Multiplication of Pseudomonas solanacearum in pure water.

Wakimoto, Satoshi; Utatsu, Ikuyo; Matsuo, Norifusa; Hayashi, Nagao

doi:10.3186/jjphytopath.48.620

Cited by 33 publications

(24 citation statements)

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“…One of them was a starvation response consisting of maintaining populations in a non-growing but culturable state, as commonly described for other bacterial species (Morita, 1997) but not for R. solanacearum as such up to now. Previous studies on survival of the pathogen were performed in sterile pure water (Kelman, 1956;van Overbeek et al, 2004;Wakimoto et al, 1982) or sterile natural water only for several months (Kelman, 1956;van Elsas et al, 2001) to a maximum of 1 year (Tanaka & Noda, 1973). During the starvation period in river water microcosms, proportions of the viable R. solanacearum populations progressively lost the ability to form colonies on plates, as already observed in starved bacteria (Besnard et al, 2000;Colwell & Huq, 1994), becoming VBNC as another survival strategy under prolonged oligotrophy.…”

Section: Discussionmentioning

confidence: 99%

“…After destruction of the plant, an inter-host life period has been proposed for this pathogen (Denny et al, 1994), where it would have to cope with the stress of oligotrophic habitats. Survival studies in sterile water have reported persistence of the bacterium for variable periods (Kelman, 1956;van Elsas et al, 2001;van Overbeek et al, 2004;Wakimoto et al, 1982), and occasional capacity to wilt susceptible hosts (Caruso et al, 2005;van Overbeek et al, 2004). Although some environmental factors affecting R. solanacearum physiology have been reviewed (Hayward, 1991;Kelman, 1953;van Elsas et al, 2005), knowledge of the survival strategies used by this pathogen under prevailing starvation in aquatic habitats is still scarce .…”

Section: Introductionmentioning

confidence: 99%

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Survival strategies and pathogenicity of Ralstonia solanacearum phylotype II subjected to prolonged starvation in environmental water microcosms

2008

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Survival strategies exhibited over 4 years by Ralstonia solanacearum phylotype (ph) II biovar (bv) 2 in environmental water microcosms were examined. The bacterium is a devastating phytopathogen whose ph II bv 2 causes bacterial wilt in solanaceous crops and ornamental plants. Outbreaks of the disease may originate from dissemination of the pathogen in watercourses, where it has to cope with prolonged nutrient limitation. To ascertain the effect of long-term starvation on survival and pathogenicity of R. solanacearum in natural water microcosms, survival experiments were conducted. Microcosms were prepared from different sterile river water samples, inoculated separately with two European strains of ph II at 10 6 c.f.u. ml "1 and maintained at 24 6C for 4 years. In all assayed waters, starved R. solanacearum remained in a non-growing but culturable state during the first year, maintaining approximately the initial numbers. Thereafter, part of the population of R. solanacearum progressively lost the ability to form colonies, and non-culturable but metabolically active cells appeared. During the whole period, the bacterium remained pathogenic on host plants and underwent a transition from typical bacilli to small cocci which tended to aggregate. Some starved R. solanacearum cells filamented and formed buds. Starvation response, viable but non-culturable state, morphological changes and aggregation have not previously been reported for this pathogen as survival mechanisms induced in oligotrophic conditions. The potential existence of long-starved pathogenic cells in environmental waters may raise new concerns about the epidemiology of bacterial wilt disease.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Survival strategies and pathogenicity of Ralstonia solanacearum phylotype II subjected to prolonged starvation in environmental water microcosms

2008

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“…Para a realização dos ensaios, o isolado foi cultivado no meio de tetrazólio (Kelman, 1954), com incubação por 48 h a 28±2 ºC. O isolado bacteriano foi preservado em tubos de ensaio contendo o meio nutriente-ágar (NA) coberto por óleo mineral esterilizado e em água destilada esterilizada (Wakimoto et al, 1982) (Di Piero, 2003). Para os testes realizados in vitro, os extratos aquosos foram esterilizados por filtragem (diâmetro do poro = 0,2 µm), sob condições assépticas, sendo posteriormente armazenados a 4 ºC até serem usados.…”

