Potential of the bacterium Pseudomonas Stutzeri as a plant growth stimulator and a destructor of technogenic pollutants

The creation of a complex action biological agent that combines both plant growth promoting and technogenic pollution degrading properties would allow the solution to a great many problems in the related fields of agrobiotechnology and bioremediation. Therefore, it makes sense to search for bacteria with PGP activity among technogenic pollutant degraders. Pseudomonas stutzeri IB-I6C was isolated as a microorganismto utilize the systemic herbicide containing 2,4-dichlorphenoxyacetic acid (2,4-D), sodium benzoate, phenol and naphthalene. After revealing the ability of the strain in question to produce indole-3-acetic acid (IAA), the research was conducted concerning the accumulation dynamics of the extracellular hormone auxin on nutrient media of different composition. It has been found that the maximum yield of the targeted plant hormone is ensured by the qualitative composition of the nutrient medium K1, namely, by its carbohydrate component and results in a two fold increase in the auxin concentration as compared to the level in the standard medium. It is shown that the level of IAA biosynthesis in nutrient media varies as follows: K1>LB+trp>LB>BS. The growth promoting activity of the strain P. stutzeri IB-I6C was found during the seed treatment of wheat Triticum aestivum L., cultivar Omskaya 35. The colonization of wheat roots by the strain IB-I6C under saline conditions resulted in a considerable increase in root length and weight attesting to a wide growth range of the culture. The ability to produce IAA correlates with the discovered positive action of the bacteria Pseudomonas stutzeri IB-I6C upon the growth of wheat plants under saline loading. The strain IB-I6C also shows phosphate-solubilization activity. Thus, the strain Pseudomonas stutzeri IB-I6C combines the necessary qualities enabling the development of a promising multifunctional biological agent for agrobiotechnology and soil bioremediation both under normal conditions and under technogenically polluted and saline stress.