Characterization of a periclinal chimera variegated tobacco (Nicotiana tabacum L.)

A plant isolated from a population of tobacco (Nicotiana tabacum L. cv. BY-4) lines, which were generated with a heavy-ion beam, exhibited green and white variegation on its leaves, stems, and calyces. Fluorescence microscopic analysis of white and green sections of the leaves of the mutant showed an absence of developed chloroplasts in the epidermis and palisade layer. There were undeveloped chloroplasts in one or two layers of spongy parenchyma cells in the green sections of the mutant. In the F-1, generation, the segregation ratio of green to white was 6:1163 and reciprocal crosses showed that the variegation was not maternally inherited. These results suggest that the mutant is a periclinal chimera with a White-White-Green histogenic composition. The mRNA levels of the photosynthetic genes rbcL and psbA in the green areas were normal, while they were significantly reduced in the white areas. (C) 2000 Published by Elsevier Science Ireland Ltd. All rights reserved.