Figure 1.

Typical Leaf Phenotypes of Transplastomic Plants Harboring a Knockout Allele for an Essential Component of the Translational Apparatus.

Leaves of transplastomic tobacco plants transformed with a knockout construct for the essential plastid gene rps18 (encoding plastid ribosomal protein S18; Rogalski et al., 2006; Table 2) are shown. The plastid transformants are heteroplasmic and, in the absence of antibiotic selection, the plants randomly segregate into homoplasmy for the wild-type plastid genome or homoplasmy for the transplastome. Homoplasmy for the rps18 knockout allele is lethal at the cellular level and results in loss of cell proliferation. Death of cell lineages during leaf development produces aberrantly shaped leaves that lack individual sectors or, in extreme cases, nearly the entire leaf blade (Ahlert et al., 2003). Scale bar = 2 cm.