Abstract
Watermelon (Citrullus lanatus) and squash (Cucurbita pepo) are traditionally grown in northern Serbia, in the province of Vojvodina. Most of the cucurbit cultivars grown in Serbia originate from imported seed. In July 2013, round, water-soaked lesions were observed on the fruits on sporadic squash plants grown in two fields of the breeder variety trials in Bački Petrovac. Affected tissue was light brown, slightly sunken, soft, and macerated. From symptomatic plants (cultivar GL Maxima), showing 30% symptom intensity, a uniform population of bacterial colonies was isolated, and one strain was chosen for the collection. In August of the following season, infection of the vine was observed on watermelon plants (cultivar unknown) grown in a commercial field in Čelarevo. Soft rot brownish lesions developed on infected stems, resulting in collapse and wilting of entire vines. The number of plants affected with symptoms was less than 10%. From the colonies isolated from the diseased tissue, two bacterial strains were purified and stored in the collection. Being pectolytic and isolated from cucurbits, the squash strain and two watermelon strains were subjected to further characterization. The strains developed white-gray, nonmucoid, round colonies with irregular margins on nutrient agar medium. They were gram and oxidase negative, tobacco HR and catalase positive, facultative anaerobes, nonfluorescent, caused soft rot on potato tuber slices, grew at 37°C, and reduced nitrate. They neither utilized arginine nor produced acid from sorbitol and inositol, showing characteristics of Pectobacterium species (De Boer and Kelman 2001). The PCR assay was carried out using primers BR1f/L1r (Duarte et al. 2004), specific for Pectobacterium carotovorum subsp. brasiliense (Pcb). A specific fragment of 322 bp was amplified for all three strains tested. The 16S rDNA sequence analysis (GenBank nos. MH031784, MH031785, and MH031786) showed 99% identity to the sequences of Pcb isolated from cucumber (CP020350), pepper (KX377597), and cabbage (KY021040) in China and potato in Japan (LC146476). The recA (MK911735, MK911736, and MK911737) and gapA (MK911738, MK911739, and MK911740) sequence analysis of three strains showed the highest nucleotide identity (100 to 98.35% and 99.42 to 98.08%, respectively) with Pcb previously deposited in NCBI GenBank database. Pathogenicity of the strains was tested on 2-week-old watermelon (cv. Rosa) and melon (cv. Sezam) seedlings, grown in a commercial potting mix in a greenhouse, as well as on mature zucchini fruits. Three seedlings per strain were inoculated by spraying with bacterial suspension (approx. 1 × 108 CFU/ml) using a handheld sprayer. Inoculated plants were incubated under plastic bags for 24 h and afterward maintained in a greenhouse at 28 ± 2°C. Two days after inoculation, water-soaked lesions developed on cotyledons of the watermelon and melon plants. No symptoms were observed on control plants sprayed with water. Three zucchini fruits were inoculated by pricking with a syringe and hypodermic needle and leaving a droplet of bacterial suspension (approx. 1 × 107 CFU/ml) at the point of inoculation. Inoculated fruits were placed on wet filter paper in a sealed plastic container at 28 ± 2°C. Treatment with sterile distilled water was used as a negative control. Discoloration of the tissue and soft rot spreading from the inoculation point developed within 48 h from inoculation. No symptoms developed on the control fruits. To complete Koch’s postulates, bacteria were reisolated from the inoculated plant and fruit tissue and were identified as Pcb by PCR assay (Duarte et al. 2004). This is the first report of Pcb causing soft rot of squash and watermelon in Serbia. The origin of the pathogen remained unknown. It might have been present in Serbia for some time but misidentified in previous studies that could not discriminate this subspecies or recently introduced by infected seed.
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Claims 13
Claim · model-written summary
Pectobacterium carotovorum subsp. brasiliense was first reported causing soft rot on squash and watermelon in Serbia.
- Taxon
- squash and watermelont0
- Interactor
- Pectobacterium carotovorum subsp. brasiliensePectobacterium brasilienset0pathogen
- Outcome
- soft rott0
- Setting
- Serbiat0
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e1“This is the first report of Pcb causing soft rot of squash and watermelon in Serbia”
Claim · model-written summary
The 16S rDNA sequence of the strains showed 99% identity to Pcb isolates from cucumber, pepper, cabbage and potato.
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e2“The 16S rDNA sequence analysis (GenBank nos. MH031784, MH031785, and MH031786) showed 99% identity to the sequences of Pcb isolated from cucumber (CP020350)”
Claim · model-written summary
The recA sequences of three strains showed the highest nucleotide identity (100 to 98.35%) with Pcb sequences in GenBank.
