Deciphering the impact of cold-adapted bioinoculants on rhizosphere dynamics, biofortification, and yield of kidney bean across varied altitudinal zones.

Agriculture stands as a thriving enterprise in India, serving as both the bedrock of economy and vital source of nutrition. In response to the escalating demands for high-quality food for swiftly expanding population, agricultural endeavors are extending their reach into the elevated terrains of the Himalayas, tapping into abundant resources for bolstering food production. Nonetheless, these Himalayan agro-ecosystems encounter persistent challenges, leading to crop losses. These challenges stem from a combination of factors including prevailing frigid temperatures, suboptimal farming practices, unpredictable climatic shifts, subdivided land ownership, and limited resources. While the utilization of chemical fertilizers has been embraced to enhance the quality of food output, genuine concerns have arisen due to the potential hazards they pose. Consequently, the present investigation was initiated with the objective of formulating environmentally friendly and cold-tolerant broad ranged bioinoculants tailored to enhance the production of Kidney bean while concurrently enriching its nutrient content across entire hilly regions. The outcomes of this study unveiled noteworthy advancements in kidney bean yield, registering a substantial increase ranging from 12.51 ± 2.39 % to 14.15 ± 0.83 % in regions of lower elevation (Jeolikote) and an even more remarkable surge ranging from 20.60 ± 3.03 % to 29.97 ± 5.02 % in higher elevated areas (Chakrata) compared to the control group. Furthermore, these cold-tolerant bioinoculants exhibited a dual advantage by fostering the enhancement of essential nutrients within the grains and fostering a positive influence on the diversity and abundance of microbial life in the rhizosphere. As a result, to effectively tackle the issues associated with chemical fertilizers and to achieve sustainable improvements in both the yield and nutrient composition of kidney bean across varying elevations, the adoption of cold-tolerant Enterobacter hormaechei CHM16, and Pantoea agglomerans HRM 23, including the consortium, presents a promising avenue. Additionally, this study has contributed significant insights-into the role of organic acids like oxalic acid in the solubilization of nutrients, thereby expanding the existing knowledge in this specialized field.

Microbial bioformulation: a microbial assisted biostimulating fertilization technique for sustainable agriculture.

Addressing the pressing issues of increased food demand, declining crop productivity under varying agroclimatic conditions, and the deteriorating soil health resulting from the overuse of agricultural chemicals, requires innovative and effective strategies for the present era. Microbial bioformulation technology is a revolutionary, and eco-friendly alternative to agrochemicals that paves the way for sustainable agriculture. This technology harnesses the power of potential microbial strains and their cell-free filtrate possessing specific properties, such as phosphorus, potassium, and zinc solubilization, nitrogen fixation, siderophore production, and pathogen protection. The application of microbial bioformulations offers several remarkable advantages, including its sustainable nature, plant probiotic properties, and long-term viability, positioning it as a promising technology for the future of agriculture. To maintain the survival and viability of microbial strains, diverse carrier materials are employed to provide essential nourishment and support. Various carrier materials with their unique pros and cons are available, and choosing the most appropriate one is a key consideration, as it substantially extends the shelf life of microbial cells and maintains the overall quality of the bioinoculants. An exemplary modern bioformulation technology involves immobilizing microbial cells and utilizing cell-free filters to preserve the efficacy of bioinoculants, showcasing cutting-edge progress in this field. Moreover, the effective delivery of bioformulations in agricultural fields is another critical aspect to improve their overall efficiency. Proper and suitable application of microbial formulations is essential to boost soil fertility, preserve the soil's microbial ecology, enhance soil nutrition, and support crop physiological and biochemical processes, leading to increased yields in a sustainable manner while reducing reliance on expensive and toxic agrochemicals. This manuscript centers on exploring microbial bioformulations and their carrier materials, providing insights into the selection criteria, the development process of bioformulations, precautions, and best practices for various agricultural lands. The potential of bioformulations in promoting plant growth and defense against pathogens and diseases, while addressing biosafety concerns, is also a focal point of this study.

Credibility assessment of cold adaptive Pseudomonas jesenni MP1 and P. palleroniana N26 on growth, rhizosphere dynamics, nutrient status, and yield of the kidney bean cultivated in Indian Central Himalaya.

