Identification of phID Gene with Fluorescent Pseudomonads from Rhizospheric Zone of Chickpea and its Relation with Biological Control of Chickpea Fusarium wilt Disease Caused by Fusarium oxysporum f. sp. ciceris

Fusarium wilt of chickpea، caused by F. oxysporum f. sp. ciceris، is one of the most important diseases of this plant in Iran. In order to control this disease، fluorescent pseudomonads were isolated from the rhizosphere of chickpea plants in Khorasan province by using King،s B medium (KB). Antifungal activity of 80 bacterial strains against F. oxysporum f. sp. ciceris was evaluated on KB and potato dextrose agar (PDA) media. Results revealed that from 80 strains tested، 81. 25% of in KB and 94. 37% in PDA had the ability to inhibit fungal growth. There was a correlation between production antifungal metabolites and biocontrol ability of strains، but there was not any significant correlation between sidrophors production and biocontrol ability the strains. Detection of phlD، which is considered as the key gene for production of 2، 4- diacetylphloroglucinol biosynthesis in bacterial strains was performed using polymerase chain reaction technique (PCR) and specific primers B2BF/BPR4. Results indicated that 20 strains were phlD+ and a specific band of 629 bp was amplified in these strains. The results of experiments realized under greenhouse conditions، showed that only M2-15 isolate reduced significantly Fusarium wilt in chickpea، with the rest having positive effect on chickpea growth factors. T26، M2-15 and T90 isolates caused a significant increase in growth factors including dry and fresh root and shoot weights comparing to those of control plants. Among strains studied in this research، M2-15 significantly decreased chickpea wilt under greenhouse conditions.