Endophytes as nature's gift to plants to combat abiotic stresses.

In recent decades, scientists have recognized that plants' distinct and immensely dynamic microbial communities are more than just "passengers," but instead, play an important role in their development, and shielding against abiotic and biotic stresses. Endophytes comprise fungi and bacteria that live within plant tissues and support growth when plants are under stress. All plants in nature are considered to have symbiotic association with endophytes. A comprehensive review of the accessible data suggests that mobility, cell-wall degradation capacity, and reactive oxygen species scavenging are critical attributes for the successful colonization of endophytes. Plants encounter several abiotic stresses caused by climate change and global warming, which have an effect on their growth and production. Abiotic stress like high temperature, salinity, and high precipitation can severely affect plants compared to biotic stress. This review aims to highlight what role endophytes play to aid plant growth under abiotic stress conditions like heat, salinity, and drought. In the current review, we discuss how endophytic microbes can be efficiently used for the improvement and promotion of plant growth and crop production under abiotic stress conditions.

Bacillus subtilis impact on plant growth, soil health and environment: Dr. Jekyll and Mr. Hyde.

The increased dependence of farmers on chemical fertilizers poses a risk to soil fertility and ecosystem stability. Plant growth-promoting rhizobacteria (PGPR) are at the forefront of sustainable agriculture, providing multiple benefits for the enhancement of crop production and soil health. Bacillus subtilis is a common PGPR in soil that plays a key role in conferring biotic and abiotic stress tolerance to plants by induced systemic resistance (ISR), biofilm formation and lipopeptide production. As a part of bioremediating technologies, Bacillus spp. can purify metal contaminated soil. It acts as a potent denitrifying agent in agroecosystems while improving the carbon sequestration process when applied in a regulated concentration. Although it harbours several antibiotic resistance genes (ARGs), it can reduce the horizontal transfer of ARGs during manure composting by modifying the genetic makeup of existing microbiota. In some instances, it affects the beneficial microbes of the rhizosphere. External inoculation of B. subtilis has both positive and negative impacts on the endophytic and semi-synthetic microbial community. Soil texture, type, pH and bacterial concentration play a crucial role in the regulation of all these processes. Soil amendments and microbial consortia of Bacillus produced by microbial engineering could be used to lessen the negative effect on soil microbial diversity. The complex plant-microbe interactions could be decoded using transcriptomics, proteomics, metabolomics and epigenomics strategies which would be beneficial for both crop productivity and the well-being of soil microbiota. Bacillus subtilis has more positive attributes similar to the character of Dr. Jekyll and some negative attributes on plant growth, soil health and the environment akin to the character of Mr. Hyde.

Bacillus sp. and arbuscular mycorrhizal fungi consortia enhance wheat nutrient and yield in the second-year field trial: Superior performance in comparison with chemical fertilizers.

AIMS: The aim of the study is to analyse the effect of microbial consortia for wheat biofortification, growth, yield and soil fertility as part of a 2-year field study and compare it with the use of chemical fertilizers. METHODS AND RESULTS: A field trial (second year) was conducted with various combinations of plant growth-promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) treatments, ranging from a single inoculant to multiple combinations. The microbial consortia used were Bacillus sp. and AMF based on first-year field trial results. The consortia based on native (CP4) and non-native (AHP3) PGPB (Bacillus sp.) and AMF performed better in terms of nutrients content in wheat grain tissue and yield-related traits compared with chemical fertilizer treated and untreated control. Dual treatment of PGPB (CP4+AHP3) combined with AMF resulted in a significant increase in antioxidants. The spatial colonization of AMF in roots indicated that both the isolates CP4 and AHP3 were able to enhance the AMF colonization in root tissue. Furthermore, soil enzymes' activities were higher with the PGPB and AMF combination giving the best results. A positive correlation was recorded between plant growth, grain yield and soil physicochemical parameters. CONCLUSIONS: Our findings confirm that the combined treatment of CP4 and AHP3 and AMF functions as an effective microbial consortium with excellent application prospects for wheat biofortification, grain yield and soil fertility compared with chemical fertilizers. SIGNIFICANCE AND IMPACT OF STUDY: The extensive application of chemical fertilizers on low-yielding field sites is a severe concern for cereal crops, especially wheat in the Asian continent. This study serves as a primer for implementing site-specific sustainable agricultural-management practices using a green technology leading to significant gains in agriculture.

