S-23S rDNA spacer region was used to differentiate Xanthomonas species pathogenic to sugarcane. Strains of X. albilineans, X. campestris pv. vasculorum Types A and B, X. sacchari and Xanthomonas sp. from Trinidad, South Africa and India were examined. The amplification products were digested with Alu I, Hae III, Hpa II and Mbo I and the results showed that the different groups of bacterial strains exhibited distinct RFLP patterns for each tested endonuclease, except X. albilineans and X. sacchari which could only be differentiated from each other by the digestion with Hpa II. The results also allowed the separation of X.c. pv. vasculorum Type A from X.c. pv. vasculorum Type B and strongly suggested that the analyzed Xanthomonas sp. strains belong to X. sacchari. Nine X. campestris (pv. not determined) strains included in this study showed identical profiles to X.c. pv. vasculorum Type A group and DNA–DNA hybridization experiments confirmed these results. PCR-RFLP of the 16S-23S rDNA spacer region could be applied as a reliable method for differentiating the xanthomonads pathogenic to sugarcane.

Pseudomonas syringae pv. tabaci in papaya seedlings

The natural occurrence of Pseudomonas syringae pv. tabaci causing leaf spot symptoms in papaya seedlings is reported. The pathogen was identified through biochemical, physiological, serological, and molecular assays and artificial inoculations in papaya plants. It was also shown that the strains were pathogenic to bean and tobacco plants. The restriction patterns obtained with Afa I, Alu I, Dde I, Hae III, Hpa II, Hinf I, Sau 3A I and Taq I of the PCR-RFLP of 16S-23S DNAr were identical to the P. s. pv. tabaci patterns. Primers corresponding to hrpL gene of P. syringae were also tested and the results grouped the papaya strains with P s. pv. tabaci. Bacterial strains were deposited at Colecao de Culturas IBSBF, Instituto Biologico, Campinas, Brazil, under access numbers 1687 and 1822.

Mancha bacteriana em Ruscus sp. causada por Burkholderia andropogonis no Brasil

Plants of ruscus (Ruscus sp.) showing symptoms of leaf spot were received for analysis in April 2008 from a field located in the region of Santo Antonio de Posse, state of Sao Paulo, Brazil. These spots were small, rounded, with 5 to 8 mm in diameter, dark brown in color, showing necrotic center and surrounded by chlorotic haloes. Slow-growing, cream-colored bacterial colonies were consistently obtained. The bacterium was Gram-negative, oxidative and not fluorescent. Artificial inoculations on healthy ruscus seedlings reproduced the symptoms observed in natural infections; the pathogen was re-isolated from the lesions. Biochemical, cultural, physiological and serological tests of the isolates identified the causal agent as Burkholderia andropogonis (former Pseudomonas andropogonis). This is the first report of this pathogen in ruscus in Brazil. Bacterial strains were deposited in the Phytobacteria Culture Collection of the Instituto Biologico (IBSBF) under numbers 2594 and 2595.

Avaliação da solarização do solo para o controle de Ralstonia solanacearum

The use of soil solarization for the control of bacterial wilt, caused by Ralstonia solanacearum, was evaluated by burrowing nylon bags containing soil infested with the bacteria in plots solarized or not. Two experiments were carried out in Campinas (SP), from February to April/2001, and Piracicaba (SP), from December/2001 to February/2002. The experiments were set up in a completely randomized factorial design, with four replications, in 4 x 4 meter plots. The factors evaluated were soil solarization with a transparent plastic film 100 µm thick, period of treatment (30 and 60 days and 37 and 60 days for the first and second experiments, respectively) and, only for the second experiment, soil depth (10 and 20 cm). The soil of each nylon bag collected after the previously established solarization periods, was placed in pots where tomato (Lycopersicon esculentum) seedlings were transplanted. In the non-solarized soil, in both experiments, 43 to 100% of the tomato plants wilted. In the second experiment, 6 to 22% of the plants grown on the soil solarized for 37 days wilted. No wilted tomato plants were observed in the solarized plots of the first experiment nor in the soil solarized for 60 days, in both soil depths, of the second experiment. The results obtained indicate that soil solarization has potential for the control of R. solanacearum.

