Actinobacteria–Plant Interactions: A Boon to Agriculture

Abstract

Plant diseases caused by soil-dwelling microorganisms are responsible for significant losses of agricultural crops each year. These losses are compounded in soils bearing insufficient micronutrients to adequately support plant health and development. While agrichemicals such as pesticides and fertilizers have played an important role in increasing crop production, the benefits have been overshadowed by damage to the environment, adverse human health effects, and the emergence of pesticide-resistant pathogens. Public perception of the risk posed by agrichemicals and their residues along with strict restrictions placed on the use of chemicals in agriculture have had serious negative economic impact. As a consequence, there is a growing market for alternative approaches to agricultural pest control and fertilization, fueled by the demand for chemical-free agricultural products. The development of microbial inoculants as plant growth promoters and biological control agents is a promising alternative to the use of agrochemicals. Actinobacteria are a group of Gram-positive bacteria that are ubiquitous in soil environments. Many species of Actinobacteria can colonize plant roots and surfaces. Additionally, they have the capacity to produce extracellular metabolites that not only enable them to outcompete phytopathogens but which also function as plant growth regulators. These qualities, among others, make Actinobacteria ideal candidates for development as microbial inoculants for use in agriculture.