Kidney bean (Phaseolus vulgaris) productivity and nutritional quality are declining due to less nutrient accessibility, poor soil health, and indigent agronomic practices in hilly regions, which collectively led to a fall in farmer's income, and to malnutrition in consumers. Addressing such issues, the present investigation was designed to assess the impact of Pseudomonas jesenii MP1 and Pseudomonas palleroniana N26 treatment on soil health, microbial shift, yield, and nutrient status of the kidney bean in the Harsil and Chakrata locations of Indian Central Himalaya. P. jesenii MP1 and P. palleroniana N26 were characterized as cold adaptive PGPR as they possessed remarkable in vitro plant growth promoting traits. Further, field trial study with PGPR treatments demonstrated remarkable and prolific influence of both strains on yield, kidney bean nutrient status, and soil health at both geographical locations, which was indicated with improved grain yield (11.61%-23.78%), protein (6.13%-24.46%), and zinc content (21.86%-61.17%) over control. The metagenomic study revealed that use of bioinoculants also concentrated the nutrient mobilizing and plant beneficial microorganisms in the rhizosphere of the kidney bean. Moreover, correlation analysis also confirmed that the plant growth-promoting traits of P. jesenii MP1 and P. palleroniana N26 are the basis for improved yield and nutrient status of the kidney bean. Further, cluster and principal component analysis revealed that both P. jesenii MP1 and P. palleroniana N26 exhibited pronounced influence on yield attributes of the kidney bean at both the locations. At the Harsil location, the P. jesenii MP1-treated seed demonstrated highest grain yield over other treatments, whereas at Chakarata, P. jesenii MP1, and P. palleroniana N26 treatment showed almost equal enhancement (~23%) in grain yield over control. The above results revealed that these bioinoculants are efficient plant growth promoters and nutrient mobilizers; they could be used as green technology to improve human health and farmer's income by enhancing soil health, yield, and nutrient status of the kidney bean at hilly regions.

Comparative e-waste plastics biodegradation efficacy of monoculture Pseudomonas aeruginosa strain PE10 and bacterial consortium under in situ condition.

A significant amount of electronic obsoletes or electronic waste (e-waste) is being generated globally each year; of these, ~20% of obsolete electronic items have plastic components. Current remediation practices for e-waste have several setbacks due to its negative impact on the environment, agro-ecosystem, and human health. Therefore, comparative biodegradation studies of e-waste plastics by monoculture Pseudomonas aeruginosa strain PE10 and bacterial consortium consisting of Achromobacter insolitus strain PE2 (MF943156), Acinetobacter nosocomialis strain PE5 (MF943157), Pseudomonas lalkuanensis PE8 (CP043311), and Stenotrophomonas pavanii strain PE15 (MF943160) were carried out in situ. Biological treatment of e-waste with these candidates in soil ecosystems has been analyzed through diversified analytical techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric-derivative thermogravimetry-differential thermal analysis (TG-DTG-DTA), and scanning electron microscopy (SEM). Both P. aeruginosa strain PE10 and the bacterial consortium have a tremendous ability to accelerate the biodegradation process in the natural environment. However, FTIR analysis implied that the monoculture had better efficacy than the consortium, and it was consistent until the incubation period used for the study. Some polymeric bonds such as ν C=C and δ C-H were completely removed, and ν C=C ring stretching, νasym C-O-C, νsym C-H, etc. were introduced by strain PE10. Furthermore, thermal analysis results validated the structural deterioration of e-waste as the treated samples showed nearly two-fold weight loss (WL; 6.8%) than the untreated control (3.1%) at comparatively lower temperatures. SEM images provided the details of surface disintegrations. Conclusively, individual monoculture P. aeruginosa strain PE10 could be explored for e-waste bio-recycling in agricultural soil ecosystems thereby reducing the cost, time, and management of bioformulation in addition to hazardous pollutant reduction.

Leveraging arsenic resistant plant growth-promoting rhizobacteria for arsenic abatement in crops.

