Document Type : Research Article
Phase variation and biofim formation ability in fluorescent pseudomonads play an important role in their biocontrol potentiality. These two phenomena increase adaptation and distributive ability of more fluorescent pseudomonads on the root during the growth of plant. Generally, as biofilm formation occur cells change phenotypically this could have determinant role in the control of various disease. In this research in seven of these bacterial strains including Um141, Um11, Um138, Um70, Um115, UmCHN5 and pseudomonas fluorescens F113 colonies with various morphology were observed. Results of this investigation on distribution pattern of the colonies both in sterilized condition and presence of Ggt, showed that these strains have been able to adopt themselves to root in various growing conditions and is able to reduce the rate of take-all disease. assay on the biofilm formation ability in these seven bacterial strains represented the high ability of these strains in the biofilm formation. However investigating on the rate of siderophore and hydrogen cyanide (HCN) production in these seven bacterial strains indicated that is no significante correlation between production of these two antifungal metabolites and decreasing of disease.