ABSTRACT
The rhizosphere is a dynamic environment in which bacteria, viruses, fungi, and microfauna, including arthropods and nematodes, develop, interact with each other, and take advantage of organic matter released by the root (1 ). A substantial consequence of this richness in comparison with the bulk soil is intense microbial activity, with feedback effects on root development and the growth of the whole plant. The complexity of the microorganisms resident in the rhizosphere has formed the subject of several studies. Plant growth-promoting rhizobacteria (PGPR), for example, are beneficial organisms whose genetic traits can easily be manipulated to some extent before their release in the field (2).
