Global hotspots for soil nature conservation.

Soils are the foundation of all terrestrial ecosystems1. However, unlike for plants and animals, a global assessment of hotspots for soil nature conservation is still lacking2. This hampers our ability to establish nature conservation priorities for the multiple dimensions that support the soil system: from soil biodiversity to ecosystem services. Here, to identify global hotspots for soil nature conservation, we performed a global field survey that includes observations of biodiversity (archaea, bacteria, fungi, protists and invertebrates) and functions (critical for six ecosystem services) in 615 composite samples of topsoil from a standardized survey in all continents. We found that each of the different ecological dimensions of soils-that is, species richness (alpha diversity, measured as amplicon sequence variants), community dissimilarity and ecosystem services-peaked in contrasting regions of the planet, and were associated with different environmental factors. Temperate ecosystems showed the highest species richness, whereas community dissimilarity peaked in the tropics, and colder high-latitudinal ecosystems were identified as hotspots of ecosystem services. These findings highlight the complexities that are involved in simultaneously protecting multiple ecological dimensions of soil. We further show that most of these hotspots are not adequately covered by protected areas (more than 70%), and are vulnerable in the context of several scenarios of global change. Our global estimation of priorities for soil nature conservation highlights the importance of accounting for the multidimensionality of soil biodiversity and ecosystem services to conserve soils for future generations.

Interplay of Light and ABA signaling to modulate plant development.

The exogenous light cues and the phytohormone Abscisic acid (ABA) regulate several aspects of plant growth and development. In recent years, the role of the crosstalk between the light and ABA signaling pathways in regulating different physiological processes has become increasingly evident. This includes the regulation of germination and early seedling development, control of stomatal development and conductance, growth and development of roots, buds, branches, and regulation of flowering. Light and ABA signaling cascades have various convergence points at both DNA and protein levels. The molecular crosstalk involves several light signaling factors like HY5, COP1, PIFs and BBXs that integrate with ABA signaling components like the PYL receptors and ABI5. Especially, ABI5 and PIF4 promoters serve as key "hotspots" for the integration of these two pathways. Plants acquired both light and ABA signaling pathways before they colonized land almost 500 million years ago. In this review, we discuss the recent advances in the interplay of light and ABA signaling regulating plant development and provide an overview of the evolution of these two pathways.

An engineered T7 RNA polymerase for efficient co-transcriptional capping with reduced dsRNA byproducts in mRNA synthesis.

Messenger RNA (mRNA) therapies have recently gained tremendous traction with the approval of mRNA vaccines for the prevention of SARS-CoV-2 infection. However, manufacturing challenges have complicated large scale mRNA production, which is necessary for the clinical viability of these therapies. Not only can the incorporation of the required 5' 7-methylguanosine cap analog be inefficient and costly, in vitro transcription (IVT) using wild-type T7 RNA polymerase generates undesirable double-stranded RNA (dsRNA) byproducts that elicit adverse host immune responses and are difficult to remove at large scale. To overcome these challenges, we have engineered a novel RNA polymerase, T7-68, that co-transcriptionally incorporates both di- and tri-nucleotide cap analogs with high efficiency, even at reduced cap analog concentrations. We also demonstrate that IVT products generated with T7-68 have reduced dsRNA content.

Regulation of chloroplast biogenesis, development, and signaling by endogenous and exogenous cues.

Chloroplasts are one of the defining features in most plants, primarily known for their unique property to carry out photosynthesis. Besides this, chloroplasts are also associated with hormone and metabolite productions. For this, biogenesis and development of chloroplast are required to be synchronized with the seedling growth to corroborate the maximum rate of photosynthesis following the emergence of seedlings. Chloroplast biogenesis and development are dependent on the signaling to and from the chloroplast, which are in turn regulated by several endogenous and exogenous cues. Light and hormones play a crucial role in chloroplast maturation and development. Chloroplast signaling involves a coordinated two-way connection between the chloroplast and nucleus, termed retrograde and anterograde signaling, respectively. Anterograde and retrograde signaling are involved in regulation at the transcriptional level and downstream modifications and are modulated by several metabolic and external cues. The communication between chloroplast and nucleus is essential for plants to develop strategies to cope with various stresses including high light or high heat. In this review, we have summarized several aspects of chloroplast development and its regulation through the interplay of various external and internal factors. We have also discussed the involvement of chloroplasts as sensors of various external environment stress factors including high light and temperature, and communicate via a series of retrograde signals to the nucleus, thus playing an essential role in plants' abiotic stress response.

