Isolation and characterization of drought resistance bacteria for plant growth promoting properties and their effect on chilli (Capsicum annuum) seedling under salt stress

The search for efficient drought resistant bacteria from unexplored environments is worldwide to alleviate the negative effects in plant growth. Thus, 67 bacteria were isolated from Commiphora wightii rhizosphere soil collected in the desert region. Initial screening for drought tolerance revealed that 29 (43.0%) isolates were able to grow in the presence of 15 g NaCl (w/v), 40 (58.20%) isolates were shown thermo tolerance capacity up to 70 °C and 32 (47.8%) isolates were shown maximum tolerance for polyethylene glycol concentration (13 g/100 ml). A subset of 10 strains was identified based on 16 S rRNA gene sequencing and belonged to four genera (Bacillus spp, Alcaligenes spp, Proteus sp. and Aneurinibacillus aneurinilyticus). All strains could produce siderophore and showed indole-3-acetic acid production ranged from 120 to 520 µg/ml. The drought resistant bacterized seeds of chilli were evaluated in the pot soil supplemented with 50 mM NaCl, the isolates showed 23.3-114.6% and 44.2-125.9% higher root and shoot lengths, respectively, compared with control. Our results demonstrated that drought resistant bacteria isolated from the rhizosphere of C. wightii grown on desert lands could be used for alleviating salinity stress in crop plants.