ABSTRACT
Three strains of Gram-negative bacterium, Rhizobium, were developed by gamma (γ)-irradiation random mutagenesis. The developed strains were evaluated for their augmented features for symbiotic association, nitrogen fixation, and crop yield of three leguminous plants-chickpea, field-pea, and lentil-in agricultural fields of the northern Indian state of Haryana. Crops treated with developed mutants exhibited significant improvement in plant features and the yield of crops when compared to the control-uninoculated crops and crops grown with indigenous or commercial crop-specific strains of Rhizobium. This improvement was attributed to generated mutants, MbPrRz1 (on chickpea), MbPrRz2 (on lentil), and MbPrRz3 (on field-pea). Additionally, the cocultured symbiotic response of MbPrRz1 and MbPrRz2 mutants was found to be more pronounced on all three crops. The statistical analysis using Pearson's correlation coefficients revealed that nodulation and plant biomass were the most related parameters of crop yield. Among the effectiveness of developed mutants, MbPrRz1 yielded the best results for all three tested crops. Moreover, the developed mutants enhanced macro- and micronutrients of the experimental fields when compared with fields harboring the indigenous rhizobial community. These developed mutants were further genetically characterized, predominantly expressing nitrogen fixation marker, nifH, and appeared to belong to Mesorhizobium ciceri (MbPrRz1) and Rhizobium leguminosarum (both MbPrRz2 and MbPrRz3). In summary, this study highlights the potential of developed Rhizobium mutants as effective biofertilizers for sustainable agriculture, showcasing their ability to enhance symbiotic relationships, crop yield, and soil fertility.
ABSTRACT
We report here isolation and analysis of PCR amplified phbC gene from Pseudomonas spp. strain phbmbb15-B3. This strain was previously developed from mutations of landfill isolates and found to be an efficient Poly Hydroxy butyrate (PHB) producer. The fragment was cloned into pTZ57R/T cloning vector and then the gene has been sequenced and submitted to GenBank (Accession Number KT933807). The sequence results confirmed the clone to be phbC homologue and the ORF was 910 base pairs long and coded for 303 amino acids, which shared 92-99% amino acid sequence identity with the available bacterial sequences in Gene Bank. We could also predict the primary and secondary structural features of the expected phbC protein. Phylogenetic analysis also revealed its similarity with several pseudomonads. The results of the present study shall provide a stable foundation for further research on modeling studies of PHB synthase and developing PHB a commercial technology.
