Inoculation of Acinetobacter johnsonii GY08 to enhance the growth of faba bean (Vicia faba L.) under different salt concentrations

Abiotic stresses affect microbial populations and soil chemical and physical properties resulting in significant yield losses of several crops. An important environmental component that impacts plant growth and development from seed germination to maturity is salinity. The objective of this study was to examine the effect of inoculating salt-tolerant rhizobacteria on the morphological and physiological characteristics of faba bean under different salt concentrations in pot experiments. Eight rhizobacterial isolates were tested for their salt tolerance ability on nutrient agar. One best tolerant isolate with the best tolerance, which showed better growth at higher salinity, was selected and evaluated for its effect on the faba bean. The experiment comprised six treatments with three replications in a completely randomized design, and the data was analyzed using a one-way analysis of variance. The results showed that seed germination decreased by 4.16% and 8.33% at 150mM and 300mM salinity, respectively. However, the application of Acinetobacter johnsonii GY08 significantly enhanced seed germination by 4.16% and 6.38% with 150mM and 300mM salinity, respectively, compared to the uninnoculated treatments with the same salt concentration. Plants inoculated with Acinetobacter johnsonii GY08 showed higher biomass, shoot, and root elongation than the uninnoculated plants under both non-saline and saline conditions. The findings indicated that Acinetobacter johnsonii GY08 facilitated the growth of faba bean seedlings under salinity stress conditions and enabled them to thrive by accumulating more proline compared to uninnoculated plants. Therefore, further studies on various varieties and under field conditions are recommended.