Mitigation of salt stress in wheat seedlings by halotolerant bacteria isolated from saline habitats

Abstract

Eighty four halotolerant bacterial strains were isolated from the saline habitats and screened for growth at different NaCl concentrations. All grew well at 5% NaCl, but only 25% isolates showed growth at 20% NaCl concentration. Five strains SL3, SL32, SL35, J8W and PU62 growing well in 20% NaCl concentrations were further characterized for multiple plant growth promoting traits such as indole −3- acetic acid (IAA) production, HCN and siderophore production, ACC deaminase activity and P-solubilization. None were positive for HCN production and PCR amplification of acdS, the structural gene for ACC deaminase enzyme was found negative. 16S rRNA gene sequencing analysis of the five strains showed them to belong to two genera Bacillus and Hallobacillus. In vitro experiments showed that salt concentrations had significant inhibitory effects on development of seedlings but not on the growth of the bacterial strains. Inoculation of the 5 halotolerant bacterial strains to ameliorate salt stress (80 mM, 160 mM and 320 mM) in wheat seedlings produced an increase in root length of 71.7% in comparison with uninoculated positive controls. In particular, Hallobacillus sp. SL3 and Bacillus halodenitrificans PU62 showed more than 90% increase in root elongation and 17.4% increase in dry weight when compared to uninoculated wheat seedlings at 320 mM NaCl stress indicating a significant reduction of the deleterious effects of NaCl. These results indicate that halotolerant bacteria isolated from saline environments have potential to enhance plant growth under saline stress through direct or indirect mechanisms and would be most appropriate as bioinoculants under such conditions.

Biocontrol and Salinity Tolerance Potential of Azospirillum lipoferum and its Inoculation Effect in Wheat Crop

“…lipoferum has shown a threshold potential uptill 150 mM of NaCl. Similar findings for salt tolerance of bacteria were documented by Ramados et al (2013). Adaptation of current environmental conditions and synthesis of protective substances is responsible for stabilizing in stress conditions (Finkel and Kolter, 1999).…”

“…Incubation was carried out at 28+2ºC for 48 h (Upadhyay et al, 2012;Ramados et al, 2013). Culture broth was centrifuged at 1000 rpm for 10 min.…”

Agronomic performance, variance component, and diversity of sixty-two sweet potato accessions

“…Early, Wang et al (2003) tried to use it by using genetic engineering methods, but the results were not optimal. Furthermore, other researchers like Sapsirisopa et al (2009) Nautiyal et al (2013), and Ramadoss et al (2013) reutilized functional bacteria with PGPR quality and as potential biofertilizer on crops in the saline field.…”

The Role of Soil Beneficial Bacteria in Wheat Production: A Review

“…Wheat (Triticum aestivum L.) is one of the three major cereals (together with maize and rice), major source of energy, renewable resource for food, feed and industrial raw material, protein and fibre source in human diet, staple food crop for more than one-third of the world population [1], grown both as a spring and winter crop.…”