Transmission of Pseudomonas syringae in soybean

Pathogens attach to seeds at various stages. A pathogen-infected mother plant can infect the seed via its vascular system or floral parts; during processing of seed and at the time of transportation or during harvest storage seed retention and threshing operations. Seed-to-seedling transmission combines the ability of a pathogen to survive outside the host seed multiply on the host and disperse and transmit to plant tissue. Once the pathogen gains entry into a plant a successful infection can only occur if a parasitic relationship between a pathogen and its host has been established. A parasitic relationship (compatible interaction) leads to symptom development whereas commensal interaction (incompatible interaction) leads to a hypersensitive reaction (HR) a form of plant defense mechanism. This work was undertaken in Zimbabwe to test for transmission of Pseudomonas syringae pv. isolates from seed to plant in order to evaluate the importance of seed as a primary source of inoculum for bacterial blight disease in soybean (Glycine max). Also brought to attention was the latent in planta growth of pathogen that was confirmed in some symptomless plants.