Bacterial halo blight of coffee crop: aggressiveness and genetic diversity of strains

Bacterial halo blight, caused by Pseudomonas syringae pv. garcae, is an important disease of coffee crop occurring in Brazil and other countries. In recent years, outbreaks of this disease have damaged several coffee crops in Brazil. Aggressiveness and genetic diversity of 25 strains of P. s. pv. garcae, obtained between the years 1958 and 2011, in 23 cities of São Paulo and Minas Gerais states, as well as three strains from Kenya were evaluated in this study. The strains were inoculated on coffee seedlings cultivar Mundo Novo, and their genetic diversity was evaluated by ERIC-PCR, REP-PCR, and their combination. All the strains were pathogenic to the coffee seedlings; the results of pathogenicity tests, in both experiments, could be divided in four aggressiviness classes (highly aggressive; aggressive; moderately aggressive and less aggressive). The Kenyan PLANT PROTECTION Article Bacterial halo blight of coffee crop: aggressiveness and genetic diversity of strains Karen Wolf Maciel1*, Suzete Aparecida Lanza Destefano1, Luis Otavio Saggion Beriam1, Irene Maria Gatti de Almeida1, Flavia Rodrigues Alves Patricio2, Lucas Mateus Rivero Rodrigues3, Oliveiro Guerreiro Filho3 1.Instituto Biológico Laboratório de Bacteriologia Vegetal Campinas (SP), Brazil. 2.Instituto Biológico Laboratório de Fitopatologia Campinas (SP), Brazil. 3.Instituto Agronômico Centro de Café Campinas (SP), Brazil. *Corresponding author: karenwmaciel@hotmail.com Received: Jul 6, 2016 – Accepted: Feb. 28, 2017 strains grouped separately from the Brazilian strains with ERIC-PCR and the combination of ERICand REP-PCR. The Brazilian strains could be grouped in two sub-clusters, the first including the older strains, obtained from 1958 to 1978, and the other comprising the remaining strains. With a few exceptions, strains isolated from 1997 to 2011, grouped mainly by their region of origin, were predominantly isolated from higher altitude regions, above 800 m. This probably occurred because the climatic conditions that prevail in these regions, characterized by milder temperatures and regular rainfall, are favorable for the coffee crop and for the production of high quality coffee beverage, but can be also favorable to bacterial halo blight.

First report of mixed infection by Pseudomonas syringae pathovars garcae and tabaci on coffee plantations

ABSTRACT: The bacterial-halo-blight ( Pseudomonas syringae pv. garcae ) is disseminated by the main coffee areas in the producing states of Brazil. On the other hand, the disease bacterial-leaf-spot ( Pseudomonas syringae pv. tabaci ) was reported only once in coffee seedlings in a sample collected in the State of Sao Paulo. In mid-2015, samples of coffee leaves with symptoms of foliar lesions surrounded by yellow halo, were collected in coffee plantations in the State of Parana and fluorescent bacteria producing or not brown pigment in culture medium were isolated and determined as belonging to the Group I PLANT PROTECTION - Article First report of mixed infection by Pseudomonas syringae pathovars garcae and tabaci on coffee plantations Lucas Mateus Rivero Rodrigues 1 *, Gustavo Hiroshi Sera 2 , Oliveiro Guerreiro Filho 1 , Luis Otavio Saggion Beriam 3 , Irene Maria Gatti de Almeida 1.Instituto Agronomico - Centro de Cafe - Campinas (SP), Brazil.2.Instituto Agronomico do Parana - Area de Melhoramento e Genetica Vegetal - Londrina (PR), Brazil.3.Instituto Biologico - Laboratorio de Bacteriologia Vegetal - Campinas (SP), Brazil.

