Biochemistry And Microbial Sciences - Research Publications

Permanent URI for this collectionhttps://kr.cup.edu.in/handle/32116/27

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Author: search.filters.author.Ramakrishna, WusirikaSubject: search.filters.subject.Plant growth promoting bacteria

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    Plant growth promoting bacteria in agriculture: Two sides of a coin
    (Elsevier, 2019) Ramakrishna, Wusirika; Yadav, Radheshyam; Li, Kefeng
    Plant growth promoting bacteria (PGPB) provide multiple benefits in agriculture by enhancing crop productivity and nutrient content and suppressing the growth of pathogens. Development of beneficial plant-microbe interactions based on genomics, transcriptomics, proteomics and metabolomic data of both PGPB and host will lead to optimized microbial inoculants for enhancing crop yield and nutrient content. PGPB are promoted as a green technology which will reduce the use of chemical fertilizers thereby improving soil health. Although a significant increase in the use of PGPB in agriculture was observed in the last two decades, there is a dearth of long-term studies addressing the effects of PGPB on existing microbial community structure. It is likely that most or all PGPB are resistant to common antibiotics used to treat human diseases. Antibiotic resistance of PGPB may be due to the presence of antibiotic resistance genes and intrinsic resistance due to the presence of efflux pumps. The biological significance of resistance to antibiotics and metals and their relation to plant growth promoting activity, if any, is not known. The consequences of harboring antibiotic resistance may be negative if the trait is transferred to other soil or environmental bacteria. Strategies to develop PGPB strains with useful traits of plant growth promotion but without resistance to common antibiotics used by humans, would enhance agricultural productivity without the negative effects on the environment. Alternately, harboring antibiotic resistance may be positive if it is due to intrinsic resistance involving proteins which also have other functions. Antibiotic resistance of PGPB may be an essential trait if it is related to their plant growth promoting activity. Overall, there is a need to conduct large-scale screening of PGPB for antibiotic resistance and long-term studies to see the effect of the introduction of biofertilizers on native soil microbial community.
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    Metabolomics, biomass and lignocellulosic total sugars analysis in foxtail millet (Setaria italica) inoculated with different combinations of plant growth promoting bacteria and mycorrhiza
    (Communications in Plant Sciences, 2017) Dhawi, Faten; Datta, Rupali; Ramakrishna, Wusirika
    Foxtail millet (Setaria italica) is the second most widely produced millet with potential as a biofuel source. Employment of plant growth promoting bacteria (PGPB) and mycorrhiza could serve as environment-friendly alternatives for the use of excessive NPK fertilizers and producing biofuel. The highest increase of biomass was associated with endomycorrhiza combined with PGPB in comparison to control. Nuclear magnetic resonance (NMR) analysis detected 28 metabolites in foxtail shoot with most of them upregulated in ecto/endomycorrhiza group and combined with PGPB. The upregulation of metabolites associated with synthesis of amino acids correlated positively with biomass. The inoculation with both PGPB and endomycorrhiza gave the best results with reference to total sugar yield. Our study indicates that PGPB and endomycorrhiza combination is well suited for enhancing biomass and boosting sugar yield, which are useful attributes for utilizing foxtail millet as a biofuel source.
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    Proteomics provides insights into biological pathways altered by plant growth promoting bacteria and arbuscular mycorrhiza in sorghum grown in marginal soil
    (Elsevier B.V., 2017) Dhawi, Faten; Datta, Rupali; Ramakrishna, Wusirika; Dhawi, F.; Datta, R.; Ramakrishna, W.
    Sorghum is an economically important crop, a model system for gene discovery and a biofuel source. Sorghum seedlings were subjected to three microbial treatments, plant growth promoting bacteria (B), arbuscular mycorrhizal (AM) fungi mix with two Glomus species (G. aggregatum and G. etunicatum), Funelliformis mosseae and Rhizophagus irregularis (My), and B and My combined (My + B). Proteomic analysis was conducted followed by integration with metabolite, plant biomass and nutrient data. Out of 366 differentially expressed proteins in sorghum roots, 44 upregulated proteins overlapping among three treatment groups showed positive correlation with sorghum biomass or element uptake or both. Proteins upregulated only in B group include asparagine synthetase which showed negative correlation with biomass and uptake of elements. Phosphoribosyl amino imidazole succinocarboxamide protein with more than 50-fold change in My and My + B groups correlated positively with Ca, Cu, S and sucrose levels in roots. The B group showed the highest number of upregulated proteins among the three groups with negative correlation with sorghum biomass and element uptake. KEGG pathway analysis identified carbon fixation as the unique pathway associated with common upregulated proteins while biosynthesis of amino acids and fatty acid degradation were associated with common downregulated proteins. Protein-protein interaction analysis using STRING identified a major network with thirteen downregulated proteins. These findings suggest that plant-growth-promoting-bacteria alone or in combination with mycorrhiza enhanced radical scavenging system and increased levels of specific proteins thereby shifting the metabolism towards synthesis of carbohydrates resulting in sorghum biomass increase and uptake of nutrients. ? 2016