Developmental and Subcellular Organization of Single-Cell C-4 Photosynthesis in Bienertia sinuspersici Determined by Large-Scale Proteomics and cDNA Assembly from 454 DNA Sequencing

摘要

Kranz C-4 species strictly depend on separation of primary and secondary carbon fixation reactions in different cell types. In contrast, the single-cell C-4 (SCC4) species Bienertia sinuspersici utilizes intracellular Compartmentation including two physiologically and biochemically different chloroplast types; however, information on identity, localization, and induction of proteins required for this SCC4 system Is currently very limited. In this study, we determined the distribution of photosynthesis-related proteins and the induction of the C-4 system during development by label,free proteomics of subcellular fractions and leaves of different developmental stages. This was enabled by inferring a protein sequence database from 454 sequencing of Bienertia cDNAs. Large-scale proteome rearrangements were observed as C-4 photosynthesis developed during leaf inattration. The proteomes of the two chloroptasts are different with differential accumulation of linear and cyclic electron transport components, primary and secondary carbon fixation reactions, and a triose-phosphate shuttle that is shared between the two chloroplast types. This differential protein distribution pattern suggests the presence of a mRNA or protein-sorting mechanism for nuclear-encoded, chloroplast-targeted proteins in SCC4 species. The combined information was used to provide a comprehensive model for NAD-ME type carbon fixation in SCC4 species.