Synergy of actinomycete co-inoculation

Abstract

Historically the symbioses between leguminous plants and rhizobia have attracted the attention of researchers due to the incidence of legumes for sustaining nutritional requirements to humans and animals. There have been large efforts to increase the ability to symbiotic N2 fixing and productivity of legumes. New research is focusing on increasing the legume-rhizobia symbiosis with increased biological nitrogen fixation (BNF), growth, and productivity. The inoculation of legumes with rhizosphere bacteria has often been found to increase symbiotic properties, plant biomass, and yields under greenhouse or field conditions. The potential to enhance plant growth, nodulation, nitrogen fixation, productivity of legumes by plant growth-promoting rhizobacteria (PGPR), and Rhizobium co-inoculation does exist, although most of studies have been conducted with Bacillus spp., Pseudomonas spp., or other genera and few with actinomycetes. The latter, a group of actinobacteria widely distributed in terrestrial ecosystems contribute to soil nutrient cycling and live in association with plants and are considered as one of the most important communities in the rhizosphere. They have a great ability to synthesize a series of bioactive metabolites and potential within the agroecosystem, where they play important roles in disease suppression and plant growth promotion in cultivated plants. In this sense, the purpose of this chapter is to show the synergistic effect of actinomycete co-inoculation on N2-fixing symbioses and their potential use in agriculture.