Potential Use of Microbial Community Genomes in Various Dimensions of Agriculture Productivity and Its Management: A Review

Biochemical and structural characterization of a family-9 glycoside hydrolase bioprospected from the termite Syntermes wheeleri gut bacteria metagenome

Glycosyl hydrolases (GH) are enzymes involved in the degradation of plant biomass. They are important for biorefineries that aim at the sustainable utilization of lignocellulosic residues to generate value-added products. The termite Syntermes wheeleri gut microbiota showed an abundance of bacteria from the phylum Firmicutes, a phylum with enzymes capable of breaking down cellulose and degrading lignin, facilitating the use of plant materials as a food source for termites. Using bioinformatics techniques, cellobiohydrolases were searched for in the gut metagenome of the termite Syntermes wheeleri, endemic to the Cerrado. After selecting sequences of the target enzymes, termite gut microbiome metatranscriptome data were used as the criteria to choose the GH9 enzyme sequence Exo8574. Here we present the biochemical and structural characterization of Exo8574, a GH9 enzyme that showed activity with the substrate p-nitrophenyl-D-cellobioside (pNPC), consistent with cellobiohydrolase activity. Bioinformatics tools were used to perform phylogeny studies of Exo8574 and to identify conserved families and domains. Exo8574 showed 48.8 % homology to a protein from a bacterium belonging to the phylum Firmicutes. The high-quality three-dimensional (3D) model of Exo8574 was obtained by protein structure prediction AlphaFold 2, a neural network-based method. After the heterologous expression of Exo8574 and its purification, biochemical experiments showed that the optimal activity of the enzyme was at a temperature of 55 ºC and pH 6.0, which was enhanced in the presence of metal ions, especially Fe2 +. The estimated kinetic parameters of Exo8574 using the synthetic substrate p-nithrophenyl-beta-D-cellobioside (pNPC) were: Vmax = 9.14 ± 0.2 x10-5 μmol/min and Km = 248.27 ± 26.35 μmol/L. The thermostability test showed a 50 % loss of activity after 1 h incubation at 55 °C. The secondary structure contents of Exo8574 evaluated by Circular Dichroism were pH dependent, with greater structuring of protein in β-antiparallel and α-helices at pH 6.0. The similarity between the CD results and the Ramachandran plot of the 3D model suggests that a reliable model has been obtained. Altogether, the results of the biochemical and structural characterization showed that Exo8574 is capable of acting on p-nithrophenyl-beta-D-cellobioside (pNPC), a substrate that mimics bonds cleaved by cellobiohydrolases. These findings have significant implications for advancing in the field of biomass conversion while also contributing to efforts aimed at overcoming challenges in developing more efficient cellulase cocktails.

Fungal and bacterial community composition and assemblage in managed and unmanaged urban landscapes in Wisconsin

Microbial communities play crucial roles in ecosystem functioning, yet their diversity and assembly in urban turfgrass systems remain underexplored. In 2017, microbial communities within 48 samples from managed turfgrass (home lawns, golf course fairways, and putting greens) and an unmanaged grass mixture in Madison, WI, USA were analyzed across leaf, thatch, rhizoplane, and rhizosphere habitats Intensive management, particularly in nitrogen-rich, sand-based putting greens, reduced fungal richness and diversity, whereas bacterial diversity patterns varied. Beta diversity analyses revealed distinct clustering: fungal communities differed most in unmanaged systems, while bacterial communities clustered within managed systems. Functional profiling demonstrated that bacterial communities maintained metabolic stability despite taxonomic shifts, while fungal communities showed dynamic functional responses to management. Furthermore, management practices also impacted microbial community assembly. Bacterial communities were predominantly shaped by neutral, stochastic processes, while fungal communities were more sensitive to management, showing deterministic, niche-based assembly and compositional shifts. These findings underscore the contrasting impacts of management on microbial communities and highlight the importance of sustainable turfgrass practices that balance plant health with microbial ecosystem functions. By linking microbial assembly processes to functional outcomes, this study provides insights for optimizing urban landscapes to enhance soil health and ecosystem resilience.

