Some Characteristics Of Pea Necrosis Elicitor From Compatible Interactions Of Pseudomonas Syringae P.v. Pisi And Pisum Sativum,

Abstract

Specific elicitors of pea necrosis were obtained from intercellular fluids of compatible race-cultivar interactions of Pseudomonas syringae pv. pisi and pea (Pisum sativum ). These elicitors induced necrosis in resistant but not in susceptible cultivars. Using pea cultivars carrying different resistance genes to the bacterial races 1 to 5 as test plants, an elicitor of necrosis was isolated and partially characterised. The necrosis inducing activity of these intercellular fluids was not lost after dialysis, gel-filtration and isoelectric focusing. The dialysed and lyophilised elicitor-active fraction of the intercellular fluids contained considerable amounts of protein and carbohydrate, and was partially sensitive to subtilisin BPN, proteinase K and protease V, but not to trypsin. These elicitors were inactivated by heat at 60 C and also by periodate. Most of the elicitor activity was recovered in a fraction of pH 11.7 after isoelectric focusing, suggesting a highly basic nature.