The microbial ecosystem is the sum of biotic and abiotic components of soil. It encompasses the total microbial flora together with the physical composition and physical characteristics of the soil. The microorganisms exhibit different types of interactions or associations. Some interactions are neutral while some are positive and some are negative in nature. The associations existing between different soil microorganisms, whether of a symbiotic or antagonistic nature, influence the activity of microorganisms in the soil. Interaction may be beneficial or harmful to the organisms depending on the behaviour of microbes
A plasmid is a molecule of DNA, independent of the bacterial nucleoid chromosome, which often has "bonus DNA" with instructions for weapons of infection. Both the bacterial nucleoid and bacterial plasmids are circular molecules of DNA - genetic information. Plasmids are, however, much smaller than the bacterial chromosome, usually only containing a few genes. Unlike the bacterial chromosome, plasmid traits are not normally required for the cell to function, but do help a bacterium survive and cause disease. Not all bacteria have plasmids, but those that do can share these advantageous molecules with other bacteria in a process called conjugation.
Disease is major threat in production of any crops, not only in the field but also in the growing substrate. Chemical is being tremendously used in agriculture which is harmful to the environment, soil, water and human beings. Cultural practices may be a better option to cure or prevent diseases