Pith Necrosis Research Articles

Characterization and host range evaluation of Pseudomonas viridiflava from melon, blite, tomato, chrysanthemum and eggplant

The fluorescent bacterium Pseudomonas viridiflava (Burkholder) Dowson was identified as the causal agent of bacterial leaf blight of melon, tomato, blite, eggplant and of pith necrosis of chrysanthemum plants. Koch's postulates were fulfilled on greenhouse-grown or on potted plants under controlled environmental conditions. Twenty seven cultivated and one weed species, when artificially inoculated, were found to be susceptible to a strain of the bacterium isolated from cucumber. In cross-inoculation tests on potted plants, each strain induced the disease symptoms, independently of the host of origin. To our knowledge, melon and blite have not been previously reported as natural hosts of P. viridiflava. Also this is the first record of the bacterium as a foliar pathogen of melon, tomato, eggplant and blite and as a stem pathogen of chrysanthemum in Greece.

Taxonomy of Pseudomonas strains isolated from tomato pith necrosis: emended description of Pseudomonas corrugata and proposal of three unnamed fluorescent Pseudomonas genomospecies.

Thirty-three fluorescent Pseudomonas strains isolated from tomato pith necrosis (FPTPN strains) and 89 Pseudomonas corrugata strains were studied by numerical taxonomy. In the dendrogram of distances, the P. corrugata strains constituted a single phenon (phenon 1), whereas 17 of the 33 FPTPN strains clustered in a separate phenon (phenon 2). The other 16 FPTPN strains were included in phena consisting of well-characterized fluorescent Pseudomonas species or were isolated phenotypes. Phena 1 and 2 were distinguished by fluorescence on King B medium, accumulation of poly-beta-hydroxybutyrate, production of levan, and assimilation of sorbitol. DNA-DNA hybridization showed that P. corrugata is a true genomic species (66 to 100% DNA relatedness) and that the FPTPN strains of phenon 2 were divided into three genomic groups. Genomic groups 1 and 2 were not distinct from each other phenotypically, and genomic group 3 could be distinguished from genomic groups 1 and 2 only on the basis of assimilation of citraconate and laevulinate. Genomic groups 1 and 2 are related to P. corrugata (40 to 55% DNA relatedness), whereas genomic group 3 is less closely related to P. corrugata (20 to 23% DNA relatedness). The lipopolysaccharide patterns on electrophoresis gels and fatty acid profiles of strains belonging to genomic group 1 through 3 are different from each other and from the lipopolysaccharide patterns and fatty acid profiles of P. corrugata. However, cross-reactions were observed between P. corrugata and the FPTPN strain genomic groups, indicating that there are common epitopes of the lipopolysaccharides. The three FPTPN strain genomic groups were not named as species but were designated Pseudomonas genomospecies FP1, FP2, and FP3.

Evidence for a New Class of Peptide Elicitor of the Hypersensitive Reaction from the Tomato PathogenPseudomonas corrugata

Three elicitor-active fractions were isolated from culture fluids of the rough isolate of Pseudomonas corrugata, a tomato pathogen that elicits the hypersensitive reaction (HR) in tobacco. Lyophilized, filtered culture fluids were extracted with methanol-ethyl acetate (80:20, vol/vol) to produce a water-soluble crude extract (CE). CE was partitioned with ethyl acetate to produce water-soluble aqueous (AQ) and organic (EA) fractions containing purified elicitor. P corrugata and the three fractions were tested for their ability to elicit HR in tobacco leaves, pith necrosis in tomato, and K + /H + exchange in tobacco tissue culture. Only P corrugata elicited pith necrosis in tomato; both bacteria and the fractions elicited HR in tobacco leaves; and bacteria and EA elicited K + /H + exchange in tobacco cells. The primary component in EA, HR2, did not cause a spreading lesion in tobacco and was therefore not a toxin. HR2 was found to be 95% pure by analytical high-performance liquid chromatography, to contain a fluorescent chromophore, and to be a peptide. HR2 contains glutamic acid, tyrosine, aspartic acid, glycine, alanine and/or arginine, isoleucine and/or leucine, and methionine and/or valine (approximate molar ratio 10:3:1:1:1:1:1). Since P corrugata is a useful biocontrol agent, these elicitors may have potential use in biocontrol.

Characterization of Spanish isolates of Pseudomonas corrugata from tomato and pepper

Pseudomonas was isolated from tomato plants with pith necrosis collected from different areas in Spain and from pepper plants with pith necrosis in Tenerife (Canary Islands). Cultural, biochemical and physiological characteristics of isolates from both hosts were similar to those of the type strain of P. corrugata. Serological heterogeneity was observed among isolates of P. corrugata in immunofluorescence tests. A plasmid of more than 273 MDa was detected in all the isolates. Inoculation of pepper and tomato plants with isolates from both hosts caused similar pith necrosis. This is apparently the first report of P. corrugata on pepper.

