Alleviation of salt stress in maize plant by co-inoculation of arbuscular mycorrhizal fungi and Methylobacterium oryzae CBMB20

Arbuscular mycorrhizal fungi (AMF) and plant growth-promoting bacteria (PGPB) can have multiple impacts on phytohormone production and nutrient uptake to improve plant growth. Co-inoculation of AMF and PGPB can mitigate the effects of salinity in plants. This study was conducted to evaluate the efficacy of co-inoculation of AMF (Glomus etunicatum) and Methylobacterium oryzae CBMB20 to alleviate salt stress and improve maize growth. Single and co-inoculation of AMF and M. oryzae CBMB20 significantly increased dry biomass, AMF root colonization, and nutrient accumulation in maize plants under salt stress. The proline content and Na uptake were significantly reduced in co-inoculation of AMF and M. oryzae CBMB20. In addition, co-inoculation of AMF and M. oryzae CBMB20 (soil) showed higher AMF density and AMF colonization compared to single AMF treatment. Among all treatments, co-inoculation of AMF and M. oryzae CBMB20 (soil) was more effective to ameliorate salt stress and improve plant growth. These results demonstrate that co-inoculation of AMF and M. oryzae CBMB20 (soil application) may be an effective alternative to enhance plant growth under salinity stress.