Wheat grain proteomic and protein-metabolite interactions analyses provide insights into plant growth promoting bacteria-arbuscular mycorrhizal fungi-wheat interactions.

KEY MESSAGE: Proteomic, protein-protein and protein-metabolite interaction analyses in wheat inoculated with PGPB and AMF identified key proteins and metabolites that may have a role in enhancing yield and biofortification. Plant growth-promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) have an impact on grain yield and nutrition. This dynamic yet complex interaction implies a broad reprogramming of the plant's metabolic and proteomic activities. However, little information is available regarding the role of native PGPB and AMF and how they affect the plant proteome, especially under field conditions. Here, proteomic, protein-protein and protein-metabolite interaction studies in wheat triggered by PGPB, Bacillus subtilis CP4 either alone or together with AMF under field conditions was carried out. The dual inoculation with native PGPB (CP4) and AMF promoted the differential abundance of many proteins, such as histones, glutenin, avenin and ATP synthase compared to the control and single inoculation. Interaction study of these differentially expressed proteins using STRING revealed that they interact with other proteins involved in seed development and abiotic stress tolerance. Furthermore, these interacting proteins are involved in carbon fixation, sugar metabolism and biosynthesis of amino acids. Molecular docking predicted that wheat seed storage proteins, avenin and glutenin interact with secondary metabolites, such as trehalose, and sugars, such as xylitol. Mapping of differentially expressed proteins to KEGG pathways showed their involvement in sugar metabolism, biosynthesis of secondary metabolites and modulation of histones. These proteins and metabolites can serve as markers for improving wheat-PGPB-AMF interactions leading to higher yield and biofortification.

Anti-inflammatory Effects of Northern Highbush Blueberry Extract on an In Vitro Inflammatory Bowel Disease Model.

Blueberry anthocyanins have the ability to efficiently reach the GI tract and exhibit a broad range of biochemical effects. In the context of inflammatory bowel disease (IBD), they remain a promising complement to current IBD treatments. Here, we investigated the anti-inflammatory and antioxidant capabilities of Highbush blueberries in-vitro on two normal colon epithelial cell lines, NCM 356 and CCD 841 CoN using fluorescent microscopy and flow cytometry following stimulation with a pro-inflammatory cytokine cocktail. Treatment with blueberry extract revealed a significant decrease in nuclear and cytoplasmic generated reactive oxygen species (ROS) compared to controls. Additionally, the blueberry extract increased cell viability following treatment with the pro-inflammatory cytokine cocktail. A comparison with previous report on rice callus suspension culture (RCSC) revealed opposing trend with reference to the levels of nuclear and cytoplasmic ROS. It is likely that blueberry extract and RCSC employ different players and pathways to mitigate inflammation.

Nutrient enhancement of chickpea grown with plant growth promoting bacteria in local soil of Bathinda, Northwestern India.

Plant growth promoting bacteria (PGPB) enhance crop productivity as part of green technology to reduce the use of chemical fertilizers. They also have the capability to enhance macro- and micronutrient content of plants. In the present study, PGPB isolates belonging to Pseudomonas citronellis (PC), Pseudomonas sp. RA6, Serratia sp. S2, Serratia marcescens CDP13, and Frateuria aurantia (Symbion-K) were tested on two chickpea varieties, PBG1 and PBG5 grown for 30 days in local soil from Bathinda region in Northwestern India. PC and CDP13 were found to be better chickpea growth stimulators compared to the commercial Symbion-K based on shoot length and biomass. Most PGPB enhanced macro- and micronutrients in shoots to varying degrees compared to the control. PBG5 gave better response compared to PBG1 with reference to plant growth attributes and enhancement of the macronutrients, calcium, nitrogen and phosphorus and micronutrients, boron, copper, iron, and zinc. PBG5 is a high yielding variety with better resistance compared to PBG1. Overall, PGPB isolated from the local soil and PGPB from other parts of India were shown to be useful for enhancement of nutrient content and plant growth.

