Identification of synchronized role of transcription factors, genes and enzymes in Arabidopsis thaliana under four Abiotic stress responsive pathways

This thesis report is submitted in partial fulfillment of the requirement for the degree of Masters of Science in Biotechnology, 2014.Cataloged from PDF version of thesis.Includes bibliographical references (page 89).DNA microarray databases are widely used tool to predict and identify functional genomics and gene expression. This plant genomic recourse can solve various biological questions related to biotic and abiotic stresses at molecular as well as cellular levels. Under stress conditions, various types of proteins and DNA sequences play important role in plant to withstand the adverse conditions. These elements can be transcription factors, regulatory genes and enzymes which independently or in connection with each other attain this task. The present study was conducted to identify these DNA sequences through microarray datasets and find out the connection between their products, and to produce a network in model plant Arabidopsis thaliana. Four microarray datasets responding to abiotic stresses, like, heat, cold, drought and abscisic acid were considered here. Preliminary study started with ArrayExpress which gave four groups of DNA sequences for each stress signals. To figure out the common physiological characters between these thousands of genes, 42 common genes were found to be up-regulated during the selected stresses. Among them, 30 found to be closely related. Further bioinformatics study and also literature mining showed that of these 30, eight genes, like, DREB2A, P5CS1, ERD5, CPL1, NHX1, SOS1, SOS2 and SOS3 are highly responsive to the above abiotic stresses. Later their protein-protein networking, protein stability, conserved sequences, interactive domain and individual interectome with other genes were studied. This was done using different web based datasoft, namely, String database, GeneMania, Gene Ontology and InterProScan. The study revealed that these eight genes not only get up-regulated but also they create a connection to each other and produce a tolerance hub. In the present study, the identified genes imply a concurrent defensive role against these abiotic stresses. In future, study needs to be undertaken to validate these findings under in vivo condition so that the knowledge can be applied in agriculture to improve crop protection and production under variable climatic conditions.Rabab MahdiM. Biotechnolog