Editorial: plant-microbial symbiosis toward sustainable food security

The use of plant-associated microorganisms is increasingly being investigated as a key tool for mitigating the impact of biotic and abiotic threats to crops and facilitating migration to sustainable agricultural practices. The microbiome is responsible for several functions in agroecosystems, such as the transformation of organic matter, nutrient cycling, and plant/pathogen growth regulation. As climate change and global warming are altering the dynamics of plant-microbial interactions in the ecosystem, it has become essential to perform comprehensive studies to decipher current and future microbial interactions, as their useful symbiotic mechanisms could be better exploited to achieve sustainable agriculture. This will allow for the development of effective microbial inoculants that facilitate nutrient supply for the plant at its minimal energy expense, thus increasing its resilience to biotic and abiotic stresses. This article collection aims to compile state-of-the-art research focused on the elucidation and optimization of symbiotic relationships between crops and their associated microbes. The information presented here will contribute to the development of next-generation microbial inoculants for achieving a more sustainable agriculture.

Exploring microbial diversity in the rhizosphere: a comprehensive review of metagenomic approaches and their applications

The rhizosphere, the soil region influenced by plant roots, represents a dynamic microenvironment where intricate interactions between plants and microorganisms shape soil health, nutrient cycling, and plant growth. Soil microorganisms are integral players in the transformation of materials, the dynamics of energy flows, and the intricate cycles of biogeochemistry. Considerable research has been dedicated to investigating the abundance, diversity, and intricacies of interactions among different microbes, as well as the relationships between plants and microbes present in the rhizosphere. Metagenomics, a powerful suite of techniques, has emerged as a transformative tool for dissecting the genetic repertoire of complex microbial communities inhabiting the rhizosphere. The review systematically navigates through various metagenomic approaches, ranging from shotgun metagenomics, enabling unbiased analysis of entire microbial genomes, to targeted sequencing of the 16S rRNA gene for taxonomic profiling. Each approach's strengths and limitations are critically evaluated, providing researchers with a nuanced understanding of their applicability in different research contexts. A central focus of the review lies in the practical applications of rhizosphere metagenomics in various fields including agriculture. By decoding the genomic content of rhizospheric microbes, researchers gain insights into their functional roles in nutrient acquisition, disease suppression, and overall plant health. The review also addresses the broader implications of metagenomic studies in advancing our understanding of microbial diversity and community dynamics in the rhizosphere. It serves as a comprehensive guide for researchers, agronomists, and policymakers, offering a roadmap for harnessing metagenomic approaches to unlock the full potential of the rhizosphere microbiome in promoting sustainable agriculture.

Modulatory Effects of Isolated Lactobacillus paracasei from Malaysian Water Kefir Grains on the Intestinal Barrier and Gut Microbiota in Diabetic Mice

Type 2 diabetes (T2DM) is one of the four major types of non-communicable diseases that have become a global health concern. Water kefir is a product of a brown sugar solution fermented with kefir grains which comprises around 30 microbial species in its grains. Water kefir possesses a wide range of health benefits, including anti-hyperlipidemic effects, and reduces hypertension and blood glucose levels in animal models. Reportedly, consuming water kefir containing probiotics may enhance the intestinal barrier and positively influence the composition of the intestinal microflora. The present study aimed to evaluate the regulatory effects of Lactobacillus paracasei isolated from Malaysian water kefir grains (MWKG) on the alterations of intestinal barrier and gut microbiota in diabetic mice via histopathological analysis of the distal colon and 16S rRNA gene sequencing on fecal microbiome. Results indicated that the administration of isolated Lactobacillus paracasei from MWKG to diabetic mice ameliorated the dominant probiotic phyla in the gut microbiota. Results showed that lower dose (LD) and high dose (HD) treatments of the isolated Lactobacillus paracasei could significantly reduce inflammatory cell infiltration in the distal colon of diabetic mice. The treatments revealed a significant decrease in the relative abundance of Firmicutes in the gut, 0.27 ± 0.06% for LD and 0.34 ± 0.04% for HD, compared to untreated (UN) diabetic mice, 0.40 ± 0.02%. These results suggest that L. paracasei isolated from MWKG could serve as a potential dietary supplement against intestinal inflammation and modify gut microbiota composition in patients with T2DM.