Occurrence of Tomato Pith Necrosis Caused by Pseudomonas corrugata in Massachusetts

Occurrence of Tomato Pith Necrosis Caused by Pseudomonas corrugata in Massachusetts

Occurrence of Pith Necrosis of Tomato Caused by Pseudomonas corrugata Roberts and Scarlett 1981 in Fukushima Prefecture

Occurrence of Pith Necrosis of Tomato Caused by <I>Pseudomonas corrugata</I> Roberts and Scarlett 1981 in Fukushima Prefecture

Occurrence in Soil and Primary Infections of Pseudomonas corrugata Roberts and Scarlett

AbstractThe occurrence of Pseudomonas corrugata in soil has been checked. Semiselective medium TNR (a modified SNR) permitted to isolate the causal agent of “tomato pith necrosis” from that source. The average soil population of the bacteria was 3.1 × 104 CFU × g of soil. P. corrugata was also isolated from plants sowed in the naturally infected soil. It was supposed that primary infections came from here.

Pseudomonas corrugata . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Pseudomonas corrugata . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Lycopersicon esculentum . Also isolated from symptomless roots of Medicago saliva . DISEASE: Tomato pith necrosis. The pith is discoloured brown to dark brown and may show cavities, especially in the lower parts of the stem. External symptoms frequently seen include chlorosis of upper leaves, sometimes a brown to black external stem lesion where the pith is most badly affected, bacterial exudate from leaf scars, pruning and other wounds, and on older plants prolific development of adventitious roots on the stems in areas where the pith is most badly affected. GEOGRAPHICAL DISTRIBUTION: South Africa, New Zealand (cultures at CMI), Denmark (62, 6), England, Germany (East 60, 5559; West 61, 6591), Italy (S. Sardinia 63, 1960), USA (CA 62, 2155; F 62, 3656; PA 59, 919 on Lucerne). The distribution is probably much more widespread than these records show. TRANSMISSION: The bacterium is probably common in the environment. It has, for example, been isolated from mains water which was being used to irrigate an affected crop. It is probably also spread from plant to plant by man in cultural operations. The disease is favoured by high humidity or wet foliage and high nitrogen levels in the soil; conditions that favour soft plant growth that is most susceptible.

New plant disease record in New Zealand: Tomato pith necrosis caused byPseudomonas corrugata

Abstract Pseudomonas corrugata Scarlett et al. 1978 is identified as the cause of tomato pith necrosis of glasshouse and field-grown tomato (Lycopersicon lycopersicum (L.) Karst ex Farw.). This is the first record of the pathogen in New Zealand.

Efeito de doses de boro aplicadas no sulco de plantio do algodoeiro, em solo deficiente

Em um Latossolo Vermelho-Amarelo - fase arenosa, deficiente em boro para a lavoura algodoeira, no município de Leme (SP), foram conduzidos ensaios de campo com doses variáveis do micronutriente durante os anos agrícolas de 1976/77, 1977/78 e 1978/79. No primeiro ano, o boro foi fornecido no sulco de plantio nas doses de 0,0, 0,5, 1,0, 1,5 e 2,0kg/ha sob a forma de bórax; nos anos subseqüentes, introduziram-se mais dois níveis: 0,75 e l,25kg/ha. A adubaçao básica anual foi 10-60-75kg/ha de N, P²O5 e K2O, no sulco de plantio, e duas coberturas de 30kg/ha de N. O efeito médio do boro sobre a produção de algodão em caroço foi positivo e altamente significativo, com, tendência para crescer com o nível de produtividade das plantas. Estudo econômico, segundo método do trinômio do segundo grau, revelou a dose de l,23kg/ha de B como a mais econômica, com receita líquida da ordem de Cr$ 22.862,00 por hectare, devida à aplicação do micronutriente. O peso médio de um capulho e a precocidade de colheita também foram influenciados favoravelmente, enquanto a maturidade da fibra se mostrou prejudicada pela adubação boratada. Dentre os sintomas relatados como de deficiência do micronutriente, destacaram-se: deformações na flor, atraso no ciclo das plantas, engrossamento e rachaduras no caule, superbrotamento e anéis concêntricos no pecíolo e no caule.

Tomato pith necrosis caused by Pseudomonas corrugata n. sp.

SUMMARYA disease of mature tomato plants is described, the symptoms of which include brown discoloration and/or necrosis and collapse of the pith. These are sometimes accompanied by vascular browning, external dark brown to black stem lesions, bacterial flux from stem wounds and adventitious root formation. The disease, which appears to be favoured by high humidity and/or free water on the plant surfaces and by high N fertiliser, has been widespread on many glasshouse holdings in England since 1971 but has caused severe loss on only a few. It is thought to be caused by a new species of the genus Pseudomonas for which the name P. corrugata Roberts and Scarlett is proposed.