Plants are constantly faced with both abiotic and biotic stresses, which seriously reduce their productivity. Current research work was carried out to evaluate the potential of endophytic bacteria Bacillus subtilis (strain 10-4) alone and in composition with salicylic acid (SA) to meliorate drought and Fusarium root rot in Triticum aestivum L. (wheat). Our findings demonstrated B. subtilis 10-4 alone and especially in composition with SA significantly improve wheat plant growth and ameliorated the damaging influence of drought, Fusarium oxysporum-caused root rot (FRR), and combined drought+FRR in plants. An important contribution to observed growth-stimulating and protective effects of B. subtilis 10-4 and SA on wheat plants most likely makes revealed ability of B. subtilis 10-4 to produce a range of bioactive compounds such as auxins, siderophores, lipopeptides surfactin as well as effectively colonize internal wheat plant tissues. Also, it was found that pre-sowing treatment of seeds with B. subtilis 10-4 both alone and especially in the mix with SA decreased stress-induсed (drought, FRR, drought+FRR) lipid peroxidation and amino acid proline accumulation in plants, thereby indicating on protecting the plant cells against reactive oxygen species and damages of plant membranes. Current research provides novel insights into the potential and mechanism of B. subtilis 10-4 and SA in the mitigation of combined drought+FRR stresses in wheat plants.

This research was funded by a grant of President RF (№ МК643.2019.11).