Project description:Photosystem I (PSI) enables photo-electron transfer and regulates photosynthesis in the bioenergetic membranes of cyanobacteria and chloroplasts. Being a multi-subunit complex, its macromolecular organization affects the dynamics of photosynthetic membranes. Here we reveal a chloroplast PSI from the green alga Chlamydomonas reinhardtii that is organized as a homodimer.
Project description:Photosystem I (PSI) enables photo-electron transfer and regulates photosynthesis in the bioenergetic membranes of cyanobacteria and chloroplasts. Being a multi-subunit complex, its macromolecular organization affects the dynamics of photosynthetic membranes. Here we reveal a chloroplast PSI from the green alga Chlamydomonas reinhardtii that is organized as a homodimer.
Project description:Different high temperatures adversely affect crop and algal yields with various responses in photosynthetic cells. The list of genes required for thermotolerance remains elusive. Additionally, it is unclear how carbon source availability affects heat responses in plants and algae. We utilized the insertional, indexed, genome-saturating mutant library of the unicellular, eukaryotic green alga Chlamydomonas reinhardtii to perform genome-wide, quantitative, pooled screens under moderate (35oC) or acute (40oC) high temperatures with or without organic carbon sources. We identified heat-sensitive mutants based on quantitative growth rates and identified putative heat tolerance genes (HTGs). By triangulating HTGs with heat-induced transcripts or proteins in wildtype cultures and MapMan functional annotations, we present a high/medium-confidence list of 933 Chlamydomonas genes with putative roles in heat tolerance. Triangulated HTGs include those with known thermotolerance roles and novel genes with little or no functional annotation. About 50% of these high-confidence HTGs in Chlamydomonas have orthologs in green lineage organisms, including crop species. Arabidopsis thaliana mutants deficient in the ortholog of a high-confidence Chlamydomonas HTG were also heat sensitive. This work expands our knowledge of heat responses in photosynthetic cells and provides engineering targets to improve thermotolerance in algae and crops.
Project description:a chromosome-level nuclear genome and organelle genomes of the alpine snow alga Chloromonas typhlos were sequenced and assembled by integrating short- and long-read sequencing and proteogenomic strategy
Project description:Non-photochemical quenching (NPQ) mechanisms are crucial for protecting photosynthesis from photoinhibition in plants, algae, and cyanobacteria. Modulating these mechanisms has long been a goal for improving photosynthesis and crop yields. The current work demonstrates that Chlorella ohadii, a green micro-alga thriving in the desert under high light intensities that are fatal to many photosynthetic organisms, neither performs nor requires NPQ to protect photosynthesis under constant high light. This dataset includes the whole-cell proteomic changes that occur in Chlorella ohadii cultures grown under high light compared to those grown under low light, with a particular focus on changes in protein oxidative damage, as indicated by the oxidation of tryptophan residues.