Proteomics provides insights into biological pathways altered by plant growth promoting bacteria and arbuscular mycorrhiza in sorghum grown in marginal soil.

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.

Identification of Biochemical Pathways Associated with Lead Tolerance and Detoxification in Chrysopogon zizanioides L. Nash (Vetiver) by Metabolic Profiling.

Lead (Pb) is a major urban pollutant, due to deteriorating lead-based paint in houses built before 1978. Phytoremediation is an inexpensive and effective technique for remediation of Pb-contaminated homes. Vetiver (Chrysopogon zizanioides), a noninvasive, fast-growing grass with high biomass, can tolerate and accumulate large quantities of Pb in its tissues. Lead is known to induce phytochelatins and antioxidative enzymes in vetiver; however, the overall impact of Pb stress on metabolic pathways of vetiver is unknown. In the current study, vetiver plants were treated with different concentrations of Pb in a hydroponic setup. Metabolites were extracted and analyzed using LC/MS/MS. Multivariate analysis of metabolites in both root and shoot tissue showed tremendous induction in key metabolic pathways including sugar metabolism, amino acid metabolism, and an increase in production of osmoprotectants, such as betaine and polyols, and metal-chelating organic acids. The data obtained provide a comprehensive insight into the overall stress response mechanisms in vetiver.

Rice callus suspension culture inhibits growth of cell lines of multiple cancer types and induces apoptosis in lung cancer cell line.

BACKGROUND: Cancer is one of the leading cause of mortality. Even though efficient drugs are being produced to treat cancer, conventional medicines are costly and have adverse effects. As a result, alternative treatments are being tried due to their low cost and little or no adverse effects. Our previous study identified one such alternative in rice callus suspension culture (RCSC) which was more efficient than Taxol® and Etoposide, in reducing the viability of human colon and renal cancer cells in culture with minimal or no effect on a normal cell line. METHODS: In this study, we tested the effect of RCSC by studying the dynamics of lactate dehydrogenase (LDH) in lung cancer cell lines (NCI-H460 and A549), breast cancer cell lines (MDA-MB-231 and MCF-7) and colorectal cancer cell lines (SW620 and Caco-2) as well as their normal-prototypes. Complementary analysis for evaluating membrane integrity was performed by estimating LDH release in non-lysed cells and cell viability with WST-1 assay. Fluorescence microscopy with stains targeting nucleus and cell membrane as well as caspase 3/7 and Annexin V assays were performed. Real-time quantitative RT-PCR was performed to evaluate expression of 92 genes associated with molecular mechanisms of cancer in RCSC treated ling cancer cell line, NCI-H460 and its normal prototype, MRC-5. High performance liquid chromatography (HPLC) was used to collect RCSC fractions, which were evaluated on NCI-H460 for their anti-cancer activity. RESULTS: Lower dilutions of RCSC showed maximum reduction in total LDH indicating reduced viability in majority of the cancer cell lines tested with minimal or no effect on normal cell lines compared to the control. Complementary analysis based on LDH release in non-lysed cells and WST-1 assay mostly supported total LDH results. RCSC showed the best effect on the lung non-small carcinoma cell line, NCI-H460. Fluorescence microscopy analyses suggested apoptosis as the most likely event in NCI-H460 treated with RCSC. Gene expression analysis identified significant upregulation of cJUN, NF-κB2 and ITGA2B in NCI-H460 which resulted most likely in the arrest of cell cycle progression and induction of apoptotic process. Further, HPLC-derived RCSC fractions were less effective in reducing cell viability than whole RCSC suggesting that a holistic approach of using RCSC is a better approach in inhibiting cancer cell proliferation. CONCLUSIONS: RCSC was found to be an effective anti-cancer agent on cell lines of multiple cancer types with the best effect on lung cancer cell lines. A possible mechanism for the anticancer activity of RCSC is through induction of apoptosis as observed in the lung cancer cell line, NCI-H460.