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e3“The recA (MK911735, MK911736, and MK911737) and gapA (MK911738, MK911739, and MK911740) sequence analysis of three strains showed the highest nucleotide identity (100 to 98.35% and 99.42 to 98.08%, respectively) with Pcb previously deposited in NCBI GenBank database”
Claim · model-written summary
The gapA sequences of three strains showed the highest nucleotide identity (99.42 to 98.08%) with Pcb sequences in GenBank.
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e3“The recA (MK911735, MK911736, and MK911737) and gapA (MK911738, MK911739, and MK911740) sequence analysis of three strains showed the highest nucleotide identity (100 to 98.35% and 99.42 to 98.08%, respectively) with Pcb previously deposited in NCBI GenBank database”
Claim · model-written summary
Spray inoculation with the strains caused water-soaked lesions on watermelon and melon seedlings, but not on water-sprayed controls.
- Taxon
- watermelon and melon
Citrullus lanatus.jpg?width=60)
Cucumis meloe5 - Treatment
- inoculated by spraying with bacterial suspensione4
- Interactor
- Pectobacterium carotovorum subsp. brasiliensePectobacterium brasilienset0pathogen
- Outcome
- water-soaked lesionse5
- Comparator
- control plants sprayed with watere6
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e4“Three seedlings per strain were inoculated by spraying with bacterial suspension (approx. 1 × 108 CFU/ml) using a handheld sprayer”
e5“Two days after inoculation, water-soaked lesions developed on cotyledons of the watermelon and melon plants”
e6“No symptoms were observed on control plants sprayed with water”
Claim · model-written summary
Inoculation by pricking caused soft rot within 48 h on zucchini fruits, but not on sterile-water controls.
- Taxon
- zucchini
Cucurbita pepo subsp. pepoe1 - Organ / stage
- fruitse1
- Treatment
- inoculated by prickinge1
- Interactor
- Pectobacterium carotovorum subsp. brasiliensePectobacterium brasilienset0pathogen
- Outcome
- soft rote2
- Qualifier
- within 48 he2
- Comparator
- sterile distilled watere3
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e1“Three zucchini fruits were inoculated by pricking with a syringe and hypodermic needle and leaving a droplet of bacterial suspension (approx. 1 × 107 CFU/ml) at the point of inoculation”
e2“Discoloration of the tissue and soft rot spreading from the inoculation point developed within 48 h from inoculation”
e3“Treatment with sterile distilled water was used as a negative control”
Claim · model-written summary
Bacteria reisolated from inoculated plant and fruit tissue were identified as Pcb by PCR, completing Koch’s postulates.
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e1“To complete Koch’s postulates, bacteria were reisolated from the inoculated plant and fruit tissue and were identified as Pcb by PCR assay”
Claim · model-written summary
Round, water-soaked lesions were observed on fruits of sporadic squash plants in two breeder variety trial fields in Bački Petrovac.
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e1“round, water-soaked lesions were observed on the fruits on sporadic squash plants grown in two fields of the breeder variety trials in Bački Petrovac”
Claim · model-written summary
Symptomatic squash plants of cultivar GL Maxima showed 30% symptom intensity.
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e1“From symptomatic plants (cultivar GL Maxima), showing 30% symptom intensity”
Claim · model-written summary
Vine infection was observed on watermelon plants in a commercial field in Čelarevo.
- Taxon
- watermelonCitrullus lanatust0
- Outcome
- infection of the vinee1
- Setting
- commercial field in Čelarevoe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e1“infection of the vine was observed on watermelon plants (cultivar unknown) grown in a commercial field in Čelarevo”
Claim · model-written summary
Soft rot lesions on infected watermelon stems led to collapse and wilting of entire vines.
- Taxon
- watermelonCitrullus lanatust0
- Organ / stage
- infected stemse1
- Outcome
- collapse and wilting of entire vinese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e1“Soft rot brownish lesions developed on infected stems, resulting in collapse and wilting of entire vines”
Claim · model-written summary
Fewer than 10% of watermelon plants showed symptoms.
- Taxon
- watermelonCitrullus lanatust0
- Outcome
- plants affected with symptomse1
- Value
- less than 10%e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e1“The number of plants affected with symptoms was less than 10%”
Claim · model-written summary
The strains caused soft rot on potato tuber slices.
- Taxon
- squash and watermelont0
- Organ / stage
- potato tuber slicese1
- Interactor
- Pectobacterium carotovorum subsp. brasiliensePectobacterium brasilienset0pathogen
- Outcome
- soft rote1
Verbatim
t0“First Report of Pectobacterium carotovorum subsp. brasiliense Causing Soft Rot on Squash and Watermelon in Serbia”
e1“caused soft rot on potato tuber slices”
The same questions in other papers
application · Pectobacterium brasiliense · Cucumis melo (muskmelon)Results agree
1 paper in the same direction as this paper
- negative
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.