Biological control of damping-off of tomato caused by Pythium aphanidermatum by using native antagonistic rhizobacteria isolated from Omani soil

Hanan S. Al-Hussini, Amna Y. Al-Rawahi, Abdullah A. Al-Marhoon, Shurooq A. Al-Abri, Issa H. Al-Mahmooli, Abdullah M. Al-Sadi, Rethinasamy Velazhahan*

*Corresponding author for this work

Research output: Contribution to journalArticle

6 Citations (Scopus)


The potential of antagonistic bacteria isolated from tomato rhizosphere soils of Oman in the control of damping-off disease of tomato was investigated. A total of 27 bacterial isolates were isolated from 18 soil samples collected from the rhizosphere of tomato from Al-Batinah South, Al-Sharqia North and Muscat Governorate. These bacterial isolates were tested in vitro for their antagonistic activity against Pythium aphanidermatum using a dual culture technique. Of the 27 bacterial isolates tested, four isolates designated D1/3, D1/8, D1/17 and D1/18 were effective in inhibiting the mycelial growth of P. aphanidermatum, by inducing an inhibition zone of 32.3, 10.3, 6.3 and 9.9 mm, respectively. Compatibility tests using a cross-streak assay on nutrient agar medium indicated that these four bacterial isolates were compatible with one another. The bacterial isolates were identified as Klebsiella oxytoca (D1/3), Exiguobacterium indicum (D1/8) and Bacillus cereus (D1/17 and D1/18), on the basis of the rRNA gene sequences. Among the isolates tested for in vitro plant growth promoting activity, D1/8 induced the maximum shoot length and seedling vigor. The potential of bacterial antagonists either individually or in combination in the control of damping-off disease of tomato was tested under greenhouse conditions. Among the biocontrol treatments, the combined application of D1/8 and D1/17 was the most effective, where damping-off incidence was reduced by 27% relative to the infected control. These bacterial antagonists appear to be potential candidates to be developed as bio-inoculants for the ecofriendly management of damping-off of tomato under desert farming ecosystem.

Original languageEnglish
Pages (from-to)315-322
Number of pages8
JournalJournal of Plant Pathology
Issue number2
Publication statusPublished - May 1 2019
Externally publishedYes


  • Bacillus cereus
  • Biocontrol
  • Damping-off
  • Exiguobacterium indicum
  • Lycopersicon esculentum

ASJC Scopus subject areas

  • Plant Science

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