Plastid Evolution and Algal Diversity Lecture Notes PDF

Plastid Evolution and Algal Diversity Lecture Molecular Cell Biology II (Molecular Cell Biology of Plants) MMLS.G3 (MCB W 15) November, 8th + 15th 2024 (WS 2024/25) Jun.-Prof. Dr. Julie Zedler Synthetic Biology of photosynthetic Organisms Matthias Schleiden Institute, Faculty of Biosciences © Adap...

Plastid Evolution and Algal Diversity Lecture Molecular Cell Biology II (Molecular Cell Biology of Plants) MMLS.G3 (MCB W 15) November, 8th + 15th 2024 (WS 2024/25) Jun.-Prof. Dr. Julie Zedler Synthetic Biology of photosynthetic Organisms Matthias Schleiden Institute, Faculty of Biosciences © AdaptNet, 2019 (Toni Gabaldon)  Abb. 7.1 plants Pflanzen Serial endosymbiosis Evolution der eukaryontischen Zelle. Es gibt starke molekulare und biochemische Hinweise animals Tiere darauf, dass ein Ur-Archaebakterium durch Phagozytose ein Ur-Bakterium (Vorläufer der fungi Pilze -Proteobakterien) aufnahm, das durch Coevo- lution mit der Wirtszelle zum Vorläufer der Mi- tochondrien wurde. Parallel dazu entstanden das Endomembransystem und die Kernhülle durch Einstülpungen der Zellmembran. Diese ancestral Ur-Eucyte führte zum stammesgeschichtlichen Ur-Eucyte Ast der Tiere und Pilze. Durch ein zweites Endo- eukaryote symbioseereignis nahm die Ur-Eucyte ein zur Photosynthese befähigtes Cyanobakterium auf, Cyanobakterien cyanobacteria woraus sich die Plastiden entwickelten. Dieser stammesgeschichtliche Ast führte zu den grü- nen Pflanzen. eubacteria Eubakterien archaea Archaea ancestral Ur-Bakterium Ur-Archaeonarchaea bacteria ancestral Modified from: Mendel (2010) Zellbiologie der Pflanzen, 3rd Ed. UTB.  Current Biology Endosymbiosis and Plastid Evolution Review A Figure 2. Endosymbiosis and plastid Eukaryote Photosynthetic evolution. Mitochondrion y eukaryote Plastid (A) Primary endosymbiosis involves the uptake Cytoskeleton of a cyanobacterium by a non-photosynthetic eukaryote. The process involves endosymbiont to host DNA transfer and the evolution of a protein DNA Primary import apparatus. Primary plastids are surrounded endosymbiosis by two membranes. The peptidoglycan layer pre- sent in the cyanobacterial progenitor of the plastid has been retained in glaucophyte algae but Peptidoglycan layer was lost in red and green algae. (B) Secondary Nucleus Outer membrane (OM) Cyanobacterial OM endosymbiosis occurs when a primary plastid- Nucleus Cyanobacterial IM bearing alga is ingested by a non-photosynthetic Cytoplasm Inner membrane (IM) eukaryote. Genes of both prokaryotic and eu- Cyanobacterium karyotic ancestry are transferred from the endo- symbiont nucleus to the secondary host nucleus. In cryptophyte and chlorarachniophyte algae, the B Eukaryote Photosynthetic endosymbiont nucleus persists as a ‘nucleo- Endosymbiont-derived eukaryote membrane (?) morph’ residing in the periplastidial compartment Host-derived (derived from the cytoplasm of the engulfed alga). membrane (?) Nucleomorphs have been lost in other secondary Plastid plastid-bearing algae. Secondary plastids are characterized by the presence of three or four Secondary membranes. Figure modified from. endosymbiosis DNA Plastid Cyanobacterial OM which appear to be of cyanobacterial Nucleomorph Cyanobacterial IM Photosynthetic ancestry. However, the plastids of the eukaryote Periplastidial compartment model lab alga Euglena have three mem- Current Biology branes, and various other algae have three- or four membrane-bound plastids Archibald (2015) Curr Biol 25: R911-R921. algae, and green algae (it is from within the green line that land. These supernumerary membranes were an enigma until plants emerged). This was not always thought to be the the 1970s and 80s when Sarah Gibbs, Max Taylor, Dennis case. Extant plastids are remarkably diverse in morphology Greenwood and colleagues recognized them for what they are: and pigmentation, and in the 1970s proponents of endosymbi- the calling card of ‘secondary endosymbiosis’, i.e., the spread osis took this diversity as support for the notion that red and of plastids from one eukaryote to another [42,95]. This process green algal plastids had evolved from different cyanobacteria has given rise to some of the most ecologically significant algal Primary endosymbiosis lineages Archaeplastida Glaucophyta http://bioinformatica.uab.es Glaucophyta Pigments: Chlorophyll a, phycobiliproteins Glaucocystis sp. Contain cyanelles (muroplast) Starch in the cytoplasm No known sexual reproduction Cyanophora paradoxa © Lee (2008) Phycology, 