Putrescine biosynthesis in Agrobacterium tumefaciens and in normal and crown gall tissues of Scorzonera hispanica L.

Abstract

Summary In order to understand the significance of increased polyamine level in crown gall of Scorzonera, putrescine biosynthesis was investigated during the growth of Agrobacterium tumefaciens and in normal and crown gall tissues of Scorzonera hispanica, on feeding arginine or ornithine labeled (14C or 3H) in different positions of molecule. Two different pathways of putrescine biosynthesis were individuated via ornithine and arginine decarboxylation, both in Agrobacterium and in Scorzonera tissues. The arginine/ornithine decarboxylases ratio seems to be less than one during the lag and stationary phases of Agrobacterium growth and in crown gall, while the ratio is reversed during the deceleration phase in Agrobacterium and in normal roots of Scorzonera. While an arginase activity or its induction was absent in Agrobacterium and in crown gall tissue, this activity was detected in the normal tissue of Scorzonera.