Biofertilizer and Biostimulant Potentials of Phosphate-Solubilizing Bacillus subtilis subsp. subtilis M1 strain and Silicon in improving Low Phosphorus Availability Tolerance in Rosemary

• Published in: Letters in applied microbiology 2024-08, Vol.77 (8)
• Main Authors: Msaad, Hamid, Lamsaadi, Nadia, Farssi, Omar, Oubenali, Aziz, Lahmaoui, Soukaina, Boulli, Abdelali, Ghoulam, Cherki, El Moukhtari, Ahmed, Farissi, Mohamed
• Format: Article
• Language: English
• ISSN: 1472-765X; 1472-765X
• DOI: 10.1093/lambio/ovae072

The present study aimed to evaluate the single and combined effects of Si exogenous treatment and Bacillus subtilis subsp. subtilis M1 strain inoculation on rosemary tolerance to low P availability. Hence, rosemary plants were fertilized with 250 µmol Ca3HPO4 (stressed plants) or 250 µmol KH2PO4 (control plants) under Si treatment and B. subtilis M1 strain inoculation. P starvation negatively affected rosemary growth and its P nutrition. However, exogenous Si supply or B. subtilis M1 strain inoculation significantly (p < 0.001) alleviated the deficiency-induced effects and significantly improved rhizogenesis, acid phosphatase activity, P uptake and eventually dry weight of shoot and root. Moreover, Si-treatment and/or B. subtilis M1 strain inoculation significantly (p < 0.001) reduced the oxidative damage, in terms of malondialdehyde and hydrogen peroxide accumulation. This was found positively correlated with the higher superoxide dismutase activity, and the elevated non-enzymatic antioxidant molecules accumulation, including total polyphenols in Si-treated and inoculated P-deficient plants. Taken together, Si supplementation and/or B. subtilis M1 strain inoculation could be a good strategy to sustain rosemary plant growth under P starvation conditions.