Screening of P. fluorescens isolates containing phenazine 1-carboxylic acid (PHZ) gene to biocontrol of wheat take-all disease

Wheat take-all disease caused by Gaeumannomyces graminis var. tritici is one of the serious wheat diseases in our country, Iran. The Pseudomonas fluorescens bacteria by root colonization and antibiotic production ability are an important biologic control agent of soil born disease. In this study, presence of the phenazine 1-carboxylic acid synthase gene was tracked in 21 Pseudomonas fluorescens isolates via PCR using specific primers of PCA2a and PCA3b. Also, the ability of antimicrobial metabolites production by all of these bacterial isolates such as siderophore and hydrogen cyanide and influences on the growth of pathogenic fungi was investigated via in vitro culture. Ability of the selected bacterial isolates for controlling wheat take-all disease were tested in a greenhouse experiment using a completely randomized design with three replications. The results showed that bacterial isolates were able to produce siderophore and hydrogen cyanide under in vitro conditions. The results of the greenhouse experiment showed that wt_20، eq1_3، wt1_65، eq1_4، 2_79، whm_3 و wbo2_7 isolates had positive effects on a number of wheat growth factors such as root/shoot length, root and shoot dry/fresh weight and also reduce in the pathogenicity index was effective in controlling take-all disease in effected plant. In total, the results of this research showed that P. fluorescens bacteria can be used to biologic control of the take-all disease.