MAIN CONCLUSION: The absence of state transitions in a Nt(Hn) cybrid is due to a cleavage of the threonine residue from the misprocessed N-terminus of the LHCII polypeptides. The cooperation between the nucleus and chloroplast genomes is essential for plant photosynthetic fitness. The rapid and specific interactions between nucleus-encoded and chloroplast-encoded proteins are under intense investigation with potential for applications in agriculture and renewable energy technology. Here, we present a novel model for photosynthesis research in which alien henbane (Hyoscyamus niger) chloroplasts function on the nuclear background of a tobacco (Nicotiana tabacum). The result of this coupling is a cytoplasmic hybrid (cybrid) with inhibited state transitions-a mechanism responsible for balancing energy absorption between photosystems. Protein analysis showed differences in the LHCII composition of the cybrid plants. SDS-PAGE analysis revealed a novel banding pattern in the cybrids with at least one additional 'LHCII' band compared to the wild-type parental species. Proteomic work suggested that the N-terminus of at least some of the cybrid Lhcb proteins was missing. These findings provide a mechanistic explanation for the lack of state transitions-the N-terminal truncation of the Lhcb proteins in the cybrid included the threonine residue that is phosphorylated/dephosphorylated in order to trigger state transitions and therefore crucial energy balancing mechanism in plants.

• MeSH
• buněčné jádro metabolismus   MeSH
• chloroplasty metabolismus   MeSH
• fosforylace MeSH
• fotosyntéza MeSH
• fotosystém II (proteinový komplex) genetika   metabolismus   MeSH
• genom chloroplastový genetika   MeSH
• genom rostlinný genetika   MeSH
• proteomika MeSH
• světlosběrné proteinové komplexy genetika   metabolismus   MeSH
• tabák genetika   fyziologie   MeSH
• threonin metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH