Herbivore induced defence is widespread in plants and are likely to be species-specific. The specificity has been suggested to be mediated by herbivore associated elicitors (HAE), however, how such specificity evolved and what are the underlying genetic bases are little understood. Species of genus Nicotiana offered a suitable system to address these questions, because they distributed in great range of variation in habitat and evolved various specialized defence traits against herbivore. In this project, firstly, I will pursue the question how specificity of herbivore induced defence could evolve in Nicotiana by comparing herbivore induced responses among different Nicotiana species under phylogenetic framework, and investigating the trade-offs between defence responses induced by different HAE. Secondly, I will investigate the genetic basis of specificity in HAE induced defence by analysing HAE induced transcriptome changes among different species and functionally validating identified candidate genes use virus induced gene silencing. In addition, the evolutionary pattern of identified candidate genes will be investigated among different Nicotiana species.This project, taking a multiple disciplinary approach, which combines highly advanced metabolic, molecular, and genomic approach in a systematic framework to the topic of herbivore induced plant defence, will be highly novel and relevant for many other plant-herbivore interactions. The investigation on evolutionary pattern of specificity in HAE induced defence could allow the assessment of evolutionary potential of plants to adapt to changing habitats with different herbivore. The identified candidate genes underlie specificity of HAE induced defence could lead a breakthrough in understanding how plant perceive herbivore and have a substantial value for crop protection.