Abstract
Cotton is one of the most widely cultivated cash crop. Biotic and abiotic stress are mainly responsible for low yield of cotton crop. Low harvests of cotton bolls are mainly due to damage by bollworms. Biotechnology is plays significant role in developing novel transgenic plants which are resistant against various biotic and abiotic stresses. The transgenic cotton containing Cry1Ac gene which synthesizes various insecticidal proteins. Crystals of Cry1Ac proteinaceous insecticidal endotoxins are encoded by cry genes. Functional annotation of Cry1Ac protein in Bt cotton is carried out using bioinformatics approaches based on its amino acid sequence and structural domain analysis. Cry1Ac protein sequence analysis included identification of similar protein sequences (database search), motif identification, calculation of physicochemical properties and phylogenetic analysis. Cry1Ac protein structural domain analysis included identification of conserved functional domain, gene ontology prediction and Cry1Ac protein globularity protein analysis. Eight protein sequence were identified which are having sequence identity more that 80% with Cry1Ac protein by using database search. Multiple sequence alignment reveals high level of conservation of amino acids in all selected Cry1Ac protein sequences. Total eight motifs were predicted at different positions in the Cry1Ac protein sequence. Functional annotations of these motifs indicated their insecticidal role. Various physicochemical properties of Cry1Ac protein sequence are calculated which give indication about nature and stability of the proteins. The evolutionary history of Cry1Ac protein sequence was inferred. There were also other proteins sequences which are also evolutionary linked with the Cry1Ac protein sequence. Total eight structural functional domains were predicted. Identified domains were pesticidal crystal protein. Gene ontology of Cry1Ac was analysed using gene ontology resource database revealing its biological process and molecular function. Globularity of Cry1Ac protein was predicted for exploring protein disorder. Finally, it can be concluded that there are conserved regions and structural domains which are involved in the insecticidal role of the Cry1Ac protein. Therefore, these pesticidal endotoxins are considered one of the significant biological source for the development of new bioinsecticides.

Key words: Cry1Ac protein, Bioinformatics, biotic stress, insecticidal