ABSTRACT
Plants allocate carbon below ground in the form of root exudates, thereby inuencing the microbial communities (Morgan et al., 2005; Drigo et al., 2010). The term “rhizosphere” was coined by Lorenz Hiltner (Hiltner, 1904) to dene the volume of soil in close proximity to roots that are characterized by elevated microbial populations. The rhizosphere is under the continuous inuence of living roots and the rich nutrient supply (rhizodeposition), which enables microorganisms to have direct inuence on plant growth. The root exudates consist of simple and complex sugars, growth regulators, primary and secondary compounds such as amino acids, organic acids, phenolic acids, avonoids, fatty acids, enzymes, steroids, alkaloids, and vitamins (Uren, 2000; Philippot et al., 2013). Some of these root exudates are known to play a role in shaping the microbial communities in the rhizosphere (Haichar et al., 2008; Bressen et al., 2009; Drigo et al., 2010).
