ABSTRACT
This chapter discusses various direct or indirect associations of plants and their crosstalks within the ecological niches they inhabit. To understand these associations, it is important to study the method of interaction between the participating organisms. Molecular communication occurs as systems of certain specific compounds are synthesized by either the plant or the microbes. The most common association found naturally is that of algae and fungi, also known as lichens. The formation of associations between bacteria and fungi involves the chemotactic movement of both moieties toward a mutualistic relationship. The fungal association with the plant's roots increases the surface area of the root hair, thus increasing the nutrient availability of the plant. In multispecies associations of microbes, a common pool of nutrients is formed where the efficient species show overexpression of a gene to provide the other with the necessary nutrient and benefit from the externally secreted product of the other.