Interplay between transcriptional regulators and VapBC toxin-antitoxin loci during thermal stress response in extremely thermoacidophilic archaea.

Thermoacidophilic archaea lack sigma factors and the large inventory of heat shock proteins (HSPs) widespread in bacterial genomes, suggesting other strategies for handling thermal stress are involved. Heat shock transcriptomes for the thermoacidophilic archaeon Saccharolobus (f. Sulfolobus) solfataricus 98/2 revealed genes that were highly responsive to thermal stress, including transcriptional regulators YtrASs (Ssol_2420) and FadRSs (Ssol_0314), as well as type II toxin-antitoxin (TA) loci VapBC6 (Ssol_2337, Ssol_2338) and VapBC22 (Ssol_0819, Ssol_0818). The role, if any, of type II TA loci during stress response in microorganisms, such as Escherichia coli, is controversial. But, when genes encoding YtrASs , FadRSs , VapC22, VapB6, and VapC6 were systematically mutated in Sa. solfataricus 98/2, significant up-regulation of the other genes within this set was observed, implicating an interconnected regulatory network during thermal stress response. VapBC6 and VapBC22 have close homologues in other Sulfolobales, as well as in other archaea (e.g. Pyrococcus furiosus and Archaeoglobus fulgidus), and their corresponding genes were also heat shock responsive. The interplay between VapBC TA loci and heat shock regulators in Sa solfataricus 98/2 not only indicates a cellular mechanism for heat shock response that differs from bacteria but one that could have common features within the thermophilic archaea.

Integration of light and ABA signaling pathways to combat drought stress in plants.

Drought is one of the most critical stresses, which causes an enormous reduction in crop yield. Plants develop various strategies like drought escape, drought avoidance, and drought tolerance to cope with the reduced availability of water during drought. Plants adopt several morphological and biochemical modifications to fine-tune their water-use efficiency to alleviate drought stress. ABA accumulation and signaling plays a crucial role in the response of plants towards drought. Here, we discuss how drought-induced ABA regulates the modifications in stomatal dynamics, root system architecture, and the timing of senescence to counter drought stress. These physiological responses are also regulated by light, indicating the possibility of convergence of light- and drought-induced ABA signaling pathways. In this review, we provide an overview of investigations reporting light-ABA signaling cross talk in Arabidopsis as well as other crop species. We have also tried to describe the potential role of different light components and their respective photoreceptors and downstream factors like HY5, PIFs, BBXs, and COP1 in modulating drought stress responses. Finally, we highlight the possibilities of enhancing the plant drought resilience by fine-tuning light environment or its signaling components in the future.

Global-level population genomics reveals differential effects of geography and phylogeny on horizontal gene transfer in soil bacteria.

Although microorganisms are known to dominate Earth's biospheres and drive biogeochemical cycling, little is known about the geographic distributions of microbial populations or the environmental factors that pattern those distributions. We used a global-level hierarchical sampling scheme to comprehensively characterize the evolutionary relationships and distributional limitations of the nitrogen-fixing bacterial symbionts of the crop chickpea, generating 1,027 draft whole-genome sequences at the level of bacterial populations, including 14 high-quality PacBio genomes from a phylogenetically representative subset. We find that diverse Mesorhizobium taxa perform symbiosis with chickpea and have largely overlapping global distributions. However, sampled locations cluster based on the phylogenetic diversity of Mesorhizobium populations, and diversity clusters correspond to edaphic and environmental factors, primarily soil type and latitude. Despite long-standing evolutionary divergence and geographic isolation, the diverse taxa observed to nodulate chickpea share a set of integrative conjugative elements (ICEs) that encode the major functions of the symbiosis. This symbiosis ICE takes 2 forms in the bacterial chromosome-tripartite and monopartite-with tripartite ICEs confined to a broadly distributed superspecies clade. The pairwise evolutionary relatedness of these elements is controlled as much by geographic distance as by the evolutionary relatedness of the background genome. In contrast, diversity in the broader gene content of Mesorhizobium genomes follows a tight linear relationship with core genome phylogenetic distance, with little detectable effect of geography. These results illustrate how geography and demography can operate differentially on the evolution of bacterial genomes and offer useful insights for the development of improved technologies for sustainable agriculture.

