In Silico Genome Mining of Nodosilinea sp. PGN35 and Chlorogloeopsis sp. ULAP02 Revealed Biofertilizer-essential Genes

The increasing price of inorganic fertilizers and their long-term detrimental effects on the environment accentuate the need for organic fertilizer supplementation. One emerging solution is the use of biofertilizers. Biofertilizers are microbial-based fertilizers that enhance plant growth, increase product yield, and produce better grain or fruit quality of crops while improving soil health. In this study, two cyanobacterial strains – namely Nodosilinea sp. PGN35 and Chlorogloeopsis sp. ULAP02 – were mined for biofertilizer-essential genes. The whole genomes of the strains were sequenced and assembled. The assemblies were then used for functional annotation, metabolic profiling, and biosynthetic gene cluster (BGC) mining. Downstream analyses revealed genes associated with nitrogen fixation and metabolism, nutrient solubilization and mobilization, phytohormone auxin production, and biostimulant/biocontrol compound production. Both strains contained the nitrogenase gene cluster Nif and genes that metabolize urea, nitrate/nitrite, cyanate, and allantoin into ammonia/ammonium (NH3/NH4 +). Genes that convert organophosphate to phosphate (PO4 3–) and transport PO4 3– and potassium (K+) into and out of the cell were also identified. The detected auxin genes belong to the tryptophan gene cluster Trp and additional genes monoamine oxidase in PGN35 and aromatic-L-amino-acid decarboxylase in ULAP02. Predicted bioactive metabolites in Nodosilinea sp. PGN35 were terpene, phenazine, arylpolyene, and resorcinol, whereas in Chlorogloeopsis sp. ULAP02 were terpene, resorcinol, phosphonate, PKS/NRPS/hybrid, indole, and RiPPs. These metabolites are known to have agricultural roles as stimulants, biocides, and signaling molecules for plant-insect interaction. The presence of all these plant growth-stimulating and biocontrol genes in the two cyanobacterial strains indicates their potential as biofertilizers. This is the first study to explore the biofertilizer potential of Nodosilinea and Chlorogloeopsis using the genome-mining approach.