A pigment-producing species of Serratia was isolated from the rhizosphere of a heavy metal resistant Cannabis sativa plant growing in effluent-affected soil of Hattar Industrial Estate, Haripur, Pakistan. Here, we report the genome sequence of this bacterium, which has been identified as Serratia nematodiphila on the basis of whole genome comparison using the OrthoANI classification scheme. The bacterium exhibited diverse traits, including plant growth promotion, antimicrobial, bioremediation, and pollutant tolerance capabilities including metal tolerance, azo dye degradation, ibuprofen degradation, etc. Plant growth-promoting exoenzyme production as well as phosphate solubilisation properties were observed. Genes for phosphate solubilisation, siderophore production, and chitin destruction were identified in addition to other industrially important enzymes like nitrilase and lipase. Secondary metabolite producing apparatus for high value chemicals in the whole genome was also analysed. The number of antibiotic resistance genes was then profiled in silico, through a match with Antibiotic Resistant Gene and CAR database. This is the first report of a S. nematodiphila genome from a polluted environment. This could significantly contribute to the understanding of pollution tolerance, antibiotic resistance, association with nematodes, production of bio-pesticide, and their role in plant growth promotion.

Rhizobacteria promote and have beneficial effects on plant growth, making them useful to agriculture. Nevertheless, the rhizosphere of the chickpea plant has not been extensively examined. The aim of the present study was to select indole-3-acetic acid (IAA) producing rhizobacteria from the rhizosphere of chickpea plants for their potential use as biofertilizers. After obtaining a collection of 864 bacterial isolates, we performed a screen using the Salkowski reaction for the presence of auxin compounds (such as IAA) in bacterial Luria-Bertani supernatant (BLBS). Our results demonstrate that the Salkowski reaction has a greater specificity for detecting IAA than other tested auxins. Ten bacterial isolates displaying a wide range of auxin accumulation were selected, producing IAA levels of 5 to 90 μmol/L (according to the Salkowski reaction). Bacterial isolates were identified on the basis of 16S rDNA partial sequences: 9 isolates belonged to Enterobacter, and 1 isolate was classified as Serratia. The effect of BLBS on root morphology was evaluated in Arabidopsis thaliana. IAA production by rhizobacteria was confirmed by means of a DR5::GFP construct that is responsive to IAA, and also by HPLC-GC/MS. Finally, we observed that IAA secreted by rhizobacteria (i) modified the root architecture of A. thaliana, (ii) caused an increase in chickpea root biomass, and (iii) activated the green fluorescent protein (GFP) reporter gene driven by the DR5 promoter. These findings provide evidence that these novel bacterial isolates may be considered as putative plant-growth-promoting rhizobacteria modifying root architecture and increasing root biomass.