Plant Microbe Partnerships: Implications for Growth and Plant Health

Abstract

The rhizosphere can be defined as the zone of soil around plant roots whereby soil properties are influenced by the presence and activity of the root. Changes to the physical, chemical and biological properties of rhizosphere soil have significant influence on the subsequent growth and health of plants. Interactions between plant roots and soil microorganisms are ubiquitous and are an essential component of ecosystem function. It has become increasingly evident that root interactions with soil microorganisms are intricate and involve highly complex communities that function in very heterogeneous environments. Although many plant-associated bacteria have beneficial effects on their host, their importance during plant growth and development is still underestimated. Plant-associated bacteria include endophytic, phyllospheric and rhizospheric bacteria. Research into how plant growth can be promoted has mainly concentrated on rhizobacteria. More recently, however, attention has focused on the plant growth-promoting capacity of endophytes. Mechanisms of plant growth promotion by plant-associated bacteria vary greatly and can be broadly categorized into direct and indirect effects. The purpose of this chapter is to examine how microorganisms can helps growth and plant health and its use in new area of research.