M.Sc. (Biochemistry) / Plants respond to various stress stimuli by activating a broad-spectrum of defence responses that can be expressed locally at the site of pathogen infection (hypersensitive response-HR) as well as systemically in uninfected tissue (systemic acquired resistance-SAR). The ability to continuously respond to both abiotic and biotic stimuli leads to changes in the plants’ physiology, morphology and development. Therefore, there is a need to define and understand the mechanism of the plant defence system, including the mode of recognition, activation of signalling pathways and subsequent defence. In so doing, a long lasting and effective protection against various pathogens may be established. In the current study, the transcriptome status of cultured cells of Nicotiana tabacum was investigated using annealing control primer (ACP)-based differential display (DD) since it is an improved technology to compare patterns of gene expression in RNA samples, isolated from tissue / cells under different biological conditions, using a novel priming system. Here, ACP-DDRT-PCR was used in combination with a next-generation sequencing technology, namely 454 pyro-sequencing, which is the only technique that generates longer reads which are suitable for de novo assembly and annotation of non-model plants like tobacco of which the genome is not yet published in Genbank. SAR occurs following induction by biotrophic or necrotising pathogens. However, it can also be manifested artificially after chemical treatment. In this study, isonitrosoacetophenone (INAP), a novel compound that was originally isolated from extracts of citrus peel undergoing oxidative stress, was used as a chemical inducer and it was hypothesised that this compound induces defence-related responses in plants. In order to investigate this, tobacco cell suspensions were elicited with 1 mM INAP, followed by ACP-DDRT-PCR and subsequent identification of differentially expressed genes using pyro-sequencing.