EFFECTS OF THE OVER-EXPRESSION OF THE ROLC GENE ON LEAF DEVELOPMENT IN TRANSGENIC PERICLINAL CHIMERIC PLANTS

Using Agrobacterium tumefaciens harboring a vector that carried the rolC gene under the control of the 35S RNA promoter of cauliflower mosaic virus, we produced several transgenic plants. Two of them were periclinal chimeras with altered leaves that had wrinkled dark green margins and inner pale green regions. One chimeric plant had shortened internodes, reduced apical dominance, small flowers and exhibited male sterility, but the other had a normal phenotype. Analysis of proteins, RNA and DNA indicated that the inner pale green tissues consisted of transformed cells while the outer dark green tissues were composed of non-transformed cells. Histological analysis indicated that mesophyll cells were distorted and larger intercellular spaces were present in the transformed pale green regions. Furthermore, in young leaves, transformed mesophyll cells were larger than non-transformed cells. However, the normal parts had larger numbers of cells per unit area than the transformed parts. These observations suggest that the expression of 35S-rolC in leaves caused inhibition of cell division in developing leaves and that the undulating margins, composed of non-transformed cells, were a consequence of the requirement for accommodating more cells in less space within the region of rolC-transformed cells.