Differential regulation of genes by retrotransposons in rice promoters.

Rice genome harbors genes and promoters with retrotransposon insertions. There is very little information about their function. The effect of retrotransposon insertions in four rice promoter regions on gene regulation, was investigated using promoter-reporter gene constructs with and without retrotransposons. Differences in expression levels of gus and egfp reporter genes in forward orientation and rfp in reverse orientation were evaluated in rice plants with transient expression employing quantitative RT-PCR analysis, histochemical GUS staining, and eGFP and RFP fluorescent microscopy. The presence of SINE in the promoter 1 (P1) resulted in higher expression levels of the reporter genes, whereas the presence of LINE in P2 or gypsy LTR retrotransposon in P3 reduced expression of the reporter genes. Furthermore, the SINE in P1 acts as an enhancer in contrast with the LINE in P2 and the gypsy LTR retrotransposon in P3 which act as silencers. CTAA and CGG motifs in these retrotransposons are the likely candidates for the downregulation compared to TCTT motif (SINE) which is a candidate for the upregulation of gene expression. The effect of retrotransposons on gene regulation correlated with the earlier investigation of conservation patterns of these four retrotransposon insertions in several rice accessions implying their evolutionary significance.

Machine learning approaches distinguish multiple stress conditions using stress-responsive genes and identify candidate genes for broad resistance in rice.

Abiotic and biotic stress responses are traditionally thought to be regulated by discrete signaling mechanisms. Recent experimental evidence revealed a more complex picture where these mechanisms are highly entangled and can have synergistic and antagonistic effects on each other. In this study, we identified shared stress-responsive genes between abiotic and biotic stresses in rice (Oryza sativa) by performing meta-analyses of microarray studies. About 70% of the 1,377 common differentially expressed genes showed conserved expression status, and the majority of the rest were down-regulated in abiotic stresses and up-regulated in biotic stresses. Using dimension reduction techniques, principal component analysis, and partial least squares discriminant analysis, we were able to segregate abiotic and biotic stresses into separate entities. The supervised machine learning model, recursive-support vector machine, could classify abiotic and biotic stresses with 100% accuracy using a subset of differentially expressed genes. Furthermore, using a random forests decision tree model, eight out of 10 stress conditions were classified with high accuracy. Comparison of genes contributing most to the accurate classification by partial least squares discriminant analysis, recursive-support vector machine, and random forests revealed 196 common genes with a dynamic range of expression levels in multiple stresses. Functional enrichment and coexpression network analysis revealed the different roles of transcription factors and genes responding to phytohormones or modulating hormone levels in the regulation of stress responses. We envisage the top-ranked genes identified in this study, which highly discriminate abiotic and biotic stresses, as key components to further our understanding of the inherently complex nature of multiple stress responses in plants.

Integrated metabolomic and proteomic approaches dissect the effect of metal-resistant bacteria on maize biomass and copper uptake.

Marginal soils arise due to various industrial and agricultural practices reducing crop productivity. Pseudomonas sp. TLC 6-6.5-4 is a free-living multiple-metal-resistant plant-growth-promoting bacteria (PGPB) isolated from Torch Lake sediment that promotes maize growth and nutrient uptake. In this study, we examined both PGPB-soil and PGPB-plant interactions. PGPB inoculation resulted in significant increase in maize biomass. Soil inoculation before sowing seeds and coating seeds with the PGPB resulted in higher copper uptake by maize compared to other methods. The PGPB-soil interaction improved phosphorus uptake by maize and led to significant decrease in organic bound copper in marginal soil and a notable increase in exchangeable copper. PGPB improved soil health based on soil enzyme activities. Metabolomic analysis of maize revealed that PGPB inoculation upregulated photosynthesis, hormone biosynthesis, and tricarboxylic acid cycle metabolites. Proteomic analysis identified upregulation of proteins related to plant development and stress response. Further, the activity of antioxidant enzymes and total phenolics decreased in plants grown in marginal soil suggesting alleviation of metal stress in presence of PGPB. The ability of PGPB to modulate interconnected biochemical pathways could be exploited to increase crop productivity in marginal soils, phytoremediation of metal contaminated soils, and organic agriculture.

