Molecular Aspects of Host—Pathogen Interaction

Like the human, plant health is also vulnerable to disease-causing entities. Plant disease is a result of interactions among the three components of the disease triangle i.e. a susceptible host, a virulent pathogen and a favourable environment (for disease development). It is therefore needed to understand why and how disease development occurs in a host plant and the various events involved in pathogenesis. The interaction between the host and its pathogen consists of a two-way communication i.e. either the pathogen be able to successfully infect its susceptible host or else the plant able to recognize the virulent pathogen and protect itself by elicitation of defense responses. Each host-pathogen interaction is an effort made by plants and pathogens to survive in nature. The R gene present inside the plants plays a key role in imparting resistance against the virulent strains of the pathogen. The studies on host-pathogen interaction can be well brought by the omics-based approaches which have paved towards a better realization of plant disease mechanisms takes into account a point-by-point image of undergoing interactions. Metabolomic analysis has proved pivotal in the identification of elicitors and secondary metabolites of plants that induce defense response in the host plant. Moreover, a large number of online repositories are available which are involved in host-pathogen interaction and increase the domain of knowledge. This chapter primarily focuses on the classification of host-pathogen interaction along with the molecular basis of resistance (PTI/ETI). In addition to it, metabolomic studies and an online database for studying host-pathogen interaction have also been discussed.