Arbuscular-Mycorrhiza-Mediated Plant-Pathogen Interactions and the Mechanisms Involved

Excessive use of chemical inputs to control diseases poses an important problem for present-day plant production systems. Research priorities for alternative management practices compatible with sustainable agriculture and the environment include the use of beneficial microorganisms as biological control agents. Biological control of plant pathogens is currently accepted as a key practice in sustainable agriculture and can be defined as direct and accurate management of common components of ecosystems to protect plants against pathogens. Biological control preserves environmental quality by a reduction in chemical inputs and is characteristic of sustainable management practices ( Mukerji and Garg, 1988 ; Mukerji et al., 1992 , 1999; Altieri, 1994 ; Barea and Jeffries, 1995 ; Upadhyay et al., 2000 , 2001 ).