Chloroplast Signaling Gates Thermotolerance in Arabidopsis
Patrick J. Dickinson,
Manoj Kumar,
Claudia Martinho,
Seong Jeon Yoo,
Hui Lan,
George Artavanis,
Varodom Charoensawan,
Mark Aurel Schöttler,
Ralph Bock,
Katja E. Jaeger,
Philip A. Wigge
Affiliations
Patrick J. Dickinson
Sainsbury Laboratory, University of Cambridge, Cambridge, UK
Manoj Kumar
Sainsbury Laboratory, University of Cambridge, Cambridge, UK; Department of Plant Molecular Biology, University of New Delhi, Delhi, India
Claudia Martinho
Sainsbury Laboratory, University of Cambridge, Cambridge, UK
Seong Jeon Yoo
Sainsbury Laboratory, University of Cambridge, Cambridge, UK
Hui Lan
Sainsbury Laboratory, University of Cambridge, Cambridge, UK
George Artavanis
Sainsbury Laboratory, University of Cambridge, Cambridge, UK
Varodom Charoensawan
Sainsbury Laboratory, University of Cambridge, Cambridge, UK; Department of Biochemistry, Faculty of Science, and Integrative Computational BioScience (ICBS) Center, Mahidol University, Bangkok 10400, Thailand
Mark Aurel Schöttler
Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
Ralph Bock
Max-Planck-Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
Katja E. Jaeger
Sainsbury Laboratory, University of Cambridge, Cambridge, UK
Philip A. Wigge
Sainsbury Laboratory, University of Cambridge, Cambridge, UK; Corresponding author
Summary: Temperature is a key environmental variable influencing plant growth and survival. Protection against high temperature stress in eukaryotes is coordinated by heat shock factors (HSFs), transcription factors that activate the expression of protective chaperones such as HEAT SHOCK PROTEIN 70 (HSP70); however, the pathway by which temperature is sensed and integrated with other environmental signals into adaptive responses is not well understood. Plants are exposed to considerable diurnal variation in temperature, and we have found that there is diurnal variation in thermotolerance in Arabidopsis thaliana, with maximal thermotolerance coinciding with higher HSP70 expression during the day. In a forward genetic screen, we identified a key role for the chloroplast in controlling this response, suggesting that light-induced chloroplast signaling plays a key role. Consistent with this, we are able to globally activate binding of HSFA1a to its targets by altering redox status in planta independently of a heat shock.