Arsenic is a toxic metalloid categorized under class 1 carcinogen and is detrimental to both plants and animals. Agricultural land in several countries is contaminated with arsenic, resulting in its accumulation in food grains. Increasing global food demand has made it essential to explore neglected lands like arsenic-contaminated lands for crop production. This has posed a severe threat to both food safety and security. Exploration of arsenic-resistant plant growth-promoting rhizobacteria (PGPR) is an environment-friendly approach that holds promise for both plant growth promotion and arsenic amelioration in food grains. However, their real-time performance is dependent upon several biotic and abiotic factors. Therefore, a detailed analysis of associated mechanisms and constraints becomes inevitable to explore the full potential of available arsenic-resistant PGPR germplasm. Authors in this review have highlighted the role and constraints of arsenic-resistant PGPR in reducing the arsenic toxicity in food crops, besides providing the details of arsenic transport in food grains.

Pseudomonas lalkuanensis sp. nov., isolated from a bacterial consortia of contaminated soil enriched for the remediation of e-waste.

A novel e-waste-degrading strain, PE08T, was isolated from contaminated soil collected from a paper mill yard in Lalkuan, Uttarakhand, India. Strain PE08T was Gram-stain-negative, rod-shaped, aerobic, oxidase-positive and catalase-positive. Optimum growth was observed at 30 °C (range, 5-40 °C), with 1-2 % NaCl (range, 0-3 %) and at pH 7 (range 6-11). The phylogeny based on 16S rRNA gene sequences delineated strain PE08T to the genus Pseudomonas and showed highest sequence similarity to Pseudomonas furukawaii KF707T (98.70 %), followed by Pseudomonas aeruginosa DSM 50071T (98.62 %) and Pseudomonas resinovorans DSM 21078T (97.93 %). The genome of strain PE08T was sequenced and had one scaffold of 6056953 bp, 99.84 % completeness and 182× coverage were obtained. The G+C content in the genome was 64.24 mol%. The DNA-DNA hybridization and average nucleotide identity values between strain PE08T and its closely related type strain, P. resinovorans DSM 21078T were below 34.8 % and 87.96 %, respectively. The phylogenetic analysis based on whole-genome sequence and concatenated GyrB and RpoB proteins revealed that strain PE08T forms a district clade in the family Pseudomonadaceae. The predominant fatty acids were summed feature 8 (C18 :  1ω7c and/or C18 :1 ω6c), summed feature 3 (C16 :  1ω7c and/or C16 :  1ω6c), C16 : 0 and C12 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The phenotypic, chemotaxonomic and genetic analysis, including overall genome relatedness index values, indicated that strain PE08T represents a novel species of the genus Pseudomonas, for which the name Pseudomonas lalkuanensis sp. nov. is proposed. The type strain is PE08T (=MCC 3792=KCTC 72454=CCUG 73691).

Psychrophilic Pseudomonas helmanticensis proteome under simulated cold stress.

Himalayan mountains are distinctly characterized for their unique climatic and topographic variations; therefore, unraveling the cold-adaptive mechanisms and processes of native life forms is always being a matter of concern for scientific community. In this perspective, the proteomic response of psychrophilic diazotroph Pseudomonas helmanticensis was studied towards low-temperature conditions. LC-MS-based analysis revealed that most of the differentially expressed proteins providing cold stress resistance were molecular chaperons and cold shock proteins. Enzymes involved in proline, polyamines, unsaturated fatty acid biosynthesis, ROS-neutralizing pathways, and arginine degradation were upregulated. However, proteins involved in the oxidative pathways of energy generation were severalfold downregulated. Besides these, the upregulation of uncharacterized proteins at low temperature suggests the expression of novel proteins by P. helmanticensis for cold adaptation. Protein interaction network of P. helmanticensis under cold revealed that Tif, Tig, DnaK, and Adk were crucial proteins involved in cold adaptation. Conclusively, this study documents the proteome and protein-protein interaction network of the Himalayan psychrophilic P. helmanticensis under cold stress.

Towards the development of a biobased economy in Europe and India.

