Evidence against involvement of pectic enzymes in the invasion of root hairs by Rhizobium trifolii

It has been postulated that polygalacturonase is significant in the infection of root hairs of leguminous plants by Rhizobium spp. Recently this theory has been strongly questioned. Evidence for polygalacturonase was based on methods which would not distinguish between this enzyme and other pectic glycosidases. The possibility that pectin lyase or polygalacturonate lyase is involved in the invasion of red clover by Rhizobium trifolii was investigated. Weak pectin lyase activity was detected in uninoculated seedlings, but no increase in the activity was produced in inoculated seedlings. It was concluded that neither of the lyases has significance in the infection process.