[01] Mansoureh-Sadat Sharifi-Noori , Department of Agronomy, Payame Noor University, Tehran, Iran. [02] Halimi Mohd Saud, Department of Agro-Technology, University Putra Malaysia, Selangor, Malaysia. [03] Elham Azizi, Department of Agronomy, Payame Noor University, Tehran, Iran.

The antagonistic effects of three Pseudomonas isolates from rhizosphere of rice were evaluated against Pyricularia.oryzae in vitro and in vivo. Fungal inhibition tests were performed using plate assay. Each isolate was tested for the production of protease, siderophore, cyanide hydrogen, indole acetic acid and phosphate solubilization activity. All the 20 tested isolates of Pseudomonads fluorescent were positive for the production of siderophores and HCN, while 15 strains (75%) were positive for the production of plant growth-promoting hormone, IAA. Among the 20 isolates, 19 isolates showed phosphate solubilisation on NBRIP medium. Biocontrol activity and plant growth promotion of bacterial strains were evaluated under greenhouse conditions, in which soil-inoculation of NCIM 2099 (the reference strain), TS3C8 and TS3B5 reduced disease index to a range of 13.50% (P ≤ 0.05) compared to the untreated control at 28.8%. Greenhouse experiments revealed that the plants treated with TS3C8 isolate recorded maximum root length, plant height, and fresh shoot weight which were increased by 32.78 cm, 76.16 cm, and 5.84 g, respectively over the diseased control. These results indicate that the tested PGPR improved growth parameters in rice plants and contribute towards biocontrol of the blast pathogen.

Antagonism, Biological Control, PGPR, Pseudomonas Spp, Rice Blast Disease

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