India has emerged as a key player with a high potential to develop a biomass and biobased economy due to its large geographic size and the massive amounts of agricultural and non agricultural biomass produced. India has joined hands with Europe to synchronize its efforts to create and facilitate the development of a biobased economy in this country. This paper aims to examine common research and development actions between the European Union (EU) and India to facilitate the development of these biobased economies. As a base, a thorough study has been performed considering the biomass potential and current status of the bioeconomy in both the EU and India based on the distillation of a series of 80 potential recommendations. The recommendations were grouped into four major categories: (1) biomass production, (2) by-products/waste, (3) biorefineries and (4) policy, market, and value-added products. A questionnaire was designed and distributed to key stakeholders belonging to: academia, industry, and policymakers in both India and the EU. A total of 231 responses were received and analyzed, based on the key recommendations made for the essential research and development topics that are of prime importance to develop biobased economies in both the EU and India. The findings of this study suggest recognizing the value-added contributions made by biobased products such as: food, feed, valuable materials and chemicals in both regions. It is important to reduce the overall process costs and minimize the environmental impacts of such a biobased economy.

Microbial diversity and soil physiochemical characteristic of higher altitude.

Altitude is the major factor affecting both biodiversity and soil physiochemical properties of soil ecosystems. In order to understand the effect of altitude on soil physiochemical properties and bacterial diversity across the Himalayan cold desert, high altitude Gangotri soil ecosystem was studied and compared with the moderate altitude Kandakhal soil. Soil physiochemical analysis showed that altitude was positively correlated with soil pH, organic matter and total nitrogen content. However soil mineral nutrients and soil phosphorus were negatively correlated to the altitude. RT-PCR based analysis revealed the decreased bacterial and diazotrophic abundance at high altitude. Metagenomic study showed that Proteobacteria, Acidobacteria and Actinobacteria were dominant bacteria phyla at high altitude soil while Bacteroidetes and Fermicutes were found dominant at low altitude. High ratio of Gram-negative to Gram positive bacteria at Gangotri suggests the selective proliferation of Gram negative bacteria at high altitude with decrease in Gram positive bacteria. Moreover, Alphaproteobacteria was found more abundant at high altitude while the opposite was true for Betaproteobacteria. Abundance of Cytophaga, Flavobacterium and Bacteroides (CFB) were also found comparatively high at high altitude. Presence of many taxonomically unclassified sequences in Gangotri soil indicates the presence of novel bacterial diversity at high altitude. Further, isolation of bacteria through indigenously designed diffusion chamber revealed the existence of bacteria which has been documented in unculturable study of WIH (Western Indian Himalaya) but never been cultivated from WIH. Nevertheless, diverse functional free-living psychrotrophic diazotrophs were isolated only from the high altitude Gangotri soil. Molecular characterization revealed them as Arthrobacter humicola, Brevibacillus invocatus, Pseudomonas mandelii and Pseudomonas helmanticensis. Thus, this study documented the bacterial and psychrophilic diazotrophic diversity at high altitude and is an effort for exploration of low temperature bacteria in agricultural productivity with the target for sustainable hill agriculture.

Differential protein profiling of soil diazotroph Rhodococcus qingshengii S10107 towards low-temperature and nitrogen deficiency.

Protein-based biomarkers can be a promising approach for identification and real-time monitoring of the bio-inoculants employed under sustainable agricultural plans. In this perspective, differential proteomics of psychrophilic diazotroph Rhodococcus qingshengii S10107 (JX173283) was performed to unravel its adaptive responses towards low-temperature nitrogen deficiency and identification of a biomarker for respective physiological conditions. LC-MS/MS-based proteome analysis mapped more than 4830 proteins including 77 up-regulated and 47 down-regulated proteins (p ≤ 0.05). Differential expression of the structural genes of nif regulon viz. nifH, nifD, and nifK along with their response regulators i.e. nifA, nifL, and nifB indicated that the nitrogenase complex was activated successfully. Besides up-regulating the biosynthesis of certain amino acids viz. Leucine, Lysine, and Alanine; the expression of the peptidoglycan synthesis proteins were also increased; while, the enzymes involved in Lipid biosynthesis were found to decrease. Furthermore, two important enzymes of the pentose phosphate pathway viz. Transketolase and Transaldolase along with Ribose import ATP-binding protein RbsA were also found to induce significantly under low temperature a nitrogen deficient condition, which suggests the cellular need for ample ribose sugar instantly. Additionally, comparative protein profiling of S10107 strain with our previous studies revealed that CowN protein was significantly up-regulated in all the cases under low-temperature nitrogen deficient conditions and therefore, can be developed as a biomarker. Conclusively, present study for the first time provides an in-depth proteome profiling of R. qingshengii S10107 and proclaims CowN as a potential protein biomarker for monitoring BNF under cold niches.