Exploring microbial worlds: a review of whole genome sequencing and its application in characterizing the microbial communities

The classical microbiology techniques have inherent limitations in unraveling the complexity of microbial communities, necessitating the pivotal role of sequencing in studying the diversity of microbial communities. Whole genome sequencing (WGS) enables researchers to uncover the metabolic capabilities of the microbial community, providing valuable insights into the microbiome. Herein, we present an overview of the rapid advancements achieved thus far in the use of WGS in microbiome research. There was an upsurge in publications, particularly in 2021 and 2022 with the United States, China, and India leading the metagenomics research landscape. The Illumina platform has emerged as the widely adopted sequencing technology, whereas a significant focus of metagenomics has been on understanding the relationship between the gut microbiome and human health where distinct bacterial species have been linked to various diseases. Additionally, studies have explored the impact of human activities on microbial communities, including the potential spread of pathogenic bacteria and antimicrobial resistance genes in different ecosystems. Furthermore, WGS is used in investigating the microbiome of various animal species and plant tissues such as the rhizosphere microbiome. Overall, this review reflects the importance of WGS in metagenomics studies and underscores its remarkable power in illuminating the variety and intricacy of the microbiome in different environments.

Association between molecular markers and resistance to bacterial blight using binary logistic analysis

The most effective strategy for managing wheat bacterial blight caused by Pseudomonas syringae pv. syringae is believed to be the use of resistant cultivars. Researching the correlation between molecular markers and stress resistance can expedite the plant breeding process. The current study aims to evaluate the response of 27 bread wheat cultivars to bacterial blight disease in order to identify resistant and susceptible cultivars and to pinpoint ISSR molecular markers associated with bacterial blight resistance genes. ISSR markers are recommended for assessing a plant's disease resistance. This experiment is focused on identifying ISSR molecular markers linked to bacterial blight resistance. After applying the bacterial solution to the leaves, we performed sampling to determine the infection percentage in the leaves at different intervals (7, 14, and 18 days after spraying). In most cultivars, the average leaf infection percentage decreased 18 days after spraying on young leaves. However, in some cultivars such as Niknegad, Darab2, and Zarin, leaf infection increased in older leaves and reached up to 100% necrosis. In our study, 12 ISSR primers generated a total of 170 bands, with 156 being polymorphic. The primers F10 and F5 showed the highest polymorphism, while the F7 primer exhibited the lowest polymorphism. Cluster analysis grouped these cultivars into four categories. The resistant group included Qods, Omid, and Atrak cultivars, while the semi-resistant and susceptible groups comprised the rest of the cultivars. Through binary logistic analysis, we identified three Super oxide dismutase-related genes that contribute to plant resistance to bacterial blight. These genes were linked to the F3, F5, and F12 primers in regions I (1500 bp), T (1000 bp), and G (850 bp), respectively. We also identified seven susceptibility-associated genes. Atrak, Omid, and Qods cultivars exhibited resistance against bacterial blight, and three genes associated with this resistance were linked to the F3, F5, and F12 primers. These markers can be used for screening or transferring tolerance to other wheat cultivars in breeding programs.

Advances in microbial based bio-inoculum for amelioration of soil health and sustainable crop production

The adoption of sustainable agricultural practices is increasingly imperative in addressing global food security and environmental concerns, with microbial based bio-inoculums emerging as a promising approach for nurturing soil health and fostering sustainable crop production.This review article explores the potential of microbial based bio-inoculumsor biofertilizers as a transformative approach toenhance plant disease resistance and growth. It explores the commercial prospects of biofertilizers, highlighting their role in addressing environmental concerns associated with conventional fertilizers while meeting the growing demand for eco-friendly agricultural practices. Additionally, this review discusses the future prospects of biofertilizers, emphasizing the ongoing advancements in biotechnology and formulation techniques that are expected to enhance their efficacy and applicability. Furthermore, this article provides insights into strategies for the successful acceptance of biofertilizers among farmers, including the importance of quality control, assurance, and education initiatives to raise awareness about their benefits and overcome barriers to adoption. By synthesizing the current research findings and industrial developments, this review offers valuable guidance for stakeholders seeking to exploit the potential of biofertilizers or beneficial microbes to promote soil health, ensure sustainable crop production, and addressing the challenges of modern agriculture.