Retrotransposon insertions in rice gene pairs associated with reduced conservation of gene pairs in grass genomes.

Small-scale changes in gene order and orientation are common in plant genomes, even across relatively short evolutionary distances. We investigated the association of retrotransposons in and near rice gene pairs with gene pair conservation, inversion, rearrangement, and deletion in sorghum, maize, and Brachypodium. Copia and Gypsy LTR-retrotransposon insertions were found to be primarily associated with reduced frequency of gene pair conservation and an increase in both gene pair rearrangement and gene deletions. SINEs are associated with gene pair rearrangement, while LINEs are associated with gene deletions. Despite being more frequently associated with retrotransposons than convergent and tandem pairs, divergent gene pairs showed the least effects from that association. In contrast, convergent pairs were least frequently associated with retrotransposons yet showed the greatest effects. Insertions between genes were associated with the greatest effects on gene pair arrangement, while insertions flanking gene pairs had significant effects only on divergent pairs.

MicroRNAs Involved in Nutritional Regulation During Plant-Microbe Symbiotic and Pathogenic Interactions with Rice as a Model.

Plants are constantly challenged with numerous adverse environmental conditions, including biotic and abiotic stresses. Coordinated regulation of plant responses requires crosstalk between regulatory pathways initiated by different external cues. Stress induced by excessiveness or deficiency of nutrients has been shown to positively or negatively interact with pathogen-induced immune responses. Also, colonization by arbuscular mycorrhizal (AM) fungi can improve plant nutrition, mainly phosphorus and resistance to pathogen infection. The proposed review addresses these issues about a new question that integrates adaptation to nutrient stress and disease resistance. The main goal of the current review is to provide insights into the interconnected regulation between nutrient signaling and immune signaling pathways in rice, focusing on phosphate, potassium and iron signaling. The underpinnings of plant/pathogen/AM fungus interaction concerning rice/M. oryzae/R. irregularis is highlighted. The role of microRNAs (miRNAs) involved in Pi (miR399, miR827) and Fe (miR7695) homeostasis in pathogenic/symbiotic interactions in rice is discussed. The intracellular dynamics of membrane proteins that function in nutrient transport transgenic rice lines expressing fluorescent protein fusion genes are outlined. Integrating functional genomic, nutritional and metal content, molecular and cell biology approaches to understand how disease resistance is regulated by nutrient status leading to novel concepts in fundamental processes underlying plant disease resistance will help to devise novel strategies for crop protection with less input of pesticides and fertilizers.

Anticancer activity of rice callus suspension culture.

A multitude of natural products from plant extracts have been tested for their ability to inhibit the progression of several diseases including cancer. A novel approach of evaluating plant (rice) callus suspension cultures for anticancer activity is reported. The ability of different dilutions of rice callus suspension cultures to inhibit growth of two human cancer cell lines was tested employing varying cell numbers and different incubation times. A crystal violet assay was performed to assess cell viability of the cancer cell lines. Furthermore, microscopic analysis was carried out to determine the effect of the rice callus culture on the morphology of the cancer cells. Rice callus suspension cultures significantly inhibited the growth of human cancer and renal cell lines at densities of 5000 and 10000 cells/mL when incubated for 72 and 96 h. Rice callus suspension culture was more efficient than paclitaxel (Taxol®) and etoposide in selectively killing human colon and renal cancer cell lines compared with a control cell line (human lung fibroblasts). The use of plant callus suspension cultures is a novel approach for inhibiting the growth of cancer cells, which will lead to the development of new agents for selectively killing cancer cells.

