Bioefficacy of fluorescent pseudomonads from wheat rhizosphere against wheat common root and crown rot caused by Bipolaris sorokiniana (Sacc.) Shoemaker

Fluorescent pseudomonads control plant pathogens by producing siderophore and inhibitory metabolites, and increase plant growth by producing plant hormones, some enzymes and mineral elements solubilization. In this study, 10 isolates of fluorescent pseudomonads from wheat rhizosphere cv. Zagros and Chamran (Dezful) and cv. Kohdasht and Zagros (Parsabad) in early April 2016 and early June 2017 were isolated by cultivation and purification on King B medium and also based on the production of green and yellow fluorescence pigment under UV light at 365 nm. These isolates were evaluated in terms of some metabolic characteristics such as inorganic phosphate solubilization, production of IAA, siderophore, ACC deaminase, hydrogen cyanide and protease, as well as control of wheat common root and crown rot disease caused by B. sorokiniana and increase in length and biomass of wheat shoots and roots in a randomized complete design (RCD) with three replications for each treatment.The UTP105 isolate showed the highest inhibition rate of pathogen growth with 62.5% and 70% in dualculture and production of volatile metabolites tests, respectively. In the greenhouse, the severity of disease was estimated at 85.3%, and UTP104 and UTP105 isolates showed the highest rate of disease reduction with 64.5% and 62.3%, respectively. Also, UTP105 and UTP104 were the most effective in increasing the wheat root and shoot growth parameters, respectively. These isolates are efficient for use in agriculture due to having favorable metabolic characteristics, disease control and plant growth enhancement..