Selection of potential bacterial strains to develop bacterial consortia for the remediation of e-waste and its in situ implications.

The management of electronic waste (e-waste) becomes a global issue in this digital era. Existing conventional practices are harmful for dealing with the e-waste, therefore, indigenous soil bacteria were explored for e-waste treatment through enrichment culture approach followed by screening, identification and their bioformulation used for in situ investigation. Soil bacteria were enriched in the presence of e-waste after 30 days of incubation under standard laboratory conditions. This finding was established through λmax values that were higher in the case of soil enrichment than the control. The biodegradation of e-waste by the selected strains during enrichment and in situ experiment was confirmed by FTIR, TG-DTG-DTA and SEM analysis. The FTIR spectra evidently support that microbial communities present in the enriched soil has affected the C-chain and used as carbon source for their growth. This chemical structural degradation of e-waste was further substantiated by thermal and SEM analysis. Thermograms experimentally show that the decomposition of the treated samples achieved comparatively at very low temperature than the control sample, while SEM micrographs revealed the surface morphology with distinct disintegrations. These result authenticated the biodegradation process carried out by the soil bacteria. Furthermore, bacterial community analysis confirmed that the used strains were persisting in the experimental pits throughout the trial period. Thus, this study besides providing direct and standardized protocol for screening and selection of efficient e-waste utilizing bacteria is also demonstrating potential consortia which are ready to be used.

Quantitative proteomics of psychotrophic diazotroph in response to nitrogen deficiency and cold stress.

Effective protocols and novel biomarkers are the need of this hour to screen potential cold adapted diazotrophs for sustainable mountain agricultural plans. LC-MS/MS based gel less quantitative proteomics was employed to investigate the metabolic response of Himalayan cold adapted diazotroph Pseudomonas palleroniana N26 (JN055435) for nitrogen deficiency and cold stress. More than 5000 proteins were identified, and 125 of them showed significant difference with a 2-fold or greater change (p < .05) between normal and stress conditions, including 29 up-regulated proteins and 35 down-regulated proteins. Expression of nifA, nifL, nifH, nifB, nifD, and nifK during N2 fixing conditions reveals that nitrogenase system was successfully activated. Further, 8% of the upregulated proteins showed similarity with uncharacterized proteins of several nitrogen fixing genera which suggests their in-depth investigation. Additionally, as per earlier studies, cowN was differentially expressed under nitrogen fixing conditions; thereby, confirming its potential to be a potent biomarker for monitoring the nitrogen fixation in cold niches. BIOLOGICAL SIGNIFICANCE: Understanding of nitrogenase expression and regulation is essential to employ potential diazotrophs under diverse ecological niches to achieve agricultural as well as environmental sustainability. The molecular mechanisms of cold adapted diazotrophy are still unaddressed. In this scenario, present study, besides characterizing diazotrophic proteins, is helpful in identifying the protein(s) or a biomarker viz. CowN to facilitate the monitoring of nitrogen fixation in cold niches. To the best of our knowledge, this is the first gel-less quantitative free-living diazotrophic proteome study using label free mass spectrometry having high mass accuracy in both MS and MS/MS scans. It enriches the diazotrophic proteome database and will complement the other "omics" technologies for improved crop protection and sustainability strategies.

Comparative in situ biodegradation studies of polyhydroxybutyrate film composites.

Application of polyhydroxybutyrate (PHB) to plastic industry has expanded over the last decades due to its attracting features over petro-based plastic, and therefore, its waste accumulation in nature is inevitable. In the present study, a total of four bacterial strains, viz., MK3, PN12, PW1, and Lna3, were formulated into a consortium and subsequently used as biological tool for degradation of biopolymers. The consortium was tested through λ max shifts under in vitro conditions for utilization of PHB as sole carbon source. Talc-based bioformulations of consortium were used for the degradation of PHB film composites under in situ conditions. After 9 months of incubation, the recovered samples were monitored through Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), respectively. Analytical data, viz., changes in λ max shifts (212-219 nm), FT-IR spectra, and SEM micrographs, revealed the biodegradation potential of developed consortium against PHB film composites, i.e., higher degradation of copolymer films was found over blend films. The used consortium had enhanced the rate of natural degradation and can be further used as a natural tool to maintain and restore global environmental safety.

