Phyllosphere can be defined as the microbial composition of the aerial part of the plant. Among the aerial parts, leaves are one of the highly dominated places microbes are able to colonize. Phyllosphere microorganisms also intervene in the metabolism of some nutrients for the plant. Some groups of leaf-associated microorganisms are able to fix nitrogen (N) from atmospheric sources. In this process, they produce organic N using the highly specialized enzyme called nitrogenase. So, How we can increase this nitrogenase enzyme?