A Study of the Effect of Pseudomonas fluorescens CHA0mcherry on the Degree of Root Colonization in some Wheat Varieties and an Induction of Systemic Resistance against Leaf Rust Disease

The interaction between root-colonizing Pseudomonas fluorescens strain CHA0mcherry and three wheat cultivars (Bolani, Roushan, Forno) was studied as a phenomenon to be employed in the control of Wheat Leaf Rust Disease (Puccinia triticina). CHA0mcherry was inoculated using seed treatment method. The application of CHA0mcherry reduced the number of pustules on leaves via inducing systemic resistance, specially in Bolani cultivar. The non-inoculated Bolani and Forno cultivars exhibited the highest infection of the leaf rust. A study of the bacteria-wheat-pathogen interaction indicated that Forno was the most responsive root- colonized variety to the bacterium. The lowest colonization was observed within the rhizosphere of Roushan cultivar. Interaction between pathogen and cultivars was shown to lead to increase of peroxidase and Phenylalanine Ammonia Lyase (PAL) activity in leaves. In summary, the results showed negative correlations between the bacterial colonization (cfu per mg dry root) and the number of rust pustules on the leaves. There was also a significant correlation noted between PAL activity and disease severity.