Flux4LIVES_Thylakoid ion flux-Linking photosynthetic efficiency with osmotic stress response

• Applicants: Professorin Dr. Ute Armbruster; Professor David Mark Kramer, Ph.D.; Professor Dr. Hans-Henning Kunz
• Subject Area: Plant Physiology ; Plant Biochemistry and Biophysics
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 355293141

• Final Report Year: 2022

Final Report Abstract

The global need for dramatic increases in food and fuel over the next decades requires the rapid development of fast-growing crops, which are robust against environmental challenges. Photosynthesis is the driver for plant growth, but its solar energy source fluctuates drastically under crop field conditions. Recent work suggested that thylakoid ion transport proteins play a crucial role for efficient photosynthesis under dynamic field conditions and are involved in stress resistance. These findings strongly suggested thylakoid ion flux as a promising, perhaps pivotal, target for robust plant growth improvements. Yet our knowledge of key components was far from complete. During the Flux4lives funding period, we greatly expanded our understanding of the thylakoid network of ion homeostatic mechanisms: We (i) developed a mathematical model which links modifications to thylakoid ion flux with photosynthetic efficiency, (ii) established a new spectroscopy approach to monitor thylakoid ion flux dynamics at unprecedented temporal resolution and showed them to interact with acclimation to specific light factors, (iii) revisited the inventory of thylakoid ion transport proteins and identified novel components, (iv) characterized the function of thylakoid and envelope K+/H+ exchange proteins in the vegetable crop species Solanum lycopersicum (tomato) in the context of natural light environments and drought stress and (v) characterized photosynthetic signatures of drought stress resistance in tomato introgression lines with the drought resistant Solanum pennellii. In summary, our joint efforts have provided new tools for studies of thylakoid ion flux and devise strategies to improve photosynthesis and plant growth. We are currently still in the process of characterizing the cross-talk between photosynthetic efficiency and stress responses via thylakoid ion flux, which we obtained the tools for during the funding period. Further work is needed to gain a mechanistic understanding of the functions of thylakoid ion flux and how adjustments may lead to resilient fast-growing crops.

Publications

• Fluctuating light experiments and semi-automated plant phenotyping enabled by self-built growth racks and simple upgrades to the IMAGING-PAM. Plant Methods, 15(1).
  Schneider, Dominik; Lopez, Laura S.; Li, Meng; Crawford, Joseph D.; Kirchhoff, Helmut & Kunz, Hans-Henning
  
• Photosynthesis in Arabidopsis Is Unaffected by the Function of the Vacuolar K + Channel TPK3. Plant Physiology, 180(3), 1322-1335.
  Höhner, Ricarda; Galvis, Viviana Correa; Strand, Deserah D.; Völkner, Carsten; Krämer, Moritz; Messer, Michaela; Dinc, Firdevs; Sjuts, Inga; Bölter, Bettina; Kramer, David M.; Armbruster, Ute & Kunz, Hans-Henning
  
• The topology of plastid inner envelope potassium cation efflux antiporter KEA1 provides new insights into its regulatory features. Photosynthesis Research, 145(1), 43-54.
  Bölter, Bettina; Mitterreiter, Melanie J.; Schwenkert, Serena; Finkemeier, Iris & Kunz, Hans-Henning
  
• Comparative analysis of thylakoid protein complexes in state transition mutants nsi and stn7: focus on PSI and LHCII. Photosynthesis Research, 145(1), 15-30.
  Koskela, Minna M.; Brünje, Annika; Ivanauskaite, Aiste; Lopez, Laura S.; Schneider, Dominik; DeTar, Rachael A.; Kunz, Hans-Henning; Finkemeier, Iris & Mulo, Paula
  
• Growth under Fluctuating Light Reveals Large Trait Variation in a Panel of Arabidopsis Accessions. Plants, 9(3), 316.
  Kaiser, Elias; Walther, Dirk & Armbruster, Ute
  