Diferenciação de bactérias do gênero Pseudomonas patogênicas ao cafeeiro por técnicas serológicas

Arq. Inst. Biol., v.84, 1-7, e0702016, 2017 ABSTRACT: Some bacterial diseases have been described causing problems in coffee, whose causal agents are Pseudomonas cichorii, P. syringae pv. garcae, P. s. pv. tabaci and Burkholderia andropogonis, all of them also occurring in Brazil. Attempts to differentiate these bacteria by double diffusion agar (dda) technique with antisera produced against whole cells of P. s. pv. garcae showed cross-reactions, especially among P. s. pv. garcae and P. s. pv. tabaci. Thus, antisera were produced against P. s. pv. garcae (pathotype strain IBSBF-248 — Phytobacteria Culture Collection of Instituto Biológico — IBSBF), using rabbit immunizations with antigens of the protein complex of membranes. These antisera were tested against different kind of antigens (autoclaved cells, cells treated with formaldehyde, capsule polysaccharides, glycoproteins, bacterial membrane proteins and bacterial suspension in 0.85% NaCl) extracted from P. cichorii, P. s. pv. garcae and P. s. pv. tabaci. The results showed that depending on the kind of antigen and the medium used in the double diffusion test (with or without MgCl2 and/or trypan blue), the antiserum reacted only with P. s. pv. garcae. Thus, these antigens may be used as an auxiliary tool in the rapid diagnosis of bacterial halo blight of coffee in the double diffusion test.

Detecção de Pseudomonas viridiflava em sementes importadas de couve chinesa (Brassica rapa var. pekinensis)

ABSTRACT A natural occurrence of Pseudomonas viridiflava inchinese cabbage ( Brassica rapa var. pekinensis ) imported seedsfrom Japan is described. From the epidemiological point of Maciel, K.W.; Almeida, I.M.G.; Silva, H.S.A; Rodrigues, L.M.S.; Beriam, L.O.S. Detection of Pseudomonas viridiflava in imported chinesecabbage ( Brassica rapa var. pekinensis ) seeds. Summa Phytopathologica, v.36, n.1, p.83-84, 2010. Keywords: bacterial disease. Palavras-chave adicionais: cdoenca bacteriana RESUMO A ocorrencia de Pseudomonas viridiflava e descrita em sementesde couve chinesa ( Brassica rapa var. pekinensis ) importadas do Japao.Do ponto de vista epidemiologico, a deteccao dessa bacteria e deextrema importância. Embora ja existam, em nosso pais, relatos desse Maciel, K.W.; Almeida, I.M.G.; Silva, H.S.A; Rodrigues, L.M.S.; Beriam, L.O.S. Deteccao de Pseudomonas viridiflava em sementes importadasde couve chinesa ( Brassica rapa var. pekinensis ). Summa Phytopathologica, v.36, n.1, p.83-84, 2010.

Host range and genotypes reaction to Pseudomonas cichorii

The occurrence of the bacterial blight, caused by Pseudomonas cichorii, was observed in two commercial tomato fields in the State of Sao Paulo in 2005. In view of this, studies were carried out in order to determine the host range of Pseudomonas cichorii isolates (IBSBF 2309 and IBSBF 2323), obtained from tomato plants at commercial fields located in the cities of Braganca Paulista and Mogi Guacu, SP, Brazil. Caserta pumpkin, lettuce, purslane, eggplant, beet, broccoli, carrot, Jimson weed, sunflower, tobacco, scarlet eggplant, melon, cucumber, petunia, green pepper, radish, cabbage, arugula, parsley, and tomato plants were spray-inoculated separately with two isolates of P. cichorii obtained from tomato and one from sunflower (GIR-1). The isolates IBSBF 2309 and IBSBF 2323 were pathogenic to purslane, Jimson weed, sunflower, green pepper, and tomato; GIR-1 was only pathogenic to purslane, Jimson weed, and sunflower, but not pathogenic to green pepper or tomato. In Brazil, no sources of resistance to this bacterium are known within the Lycopersicon genus. The reaction of tomato cultivars to the bacterium is also unknown. Twenty-eight tomato genotypes from the Sakata Seed Sudamerica Ltda. Germplasm Bank were evaluated for their reaction to P. cichorii isolates IBSBF 2309 and IBSBF 2323, using the leaf inoculation method. The highest resistance levels were observed in tomato genotypes AF 11768, AF 2521, AF 11766, AF 11772, AF 229, AF 5719-1, and AF 8162. The genotype AF 5719-1, wich has the Pto gene imparting resistance to P. syringae pv. tomato, showed a good level of resistance to P. cichorii. The identification of genotypes with good levels of resistance to this pathogen is important, since they represent potential resources to be used in tomato breeding programs for incorporation of resistance genes against P. cichorii.