Rhizobacteria for management of nematode disease in plants

Abstract

Plant-parasitic nematodes are considered worst enemies of mankind because of devastation they cause to crops. There is hardly any crop which is not affected by nematodes. Management of the nematode disease appears to be less straightforward than one might anticipate. Therefore, it is fundamental to have prior knowledge of the interactions involved, as even low densities of nematode can result in a disease of significant importance. One of the solutions is to use chemicals to control the interacting microorganisms and thus preventing the formation of disease-like complexes. However, potential threat to environment, their harmful effects on nontarget species, including human, as well as their residual effects on climax communities, the time required for the development of nematode-resistant host cultivars, and high costs of chemical control agents possess a serious problem in their wide application. An alternative to chemicals that fulfill all requirements and brings sustainability of agricultural crops is the range of rhizospheric microorganisms which attack the plant-parasitic nematodes. Hence, nematode management strategies using biological microorganisms have gained considerable interest. As a group of important natural enemies of nematode disease, microorganisms exhibit diverse modes of action: these include parasitizing; producing toxins, antibiotics, or enzymes; competing for nutrients; inducing systemic resistance of plants; and promoting plant health. They act synergistically on plants through the direct suppression of nematodes, promoting plant growth and facilitating the rhizospheric colonization and activity of microbial antagonists.