Deep Learning Model for Identifying Critical Structural Motifs in Potential Endocrine Disruptors.

This paper aims to identify structural motifs within a molecule that contribute the most toward a chemical being an endocrine disruptor. We have developed a deep neural network-based toolkit toward this aim. The trained model can virtually assess a synthetic chemical's potential to be an endocrine disruptor using machine-readable molecular representation, simplified molecular input line entry system (SMILES). Our proposed toolkit is a multilabel or multioutput classification model that combines both convolution and long short-term memory (LSTM) architectures. The toolkit leverages the advantages of an active learning-based framework that combines multiple sources of data. Class activation maps (CAMs) generated from the feature-extraction layers can identify the structural alerts and the chemical environment that determines the specificity of the structural alerts.

Quantum signatures for screening metavalent solids.

The objective of this paper is to describe a new data-driven framework for computational screening and discovery of a class of materials termed "metavalent" solids. "Metavalent" solids possess characteristics that are nominally associated with metallic and covalent bonding (in terms of conductivity and coordination numbers) but are distinctly different from both because they show anomalously large response properties and a unique bond-breaking mechanism that is not observed in either covalent or metallic solids. The paper introduces the use of Hirshfeld surface analysis to provide quantum level descriptors that can be used for rapid screening of crystallographic data to identify potentially new "metavalent" solids with novel and emergent properties.

Effect of N,N Coordination and RuII Halide Bond in Enhancing Selective Toxicity of a Tyramine-Based RuII (p-Cymene) Complex.

Ruthenium compounds are promising anticancer candidates owing to their lower side-effects and encouraging activities against resistant tumors. Half-sandwich piano-stool type RuII compounds of general formula [(L)RuII(η6-arene)(X)]+ (L = chelating bidentate ligand, X = halide) have exhibited significant therapeutic potential against cisplatin-resistant tumor cell lines. In RuII (p-cymene) based complexes, the change of the halide leaving group has led to several interesting features, viz., hydrolytic stability, resistance toward thiols, and alteration in pathways of action. Tyramine is a naturally occurring monoamine which acts as a catecholamine precursor in humans. We synthesized a family of N,N and N,O coordinated RuII (p-cymene) complexes, [(L)RuII(η6-arene)(X)]+ (1-4), with tyramine and varied the halide (X = Cl, I) to investigate the difference in reactivity. Our studies showed that complex 2 bearing N,N coordination with an iodido leaving group shows selective in vitro cytotoxicity against the pancreatic cancer cell line MIA PaCa-2 (IC50 ca. 5 µM) but is less toxic to triple-negative breast cancer (MDA-MB-231), hepatocellular carcinoma (Hep G2), and the normal human foreskin fibroblasts (HFF-1). Complex 2 displays stability toward hydrolysis and does not bind with glutathione, as confirmed by 1H NMR and ESI-HRMS experiments. The inert nature of 2 leads to enhancement of cytotoxicity (IC50 = 5.3 ± 1 µM) upon increasing the cellular treatment time from 48 to 72 h.

Yeast a potential bio-agent: future for plant growth and postharvest disease management for sustainable agriculture.

The native microbial flora and fauna are replaced by commercial chemical fertilizers and pesticides, in the current agricultural system. Imbalance of beneficial microbial diversity and natural competitors increases the severity of plant diseases. Hence, sustainable agricultural practices like bio-inoculant, stress tolerant consortium, crop rotation and mix cropping sequences is only the solution of recharging the microbial population in soils to make healthier for crop productivity and suppression of soil borne phytopathogen. Microorganisms use several direct mechanism activities, e.g. production of plant hormones (indole-3-acetic acid), ammonium, siderophore and nutrient solubilization, and indirect mechanism activities, e.g. hydrogen cyanide, chitinase, protease and antibiotic for plant growth promotion. The plant growth-promoting effect of bacteria, fungi, mycorrhizal fungi and algae is widely explored. Yeast is a single-celled microbe classified as members of the kingdom fungi. Yeast and their product use in the food industry, medical science and biotechnological research purpose but very few literatures reported that yeasts have the ability to produce a group of plant growth-promoting activities and biocontrolling activity. Therefore, the main aim of this mini review is to highlight the application of yeasts as biological agents in different sectors of sustainable farming practices.

Extremely Thermoacidophilic Metallosphaera Species Mediate Mobilization and Oxidation of Vanadium and Molybdenum Oxides.

