Wheat salinity tolerance is enhanced by application of Bacillus megaterium or arbuscular mycorrhizal fungi via improving physio-biochemical and anatomical characteristics

This study aimed to evaluate the role of Bacillus megaterium and Arbuscular Mycorrhizal Fungi (AMF) in increasing salt tolerance in wheat associated with physio-biochemical and anatomical characteristics. Results displayed that salinity stress (6 dS m⁻¹ NaCl) significantly decreased (p ≤ 0.05) nitrogen, phosphorus, potassium, chlorophyll a and b content, maximum quantum yield of PSII and relative water content (RWC) in both seasons. Additionally, the anatomical characteristics of flag leaf were harmfully affected. However, malondialdehyde (MDA), superoxide (O^2•−), hydrogen peroxide (H₂O₂) and electrolyte leakage (EL) were increased significantly (p ≤ 0.05) in both seasons. Also, proline and total phenolic compounds were increased significantly in the stressed seedlings. On the other hand, inoculation of grains with B. megaterium and AMF significantly augmented nitrogen, phosphorus, potassium, chlorophyll a and b content, maximum quantum yield of PSII and relative water content as well as modified the antioxidant defense system such as catalase, peroxidase, proline and total phenolic compounds in both seasons. Also, the anatomical structures of flag leaves were significantly improved in the stressed wheat seedlings under treatment with B. megaterium and AMF in comparison to stressed uninoculated seedlings. Generally, application of B. megaterium and AMF can improve the physio-biochemical and anatomical characteristics of wheat seedlings under salinity conditions.