Phytohormonal Role of Microorganisms Involved in Bioinoculants

Abstract

The world population is supported by food availability that depends on cultivation. Agriculture, however, comports environmental threats related with global warming and nature contamination. Therefore, more friendly techniques that are less damaging for the environment without resignation of yield have gained attention. Among them, bioinoculants containing microbial species (bacteria and fungi) emerge in the farming market as possible contributors. This review revises the scientific basis of such products as biofertilizers, biostimulators, stress regulators, biopesticides, and bioremediation agents. More than 40 years of research suggests that bioinoculants’ efficiency relies on root growth promotion that enhances soil exploration and root capability for superior nutrient and water uptake, and such growth promotion is mostly dependent (directly and/or indirectly) on production of plant growth regulators (phytohormones) by microorganisms. Notwithstanding, in keeping yield, bioinoculants are not enough by themselves, and they should be combined with other technologies, namely, plants genetically designed for more efficient use of resources, direct sowing, moderate and specifically oriented fertilization, green soil coverage, and crop rotation.