Certain species from the extremely thermoacidophilic genus Metallosphaera directly oxidize Fe(II) to Fe(III), which in turn catalyzes abiotic solubilization of copper from chalcopyrite to facilitate recovery of this valuable metal. In this process, the redox status of copper does not change as it is mobilized. Metallosphaera species can also catalyze the release of metals from ores with a change in the metal's redox state. For example, Metallosphaera sedula catalyzes the mobilization of uranium from the solid oxide U3O8, concomitant with the generation of soluble U(VI). Here, the mobilization of metals from solid oxides (V2O3, Cu2O, FeO, MnO, CoO, SnO, MoO2, Cr2O3, Ti2O3, and Rh2O3) was examined for M. sedula and M. prunae at 70°C and pH 2.0. Of these oxides, only V and Mo were solubilized, a process accelerated in the presence of FeCl3 However, it was not clear whether the solubilization and oxidation of these metals could be attributed entirely to an Fe-mediated indirect mechanism. Transcriptomic analysis for growth on molybdenum and vanadium oxides revealed transcriptional patterns not previously observed for growth on other energetic substrates (i.e., iron, chalcopyrite, organic compounds, reduced sulfur compounds, and molecular hydrogen). Of particular interest was the upregulation of Msed_1191, which encodes a Rieske cytochrome b6 fusion protein (Rcbf, referred to here as V/MoxA) that was not transcriptomically responsive during iron biooxidation. These results suggest that direct oxidation of V and Mo occurs, in addition to Fe-mediated oxidation, such that both direct and indirect mechanisms are involved in the mobilization of redox-active metals by Metallosphaera species.IMPORTANCE In order to effectively leverage extremely thermoacidophilic archaea for the microbially based solubilization of solid-phase metal substrates (e.g., sulfides and oxides), understanding the mechanisms by which these archaea solubilize metals is important. Physiological analysis of Metallosphaera species growth in the presence of molybdenum and vanadium oxides revealed an indirect mode of metal mobilization, catalyzed by iron cycling. However, since the mobilized metals exist in more than one oxidation state, they could potentially serve directly as energetic substrates. Transcriptomic response to molybdenum and vanadium oxides provided evidence for new biomolecules participating in direct metal biooxidation. The findings expand the knowledge on the physiological versatility of these extremely thermoacidophilic archaea.

VapC toxins drive cellular dormancy under uranium stress for the extreme thermoacidophile Metallosphaera prunae.

When abruptly exposed to toxic levels of hexavalent uranium, the extremely thermoacidophilic archaeon Metallosphaera prunae, originally isolated from an abandoned uranium mine, ceased to grow, and concomitantly exhibited heightened levels of cytosolic ribonuclease activity that corresponded to substantial degradation of cellular RNA. The M. prunae transcriptome during 'uranium-shock' implicated VapC toxins as possible causative agents of the observed RNA degradation. Identifiable VapC toxins and PIN-domain proteins encoded in the M. prunae genome were produced and characterized, three of which (VapC4, VapC7, VapC8) substantially degraded M. prunae rRNA in vitro. RNA cleavage specificity for these VapCs mapped to motifs within M. prunae rRNA. Furthermore, based on frequency of cleavage sequences, putative target mRNAs for these VapCs were identified; these were closely associated with translation, transcription, and replication. It is interesting to note that Metallosphaera sedula, a member of the same genus and which has a nearly identical genome sequence but not isolated from a uranium-rich biotope, showed no evidence of dormancy when exposed to this metal. M. prunae utilizes VapC toxins for post-transcriptional regulation under uranium stress to enter a cellular dormant state, thereby providing an adaptive response to what would otherwise be a deleterious environmental perturbation.

Transcriptomes of the Extremely Thermoacidophilic Archaeon Metallosphaera sedula Exposed to Metal "Shock" Reveal Generic and Specific Metal Responses.

