Phenotypic analysis of Phytophthora parasitica by using high throughput phenotypic microarray.

OBJECTIVE

We studied the phenotypic characterization of Phytophthora parasitica Dastur var. nicotianae.

METHODS

Phenotypic characterization of the pathogen was studied to provide information for disease management program by using BIOLOG phenotype MicroArray (PM ). Using PM plates 1 to 10, 950 different phenotypic characterizations were tested.

RESULTS

P. parasitica was able to metabolize 74% of tested carbon sources, 96% of nitrogen sources, 100% of sulfur sources, and 98% of phosphorus sources. Most informative utilization patterns for carbon sources of P. parasitica were organic acids and carbohydrates, and for nitrogen were various amino acids. The pathogen presented 285 different nitrogen pathways. It had wide range adaptabilities in osmolytes with up to 1% sodium chloride, up to 3% potassium chloride, up to 5% sodium sulfate, up to 20% ethylene glycol, up to 2% sodium formate, up to 5% urea, and up to 2% sodium lactate. It also exhibited active metabolism under pH values between 3.5 and 10, with optimal pH of around 7.0. The pathogen showed both decarboxylase and deaminase activities in the presence of various amino acids.

CONCLUSION

These phenotypic characterizations of P. parasitica provided the theoretical basis for the next study of the pathogen in physiology and metabolism, and provided potential new way for tobacco black shank management.