4th Ed. Cambridge University Press. Rhodophyta Pigments: chlorophyll a (+d), phycocyanin, phycoerythrin No flagellated cells Cell walls: cellulose, mucilage (agars, carrageenans) or CaCO3 Floridean starch as a storage compound © Serisawa & Matsuyama-Serisawa (2010) Pit connections Corallina officinalis © Lee (2008) Phycology, 4th Ed. Cambridge University Press. Viridiplantae Chlorophyta lutein Pyrenoids are typically spherical or ellipsoidal bodies composed primarily of the enzyme ribulose-1,5- bisphosphate carboxylase/oxygenase (RuBisCO). This enzyme is essential for carbon fixation during Pigments: photosynthesis. The pyrenoid is often surrounded by a starch sheath, though this can vary among species. chlorophyll a, b starch: in the chloroplast (+pyrenoid) plastid with two membranes Thylakoid membranes: no grana stacks Cell wall: mainly cellulose Sasso et al. (2018) eLife 7: e39233.  Life cycle stages of Chlamydomonas reinhardtii Sasso et al. (2018) eLife 7: e39233. Algae lineages Gentil et al. (2017) Protoplasma 254: 1835–1843. The special case of Paulinella www.arcella.nl Paulinella + picocyanobacterium (Synechococcus sp.) Second primary endosymbiosis Paulinella chromatophora chromatophore Keeling & Archibald (2008). Curr Biol 18: R345–R347. Mackiewicz et al (2012). Theory Biosci 131: 1–18. Algal lineages with complex plastids  Glaucophyta Secondary Plastids, Green Lineage http://bioinformatica.uab.es Chlorarachniophyta Pigments: chlorophyll a, b Nucleomorph between chloroplast ER membrane and second membrane (in total four membranes) © Lee (2008) Phycology, 4th Ed. Cambridge University Press. Storage compound: paramylon amoeboflagellates shigen.nig.ac.jp Euglenophyta © Protist information server Mainly unicellular flagellates (2 flagella) mostly freshwater organisms Euglena spirogyra Mixotrophic, many hetero-trophic species Plastids with 3 membranes Pigments: chlorophyll a, b Storage compound: paramylon No cell wall Euglenophyta Pellicle: euglenoid movement (metaboly) © Brian S. Leander youtube.com/watch?v=91yFpzzz4O8  Glaucophyta Secondary Plastids, Red Lineage http://bioinformatica.uab.es Cryptophyta Pigments: chlorophyll a, c, phycobiliproteins Nucleomorph Periplast inside plasma membrane Between chloroplast membranes starch product ejectosome © Lee (2008) Phycology, 4th Ed. Cambridge University Press. Cryptomonas sp. © Lee (2008) Phycology, 4th Ed. Cambridge University Press. Heterokontophyta fucoxanthin Pigments: chlorophyll a, c, fucoxanthin Heterokont flagella (stramenopiles) Storage compound: chrysolaminarin (cytoplasmic vesicles) 4 chloroplast membranes (chloroplast ER), nucleomorph lost Phaeophyta (“brown algae”) Chrysophyta Important classes: Chrysophyceae Xanthophyceae Bacillariophyceae Chrysophyta © Frank Fox Chrysophyceae: “Golden algae” © Landcare Research Dinobryon divergens Synura sp. Xanthophyceae: “Yellow-green algae” Tribonema sp. Vaucheria sp. Bacillariophyceae (“Diatoms”) Most important algal class for primary production in the oceans Silica cell wall (frustule) Unicellular, some colonial Pennales vs. Centrales De Tommasi et al. (2017) Marine Genomics 35: 1-18. Life Cycle Centric Diatoms Moore et al (2017) PLOS One 12: 0181098. Haptophyta (Prymnesiophyta) Two flagella Pigments: chlorophyll a, c, fucoxanthin Coccoliths: Scales outside cell (CaCO3, cellulose) Storage product: chrysolaminarin (cytoplasmic vesicles) Haptonema © Lee (2008) Phycology, 4th Ed. Cambridge University Press. © Alison R. Taylor Emiliania huxleyi  Glaucophyta Secondary/ Tertiary Plastids http://bioinformatica.uab.es Pigments Chlorophyll a & b: Dinophyta Primary photosynthetic pigments found in these organisms, enabling them to capture light for photosynthesis. Carotenoids (e.g., peridinin): Accessory pigments like carotenoids absorb light energy and protect cells from photodamage. © Lee (2008) Phycology, 4th Ed. Cambridge University Peridinin is unique to dinoflagellates and plays a role in light absorption for photosynthesis. Chlorophyll c & fucoxanthin: peridinin Some dinoflagellates may also contain chlorophyll c and fucoxanthin, indicating a mixotrophic lifestyle (a mix of autotrophic and heterotrophic behaviors). Two Flagella Pigments: chlorophyll a, b + carotene/ c + Dinoflagellates are biflagellate, meaning they have two flagella: Transverse Flagellum (TF): Lies in a groove (cingulum) around the cell, providing a spinning motion. peridinin /c + fucoxanthin Longitudinal Flagellum (LF): Extends posteriorly and helps with directional movement. This unique