UNLABELLED: The extremely thermoacidophilic archaeon Metallosphaera sedula mobilizes metals by novel membrane-associated oxidase clusters and, consequently, requires metal resistance strategies. This issue was examined by "shocking" M. sedula with representative metals (Co(2+), Cu(2+), Ni(2+), UO2 (2+), Zn(2+)) at inhibitory and subinhibitory levels. Collectively, one-quarter of the genome (554 open reading frames [ORFs]) responded to inhibitory levels, and two-thirds (354) of the ORFs were responsive to a single metal. Cu(2+) (259 ORFs, 106 Cu(2+)-specific ORFs) and Zn(2+) (262 ORFs, 131 Zn(2+)-specific ORFs) triggered the largest responses, followed by UO2 (2+) (187 ORFs, 91 UO2 (2+)-specific ORFs), Ni(2+) (93 ORFs, 25 Ni(2+)-specific ORFs), and Co(2+) (61 ORFs, 1 Co(2+)-specific ORF). While one-third of the metal-responsive ORFs are annotated as encoding hypothetical proteins, metal challenge also impacted ORFs responsible for identifiable processes related to the cell cycle, DNA repair, and oxidative stress. Surprisingly, there were only 30 ORFs that responded to at least four metals, and 10 of these responded to all five metals. This core transcriptome indicated induction of Fe-S cluster assembly (Msed_1656-Msed_1657), tungsten/molybdenum transport (Msed_1780-Msed_1781), and decreased central metabolism. Not surprisingly, a metal-translocating P-type ATPase (Msed_0490) associated with a copper resistance system (Cop) was upregulated in response to Cu(2+) (6-fold) but also in response to UO2 (2+) (4-fold) and Zn(2+) (9-fold). Cu(2+) challenge uniquely induced assimilatory sulfur metabolism for cysteine biosynthesis, suggesting a role for this amino acid in Cu(2+) resistance or issues in sulfur metabolism. The results indicate that M. sedula employs a range of physiological and biochemical responses to metal challenge, many of which are specific to a single metal and involve proteins with yet unassigned or definitive functions. IMPORTANCE: The mechanisms by which extremely thermoacidophilic archaea resist and are negatively impacted by metals encountered in their natural environments are important to understand so that technologies such as bioleaching, which leverage microbially based conversion of insoluble metal sulfides to soluble species, can be improved. Transcriptomic analysis of the cellular response to metal challenge provided both global and specific insights into how these novel microorganisms negotiate metal toxicity in natural and technological settings. As genetics tools are further developed and implemented for extreme thermoacidophiles, information about metal toxicity and resistance can be leveraged to create metabolically engineered strains with improved bioleaching characteristics.

Uranium extremophily is an adaptive, rather than intrinsic, feature for extremely thermoacidophilic Metallosphaera species.

Thermoacidophilic archaea are found in heavy metal-rich environments, and, in some cases, these microorganisms are causative agents of metal mobilization through cellular processes related to their bioenergetics. Given the nature of their habitats, these microorganisms must deal with the potentially toxic effect of heavy metals. Here, we show that two thermoacidophilic Metallosphaera species with nearly identical (99.99%) genomes differed significantly in their sensitivity and reactivity to uranium (U). Metallosphaera prunae, isolated from a smoldering heap on a uranium mine in Thüringen, Germany, could be viewed as a "spontaneous mutant" of Metallosphaera sedula, an isolate from Pisciarelli Solfatara near Naples. Metallosphaera prunae tolerated triuranium octaoxide (U(3)O(8)) and soluble uranium [U(VI)] to a much greater extent than M. sedula. Within 15 min following exposure to "U(VI) shock," M. sedula, and not M. prunae, exhibited transcriptomic features associated with severe stress response. Furthermore, within 15 min post-U(VI) shock, M. prunae, and not M. sedula, showed evidence of substantial degradation of cellular RNA, suggesting that transcriptional and translational processes were aborted as a dynamic mechanism for resisting U toxicity; by 60 min post-U(VI) shock, RNA integrity in M. prunae recovered, and known modes for heavy metal resistance were activated. In addition, M. sedula rapidly oxidized solid U(3)O(8) to soluble U(VI) for bioenergetic purposes, a chemolithoautotrophic feature not previously reported. M. prunae, however, did not solubilize solid U(3)O(8) to any significant extent, thereby not exacerbating U(VI) toxicity. These results point to uranium extremophily as an adaptive, rather than intrinsic, feature for Metallosphaera species, driven by environmental factors.

Impact of bacterial volatiles on the plant growth attributes and defense mechanism of rice seedling.

