Details

Autor(en) / Beteiligte

• McGrath, Justin M.
• Long, Stephen P.

Titel

Can the Cyanobacterial Carbon-Concentrating Mechanism Increase Photosynthesis in Crop Species? A Theoretical Analysis1[W][OPEN]

Ist Teil von

• Plant physiology (Bethesda), 2014-02, Vol.164 (4), p.2247-2261

Ort / Verlag

American Society of Plant Biologists

Erscheinungsjahr

2014

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• A model incorporating the full cyanobacterial carbon-concentrating mechanism into C3 plants indicates that CO2 uptake rate could be increased by 60%, thus increasing yield during a time when yield growth has stagnated . Experimental elevation of [CO 2 ] around C 3 crops in the field has been shown to increase yields by suppressing the Rubisco oxygenase reaction and, in turn, photorespiration. Bioengineering a cyanobacterial carbon-concentrating mechanism ( CCM ) into C 3 crop species provides a potential means of elevating [CO 2 ] at Rubisco, thereby decreasing photorespiration and increasing photosynthetic efficiency and yield. The cyanobacterial CCM is an attractive alternative relative to other CCM s, because its features do not require anatomical changes to leaf tissue. However, the potential benefits of engineering the entire CCM into a C 3 leaf are unexamined. Here, a CO 2 and HCO 3 − diffusion-reaction model is developed to examine how components of the cyanobacterial CCM affect leaf light-saturated CO 2 uptake ( A sat ) and to determine whether a different Rubisco isoform would perform better in a leaf with a cyanobacterial CCM . The results show that the addition of carboxysomes without other CCM components substantially decreases A sat and that the best first step is the addition of HCO 3 − transporters, as a single HCO 3 − transporter increased modeled A sat by 9%. Addition of all major CCM components increased A sat from 24 to 38 µmol m −2 s −1 . Several Rubisco isoforms were compared in the model, and increasing ribulose bisphosphate regeneration rate will allow for further improvements by using a Rubisco isoform adapted to high [CO 2 ]. Results from field studies that artificially raise [CO 2 ] suggest that this 60% increase in A sat could result in a 36% to 60% increase in yield.