Metagenomics: An Effective Approach for Exploring Microbial Diversity and Functions

Various fields have been identified in the "omics" era, such as genomics, proteomics, transcriptomics, metabolomics, phenomics, and metagenomics. Among these, metagenomics has enabled a significant increase in discoveries related to the microbial world. Newly discovered microbiomes in different ecologies provide meaningful information on the diversity and functions of microorganisms on the Earth. Therefore, the results of metagenomic studies have enabled new microbe-based applications in human health, agriculture, and the food industry, among others. This review summarizes the fundamental procedures on recent advances in bioinformatic tools. It also explores up-to-date applications of metagenomics in human health, food study, plant research, environmental sciences, and other fields. Finally, metagenomics is a powerful tool for studying the microbial world, and it still has numerous applications that are currently hidden and awaiting discovery. Therefore, this review also discusses the future perspectives of metagenomics.

A wide foodomics approach coupled with metagenomics elucidates the environmental signature of potatoes

The term "terroir" has been widely employed to link differential geographic phenotypes with sensorial signatures of agricultural food products, influenced by agricultural practices, soil type, and climate. Nowadays, the geographical indications labeling has been developed to safeguard the quality of plant-derived food that is linked to a certain terroir and is generally considered as an indication of superior organoleptic properties. As the dynamics of agroecosystems are highly intricate, consisting of tangled networks of interactions between plants, microorganisms, and the surrounding environment, the recognition of the key molecular components of terroir fingerprinting remains a great challenge to protect both the origin and the safety of food commodities. Furthermore, the contribution of microbiome as a potential driver of the terroir signature has been underestimated. Herein, we present a first comprehensive view of the multi-omic landscape related to transcriptome, proteome, epigenome, and metagenome of the popular Protected Geographical Indication potatoes of Naxos.

The Application of Metagenomics to Study Microbial Communities and Develop Desirable Traits in Fermented Foods

The microbial communities present within fermented foods are diverse and dynamic, producing a variety of metabolites responsible for the fermentation processes, imparting characteristic organoleptic qualities and health-promoting traits, and maintaining microbiological safety of fermented foods. In this context, it is crucial to study these microbial communities to characterise fermented foods and the production processes involved. High Throughput Sequencing (HTS)-based methods such as metagenomics enable microbial community studies through amplicon and shotgun sequencing approaches. As the field constantly develops, sequencing technologies are becoming more accessible, affordable and accurate with a further shift from short read to long read sequencing being observed. Metagenomics is enjoying wide-spread application in fermented food studies and in recent years is also being employed in concert with synthetic biology techniques to help tackle problems with the large amounts of waste generated in the food sector. This review presents an introduction to current sequencing technologies and the benefits of their application in fermented foods.

Metabolomic analysis of halotolerant endophytic bacterium Salinivibrio costicola isolated from Suaeda maritima (L.) dumort

In this study, the Salinivibrio costicola strain was isolated from Suaeda maritima (L.) Dumort. collected in Sinan, Republic of Korea. The endophytic characteristics of the Gram-negative bacterium S. costicola were verified with metagenomics sequencing of S. maritima. S. costicola was cultivated for 3 days in a liquid medium with 3.3% sea salt and analyzed the metabolites produced by the strain cultured in five different bacterial cultivation media. From the bacterial cultures, polyhydroxybutyrate derivatives were detected using high-resolution mass spectrometry, and three major compounds were isolated by high-performance liquid chromatography. The chemical structures of the compounds were elucidated using nuclear magnetic resonance and MS analyses. The relationship between the compounds was confirmed with Global Natural Product Social Molecular Networking, which showed clustering of the compounds. From the S. maritima extract, polyhydroxybutyrate derivatives produced by S. costicola were detected as being accumulated in the host plant.