Rice is a major dietary element for about two billion people worldwide and it faces numerous biotic and abiotic stress for its cultivation. Rice blast disease caused by Magnaporthe oryzae reduce up to 30 % rice yield. Overuse of synthetic chemicals raises concerns about health and environment; so, there is an urgent need to explore innovative sustainable strategies for crop productivity. The main aim of this study is to explore the impact of bacterial volatiles (BVCs) on seedling growth and defense mechanisms of rice under in-vitro condition. On the basis of plant growth promoting properties, six bacterial strains were selected out of ninety-one isolated strains for this study; Pantoea dispersa BHUJPVR01, Enterobacter cloacae BHUJPVR02, Enterobacter sp. BHUJPVR12, Priestia aryabhattai BHUJPVR13, Pseudomonas sp. BHUJPVWRO5 and Staphylococcus sp. BHUJPVWLE7. Through the emission of bacterial volatiles compounds (BVCs), Enterobacter sp., P. dispersa and P. aryabhattai significantly reduces the growth of rice blast fungus Magnaporthe oryzae by 69.20 %, 66.15 % and 62.31 % respectively. Treatment of rice seedlings with BVCs exhibited significant enhancement in defence enzyme levels, including guaiacol peroxidase, polyphenol oxidase, total polyphenols, and total flavonoids by a maximum of up to 24 %, 48 %, 116 % and 80 %, respectively. Furthermore, BVCs effectively promote shoot height, root height, and root counts of rice. All BVCs treated plant showed a significant increase in shoot height. P. dispersa treated plants showed the highest increase of 60 % shoot and 110 % root length, respectively. Root counts increased up to 30% in plants treated with E. cloacae and Staphylococcus sp. The BVCs can be used as a sustainable approach for enhancing plant growth attributes, productivity and defence mechanism of rice plant under biotic and abiotic stresses.

Chickpea seed endophyte Enterobacter sp. mediated yield and nutritional enrichment of chickpea for improving human and livestock health.

Chickpeas (Cicer arietinum L.) are used as a good source of proteins and energy in the diets of various organisms including humans and animals. Chickpea straws can serve as an alternative option for forage for different ruminants. This research mainly focussed on screening the effects of adding beneficial chickpea seed endophytes on increasing the nutritional properties of the different edible parts of chickpea plants. Two efficient chickpea seed endophytes (Enterobacter sp. strain BHUJPCS-2 and BHUJPCS-8) were selected and applied to the chickpea seeds before sowing in the experiment conducted on clay pots. Chickpea seeds treated with both endophytes showed improved plant growth and biomass accumulation. Notably, improvements in the uptake of mineral nutrients were found in the foliage, pericarp, and seed of the chickpea plants. Additionally, nutritional properties such as total phenolics (0.47, 0.25, and 0.55 folds), total protein (0.04, 0.21, and 0.18 folds), carbohydrate content (0.31, 0.32, and 0.31 folds), and total flavonoid content (0.45, 027, and 0.8 folds) were increased in different parts (foliage, pericarp, and seed) of the chickpea plants compared to the control plants. The seed endophyte-treated plants showed a significant increase in mineral accumulation and improvement in nutrition in the different edible parts of chickpea plants. The results showed that the seed endophyte-mediated increase in dietary and nutrient value of the different parts (pericarp, foliage, and seeds) of chickpea are consumed by humans, whereas the other parts (pericarp and foliage) are used as alternative options for forage and chaff in livestock diets and may have direct effects on their nutritional conditions.

Unearthing the power of microbes as plant microbiome for sustainable agriculture.

In recent years, research into the complex interactions and crosstalk between plants and their associated microbiota, collectively known as the plant microbiome has revealed the pivotal role of microbial communities for promoting plant growth and health. Plants have evolved intricate relationships with a diverse array of microorganisms inhabiting their roots, leaves, and other plant tissues. This microbiota mainly includes bacteria, archaea, fungi, protozoans, and viruses, forming a dynamic and interconnected network within and around the plant. Through mutualistic or cooperative interactions, these microbes contribute to various aspects of plant health and development. The direct mechanisms of the plant microbiome include the enhancement of plant growth and development through nutrient acquisition. Microbes have the ability to solubilize essential minerals, fix atmospheric nitrogen, and convert organic matter into accessible forms, thereby augmenting the nutrient pool available to the plant. Additionally, the microbiome helps plants to withstand biotic and abiotic stresses, such as pathogen attacks and adverse environmental conditions, by priming the plant's immune responses, antagonizing phytopathogens, and improving stress tolerance. Furthermore, the plant microbiome plays a vital role in phytohormone regulation, facilitating hormonal balance within the plant. This regulation influences various growth processes, including root development, flowering, and fruiting. Microbial communities can also produce secondary metabolites, which directly or indirectly promote plant growth, development, and health. Understanding the functional potential of the plant microbiome has led to innovative agricultural practices, such as microbiome-based biofertilizers and biopesticides, which harness the power of beneficial microorganisms to enhance crop yields while reducing the dependency on chemical inputs. In the present review, we discuss and highlight research gaps regarding the plant microbiome and how the plant microbiome can be used as a source of single and synthetic bioinoculants for plant growth and health.

