Integrating Energy Status, Growth, and Deposition
Figure 1: Biological processes underlying energy flow (thick arrows) from light capture to carbon assimilation and storage. Red arrows conceptualize points of feedback regulation that serve to integrate these processes for optimal photosynthesis and energy coupling between photon capture and carbon deposition.
For photosynthesis to be effective, the energy derived from the absorption of light must be efficiently coupled to the deposition of carbon into cell wall components, protein, defense-related secondary metabolites, reproductive structures, and transient energy storage compounds such as starch and glycogen. Indeed, photosynthetic cells use the energy of sunlight to create billions of tons of biomass annually. Understanding how plants and microalgae sense and allocate fixed carbon is a fundamental challenge in energy biology. Despite detailed knowledge of the core reactions of photosynthesis, relatively little is known about how carbon building blocks derived from the Calvin-Benson cycle are proportioned to various metabolic sinks. For example, one question under investigation concerns the mechanisms by which environmental stress redirects the partitioning of carbon from growth to defense. A second key question is to better understand how sink strength, defined as the total capacity of a photosynthetic system to utilize the products of the Calvin-Benson cycle, exerts feedback control on photosynthetic efficiency. Ongoing research in this collaborative project spans multiple scales, disciplines, and organismal platforms to generate knowledge along the continuum of energy capture, conversion, and deposition.
Figure 2: Underlying scheme to represent carbon flow in the Arabidopsis leaf area growth model described by Weraduwage et al (2015).
Primary Research Groups Involved:
Attaran E, Major IT, Cruz JA, Rosa BA, Koo AJK, Chen J, Kramer DM, He SY, Howe GA (2014) Temporal dynamics of growth and photosynthesis suppression by jasmonate signaling. Plant Physiol. 165: 1302-1314
Hays SG and Ducat DC (2014) Engineering cyanobacteria as photosynthetic feedstock factories. Photosyn Res doi:10.1007/s11120–014–9980–0
Weraduwage SM, Chen J, Anozie FC, Morales A, Sean SE, Sharkey TD. (2015) The relationship between leaf area growth and biomass accumulation in Arabidopsis thaliana. Front Plant Sci, 6:167
Havko NE, Major IT, Jewell JB, Attaran E, Browse J, Howe GA. (2016) Control of Carbon Assimilation and Partitioning by Jasmonate: An Accounting of Growth-Defense Tradeoffs. Plants (Basel). Jan 15;5(1). pii: E7. doi: 10.3390/plants5010007. Review. PMID: 27135227
M Weraduwage S, Kim SJ, Renna L, C Anozie F, D Sharkey T, Brandizzi F. (2016) Pectin Methylesterification Impacts the Relationship between Photosynthesis and Plant Growth Plant Physiol. Jun;171(2):833-48. doi: 10.1104/pp.16.00173. Epub 2016 Apr 4 PMID: 27208234
Marcelo L. Campos, Yuki Yoshida, Ian T. Major, Dalton de Oliveira Ferreira, Sarathi M. Weraduwage, John E. Froehlich, Brendan F. Johnson, David M. Kramer, Georg Jander, Thomas D. Sharkey & Gregg A. Howe. (2016) Rewiring of jasmonate and phytochrome B signalling uncouples plant growth-defense tradeoffs. Nature Communications. Article number: 12570 (2016). doi:10.1038/ncomms12570