The Effects of Seed Pretreatment with Endophytic Bacteria Bacillus subtilis on the Water Balance of Spring and Winter Wheat Seedlings under Short-Time Water Deficit

Abstract

We investigated the effect of pre-sowing seed treatment with endophytic Bacillus subtilis 10-4 (B. subtilis) on spring and winter wheat (Triticum aestivum L.; cultivars Ekada-70 (Ek) and Scepter (Sc), respectively) growth and tolerance under 1–24 h of drought stress, modulated by 12% polyethylene glycol 6000 (PEG). The results showed that drought decreased transpiration intensity (TI), root relative water content (RWC), osmotic potential (Ψπ) of cell sap, and induced proline accumulation and electrolyte leakage (EL) in both wheat cultivars. It was revealed that Sc was more responsive to PEG and B. subtilis treatments than Ek. Under drought, Ek did not significantly change root length, shoot height, or dry biomass. The pretreatment of wheat plants with B. subtilis performed significantly better under drought conditions through the enhanced TI, RWC, and Ψπ of the cell sap in comparison with the plants treated with 12% PEG alone. B. subtilis also reduced stress-caused EL, especially in the Sc cultivar. Under water deficit wheat seedlings, pretreated with B. subtilis, have a higher proline accumulation in comparison to untreated stressed plants. Taken together, our results demonstrate the crucial role of endophytic B. subtilis in ameliorating the adverse effects of water stress on the water balance of both winter and spring wheat cultivars.

Bacterial Endophytes and Their Contributions to Alleviating Drought and Salinity Stresses in Wheat: A Systematic Review of Physiological Mechanisms

“…The inoculation treatment increased above-ground biomass under drought by enhancing nutrient uptake and increasing chlorophyll content, as indicated by Lubyanova et al [125]. They reported a 10% increase in shoot length and a 15% increase in root length in response to inoculation with Bacillus subtilis.…”

“…Inoculation with B. subtilis on the growth parameters of wheat showed a range of responses from low to high values or high variation, as follows: shoot length (−1-8%), root length (−1-26%), shoot fresh weight (15-85%), root fresh weight (2-20%), shoot dry weight (3-17%), and root dry weight (6-16%). B. subtilis ameliorated the effect of drought on the linear size of treated wheat where bacterial-inoculated and drought-exposed wheat seedlings exhibited similar root length, plant height, and flag leaf area to non-stressed plants [125].…”

Endophytic Bacillus pumilus G5 Interacting with Silicon to Improve Drought Stress Resilience in Glycyrrhiza uralensis Fisch. by Modulating Nitrogen Absorption, Assimilation, and Metabolism Pathways

“…Interestingly, the G5 and G5+Si remarkably increased P5CS and P5CR activities and decreased ProDH activity in drought-stress G. uralensis, which might maintain peroxide level and turgor pressure via promoting Pro accumulation, thus mitigating drought-induced osmotic stress. 35 Differentially, Si has no effect on Pro accumulation, although Si significantly enhanced the activities of δ-OAT and P5CR, indicating that G5 plays a leading role and Si assists G5 in the collaborative response of G5+Si to drought stress. In addition, G5+Si significantly inhibited the activity of δ-OAT, suggesting that it might be due to the production of large amounts of GSA.…”

Nitric Oxide (NO) Improves Wheat Growth under Dehydration Conditions by Regulating Phytohormone Levels and Induction of the Expression of the TADHN Dehydrin Gene

“…RWC analysis was performed using the same samples in which TI was evaluated. For calculation of the RWC, it was necessary to determine the fresh weight (FW), turgor weight (TW), and dry weight (DW) of roots and shoots [60]. For this purpose, 5-day-old seedlings were dissected into roots and shoots, and their FW was immediately determined.…”