A shadow detector for photosynthesis efficiency

JOURNAL OF THEORETICAL BIOLOGY

卷:414

Article

Liao, Kang-Ling¹  Jones, Roger D.³  McCarter, Patrick²  Tunc-Ozdemir, Meral¹  Draper, James A.¹  Elston, Timothy C.²  Kramer, David⁴  Jones, Alan M.^1,2 

[1] Univ N Carolina, Dept Biol, Coker Hall,CB 3280, Chapel Hill, NC 27599 USA

[2] Univ N Carolina, Dept Pharmacol, Chapel Hill, NC 27599 USA

[3] Stevens Inst Technol, Ctr Complex Syst & Enterprises, Hoboken, NJ 07030 USA

[4] Michigan State Univ, Plant Res Lab, E Lansing, MI 48824 USA

关键词: Photosynthesis efficiency;    Regulator of G signaling;    WNK kinase;    Heterotrimeric G protein;    Endocytosis;    Shadow detector;   

DOI  :  10.1016/j.jtbi.2016.11.027

来源: Elsevier

【 摘 要 】

Plants tolerate large variations in the intensity of the light environment by controlling the efficiency of solar to chemical energy conversion. To do this, plants have a mechanism to detect the intensity, duration, and change in light as they experience moving shadows, flickering light, and cloud cover. Sugars are the primary products of CO2 fixation, a metabolic pathway that is rate limited by this solar energy conversion. We propose that sugar is a signal encoding information about the intensity, duration and change in the light environment. We previously showed that the Arabidopsis heterotrimeric G protein complex including its receptor-like Regulator of G signaling protein, AtRGS1, detects both the concentration and the exposure time of sugars (Fu et al., 2014. Cell 156: 1084-1095). This unique property, designated dose-duration reciprocity, is a behavior that emerges from the system architecture / system motif. Here, we show that another property of the signaling system is to detect large changes in light while at the same time, filtering types of fluctuation in light that do not affect photosynthesis efficiency. When AtRGS1 is genetically ablated, photosynthesis efficiency is reduced in a changing- but not a constant-light environment. Mathematical modeling revealed that information about changes in the light environment is encoded in the amount of free AtRGS1 that becomes compartmentalized following stimulation. We propose that this property determines when to adjust photosynthetic efficiency in an environment where light intensity changes abruptly caused by moving shadows on top of a background of light changing gradually from sun rise to sun set and fluctuating light such as that caused by fluttering leaves.

【 授权许可】

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