Influence of Arbuscular mycorrhiza fungi and Bradyrhizobium japonicum on the fatty acids profile of soybean (Glycine max L.) under drought stress conditions

Objective: Water deficiency changes the composition of soybean fatty acids. Arbuscular mycorrhiza fungi and Bradyrhizobium play a vital role in the improvement of soybean protein and oil. Therefore, this study aimed to evaluate the effects of different drought levels and inoculation/non-inoculation with mycorrhiza fungi and Bradyrhizobium on the soybean oil, protein percentage, and fatty acid composition. Methods: This experiment was conducted a split-plot factorial layout based on a randomized complete block design with three replications in 2017. The main factor was irrigation after 70, 110, and 150 mm of evaporation from a class A evaporation pan. Subplots included mycorrhiza fungal inoculations with Funneliformis mosseae, Rhizophagus intraradices, and without fungus, and bacterium inoculation at two levels (Bradyrhizobium japonicum and without bacteria). Results: Drought stress significantly reduced the oil percentage. The highest oil content (21.94%) was observed in F. mosseae mycorrhiza inoculation. The highest amount of unsaturated fatty acid (74.75%) was observed after inoculation with R. intraradices and bacteria under full irrigation conditions. Inoculation with mycorrhiza fungi and bacteria increased the unsaturated fatty acids in some cases. Conclusion: In conclusion, to improve the oil and protein percent, enhance unsaturated fatty acids, and reduce saturated fatty acids in the soybean, the application of mycorrhiza fungi and inoculation with B. japonicum may be beneficial.