Hydrogen Peroxide and Strigolactones Signaling Are Involved in Alleviation of Salt Stress Induced by Arbuscular Mycorrhizal Fungus in Sesbania cannabina Seedlings

The arbuscular mycorrhizal symbiosis can alleviate salt stress in plants by altering strigolactone levels in the host plant. The aim of this study was to investigate the mechanism by which strigolactones enhance salt stress tolerance in arbuscular mycorrhizal Sesbania cannabina seedlings. Strigolactone levels, as determined by means of germination bioassay, gradually increased with treatment time of NaCl applied. Inhibition of NADPH oxidase activity and chemical scavenging of H2O2 significantly reduced strigolactone-induced salt tolerance and decreased strigolactone levels. The H2O2-induced strigolactone accumulation was accompanied by increased tolerance to salt stress. These results strongly indicated that elevated H2O2 concentration resulting from enhanced NADPH oxidase activity regulated strigolactone-induced salt stress tolerance in arbuscular mycorrhizal S. cannabina seedlings.