• Plastidial transporters KEA1 and KEA2 at the inner envelope membrane adjust stromal pH in the dark. New Phytologist, 229(4), 2080-2090.
  Aranda, Sicilia María Nieves; Sánchez, Romero María Elena; Rodríguez, Rosales María Pilar & Venema, Kees
  
• Cadmium interference with iron sensing reveals transcriptional programs sensitive and insensitive to reactive oxygen species. Journal of Experimental Botany, 73(1), 324-338.
  McInturf, Samuel A.; Khan, Mather A.; Gokul, Arun; Castro-Guerrero, Norma A.; Höhner, Ricarda; Li, Jiamei; Marjault, Henri-Baptiste; Fichman, Yosef; Kunz, Hans-Henning; Goggin, Fiona L.; Keyster, Marshall; Nechushtai, Rachel; Mittler, Ron & Mendoza-Cózatl, David G.
  
• Functional characterization of proton antiport regulation in the thylakoid membrane. Plant Physiology, 187(4), 2209-2229.
  Uflewski, Michał; Mielke, Sarah; Correa, Galvis Viviana; von Bismarck, Thekla; Chen, Xiaoheng; Tietz, Enrico; Ruß, Jeremy; Luzarowski, Marcin; Sokolowska, Ewelina; Skirycz, Aleksandra; Eirich, Jürgen; Finkemeier, Iris; Schöttler, Mark Aurel & Armbruster, Ute
  
• Impact of ion fluxes across thylakoid membranes on photosynthetic electron transport and photoprotection. Nature Plants, 7(7), 979-988.
  Li, Meng; Svoboda, Vaclav; Davis, Geoffry; Kramer, David; Kunz, Hans-Henning & Kirchhoff, Helmut
  
• Indirect Export of Reducing Equivalents From the Chloroplast to Resupply NADP for C3 Photosynthesis—Growing Importance for Stromal NAD(H)?. Frontiers in Plant Science, 12.
  Krämer, Moritz & Kunz, Hans-Henning
  
• Stromal NADH supplied by PHOSPHOGLYCERATE DEHYDROGENASE3 is crucial for photosynthetic performance. Plant Physiology, 186(1), 142-167.
  Höhner, Ricarda; Day, Philip M.; Zimmermann, Sandra E.; Lopez, Laura S.; Krämer, Moritz; Giavalisco, Patrick; Correa, Galvis Viviana; Armbruster, Ute; Schöttler, Mark Aurel; Jahns, Peter; Krueger, Stephan & Kunz, Hans-Henning
  
• Two plastid POLLUX ion channel-like proteins are required for stress-triggered stromal Ca2+release. Plant Physiology, 187(4), 2110-2125.
  Völkner, Carsten; Holzner, Lorenz Josef; Day, Philip M.; Ashok, Amra Dhabalia; de Vries, Jan; Bölter, Bettina & Kunz, Hans-Henning
  
• Light acclimation interacts with thylakoid ion transport to govern the dynamics of photosynthesis in Arabidopsis. New Phytologist, 237(1), 160-176.
  von Bismarck, Thekla; Korkmaz, Kübra; Ruß, Jeremy; Skurk, Kira; Kaiser, Elias; Correa, Galvis Viviana; Cruz, Jeffrey A.; Strand, Deserah D.; Köhl, Karin; Eirich, Jürgen; Finkemeier, Iris; Jahns, Peter; Kramer, David M. & Armbruster, Ute
  
• The Arabidopsis T‐DNA mutant SALK_008491 carries a 14‐kb deletion on chromosome 3 that provides rare insights into the plant response to dynamic light stress. Plant Direct, 6(7).
  Lopez, Laura S.; Völkner, Carsten; Day, Philip M.; Lewis, Chance M.; Lewis, Chase L.; Schneider, Dominik; Correa, Galvis Viviana; Cruz, Jeffrey A.; Armbruster, Ute; Kramer, David M. & Kunz, Hans‐Henning