movement allows , them to swim in a spiraling pattern. two areflagella Theca (Cellulose Plates) Dinoflagellates covered by a tough armor called theca, made of cellulose plates. Provides structural support and protection. The arrangement of these plates is used for classification within the group. Theca, (cellulose Heterotrophic, Autotrophic, Mixotrophic Dinoflagellates exhibit diverse plates) feeding strategies: Press. Autotrophic: Use photosynthesis to produce their own energy. Heterotrophic, Mixotrophic: Combine photosynthesis and Second Most Important Algal Class autotrophic, Heterotrophic: Ingest other organisms or organic material for energy. mixotrophic ingestion depending on environmental conditions. Second a crucial role inmost important algal class of Dinophyta is the second most significant group of phytoplankton (after diatoms) in aquatic ecosystems. They play the marine food web as primary producers. Zooxanthellae phytoplankton corals offer shelter and CO for (after diatoms) Zooxanthellae are symbiotic dinoflagellates that live inside corals, providing them with nutrients via photosynthesis. In return, photosynthesis. This mutualistic relationship is critical for coral reef ecosystems. Zooxanthellae dinoflagellates Highly Toxic Species (HABs) Some cause Harmful Algal Blooms (HABs): Examples include Karenia brevis (red tide) and Alexandrium species (causing paralytic shellfish poisoning). These blooms release toxins that can harm marine life and humans. Highly toxic species (HABs) Toxins may bioaccumulate in the food web, affecting higher organisms. Symbodinium kawagutii © Scott R. Santos © 1996-2006, Mats Kuylenstierna & Bengt Karlson Bioluminescence in Dinoflagellates © Andy Crabb Bioluminescence in Dinophyta dinoflagellate luciferase: Step 1: Shear Stress Detection Trigger: dinoflagellate luciferin + O2 → dinoflagellate luciferinox + H2O + light Mechanical stimulation, such as turbulence in water caused by waves, boat movements, or predators, creates shear stress. Mechanism: Shear stress is detected by G-protein coupled receptors (GPCRs) on the dinoflagellate's cell membrane. This activation leads to intracellular signaling that causes an increase in calcium ion (Ca²) concentration in the cytoplasm. Step 2: Calcium Ion (Ca²) Increase What Happens: The increase in calcium ions triggers the activation of scintillons (specialized organelles where the bioluminescent reaction occurs). Scintillons: Contain the necessary components for the light-producing reaction, including luciferin, luciferase, and accessory proteins. © carolina.com These organelles respond to the influx of calcium by initiating the next steps of the reaction. Step 3: Voltage-Gated Proton Channels Action Potential Formation: The increased calcium ions generate an action potential, which activates voltage-gated proton (H) channels in the vacuole membrane. This causes protons (H) to be pumped from the cytoplasm into the vacuole. pH Change: The movement of protons lowers the pH inside the scintillons (acidification), creating the optimal conditions for the bioluminescent reaction. Step 4: Biochemical Light Reaction Luciferin-Luciferase Reaction: In the acidic environment, luciferin (a light-emitting molecule) reacts with oxygen (O) in the presence of the enzyme luciferase. This reaction produces an oxidized form of luciferin, water (HO), and light as a byproduct. Proteins Involved: LCF (luciferin binding protein) stabilizes luciferin and assists in the reaction. The light is emitted in the bluish-green spectrum (~470 nm), which is visible in the dark. Valiadi & Iglesias-Rodriguez (2013) Microorganisms 1: 3-25. Project “Lohafex” Fertilisation of ocean with iron Project in 2009 (Alfred Wegener Institute, National Institute of Oceanography India) 20 t FeSO4 spread over 300 km2 Further reading Archibald JM. 2015. Endosymbiosis and Eukaryotic Cell Evolution. Curr Biol 25, R911–R921. Larkum AWD, Lockhart PJ, Howe CJ. 2007. Shopping for plastids. Trends in Plant Science 12, 189–195. Lee RE. 2008. Phycology, 4th Ed., Cambridge University Press. Leliaert F, Smith DR, Moreau H, Herron MD, Verbruggen H, Delwiche CF, De Clerck O. 2012. Phylogeny and Molecular Evolution of the Green Algae. Crit Rev Plant Sci 31, 1–46. Sasso S, Stibor H, Mittag M, Grossman AR. 2018. From molecular manipulation of domesticated Chlamydomonas reinhardtii to survival in nature. eLife 7: e39233. Valiadi M, Iglesias-Rodriguez D. 2013. Understanding Bioluminescence in Dinoflagellates—How Far Have We Come? Microorganisms 1, 3–25.