Rubisco and Crop Output: Difference between revisions

The major problem researchers have been working to change with Rubisco is the oxygenation instead of the carboxylation. The reason this is a problem is because the plant has to fix this, making this issue energetically unfavorable, by losing around 30% of the plants ATP in that step. When Rubisco binds oxygen instead, crop yield becomes lower, this is because it only makes half the product amount of 3-Phosphoglycerate. This limits how many times a plant can undergo the Calvin Cycle to make sugar. When temperatures begin to increase it is even more of an inconvenience and much more difficult for a plant to fix this problem. If we can fix this issue, Rubisco can not only be more successful with photosynthesis, but extremely successful with changing crop growth and quantity. (<ref>PMID: 27935049</ref>)

“In recent times, major advances in Rubisco engineering have been achieved through improvement of our knowledge of Rubisco synthesis and assembly, and identifying amino acid catalytic switches in the L-subunit responsible for improvements in catalysis. in crops such as rice will require further advances in chloroplast bioengineering and Rubisco biogenesis.” (<ref>PMID: 27935049</ref>) Carefully modifying genes in specific major functioning subunits can help change Rubisco to adjust the Calvin cycle and save ATP. This all starts in the chloroplasts, where Rubisco works. Improvements can also be made in C3 plants as well. They can be engineered to harvest Co2 as well, just like C4 plants. There are also alternative pathways that can be created to avoid oxygenation. (<ref>PMID: 27935049</ref>)

Success of Rubisco can be measured by the Michaelis constant of O2 and of Co2. RCA plays an important part in maintaining Rubisco activity. RCA is a nuclear gene that encodes a chloroplast protein. It is a member of the AAA(+) protein superfamily. Without RCA, plants would need a high amount of CO2 because Rubisco activity wouldn’t be maintained. Sugar phosphate molecules inhibit catalysis and prevent carbamylation. RCA removes these sugar phosphate molecules. “In most plants, RCA comprises two isoforms, an α isoform equipped with a C-terminal extension containing two cysteine residues that confer redox regulation and a shorter b isoform (Carmo-Silva et al., 2015). In Arabidopsis, the b isoform does not contain the redoxsensitive cysteine residues and is less sensitive to ADP inhibition (Carmo-Silva & Salvucci, 2013). However, the b form of tobacco RCA is sensitive to ADP inhibition, which may be explained by the absence of the α isoform (Carmo-Silva & Salvucci, 2013).” (<ref>PMID: 27935049</ref>)