Streptomyces: implications and interactions in plant growth promotion

Abstract

With the impending increase of the world population by 2050, more activities have been directed toward the improvement of crop yield and a safe environment. The need for chemical-free agricultural practices is becoming eminent due to the effects of these chemicals on the environment and human health. Actinomycetes constitute a significant percentage of the soil microbial community. The Streptomyces genus, which is the most abundant and arguably the most important actinomycetes, is a good source of bioactive compounds, antibiotics, and extracellular enzymes. These genera have shown over time great potential in improving the future of agriculture. This review highlights and buttresses the agricultural importance of Streptomyces through its biocontrol and plant growth-promoting activities. These activities are highlighted and discussed in this review. Some biocontrol products from this genus are already being marketed while work is still ongoing on this productive genus. Compared to more focus on its biocontrol ability, less work has been done on it as a biofertilizer until recently. This genus is as efficient as a biofertilizer as it is as a biocontrol.

From Isolation of Phosphate Solubilizing Microbes to Their Formulation and Use as Biofertilizers: Status and Needs

“…Actinobacteria produce approximately two-thirds of the known antibiotics produced by all microorganisms (Dhanasekaran et al, 2012;Feina et al, 2019). This nutrient cycling capacity makes them an ideal candidate for natural fertilizers (Jog et al, 2016;Olanrewaju and Babalola, 2019). In addition, the ubiquitous presence and possible global distribution of many of these actinobacteria suggest a great environmental tolerance.…”

“…Indeed, Actinobacteria have the advantage of surviving in very competitive environments and produce spores during unfavorable conditions (Nandimath et al, 2017). These filamentous organisms can bridge water free gaps between soil particles to move to a new nutritional site (Olanrewaju and Babalola, 2019). Their morphology also gives them a much higher surface to volume ratio and improves their ability to solubilize phosphorus.…”

Ega3 from the fungal pathogen Aspergillus fumigatus is an endo-α-1,4-galactosaminidase that disrupts microbial biofilms

“…Previously, it was shown that the GAG gene cluster, including ega3 orthologues, was present in numerous fungal plant pathogens and emerging human pathogens (6). GH114 members are found in many Streptomyces spp., a genus of industrial import that was cultivated for production of antibiotic, hydrolytic enzymes, and other biomolecules, as well as agricultural uses (63,64). This includes Streptomyces lydicis and Streptomyces griseoviridis, which both encode GH114 enzymes and have been commercially developed as plant-growth-promoting products.…”

Natural Products as Fungicide and Their Role in Crop Protection

“…Actinobacteria are a group of gram-positive filamentous bacteria that are called as the branched bacteria or ray fungi (from Greek actis, ray beam, and mykes, fungus) and are characterized with the high G + C content occurring in mostly aerobic conditions but occasionally being anaerobes (Ludwig and Klenk 2005;Olanrewaju and Babalola 2019). Their morphology varies from forming branching filaments or mycelial growth to external spores.…”