ABSTRACT
Microorganisms are abundant and ubiquitous in our environment. They occur on phylloplane, on/in soil and the rhizosphere, and some of them are generally associated with bacterial plant pathogens causing diseases of root systems or on above-ground plant parts. A culture containing a single unadulterated species of cells is called a pure culture. Several different techniques are applied to isolate and study microorganisms in pure culture. The term rhizosphere was introduced in 1904 by the German scientist Lorenz Hiltner to denote the region of soil that is under the influence of plant roots. The number of bacteria in the rhizosphere usually exceeds the numbers in the neighboring soil by a factor of ten and often by a factor of several hundred. The phylloplane microbes cover a wide variety of microorganisms, including yeasts, filamentous fungi, bacteria, actinomycetes, blue green algae, and even ferns.
