INTERACTION BETWEEN PSEUDOMONAS-SYRINGAE PV PISI AND ISOLATED PEA MESOPHYLL PROTOPLASTS

The interaction between five races of Pseudomonas syringae pv. pisi (P SP) and isolated mesophyll protoplasts obtained from five pea cultivar s was studied. There was no trend in the attachment of bacterial cells to surfaces of compatible and incompatible host protoplasts. The viab ility of protoplasts from compatible and incompatible host-pathogen in teractions did not differ significantly; however, changes in the viabi lity of cultivar Kelvedon Wonder protoplasts, compatible with all five races, was relatively more stable following inoculation with bacteria than those of cultivar Fortune, incompatible with all of the five rac es. Protoplast cell wall regeneration did not take place until 24-48 h after isolation. It is concluded that the use of pea protoplasts as a model system for studying the pea-PSP interaction appears to have con siderable potential for the future, but more basic research is require d.