MORPHOGENESIS OF CROWN
GALL
SIRKKA KUPILA-AHVENNIEMI
Department of Botany, University of Oulu, Oulu, Finland
AND
EEVA THERMAN
Department of Medical Genetics, University of Wisconsin, Madison,
Wisconsin
I. Introduction
45
II. The Occurrence of Crown Gall and the Characteristics of the Bacteria .
46
III. Cell Conditioning and Tumor Induction
47
A. Conditioning
47
B. Tumor Induction
50
IV. Factors Affecting the Developmental Phase
54
V. Wound and Crown Gall Tissue
55
A. Anatomical Aspects
55
B. Cytological Aspects
64
VI. Origin of Crown Gall
71
VII. Summary
75
References
76
I. Introduction
Crown gall, a plant tumor, offers in many ways an almost ideal system for studying problems of morphogenesis. Under suitable experimental
conditions it can be induced in practically all wounds inoculated with
Agrobacterium
tumefaciens.
Using temperature as an experimental tool,
the induction can be divided into a number of phases which can be
analyzed separately. The inducing organism can be killed after the
transformation is completed, and the tumor tissue can thus be studied
without the complicating presence of bacteria. It is possible to grow
crown gall tissue both in vitro and grafted to new hosts.
Since the early days of crown gall research, the similarity of this
plant tumor and of animal neoplasms has attracted attention. Indeed,
crown gall probably resembles animal cancer as much as it is possible
for any plant tissue to do. The transformation of wound cells into tumor
45