The Effect of Bacillus subtilis IB-22 on Hydraulic Conductivity and Immunolocalization of PIP2-Aquaporins in the Roots of an ABA-Deficient Barley Mutant

Abscisic acid (ABA) has the ability to reduce stomatal conductance and maintain water balance in plants. However, there is very little information about the nature of the effect of rhizospheric bacteria on the content of ABA in plant roots. In order to test the hypothesis of the relationship between plant growth stimulation and the ability of ABA to increase the hydraulic conductivity of roots due to the activation of aquaporins, the effect of hormone-producing bacteria on the Az34 barley mutant with impaired ABA biosynthesis was studied. Under the influence of bacterial inoculation, there was compensation for the deficiency of ABA in the Az34 mutant and an increase in endogenous ABA due to the influence of bacteria on the metabolism of this hormone. Bacterial treatment contributed to an increase in the hydraulic conductivity of plants due to an increase in the number of PIP2-aquaporins, which contributed to the manifestation of a growth-stimulating effect.