Pseudomonas populations causing pith necrosis of tomato and pepper in Argentina are highly diverse

Abstract

Pseudomonas species causing pith necrosis symptoms on tomato and pepper collected in different areas of Argentina were identified as Pseudomonas corrugata , P. viridiflava and Pseudomonas spp. Their diversity was analysed and compared with reference strains on the basis of their phenotypic characteristics, copper and antibiotic sensitivity tests, serology, pathogenicity, DNA fingerprinting and restriction fragment length polymorphism (RFLP) analysis of a 16S rRNA gene fragment. All P. corrugata strains tested were copper-resistant while P. viridiflava strains were more variable. Numerical analysis of phenotypic data showed that all P. corrugata strains formed a single phenon that clustered at a level of about 93%, while all the P. viridiflava strains clustered in a separated phenon at a level of 94%. Genomic analysis by repetitive (rep)-PCR and 16S rRNA-RFLP fingerprinting and serological analysis showed that the two species contained considerable genetic diversity. Inoculations of tomato and pepper plants with strains from both hosts caused similar pith necrosis symptoms. Strains of both P. corrugata and P. viridiflava were grouped according to their geographical origin and not according to the original host. This is the first report of Pseudomonas viridiflava causing pith necrosis on pepper.

Characterization of Pseudomonas viridiflava Causing Alfalfa Root Rot Disease in Hamedan Province of Iran

“…viridiflava which causes alfalfa crown and root rot disease also affects melon, tomato, pumpkin, cauliflower, cabbage, grapevine, lettuce, carrot, peas, poppy, turnip, eggplant, sweet onion, kiwi, and clover [4,6,16]. The causal bacterium of the disease is found in the intercellular spaces of the seed parenchyma [17].…”

“…The bacterium is more active under humid and raining condition, and it can spread through the rain drops [3]. P. viridiflava has broad host range and causes leaf blight on melon, tomato, pumpkin, cauliflower, cabbage, grapevine, lettuce, carrot, peas, poppy, turnip and eggplant, wilt of sweet onion, and canker and nude blight of kiwi [4][5][6]. This bacterium was observed as second pathogen for pith necrosis of tomato and pepper, and has ability of transfer through the seeds in tomato and pepper.…”

Perturbation of spermine synthase Gene Expression and Transcript Profiling Provide New Insights on the Role of the Tetraamine Spermine in Arabidopsis Defense against Pseudomonas viridiflava

“…Pseudomonas viridiflava strain Pvalb8 (Alippi et al, 2003) was kindly supplied by Dr. Adriana Alippi (Facultad de Agronomía, Universidad Nacional de La Plata, Argentina). This bacterium was cultivated at 28°C in King's B medium (King et al, 1954).…”

Apoplastic Polyamine Oxidation Plays Different Roles in Local Responses of Tobacco to Infection by the Necrotrophic FungusSclerotinia sclerotiorumand the Biotrophic BacteriumPseudomonas viridiflava

“…The fungus was routinely maintained in potato-dextrose agar slants at 4°C. Prior to inoculation on tobacco (Nicotiana tabacum), mycelium was grown in solid Czapek-Dox medium (50 g L (Alippi et al, 2003) was maintained at 280°C in King's B medium (King et al, 1954) amended with 20% glycerol.…”

“…This fungus is considered a necrotroph because it kills host cells during the infection process and causes extensive tissue damage (Bolton et al, 2006). The other pathogen employed in this study was Pseudomonas viridiflava, a bacterium that causes tomato (Solanum lycopersicum) pith and basal stem rot (Malathrakis and Goumas, 1987), and is also pathogenic on other hosts, including tobacco (Alippi et al, 2003). Similarly to other Pseudomonas species (Glazebrook, 2005), P. viridiflava multiplies asymptomatically in the intercellular spaces of the host early during the infection process, chlorosis and necrosis being evident only at later stages.…”