Differential accumulation of plastid preprotein translocon components during spruce (Picea abies L. Karst.) needle development.
We demonstrate that basic components of the plastid protein-import apparatus originally found in pea, Toc34, Toc159, and Tic110, are also conserved in evolutionarily younger gymnosperms. We show that multiple isoforms of the preprotein receptor Toc34 differentially accumulate in various stages of needle development, while the amounts of Toc159 drastically decrease during chloroplast morphogenesis. Spruce Toc34 and Toc159 receptors are able to recognise and interact with the angiosperm precursor of the Rubisco small subunit. Young proplastids found in closed buds contain a highly elevated number of protein translocation complexes equipped with only two types of outer envelope receptors, Toc159 and a 30-kDa Toc34-related protein. Photosystem II (PSII) can already be assembled in a fully functional complex at this very early stage of needle development, suggesting that no additional receptor isoforms are needed for translocation of all necessary PSII components. We conclude that the accumulation of evolutionarily conserved plastid preprotein translocation components is differentially regulated during spruce needle development.
Fulgosi
Hrvoje
H
Department of Molecular Biology, Ruder Bosković Institute, Zagreb, Croatia. fulgosi@irb.hr
Lepedus
Hrvoje
H
Cesar
Vera
V
Ljubesić
Nikola
N
D029681:Arabidopsis Proteins / Q000378:metabolism*; D001693:Biological Transport, Active; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008970:Molecular Weight; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000378:metabolism; D028222:Picea / Q000254:growth & development / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D018087:Plastids / Q000737:chemistry / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D018000:Receptors, Peptide / Q000378:metabolism*; D013379:Substrate Specificity
D029681:Arabidopsis Proteins; D002135:Calcium-Binding Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D018000:Receptors, Peptide; C403444:TOC159 protein, Arabidopsis; C112475:Toc34 protein, plant; C066973:signal sequence receptor; D020558:GTP Phosphohydrolases