Plastid genomes contain a conserved set of genes most of which are involved in either photosynthesis or gene expression. Among the ribosomal protein genes present in higher plant plastid genomes, rps18 is special in that it is absent from the plastid genomes of several non-green unicellular organisms, including Euglena longa and Toxoplasma gondii. Here we have tested whether the ribosomal prote...

In this issue of Plant Physiology, Pal Maliga’s laboratory reported a major advance in plastid transformation. Stable manipulation of the plastid genome of flowering plants was first reported nearly 30 years ago (Svab et al., 1990). The approach was to select transplastomic plants using spectinomycin, which blocks translation by the prokaryotic-type 70S ribosomes found in plastids. Thus, in the...

PhycoBiologics is developing an oral vaccine delivery system using vaccines expressed in the chloroplast of microalgae. Despite many advances in plastid transformation technology, levels of expression remain inconsistent. We have concluded that the main factors affecting the level of recombinant protein expression in the chloroplast of Chlamydomonas are: codon optimization, protease activity, p...

Tobacco chloroplasts are ready to be tested as a platform for the expression of recombinant proteins on a commercial scale. They hold the promise of reproducible yields of 5-25% of total soluble cellular protein in leaves and reliability has been achieved through refinement of an expression toolkit that includes vectors, recently developed expression cassettes and systems for marker gene remova...

Nicotiana plumbaginifolia protoplasts were directly transformed by PEG treatment with a cloned 16S rRNA gene isolated from a double antibiotic-resistant Nicotiana tabacum plastid mutant. Putative plastid transformants were selected in cell culture by their spectinomycin resistance and identified by their unselected streptomycin resistance. Alternatively, cell lines were selected in the presence...

Chloroplasts fulfill important functions in cellular metabolism. The majority of plastid genome-encoded genes is involved in either photosynthesis or chloroplast gene expression. Whether or not plastid genes also can determine extraplastidic functions has remained controversial. We demonstrate here an essential role of plastid protein synthesis in tobacco leaf development. By using chloroplast ...

This paper [1] has been retracted as it is found to contain a substantial amount of material from the paper " Chlamy-domonas Reinhardtii Chloroplasts as Protein Factories " by Stable plastid transformation for high-level recombinant protein expression: promises and challenges, "

D-serine is toxic to plants. D-serine ammonia lyase, which is encoded by the dsdA gene, can attenuate this toxicity with high specificity. In the present study, we explored the function of codon-optimized dsdA with tobacco plastids and rice nuclear transformation system. It was shown that dsdA gene was site-specifically integrated into the tobacco plastid genome and displayed a high level of ex...