Potential and expression of microbial proteolytic genes apr and npr under the influence of atmospheric CO2.

CO2 in atmosphere is approaching an alarming 400 ppm mark, which is a big concern for present day environment. There is a lack of understanding on how potential it is in altering microbial structure and important soil functions. Soil proteases are enzymes that carry out proteolysis in soil, which results in nitrogenous products that can be easily accessed by plants for their growth . In this way Proteases and peptidases contribute a major share towards soil growth. Aim of this study is to see the effect of raised CO2 on potential and expression of proteolytic  soil microbial communities. To carry out this study special fields were designed  where high levels of CO2 (550 ppm ) were maintained in an experiment called Free Air Carbon dioxide Enrichment abbreviated as FACE.  Soil samples were collected from rhizosphere and bulk of wheat crops .  To compare FACE experiment site soil, a control field having same variety of wheat but with normal atmospheric CO2 was maintained. Three replicates of each,  rhizosphere and bulk soil from FACE field and three replicates from rhizosphere and bulk soil from control field were sampled for extraction of RNA and DNA. DNA was extracted with a purpose to quantify two most widely available bacterial soil protease genes apr and npr (coding for alkaline protease and neutral metalloprotease). RNA extraction will be carried out to study the expression of two genes. Enzyme assays will also be performed on the soils from respective fields.  Elevated levels of CO2 seems to have an effect on shifts in alkaline protease genes as observed in qpcr results. Furthermore it has been observed that plant rhizosphere  has a pronounced effect on proteolytic community structure under both conditions i.e. in soil from FACE site and in control .  We are now working on whether it has similar effect on npr genes. Afterward RNA extraction will be performed to see the effect on expression of both proteolytic genes under different conditions.  Study of enzymatic activity will further add to proteolytic potential of soils under different conditions. Preliminary results suggest that the alkaline proteolytic communities in soil are adapting themselves in response to rising CO2 in soil, with different effects in rhizosphere and bulk soils.