Transposons: Unexpected players in cancer.

Transposons are repetitive DNA sequences encompassing about half of the human genome. They play a vital role in genome stability maintenance and contribute to genomic diversity and evolution. Their activity is regulated by various mechanisms considering the deleterious effects of these mobile elements. Various genetic risk factors and environmental stress conditions affect the regulatory pathways causing alteration of transposon expression. Our knowledge of the biological role of transposons is limited especially in various types of cancers. Retrotransposons of different types (LTR-retrotransposons, LINEs and SINEs) regulate a plethora of genes that have a role in cell reprogramming, tumor suppression, cell cycle, apoptosis, cell adhesion and migration, and DNA repair. The regulatory mechanisms of transposons, their deregulation and different mechanisms underlying transposon-mediated carcinogenesis in humans focusing on the three most prevalent types, lung, breast and colorectal cancers, were reviewed. The modes of regulation employed include alternative splicing, deletion, insertion, duplication in genes and promoters resulting in upregulation, downregulation or silencing of genes.

Pseudomonas citronellolis alleviates arsenic toxicity and maintains cellular homeostasis in chickpea (Cicer arietinum L.).

Arsenic is a hazardous metalloid that causes detrimental effects on plant growth and metabolism. Plants accumulate arsenic in edible parts that consequently enter the food chain leading to many health problems. Metal tolerant plant growth-promoting bacteria (PGPB) ameliorate heavy metal toxicity. In this study, the effect of arsenic (As5+) and the role of PGPB Pseudomonas citronellolis (PC) in mitigating As5+ toxicity and associated metabolic alterations in chickpea were assessed. Five chickpea varieties (PBG1, GPF2, PDG3, PDG4 and PBG5) were evaluated for arsenic accumulation, translocation, and its interference with metabolic and defense processes. As5+ (40 mg kg-1) interfered with plant metabolism and enhanced the antioxidative and carbohydrate metabolizing enzyme's activity but PC treatment maintained the activity at par with control. PC also facilitated the accumulation of As5+ in the root system and restricted its translocation to the shoot. Further, to map the metabolic changes, Gas chromatography Mass Spectroscopy (GC-MS) based metabolite profiling and gene expression analysis (qRT-PCR) were performed in the best and worst-performing chickpea varieties (PBG1 and PBG5). 48 metabolites of various metabolic pathways (amino acid, carbohydrate, and fatty acid) were altered in As5+ and PC treatment. Gene expressions showed correlation with biochemical analysis of the antioxidative enzymes and carbohydrate metabolizing enzymes while PC treatment improved chlorophyll biosynthesis enzyme CaDALA expression in As5+ treated plants. Therefore, PC mitigates As5+ toxicity by restricting it in the roots thereby maintaining the cellular homeostasis under As5+ stress in chickpeas.

Synergistic Effect of Azotobacter nigricans and Nitrogen Phosphorus Potassium Fertilizer on Agronomic and Yieldtraits of Maize (Zea mays L.).

