Microbial interactions in the rhizosphere

Abstract

Microbial populations living at the root–soil interfaces, the rhizosphere, are immersed in a framework of interactions known to influence plant growth and health, and soil quality. In the past years, research has been focused on improving the understanding of the diversity, dynamics, and significance of rhizosphere microbial populations, and to gain more information on the molecular determinants of their cooperative interactions. Thus the aim of this chapter is to review current knowledge on microbial interactions that take place in the rhizosphere scenario, with emphasis on ecological and molecular issues. In particular, this article summarizes and discusses significant aspects of this topic including: (i) activities of the diverse trophic and functional groups of rhizosphere microorganisms and their interactions with the plant; (ii) analysis of the direct microbe–microbe interactions focused on those benefiting agroecosystem developments; (iii) analysis of beneficial microbial interactions involving arbuscular mycorrhiza, the omnipresent fungus–plant beneficial symbiosis, which occurs in the so-called mycorrhizosphere. The trends of this thematic area will be outlined to suggest what research is needed in the future.