Isolation and characterization of phosphate solubilizing bacteria from Western Indian Himalayan soils.

Previous studies confirmed the existence of diversified microbial flora in the rhizosphere of Himalayan Red Kidney Bean (RKB) (Phaseolus vulgaris L.). Therefore, fifteen different temperate and subtropical regions of Western Indian Himalaya (WIH) were explored for the isolation of RKB rhizosphere-associated Phosphorus (P) solubilizing bacteria. On the basis of qPCR analysis, three soils, i.e., Munsyari, Kandakhal and Nainital soils were selected for the isolation of P solubilizers. Among 133 isolates, three bacteria viz. Lysinibaccilus macroides ST-30, Pseudomonas palleroniana N-26 and Pseudomonas jessenii MP-1 were selected based on their P solubilization potential. Moreover, in vitro seed germination assay was performed to investigate their effectiveness against four native crops viz. (Cicer arietrinum L.), (Vigna radiata L.), (Pisum sativum L.) and (Zea mays L.). Treated seeds showed significant increase in germination efficiency over their respective controls. The results suggest that Lysinibaccilus macroides ST-30, strain is a potential plant growth-promoting bacterium for chickpea (Cicer arietrinum L.) and, therefore, could be implemented as a low-cost bio-inoculant in hill agriculture system.

Cold Stress and Nitrogen Deficiency Affected Protein Expression of Psychrotrophic Dyadobacter psychrophilus B2 and Pseudomonas jessenii MP1.

Nitrogen (N) deficiency and low temperature conditions are the prominent facet of Western Himalayan agro-ecosystems. A slight change in the environment alters the protein expression of the microorganisms. Therefore, proteomes of the two psychrotrophs Dyadobacter psychrophilus B2 and Pseudomonas jessenii MP1 were analyzed using two dimensional electrophoresis and MALDI-TOF-MS, to determine the physiological response of altitudinally different but indigenous microorganisms in response to cold stress under N depleting conditions. Functional assessment of 150 differentially expressed proteins from both the psychrotrophs revealed several mechanisms might be involved in cold stress adaptation, protein synthesis/modifications, energy metabolism, cell growth/maintenance, etc. In both the proteomes, abundance of the proteins related to energy production and stress were significantly increased while, proteins related to biosynthesis and energy consuming processes decreased. ATP synthase subunit alpha, beta, ATP-dependent Clp protease, Enolase, groL HtpG and N(2)-fixation sustaining protein CowN proteins were found to be expressed in both B2 and MP1, similarly to previously studied diazotrophs under low temperature N2 fixing conditions and therefore, can be considered as a biomarker for monitoring the nitrogen fixation in cold niches. Nevertheless, in both the diazotrophs, a good fraction of the proteins were related to hypothetical proteins which are still uncharacterized, thereby, suggesting the need for in-depth studies on cold adapted diazotrophs and their adaptive mechanisms.

Exploration of nifH gene through soil metagenomes of the western Indian Himalayas.

This group has previously highlighted the prevalence of Csp genes from cold Himalayan environments. However, this study has explored the uncultured diazotrophs from metagenomes of western Indian Himalayas. The metagenomic nifH gene clone library was constructed from the Temperate, Subtropical and Tarai soils of Western Himalaya, India followed by polymerase chain reaction (PCR) amplification. After preliminary screening, selected clones were sequenced. In silico analysis of the clones was done, which documented 83.33 % similarities with unculturable sequence database and more than 70 % similarity with culturable bacterial database. Detailed sequence analysis of 24 nifH clones showed similarity to the corresponding genera of diazotrophs belonging to alpha-, beta-, gamma- and delta-proteobacteria. The prominent diazotrophs were Azotobacter spp., Agrobacterium tumefaciens, Methylococcus capsulatus, Geobacter bemidjiensis, Dechloromonas aromatica, Burkholderia xenovorans, Xanthobacter autotrophicus and Sideroxydans lithotrophicus, respectively. Alignment of these clones with culturable bacterial database suggests that most of the sequences belong to γ-proteobacterium group.

