Researchers from the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences engineered a new pathway in chloroplasts to improve plant biomass and productivity.
Plant photosynthesis produces carbohydrates to sustain lives and ecosystems on earth. The major carbohydrate generated in plants is starch, which is a glucose homopolymer deposited in plastids that can be quickly converted into glucose molecules to supply carbon skeletons and energy.
There are two types of phosphoglucose isomerase (PGI) in plants, which catalyzes the interconversion between glucose 6-phosphate (G6P) and fructose 6-phosphate (F6P). One type of enzyme locates to chloroplast involved in starch synthesis, and another type of enzyme locates to cytosol involved in sucrose synthesis and glycolysis.
GAO et al. found that specific activity of recombinantly purified PGI localized in cytosol (PGIc) was much higher than its plastidic isoenzyme counterpart (PGIp). Engineering of PGIc into chloroplasts of a pgip mutant of Arabidopsis thaliana (atpgip) resulted in starch over-accumulation, higher photosynthesis rate, up to 19% more plant biomass and 27% seed yield productivity.
This work showed that manipulating starch metabolic pathways in chloroplasts can improve plant biomass and yield productivity.
The strategy used in this research is straight forward and powerful, with easy handling, less work and stable inheritance in progeny plants.
This work reminds us that synthetic biology is one of important ice-breaking tools to improve agricultural yield and crop characteristics after "the green revolution".
Figure. Engineering of phosphoglucose isomerase in chloroplasts improves plant photosynthesis and biomass (Image by IGDB)