Background: Today, the application of microorganisms such as bacteria, fungi and alga for enhancing cashing crops growth has been increased. A wide-spectrum ranges of microorganisms have been isolated from rhizosphere, phyllosphere, soils and mines that showed potential benefits for enhancing plant production. These microorganisms are effective beneficial, symbiont and plant stimulator that could provide a considerable amount of essential nutrient for plant roots, protect plants from stresses and finally affected the total yield of plants. The selection of proper bacteria or fungus species for introducing into the agricultural soils that used for cultivation of economic and strategic plants such as cereals, oil-yielding trees and commercial seeds, depend on various factors such as target hosts, the population of soil microorganisms, environmental tensions and survival potential of introduced bacteria. Various microbiological methods such as engineering the bacterial genome, introduction of exotic genes into bacterial/fungal strains, enhancing metabolic pathways of microorganism and something like that have been followed to improve the interaction between strategic plant roots and nearby microorganisms.
Results: The accumulating body of evidence speculates that any modification in the genome sequence of PGPRs could affect their potential to produce plant growth stimulants. In this regard, studies suggested that over-expression of genes involved in plants yield and regulation of them could relatively support stronger interaction of soil microorganisms with plant roots. Microbiological engineering of soil could also effectively change nutrient recycle around plant roots provided higher level of nutritional elements for plant growth. Therefore, any changes in the population of beneficial soil microbiota are associated with higher growth of plants and their sustainable development in zero-element soils.
Conclusion: Because the inappropriate application of plant-growth-enhancing microbiota may show injudicious effects on native soil microorganism, the utilization of novel and practical microbial biotechnology methods can overcome this problem for long-term application of bacterium/fungal-based biofertilizers for agricultural goals.