Management of tomato wilt disease caused by Fusarium oxysporum f. sp. lycopersici with Silicon and Pseudomonas fluorescens (CHAO) and assaying activity of Phenylalanine ammonia lyase (PAL)

In this research combined application of Pseudomonas fluorescens and Silicon against Fusarium oxysporum f. sp. lycopersici and induction of resistance in tomato against pathogen was studied. Effect of different concentrations of silicon (1-7 mM) on growth of F. oxysporum f. sp. lycopersici and P. flourescens was measured. The results showed that all concentrations of silicon had adverse effect on growth of P. fluorescens. Silicon upto 5mM concentration had no effect on the growth of F. oxysporum f. sp. lycopersici، but at concentrations of 6 and 7 mM، growth of the fungus was significantly affected compared with control. Due to the negative effect of silicon on growth of P. fluorescens، 3mM concentration of silicon was selected for greenhouse studies. Greenhouse experiments showed that treatment with P. fluorescens as soil application and silicon as aerial application had the greatest effect on reducing disease indexes and increasing plant growth. Also maximum activity of Phenyl Alanin Amonialyase occurred on the 5th day after combined applications of silicon (as aerial) and P. fluorescens (as soil drench). Use of silicon as an inducer of resistance and P. fluorescens as biocontrol agent and plant growth enhancer can be effective method for control of soil borne plant pathogens such as F. oxysporum f. sp. lycopersici