Section: Obtenção E Manutenção Dos Fitopatógenos E Das Plantasunclassified

Indução de resistência em tomateiro por extratos aquosos de Lentinula edodes e Agaricus blazei contra Ralstonia solanacearum

2007

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O presente trabalho foi conduzido com o objetivo de avaliar o efeito dos extratos aquosos dos cogumelos Lentinula edodes e Agaricus blazei e do indutor de resistência acibenzolar-S-metil (ASM) no controle da murcha bacteriana em tomate (Lycopersicon esculentum Mill.), bem como investigar o modo de ação destes produtos na atividade protetora, através de alterações na atividade de determinadas enzimas. Extratos aquosos dos cogumelos e o ASM foram testados na inibição do crescimento da bactéria in vitro. Em casa-de-vegetação, plantas foram tratadas com diferentes doses dos extratos e com ASM (0,05 g/L), dois dias antes da inoculação. As avaliações foram efetuadas com base na severidade da doença e determinação da atividade de algumas enzimas. Os isolados de A. blazei e L. edodes, bem como o ASM, não exerceram efeito inibitório direto no crescimento da bactéria. Quanto à indução de resistência, o isolado Le-96/17 de L. edodes na concentração de 10 % (v/v) e o ASM reduziram significativamente a ocorrência de murcha. As atividades de quitinase, fenilalanina amônia-liase e polifenoloxidase não foram alteradas para a maioria dos tratamentos, porém foi constatado um aumento na atividade de quitinase nas plantas tratadas com ASM. Para a peroxidase, os tratamentos ASM, Abl-26 e Le-96/17 ocasionaram aumentos na atividade da enzima e, com base nos resultados, o cogumelo L. edodes e o ASM apresentam potencial para reduzir a murcha bacteriana provavelmente através da indução de resistência.

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“…Para a realização dos ensaios, o isolado foi cultivado no meio de tetrazólio (14) e incubado por 48 h a 28±2ºC. O isolado bacteriano foi preservado em tubos de ensaio contendo o meio nutriente-agar (NA) coberto por óleo mineral esterilizado e em água destilada esterilizada (30), em temperatura ambiente ou na geladeira. Em todos os bioensaios, foi utilizado o híbrido de berinjela Hib.…”

Section: Obtenção E Manutenção Dos Fitopatógenos E Das Plantasunclassified

Indução de resistência em plantas de berinjela por Lentinula edodes e Agaricus blazei contra Ralstonia solanacearum: aspectos bioquímicos e biomassa vegetal

Silva

Pascholati²,

Bedendo³

2008

Summa phytopathol.

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The bacterial wilt, caused by Ralstonia solanacearum, is an important disease for eggplants, which control is difficult. Induction of resistance in plants is a promising method for disease control. Fruiting bodies of Agaricus blazei and Lentinula edodes have substances that exhibit antibiotic activity or are able of acting as elicitors of resistance in plants. The objectives of the present work were to verify the effect of aqueous extracts from the mushrooms and the plant activator acibenzolar-S-methyl (aSm) on in vitro bacterial growth and to control bacterial wilt as well as to investigate the activity of certain enzymes. The inhibitory effect on the pathogen was evaluated by using different concentrations of aqueous extracts. The induced resistance was studied in plants treated with the biological or chemical inducers, by measuring the intensity of wilt and alterations in some defense-related enzymes. The results showed that the isolates

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Multiplication of Pseudomonas solanacearum in pure water.

Abstract: Washed cells of the virulent isolates and avirulent or weakly-virulent mutants of Pseudomonas solanacearum suspended in pure water at a concentration of 102-3 cells/ml rapidly multiplied up to a level of 106 cells/ml during four days of incubation at 22C.

Cited by 33 publications

References 0 publications

Survival strategies and pathogenicity of Ralstonia solanacearum phylotype II subjected to prolonged starvation in environmental water microcosms

Survival strategies and pathogenicity of Ralstonia solanacearum phylotype II subjected to prolonged starvation in environmental water microcosms

Indução de resistência em tomateiro por extratos aquosos de Lentinula edodes e Agaricus blazei contra Ralstonia solanacearum

Indução de resistência em plantas de berinjela por Lentinula edodes e Agaricus blazei contra Ralstonia solanacearum: aspectos bioquímicos e biomassa vegetal

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