Screening of plant growth promoting and salt tolerant rhizobacteria in Sesbania cannabina

Abstract:

[Objective] To explore the effects of halophyte Sesbania cannabina and its rhizosphere functional microorganisms on ameliorating saline alkali soil, we isolated and identified the plant growth promoting rhizobacteria (PGPR) of S. cannabina grew in saline-alkali soil of Yellow River Delta, and further studied the growth-promoting and salt-tolerant characteristics of PGPRs. [Methods] Nitrogen-fixing, phosphorus-dissolving and potassium-dissolving bacteria were isolated from rhizosphere soil of S. cannabina by selective culture and identified by 16S rRNA molecular biology. Traits of plant growth-promoting and salt tolerance of the strains were determined and analyzed, and strains with excellent traits were selected to further study their growth promotion effect on corn. [Results] We totally obtained 105 rhizosphere isolates, of which N102 had growth-promoting and salt tolerance activities. As shown by seed germination test, N102 could significantly increase the germination rate (47%, P<0.05), bud length (48.5%, P<0.05), root length (60%, P<0.05) of S. cannabina. The pot experiment also shows that N102 could significantly improve plant height, root length, shoot dry weight, root dry weight and chlorophyll content of corn under salt stress. According to phylogenetic analysis, the similarity between N102 and Enterobacter soli ATCC BAA-2102 (NR117547) sequence was 99.30%, this it was identified as Enterobacter genus.[Conclusion] Strain N102 has high salt-tolerant and plant growth-promoting characteristics, promising to develop as microbial inoculants or microbial fertilizers that can effectively promote the growth of crops in saline-alkali soils.

Key words:plant growth promoting rhizobacteria;Sesbania cannabina;salt tolerance