Plant growth-promoting bacteria (PGPB) Azotobacter spp. is the most promising bacteria among all microorganisms. It is an aerobic, free-living, and N2-fixing bacterium that commonly lives in soil, water, and sediments. It can be used as a biofertilizer for plant growth and nutrient utilization efficiency. Maize is the highly consumed cereal food crop of the cosmopolitan population, and the sustainable maize productivity achieved by applying bacteria in combination with nitrogen phosphorus potassium (NPK) is promising. In the present study, a bacterial isolate (PR19). Azotobacter nigricans, obtained from the soil of an organic farm was evaluated for its plant growth promoting potential alone and in combination with an inorganic fertilizer (NPK) included. The bacterial cultue (PR19) was screened for its morphological, biochemical, and plant growth-promoting characteristics, sequenced by the 16S rDNA method, and submitted to NCBI for the confirmation of strain identification. Further, the inoculation effect of the bacterial culture (PR19) in combination with NPK on growth and yield parameters of maize under pot were analyzed. Based on phenotypic and molecular characteristics, PR19 was identified as Azotobacter nigricans it was submitted to NCBI genbank under the accession No. KP966496. The bacterial isolate possessed multiple plant growth-promoting (MPGP) traits such as the production of ammonia, siderophore, indole-3-acetic acid (IAA), and ACC Deaminase (ACCD). It showed phosphate solubilization activity and tolerance to 20% salt, wide range of pH 5-9, higher levels of trace elements and heavy metals, and resistance to multiple antibiotics. PR19 expressed significantly increased (p < 0.001) antioxidant enzyme activities (SOD, CAT, and GSH) under the abiotic stress of salinity and pH. In vitro condition, inoculation of maize with the PR19 showed a significant increase in seed germination and enhancement in elongation of root and shoot compared to untreated control. The combined application of the PR19 and NPK treatments showed similar significant results in all growth and yield parameters of maize variety SHIATS-M S2. This study is the first report on the beneficial effects of organic farm isolated PR19-NPK treatment combinations on sustainable maize productivity.

Application of CRISPR-Cas9 in plant-plant growth-promoting rhizobacteria interactions for next Green Revolution.

Agriculture's beginnings resulted in the domestication of numerous plant species as well as the use of natural resources. Food grain production took about 10,000 years to reach a billion tonnes in 1960, however, it took only 40 years to achieve 2 billion tonnes in year 2000. The creation of genetically modified crops, together with the use of enhanced agronomic practices, resulted in this remarkable increase, dubbed the "Green Revolution". Plants and bacteria that interact with each other in nature are co-evolving, according to Red Queen dynamics. Plant microorganisms, also known as plant microbiota, are an essential component of plant life. Plant-microbe (PM) interactions can be beneficial or harmful to hosts, depending on the health impact. The significance of microbiota in plant growth promotion (PGP) and stress resistance is well known. Our understanding of the community composition of the plant microbiome and important driving forces has advanced significantly. As a result, utilising the plant microbiota is a viable strategy for the next Green Revolution for meeting food demand. The utilisation of newer methods to understand essential genetic and molecular components of the multiple PM interactions is required for their application. The use of clustered regularly interspaced short palindromic repeats (CRISPR)/Cas-mediated genome editing (GE) techniques to investigate PM interactions is of tremendous interest. The implementation of GE techniques to boost the ability of microorganisms or plants for agronomic trait development will be enabled by a comprehensive understanding of PM interactions. This review focuses on using GE approaches to investigate the principles of PM interactions, disease resistance, PGP activity, and future implications in agriculture in plants or associated microbiota.

Co-occurrence and patterns of phosphate solubilizing, salt and metal tolerant and antibiotic-resistant bacteria in diverse soils.

Soil is a treasure chest for beneficial bacteria with applications in diverse fields, which include agriculture, rhizoremediation, and medicine. Metagenomic analysis of four soil samples identified Proteobacteria as the dominant phylum (32-52%) followed by the phylum Acidobacteria (11-21% in three out of four soils). Bacteria that were prevalent at the highest level belong to the genus Kaistobacter (8-19%). PICRUSt analysis predicted KEGG functional pathways associated with the metagenomes of the four soils. The identified pathways could be attributed to metal tolerance, antibiotic resistance and plant growth promotion. The prevalence of phosphate solubilizing bacteria (PSB) was investigated in four soil samples, ranging from 26 to 59% of the total culturable bacteria. The abundance of salt-tolerant and metal-tolerant bacteria showed considerable variation ranging from 1 to 62% and 4-69%, respectively. In comparison, the soil with the maximum prevalence of temperature-tolerant and antibiotic-resistant bacteria was close 30%. In this study, the common pattern observed was that PSB were the most abundant in all types of soils compared to other traits. Conversely, most of the isolates, which are salt-tolerant, copper-tolerant, and ampicillin-resistant, showed phosphate solubilization activity. The sequencing of the partial 16S-rRNA gene revealed that PSB belonged to Bacillus genera. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02904-7.