ABSTRACT
Plants growing in natural environments or cultivated agricultural systems form interactions with microorganisms. The rhizosphere contains a high percentage of microbial diversity and abundance, with plants secreting root exudates that serve as substrates and attractants for bacterial and fungal organisms (Dakora and Phillips, 2002; Chaparro et al., 2014). Some bacteria develop symbiotic relationships with plants, which promote plant performance and survival in a wide range of environmental conditions, including root-colonizing plant growth-promoting rhizobacteria (PGPR) (Lugtenberg and Kamilova, 2009; Yang et al., 2009; Berg et al., 2014; Liu and Zhang, 2015; Poupin et al., 2016). Endophytic PGPR in the microbial communities form closer associations with the plant host than free-living bacteria in the rhizosphere, as they colonize the internal tissues and can directly regulate cellular processes of their host plant (Conn et al., 1997; Chanway et al., 2000).
