Identification of Bacterial Isolates with Antagonistic Activity Against Pseudomonas syringae pv. atrofaciens, the Causal Agent of Basal Glume Rot in Wheat, and Their Plant Growth-Promoting Traits

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Aydın E., Öztürk M.

KSU TARIM VE DOGA DERGISI-KSU JOURNAL OF AGRICULTURE AND NATURE, vol.29, no.3, pp.665-677, 2026 (ESCI, TRDizin)

Abstract

In this study, bacterial isolates exhibiting antagonistic properties against

the seed-borne pathogen Pseudomonas syringae pv. atrofaciens in wheat

were investigated. Among a total of 298 bacterial isolates obtained from

wheat seed samples, 19 candidate antagonistic isolates were selected

based on their pectolytic activity and hypersensitivity test results.

Molecular identification revealed that these isolates belonged to the

genera Pseudomonas, Bacillus, Paenibacillus, Citrobacter, and

Staphylococcus. In vitro antagonistic tests showed that Pseudomonas

japonica isolates W57.4 and W57.5, along with Paenibacillus polymyxa

isolate W58.1, exhibited the highest inhibitory effects. These isolates also

demonstrated multiple plant growth-promoting traits such as protease

enzyme production, phosphate solubilization, siderophore synthesis,

ammonia production, and indole-3-acetic acid (IAA) production. Notably,

P. japonica isolates (W57.4, W57.5) exhibited strong siderophore

production and phosphate solubilization, while P. polymyxa (W58.1)

showed high protease activity. These multifunctional traits indicate the

potential of these isolates to be used as biological control agents against

seed-borne pathogens. As the first study in Türkiye focusing on the

biological control of seed-borne bacterial pathogens causing basal glume

rot in wheat, this research provides a significant contribution to the

development of environmentally friendly and effective alternative

management strategies.