Free proline in normal and in crown-gall tumor tissue of tomato and tobacco

Abstract

Proline- and hydroxyproline-rich bulk proteins were first reported in tumors growing on Kalanchoe daigremontana infected with Agrobacterium tumefaciens (1). The evidence was obtained by acid hydrolysis of the proteins isolated from this rapidly growing tissue. Weinstein et al . (2) stated that the free (alcohol soluble) hydroxyproline content of leaf tissue ( Agave toumeyana ) increased greatly as tissue cultures were developed from these leaves. In this case however, the free proline content remained as a trace throughout. It was reported also (3) that the content of free proline rises as vegetative cells of Saccharomyces cerevisiae sporulate. In view of our recent observation (4) that primary crown-gall tumor tissue of tobacco and tomato contains twenty-four times as much free lysopine as normal tissue, a further examination of these tumor tissues was made and a greatly increased content of free proline as compared with the corresponding normal tissue discovered. The purpose of this communication is to document this finding in view of the possibility that it might be related to tumorogenesis.