Towards engineering carboxysomes into C3 plants. (20th June 2016)

• Record Type: Journal Article
• Authors: Hanson, Maureen R.; Lin, Myat T.; Carmo‐Silva, A. Elizabete; Parry, Martin A.J.
• Is Part Of: Plant journal. Volume 87:Number 1(2016:Jul.)
• Page Start: 38
• Page End: 50
• Publication Date: 2016-06-20
• Subjects: carbon‐concentrating mechanism -- chloroplast -- Rubisco -- photosynthesis -- carboxysome -- chloroplast transformation -- Nicotiana -- Synechococcus elongatus -- transgenic -- transplastomic; Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.13139
• Languages: English
• ISSNs: 0960-7412

Abstract

Summary: Photosynthesis in C3 plants is limited by features of the carbon‐fixing enzyme Rubisco, which exhibits a low turnover rate and can react with O2 instead of CO2, leading to photorespiration. In cyanobacteria, bacterial microcompartments, known as carboxysomes, improve the efficiency of photosynthesis by concentrating CO2 near the enzyme Rubisco. Cyanobacterial Rubisco enzymes are faster than those of C3 plants, though they have lower specificity toward CO2 than the land plant enzyme. Replacement of land plant Rubisco by faster bacterial variants with lower CO2 specificity will improve photosynthesis only if a microcompartment capable of concentrating CO2 can also be installed into the chloroplast. We review current information about cyanobacterial microcompartments and carbon‐concentrating mechanisms, plant transformation strategies, replacement of Rubisco in a model C3 plant with cyanobacterial Rubisco and progress toward synthesizing a carboxysome in chloroplasts. Significance Statement: Photosynthesis in C3 plants is limited by features of the carbon‐fixing enzyme Rubisco, which exhibits a low turnover rate and can also react with O2, leading to photorespiration. In cyanobacteria, bacterial microcompartments known as carboxysomes improve photosynthetic efficiency by concentrating CO2 near Rubisco. Thus transferring the carbon‐concentrating mechanism from cyanobacteria to C3 plants is an attractive approach for improving crop photosynthesis. Here we review recent progress in engineering cyanobacterial β‐carboxysomes into plant chloroplasts and in replacing C3 plant Rubisco with cyanobacterial Rubisco.