Sample preparation method for tissue based proteomic analysis of Azolla microphylla

The nitrogen fixing aquatic pteridophyte Azolla is used as biofertilizer for rice paddy. It is also used as poultry and cattle feed due to high protein content. However, its mass cultivation and exploitation is constrained due to the abiotic stress conditions it is exposed to. The system is interesting due to the presence of symbiotic nitrogen fixing cyanobacteria and its interaction with the carbon fixing host. Therefore these interactions have to be studied at the molecular level using advanced techniques. Proteomics is a technique which can be employed to reveal the mechanism of cross talk between the host and its symbiont as well as its response to abiotc stress. The primary step that contributes to successful proteomic analysis is standardization of sound protocols for protein extraction and sufficient yield to initiate proteomic studies using 2-dimensional electrophoresis. However, reports are not available on the protein extraction procedures in Azolla. Therefore in the present study we attempted to optimize protein extraction protocol in the whole plant, roots and the chloroplast of Azolla microphylla using phenol extraction, TCA-acetone and phosphate buffer methods. Our studies showed the efficacy of phenol extraction method in terms of maximum yield and resolution of proteins in Azolla.