Response of indigenously developed bacterial consortia in progressive degradation of polyvinyl chloride.

Thermoplastic-based materials are recalcitrant in nature, which extensive use affect environmental health. Here, we attempt to compare the response of indigenously produced bacterial consortium-I and consortium-II in degrading polyvinyl chloride (PVC). These consortia were developed by using different combination of bacterial strains of Pseudomonas otitidis, Bacillus cereus, and Acanthopleurobacter pedis from waste disposal sites of Northern India after their identification via 16S rDNA sequencing. The progressive degradation of PVC by consortia was examined via scanning electron microscopy, atomic force microscopy, UV-vis, FT-IR spectra, gel permeation chromatography, and differential scanning calorimetry analysis at different incubations and time intervals. The consortium-II was superior over consortium-I in degrading the PVC. Further, the carbon source utilization analysis revealed that the extensive use of consortia has not any effect on functional diversity of native soil microbes.

Differential proteomic expression of himalayan psychrotrophic diazotroph Pseudomonas palleroniana N26 under low temperature diazotrophic conditions.

BACKGROUND: In low temperature nitrogen-deficient ecosystems, native microorganisms must possess adaptive mechanisms to cope with environmental stress as well as nitrogen (N) starvation-like conditions. However, moderate information is available about the cold adapted diazotrophs and diazotrophy. OBJECTIVE: The aim of this study was to examine the proteomic response(s) of Himalayan psychrotrophic diazotroph under low temperature nitrogen fixing conditions. MATERIALS AND METHODS: Proteomic analysis of Pseudomonas palleroniana N26 was carried out using two dimensional electrophoresis technique. RESULTS: Altogether, fifty three protein spots were found to be differentially expressed revealing several mechanisms thought to be involved in low temperature adaptation and nitrogen fixation, including general stress adaptation, protein synthesis and modifications, and energy metabolism. Expression profiling of the spots revealed the up-regulation of low molecular weight acidic proteins; a majority of which were stress proteins. The largest group of down-regulated proteins were related to biosynthetic processes; thereby, providing the evidence for stress-associated metabolic adaptations. CONCLUSION: The present study, which provides an overview of the cold diazotrophy of a Himalayan psychrotrophic bacterium and its adaptive responses, can facilitate further studies of low temperature nitrogen fixing mechanisms, psychrophilic diazotrophic markers, and transgenic microorganism(s)/crop(s) development.

Diversified diazotrophs associated with the rhizosphere of Western Indian Himalayan native red kidney beans (Phaseolus vulgaris L.).

Red kidney beans (RKBs) are one of the major components in the human diet of Western Indian Himalaya (WIH). Their cultivation in these habitats is strongly influenced by various biotic and abiotic stresses and therefore, there must be a selection of RKB associated microorganisms that are adapted to these harsh conditions. Seven cold adaptive diazotrophs from the same rhizosphere were isolated in our previous study to reveal the low-temperature associated proteins and mechanisms. However, the diversity and phylogenetic affiliations of these rhizosphere diazotrophs are still unknown. In this study, RKB rhizospheric soil from two different agro-ecosystems of WIH namely S1 (Chhiplakot, 30.70°N/80.30°E) and S2 (Munsyari, 30.60°N/80.20°E) were explored for the assessment of nitrogenase reductase gene (nifH) diversity by plating respective clone libraries SN1 and SN2. The RKB rhizosphere diazotroph assemblage was very diverse and apparently consists mainly of the genera Rhizobium, followed by unknown diazotrophic microorganisms. Deduced amino acid sequence analysis revealed the presence of diverse nifH sequences, affiliated with a wide range of taxa, encompassing members of the Proteobacteria, Actinobacteria and Firmicutes. Members of cyanobacteria, methanotrophs and archaea were also detected. To the best of our knowledge, this is the first major metagenomic effort that revealed the presence of diverse nitrogen-fixing microbial assemblages in indigenous RKB rhizospheric soil which can further be explored for improved crop yield/productivity.