Send to

Choose Destination
Plant Physiol. 2019 Jun 10. pii: pp.00286.2019. doi: 10.1104/pp.19.00286. [Epub ahead of print]

The clock gene TOC1 in shoots, not roots, determines fitness of Nicotiana attenuata under drought.

Author information

Max Planck Institute for Chemical Ecology CITY: Jena Germany [DE].
Centro de Investigación Científico Ecológico Académico, Campus Santa María del Mar CITY: Lima Peru [PE].
Max Planck Institute for Chemical Ecology CITY: Jena POSTAL_CODE: 07745 Germany [DE].
University of Zurich CITY: Zurich Switzerland [CH]
Max-Planck-Institute for Chemical Ecology Department of Molecular Ecology, Hans Knoll strasse 8 CITY: Jena POSTAL_CODE: D-07745 Germany [DE].


The highly conserved core circadian clock component TIMING OF CAB EXPRESSION 1 (TOC1) contextualizes environmental stress responses in plants, for example by gating abscisic acid (ABA) signaling and suppressing thermoresponsive growth. Selective interaction of TOC1 with PHYTOCHROME B (PHYB) under far-red-enriched light suggests a connection between circadian gating of light responses and sensitivity to ABA, an important regulator of growth and stress responses, including under drought. However, the fitness consequences of TOC1 function, particularly in the root, are poorly understood. Here, we used the desert annual, Nicotiana attenuata, to investigate the function of TOC1 in shoots and roots for maintaining fitness under drought, in both field and glasshouse experiments. Despite marked decreases in leaf water loss, TOC1-deficient (irTOC1) lines failed to maintain fitness in response to drought stress as measured by total seed capsule production. Restoring TOC1 transcript levels in shoots via micrografting was sufficient to restore wild-type drought responses under field conditions. Microarrays identified a co-expression module in leaves strongly linking red and far-red light signaling to drought responses in a TOC1-dependent manner, but experiments with phytochrome-deficient lines revealed that the effects of TOC1 deficiency under drought cannot be attributed to changes in red/far-red light perception alone. Taken together, these results elucidate the sophisticated, tissue-dependent role of the circadian clock in maintaining fitness in the face of long-term abiotic stresses such as drought.


Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center