ABSTRACT
In nature, no organism exists in isolation and interactions among organisms are necessary for survival, ecological balance, and constant evolution. Such interactions could range from casual to extreme where two different species live on or in one another permanently or for a considerable period of their life involving exchange of metabolites between the partners [1,2]. Such close associations are described as symbiosis [3] and the associating partners are termed as “symbionts” with the larger partner commonly referred as the “host.” Accordingly, symbiosis can be described as a life style in which originally independent entities form integrated units as a result of series of events directed toward intimate and orchestrated development for improved living and survival together in association. During the process of development, the partners often lose their independent identity. In the history of evolution of life on earth, such intermingling and permanent dependency of organisms may have contributed toward evolution and origin of species [2,4-8].
