Enhancement of drought tolerance in Triticum aestivum L. seedlings using Azospirillum brasilense NO40 and Stenotrophomonas maltophilia B11

Abstract

Background The effectiveness of two PGPB; Azospirillum brasilense NO40 and Stenotrophomonas maltophilia B11 was investigated in enhancing the drought tolerance of wheat (Triticum aestivum L.) seedlings cultivar Gemiza9. The inoculated or uninoculated grains were sown in unsterilized sandy soil and watered normally untill the 8th day. Drought stress was initiated by completely withholding water for 7 days (until wilting). Samples were collected after 15 days from sowing to evaluate some growth criteria, damage and defense indicators and to analyze the roots’ protein pattern. Results The results showed that inoculating wheat seedlings with these strains significantly diminished the inhibitory effects of drought stress on the relative water content of roots, shoots and leaves; area of leaves; contents of pigments (chlorophyll a and b) and ascorbic acid; and on the protein patterns of roots. Moreover, the bacterial inoculation notably reduced the drought-induced damage indicated by lower leakage of electrolytes and less accumulation of Malondialdehyde and hydrogen peroxide, surprisingly with less enhanced production of proline and activities of catalase and peroxidase than their uninoculated counterparts. Under normal conditions, inoculating wheat plants with these PGPB resulted in significantly promoted growth and elevated contents of pigments and altered protein patterns of roots. Conclusion Overall, we can say that both Azospirillum brasilense NO40 and Stenotrophomonas maltophilia B11 were able to deactivate the growth inhibition in wheat seedlings to some extent, while maintaining a certain level of efficient protection against damage under drought stress.

Effect of endophytic bacterium, Stenotrophomonas maltophilia JVB5 on sunflowers

“…The root development and early flowering in sunflowers may be linked to the phytohormone synthesis and detection of phytohormone genes in the bacterial genome. The effect of the co-inoculation of endophytic bacteria genera, such as Stenotrophomonas, Bradyrhizobium, Pseudomonas, Kosakonia, and Azospirillum, on the growth parameters and yield of sunflowers and other crops under greenhouse experiments have been performed with success (Egamberdieva et al 2016;Youseif 2018;Singh et al 2020;Adeleke et al 2021;Kasim et al 2021). Furthermore, the sunflower yield enhancement by S. maltophilia JVB5 upon inoculation in the greenhouse corroborates the results of Adeleke et al (2021) who reported a significant difference in the yield of sunflowers inoculated with endophytic S. indicatrix BOVIS40.…”

“…The ability of bacterial endophytes to fix phosphorus in the soil has played an important role in plant nutrition (Passari et al 2016). Endophytic S. maltophilia strains, namely, SEN 1 (Etesami & Alikhani 2016), B11 (Kasim et al 2021), SY-2 (Liaquat et al 2020), have been identified as phosphate solubilisers with the potential of enhancing plant growth. The phosphorus-solubilising potential of S. maltophilia JVB5 in a tricalcium medium was confirmed in the genome analysis, as diverse genes involving phosphate transport and metabolism were predicted in the genome.…”

Mechanisms and Applications of Bacterial Inoculants in Plant Drought Stress Tolerance

“…These osmolytes act synergistically with osmolytes synthesized by plants (such as glycine-betaine, soluble sugars, trehalose, and proline), act as osmoprotectants, and prevent cell damage caused by drought [ 93 ]. Thus, the accumulation of these osmolytes in plants, triggered by these microbes, influences an increase in tolerance to water stress [ 59 , 61 , 62 , 66 , 67 ].…”

Geographically Disperse, Culturable Seed-Associated Microbiota in Forage Plants of Alfalfa (Medicago sativa L.) and Pitch Clover (Bituminaria bituminosa L.): Characterization of Beneficial Inherited Strains as Plant Stress-Tolerance Enhancers

“…Considering those strains selected from more arid environments, despite the fact that Paenibacillus amylolyticus B2A is not often referred to in the literature, here, we can see how this strain may be a good treatment to promote growth and improve tolerance to drought in plants. In the case of Stenotrophomonas maltophilia M1B, there are many reports of its capacity to induce higher shoots and longer roots, even under salt conditions; however, here, we show one of the few reports that this strain induces drought tolerance [ 117 ], and the first evaluation of their effect as root architecture enhancers, especially under drought conditions. Finally, plants treated with the strains Paenibacillus xylanexedens M1C and Enterobacter hormaechei B2C showed an interesting root thickness pattern, with thinner roots during continuous irrigation, and thicker roots than with any other treatment during drought.…”