FRET-based reporters for the direct visualization of abscisic acid concentration changes and distribution in Arabidopsis
Rainer Waadt,
Kenichi Hitomi,
Noriyuki Nishimura,
Chiharu Hitomi,
Stephen R Adams,
Elizabeth D Getzoff,
Julian I Schroeder
Affiliations
Rainer Waadt
Division of Biological Sciences, Cell and Developmental Biology Section, University of California, San Diego, La Jolla, United States; Food and Fuel for the 21st Century, University of California, San Diego, La Jolla, United States
Kenichi Hitomi
Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, United States; The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, United States
Noriyuki Nishimura
Division of Biological Sciences, Cell and Developmental Biology Section, University of California, San Diego, La Jolla, United States; Food and Fuel for the 21st Century, University of California, San Diego, La Jolla, United States
Chiharu Hitomi
Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, United States; The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, United States
Stephen R Adams
Department of Pharmacology, University of California, San Diego, La Jolla, United States
Elizabeth D Getzoff
Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, United States; The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, United States
Julian I Schroeder
Division of Biological Sciences, Cell and Developmental Biology Section, University of California, San Diego, La Jolla, United States; Food and Fuel for the 21st Century, University of California, San Diego, La Jolla, United States
Abscisic acid (ABA) is a plant hormone that regulates plant growth and development and mediates abiotic stress responses. Direct cellular monitoring of dynamic ABA concentration changes in response to environmental cues is essential for understanding ABA action. We have developed ABAleons: ABA-specific optogenetic reporters that instantaneously convert the phytohormone-triggered interaction of ABA receptors with PP2C-type phosphatases to send a fluorescence resonance energy transfer (FRET) signal in response to ABA. We report the design, engineering and use of ABAleons with ABA affinities in the range of 100–600 nM to map ABA concentration changes in plant tissues with spatial and temporal resolution. High ABAleon expression can partially repress Arabidopsis ABA responses. ABAleons report ABA concentration differences in distinct cell types, ABA concentration increases in response to low humidity and NaCl in guard cells and to NaCl and osmotic stress in roots and ABA transport from the hypocotyl to the shoot and root.
