Seed Biostimulant MGW9 (SB-MGW9) Biopriming Improves Salt Tolerance during Maize Seed Germination

Abstract Crop performance is seriously affected by high salt concentrations in soils. To develop more new seed pre-sowing treatment technologies it is crucial to improve the salt tolerance of seed germination. Here we isolated and identified the strain Bacillus sp. MGW9 and developed the seed biostimulant MGW9 (SB-MGW9) by the strain. Effect of seed biopriming with SB-MGW9 in maize (Zea mays L.) under saline condition were studied. The results showed that the Bacillus sp. MGW9 has the characteristics of salt tolerance, nitrogen fixation, phosphorus dissolution, indole-3-acetic acid production and the like. Seed biopriming with SB-MGW9 enhanced the performance of maize during seed germination under salinity stress to improve the germination energy, germination percentage, shoot/seedling length, primary root length, shoot/seedling fresh weight, shoot/seedling dry weight, root fresh weight and root dry weight. SB-MGW9 biopriming also alleviates the salinity damage to maize by improving relative water content, chlorophyll content, proline content, soluble sugar content, root activity, activities of superoxide dismutase, catalase, peroxidase and ascorbate peroxidase, decreasing the malondialdehyde content. Especially, the field seedling emergence of maize seeds in saline-alkali soil can be improved by SB-MGW9 biopriming. Therefore, maize seed biopriming with SB-MGW9 can be an effective approach to resist the inhibitory effects of salinity stress and promote seed germination and seedling growth.