Introduction
Ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO), is the most abundant protein on Earth; it is universal in plants and is highly expressed because of its role in photosynthesis. RUBISCO represents 40-80% of the protein found in leaf tissue and is composed of two major subunits a large chain, 55,000kD, and a small chain, 15,000kD. The active sites for substrate binding are located on the large chain (rbcL). The effects of growing conditions such as temperature, salinity and the presence of chemical agents on RUBISCO expression levels have been well demonstrated. Long term exposure to stressful ozone levels has been shown to down regulate RUBISCO expression in the leaf tissue of Zea mays. (Leitao, 1997) Additionally, the presence of lead has been shown to down regulate the expression of RUBISCO and RUBISCO activase in Spinacia oleracea. (Xiao, 2008) RUBISCO expression can be an indicator of the plant health and higher levels of expression are beneficial to crops. Modifications to increase RUBISCO expression could dramatically increase farm yields or make crops more resistant to droughts.
We propose a comparison study between the two existing methods of farming vegetables: organic and non-organic, to determine if farming method impacts overall health of crops. We predict organic farming will have higher levels of DNA and protein, because stress has been shown to reduce RBCL expression and organic farming is less stressful than non-organic because of the reduction in synthetic chemicals. To measure this condition, we will use protein assays to determine RUBISCO concentrations and real-time PCR to measure the number of rbcL copies. This study will use parsley, Petroselinum crispum, and collard greens, Brassica oleracea, as independent variables to compare the effects of farming method across species. Both P. crispum and B. oleracea use the C3 pathway to fix atmospheric CO2 .