Screening growth promoting potential of Halotolerant bacillus strains in maize under saline stress

Abstract

This current study was conducted to screen halotolerant bacterial strains for their ability to enhance the productivity of Zea mays (L,) under saline stress. The soil samples were collected from the rhizosphere of Acacia arabica (L.) tree growing in saline areas. Halotolerant strains were isolated by using salt amended growth media. The final taxonomic status of strains was confirmed by 16S RNA sequence analysis. The strains were analysed for auxin production, phosphate solubilisation, antibiotic sensitivity, and hydrogen cyanide production. The effect of isolated strains on the growth of maize was checked under both in vitro and in vivo conditions. The sequence analysis confirmed local strains belonged to the genus Bacillus. For auxin production, strains B7and B4 were recorded to produce a 1-fold and 96% improvement, in the presence of L-tryptophan. Rooting assay recorded up to a 70% increase with B3 strain, over control. In vivo pot trials at 100 mM NaCl, B1 (82%) recorded statistically significant improvement in shoot length, over control. While for dry weight B5, and B3 were giving 2-fold and 1-fold improvement in growth, respectively. For fresh weight, B5 strain recorded a maximum growth response of 1.5-fold at 200mM NaCl, over the control in vivo.  The results of current study confirmed that salt-tolerant strains can minimize the effects of salinity on the growth of maize plants