Thirty five endophytic fluorescent bacteria were isolated from root tissues of healthy tomato plants in Egypt (El-Giza, El-Quliobiya, El-Fayoum and El-Behira Governorates) and tested for their efficiency for inhibiting growth of tomato pathogen, Alternaria solani and Pseudomonas syringae. Two most effective isolates MG4 and MG18 against the three pathogens were selected and identified as Pseudomonas putida and P. fluorescens. Plant growth promoting activity of the two Pseudomonas spp. was evaluated. Both endophytic bacterial species produced siderophore, HCN, ammonia and IAA but IAA production was higher with P. putida which was also able to solubilize phosphate. Tomato roots were subjected to colonization after bacterization with two Pseudomonas species. Treatments with P. putida or P. fluorescens through seedling dip were highly effective in inhibiting leaf spot caused by A. solani and bacterial speck caused by P. syringae but P. fluorescens was more effective than P. putida. The potential of two Pseudomonas spp, for tomato growth promotion was evaluated in green house either individually or in mixtures. They significantly enhanced all growth parameters.
Key words: Tomato (Lycopersicon esculentum), Alternaria solani, Pseudomonas syringae, Pseudomonas putida, Pseudomonas fluorescens, siderphores, HCN production chitinolytic activity, phosphate solubilization, Biological control
|
