Abstract
Pythium aphanidermatum damping-off is an important soilborne disease in tomato in Oman, causing seedling mortality. In addition, soil salinity, high summer temperature and drought affect the productivity of this crop in Oman. In this work, the antagonistic potential of bacteria isolated from tomato rhizosphere soil against P. aphanidermatum and their tolerance to salinity, heat and drought were investigated. A total of seven morphologically different bacterial isolates were obtained from tomato rhizosphere soil collected from farmers’ fields in Barka, Oman. These isolates were identified as Bacillus cereus (TRB1 and TRB2), Oceanobacillus neutriphilus (TRB3), Cytobacillus kochii (TRB4), Bacillus paramycoides (TRB5), Oceanobacillus iheyensis (TRB7) and Priestia endophytica (TRB8) based on their 16S rRNA gene sequence data. Among them, O. iheyensis TRB7 was the most active in inhibiting P. aphanidermatum mycelial growth in the dual culture plate assay, achieving 35.5% inhibition compared to the control. The isolates O. neutriphilus TRB3 and C. kochii TRB4 demonstrated tolerance to 10% NaCl, while B. cereus TRB2 and P. endophytica TRB8 exhibited tolerance up to 7.5% NaCl in the culture medium. Four bacterial isolates viz., B. cereus TRB2, C. kochii TRB4, B. paramycoides TRB5, and O. iheyensis TRB7 exhibited heat tolerance (50°C), while all seven bacterial isolates showed drought tolerance. The in vitro compatibility analysis showed that O. iheyensis TRB7 was incompatible with the other bacterial isolates tested. Pot experiment under controlled glasshouse conditions revealed that soil treatment with O. iheyensis TRB7 decreased the level of damping-off in tomato by 73.3%, compared to Pythium-infected control, which recorded 100% disease incidence.
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Claims 9
Claim · model-written summary
Seven morphologically different bacterial isolates were obtained from tomato rhizosphere soil from farmers’ fields in Barka, Oman.
- Taxon
- tomato
Solanum lycopersicume0 - Outcome
- morphologically different bacterial isolatese0
- Value
- sevene0
- Setting
- Barka, Omane0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A total of seven morphologically different bacterial isolates were obtained from tomato rhizosphere soil collected from farmers’ fields in Barka, Oman”
Claim · model-written summary
The isolates were identified by 16S rRNA gene sequencing as Bacillus cereus, Oceanobacillus neutriphilus, Cytobacillus kochii, Bacillus paramycoides, Oceanobacillus iheyensis and Priestia endophytica.
- Outcome
- identified as Bacillus cereus (TRB1 and TRB2), Oceanobacillus neutriphilus (TRB3), Cytobacillus kochii (TRB4), Bacillus paramycoides (TRB5), Oceanobacillus iheyensis (TRB7) and Priestia endophytica (TRB8)e0
Not reportedTaxon
Verbatim
e0“These isolates were identified as Bacillus cereus (TRB1 and TRB2), Oceanobacillus neutriphilus (TRB3), Cytobacillus kochii (TRB4), Bacillus paramycoides (TRB5), Oceanobacillus iheyensis (TRB7) and Priestia endophytica (TRB8) based on their 16S rRNA gene sequence data”
Claim · model-written summary
O. iheyensis TRB7 was the most active isolate against P. aphanidermatum mycelial growth in dual culture, with 35.5% inhibition compared with the control.
- Treatment
- O. iheyensis TRB7e0
- Interactor
- P. aphanidermatumPythium aphanidermatume0pathogen
- Second interactor
- O. iheyensis TRB7Oceanobacillus iheyensise0biocontrol_agent
- Outcome
- P. aphanidermatum mycelial growthe0
- Direction
- inhibitinge0
- Value
- 35.5%e0
- Comparator
- the controle0
- Setting
- dual culture plate assaye0
Not reportedTaxon
Verbatim
e0“O. iheyensis TRB7 was the most active in inhibiting P. aphanidermatum mycelial growth in the dual culture plate assay, achieving 35.5% inhibition compared to the control”
Claim · model-written summary
O. neutriphilus TRB3 and C. kochii TRB4 tolerated 10% NaCl in the culture medium.
- Taxon
- O. neutriphilus TRB3 and C. kochii TRB4Oceanobacillus neutriphilusCytobacillus kochiie0
- Outcome
- tolerance to 10% NaCle0
- Setting
- culture mediume0
Verbatim
e0“The isolates O. neutriphilus TRB3 and C. kochii TRB4 demonstrated tolerance to 10% NaCl, while B. cereus TRB2 and P. endophytica TRB8 exhibited tolerance up to 7.5% NaCl in the culture medium”
Claim · model-written summary
B. cereus TRB2 and P. endophytica TRB8 tolerated NaCl up to 7.5% in the culture medium.
- Taxon
- B. cereus TRB2 and P. endophytica TRB8
Bacillus cereusPriestia endophyticae0 - Outcome
- tolerance up to 7.5% NaCle0
- Setting
- culture mediume0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The isolates O. neutriphilus TRB3 and C. kochii TRB4 demonstrated tolerance to 10% NaCl, while B. cereus TRB2 and P. endophytica TRB8 exhibited tolerance up to 7.5% NaCl in the culture medium”
Claim · model-written summary
Four isolates (B. cereus TRB2, C. kochii TRB4, B. paramycoides TRB5, O. iheyensis TRB7) tolerated heat at 50°C.
- Taxon
- B. cereus TRB2, C. kochii TRB4, B. paramycoides TRB5, and O. iheyensis TRB7Bacillus cereusOceanobacillus iheyensisCytobacillus kochiiBacillus paramycoidese0
- Outcome
- heat tolerancee0
- Value
- 50°Ce0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Four bacterial isolates viz., B. cereus TRB2, C. kochii TRB4, B. paramycoides TRB5, and O. iheyensis TRB7 exhibited heat tolerance (50°C), while all seven bacterial isolates showed drought tolerance”
Claim · model-written summary
All seven bacterial isolates showed drought tolerance.
Verbatim
e0“Four bacterial isolates viz., B. cereus TRB2, C. kochii TRB4, B. paramycoides TRB5, and O. iheyensis TRB7 exhibited heat tolerance (50°C), while all seven bacterial isolates showed drought tolerance”
Claim · model-written summary
O. iheyensis TRB7 was incompatible with the other bacterial isolates tested in vitro.
- Taxon
- O. iheyensisOceanobacillus iheyensise0
- Outcome
- incompatiblee0
Verbatim
e0“O. iheyensis TRB7 was incompatible with the other bacterial isolates tested”
Claim · model-written summary
In a glasshouse pot experiment, soil treatment with O. iheyensis TRB7 decreased damping-off in tomato by 73.3% compared with the Pythium-infected control, which had 100% disease incidence.
- Taxon
- tomatoSolanum lycopersicume0
- Treatment
- soil treatment with O. iheyensis TRB7e0
- Second interactor
- O. iheyensis TRB7Oceanobacillus iheyensise0biocontrol_agent
- Outcome
- damping-offe0
- Direction
- decreasede0
- Value
- 73.3%e0
- Qualifier
- 100% disease incidencee0
- Comparator
- Pythium-infected controle0
- Setting
- controlled glasshouse conditionse0
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PythiumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
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Verbatim
e0“Pot experiment under controlled glasshouse conditions revealed that soil treatment with O. iheyensis TRB7 decreased the level of damping-off in tomato by 73.3%, compared to Pythium-infected control, which recorded 100% disease incidence”