Harnessing bacterial strain from rhizosphere to develop indigenous PGPR consortium for enhancing lobia (Vigna unguiculata) production.

The rhizosphere microbes play a key role in plant nutrition and health. However, the interaction of beneficial microbes and Vigna unguiculata (lobia) production remains poorly understood. Thus, we aimed to isolate and characterize the soil microbes from the rhizosphere and develop novel microbial consortia for enhancing lobia production. Fifty bacterial strains were isolated from the rhizosphere soil samples of lobia. Finally, five effective strains (e.g., Pseudomonas sp. IESDJP-V1 and Pseudomonas sp. IESDJP-V2, Serratia marcescens IESDJP-V3, Bacillus cereus IESDJP-V4, Ochrobactrum sp. IESDJP-V5) were identified and molecularly characterized by 16 S rDNA gene amplification. All selected strains showed positive plant growth promoting (PGP) properties in broth culture. Based on morphological, biochemical, and plant growth promoting activities, five effective isolated strains and two collected strains (Azospirillum brasilense MTCC-4037 and Paenibacillus polymyxa BHUPSB17) were selected. The pot trials were conducted with seed inoculations of lobia (Vigna unguiculata) var. Kashi Kanchan with thirty treatments and three replications. The treatment combination T3 (Pseudomonas sp. IESDJP-V2), T14 (Pseudomonas sp. IESDJP-V2 + A. brasilense), T26 (Pseudomonas sp. IESDJP-V1+ B. cereus IESDJP-V4 + P. polymyxa) and T27 (IESDJP-V1+ IESDJP-V5+ A. brasilense) were recorded for enhancing plant growth attributes, yield, nutritional content like protein, total sugar, flavonoid and soil properties as compared to control and others. The effective treatments T3 (Pseudomonas sp.), T14 (Pseudomonas sp. IESDJP-V2 + A. brasilense), T26 (Pseudomonas sp. IESDJP-V1+ B. cereus IESDJP-V4 + P. polymyxa) and T27 (IESDJP-V1+ IESDJP-V5+ A. brasilense) recorded as potential PGPR consortium for lobia production. The treatment of single (Pseudomonas sp.), duel (IESDJP-V2 + A. brasilense) and triple combination (IESDJP-V1+ IESDJP-V4 + P. polymyxa) and (IESDJP-V1+ IESDJP-V5+ A. brasilense) can be further used for developing effective indigenous consortium for lobia production under sustainable farming practices. These PGPR bio-inoculant will be cost-effective, environment-friendly and socially acceptable.

Soil biodiversity supports the delivery of multiple ecosystem functions in urban greenspaces.

While the contribution of biodiversity to supporting multiple ecosystem functions is well established in natural ecosystems, the relationship of the above- and below-ground diversity with ecosystem multifunctionality remains virtually unknown in urban greenspaces. Here we conducted a standardized survey of urban greenspaces from 56 municipalities across six continents, aiming to investigate the relationships of plant and soil biodiversity (diversity of bacteria, fungi, protists and invertebrates, and metagenomics-based functional diversity) with 18 surrogates of ecosystem functions from nine ecosystem services. We found that soil biodiversity across biomes was significantly and positively correlated with multiple dimensions of ecosystem functions, and contributed to key ecosystem services such as microbially driven carbon pools, organic matter decomposition, plant productivity, nutrient cycling, water regulation, plant-soil mutualism, plant pathogen control and antibiotic resistance regulation. Plant diversity only indirectly influenced multifunctionality in urban greenspaces via changes in soil conditions that were associated with soil biodiversity. These findings were maintained after controlling for climate, spatial context, soil properties, vegetation and management practices. This study provides solid evidence that conserving soil biodiversity in urban greenspaces is key to supporting multiple dimensions of ecosystem functioning, which is critical for the sustainability of urban ecosystems and human wellbeing.