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.

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.

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.

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.

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.

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.

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.

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.

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.

Plant Growth Promoting Rhizobacteria, Arbuscular Mycorrhizal Fungi and Their Synergistic Interactions to Counteract the Negative Effects of Saline Soil on Agriculture: Key Macromolecules and Mechanisms.

Soil saltiness is a noteworthy issue as it results in loss of profitability and development of agrarian harvests and decline in soil health. Microorganisms associated with plants contribute to their growth promotion and salinity tolerance by employing a multitude of macromolecules and pathways. Plant growth promoting rhizobacteria (PGPR) have an immediate impact on improving profitability based on higher crop yield. Some PGPR produce 1-aminocyclopropane-1-carboxylic (ACC) deaminase (EC 4.1.99.4), which controls ethylene production by diverting ACC into α-ketobutyrate and ammonia. ACC deaminase enhances germination rate and growth parameters of root and shoot in different harvests with and without salt stress. Arbuscular mycorrhizal fungi (AMF) show a symbiotic relationship with plants, which helps in efficient uptake of mineral nutrients and water by the plants and also provide protection to the plants against pathogens and various abiotic stresses. The dual inoculation of PGPR and AMF enhances nutrient uptake and productivity of several crops compared to a single inoculation in both normal and stressed environments. Positively interacting PGPR + AMF combination is an efficient and cost-effective recipe for improving plant tolerance against salinity stress, which can be an extremely useful approach for sustainable agriculture.

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.

Bacteria from native soil in combination with arbuscular mycorrhizal fungi augment wheat yield and biofortification.

Plant growth promoting bacteria (PGPB) have been used to enhance crop productivity. The effect of native PGPB and arbuscular mycorrhizal (AM) fungi in combination on wheat yield, biofortification and soil enzymatic activity is a relatively unexplored area. Twenty seven bacterial isolates from three different soils were characterized for their plant growth promoting traits. A total of three native and five non-native bacteria were used with and without arbuscular mycorrhizal (AM) fungi in an open greenhouse pot experiment with two wheat varieties to evaluate their effect on wheat yield, nutrient uptake, and soil health parameters. Wheat plants subjected to native PGPB (CP4) (Bacillus subtilis) and AM fungi treatment gave the best results with reference to macronutrient (nitrogen and phosphorus), micronutrient (iron and zinc) content in wheat grains and yield-related parameters, including thousand grain weight, number of grains per spike and total tillers per plant in both wheat cultivars. Treatment with CP4 and CP4 plus AM fungi enhanced total chlorophyll in wheat leaves indicating higher photosynthetic activity. Significant improvement in soil health-related parameters, including soil organic matter and dehydrogenase activity, was observed. Significant correlation among grain yield-related parameters, nutrient enhancement, and soil health parameters was observed in PGPB and AM fungi treated plants, especially HD-3086. These results provide a roadmap for utilizing native PGPB and AM fungi for enhancing wheat production in Punjab state of India and exploring their utility in other parts of the country with different soil and environmental conditions.

Brown gold of marginal soil: Plant growth promoting bacteria to overcome plant abiotic stress for agriculture, biofuels and carbon sequestration.

Marginal land is defined as land with poor soil characteristics and low crop productivity with no potential for profit. Poor soil quality due to the presence of xenobiotics or climate change is of great concern. Sustainable food production with increasing population is a challenge which becomes more difficult due to poor soil quality. Marginal soil can be made productive with the use of Plant Growth Promoting Bacteria (PGPB). This review outlines how PGPB can be used to improve marginal soil quality and its implications on agriculture, rhizoremediation, abiotic stress (drought, salinity and heavy metals) tolerance, carbon sequestration and production of biofuels. The feasibility of the idea is supported by several studies which showed maximal increase in the growth of plants inoculated with PGPB than to uninoculated plants grown in marginal soil when compared to the growth of plants inoculated with PGPB in healthy soil. The combination of PGPB and plants grown in marginal soil will serve as a green technology leading to the next green revolution, reduction in soil pollution and fossil fuel use, neutralizing abiotic stress and climate change effects.

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.

Anti-inflammatory and immune-modulating effects of rice callus suspension culture (RCSC) and bioactive fractions in an in vitro inflammatory bowel disease model.

BACKGROUND: Rice callus suspension culture (RCSC) has been shown to exhibit potent antiproliferative activity in multiple cancer cell lines. RCSC and its bioactive compounds can fill the need for drugs with no side effects. HYPOTHESIS/PURPOSE: The anti-inflammatory potential of RCSC and its bioactive fractions on normal colon epithelial cell lines, was investigated. STUDY DESIGN: Three cell lines, InEpC, NCM356 and CCD841-CoN were treated with proinflammatory cytokines followed by RCSC. Cytoplasmic and nuclear ROS were assayed with fluorescent microscopy and flow cytometer. Expression analysis of immune-related genes was performed in RCSC-treated cell lines. RCSC was fractionated using column chromatography and HPLC. Pooled fractions 10-18 was used to test for antiproliferative activity using colon adenocarcinoma cell line, SW620 and anti-inflammatory activity using CCD841-CoN. Mass spectrometric analysis was performed to identify candidate compounds in four fractions. RESULTS: RCSC treatment showed differential effects with higher cytoplasmic ROS levels in NCM356 and CCD841-CoN and lower ROS levels in InEpC. Nuclear generated ROS levels increased in all three treated cell lines. Flow cytometry analysis of propidium iodide stained cells indicated mitigation of cell death caused by inflammation in RCSC treated groups in both NCM356 and CCD841-CoN. Genes encoding transcription factors and cytokines were differentially regulated in NCM356 and CCD841-CoN cell lines treated with RCSC which provided insights into possible pathways. Analysis of pooled fractions 10-18 by HPLC identified 8 peaks. Cell viability assay with fractions 10-18 using SW620 showed that the number of viable cells were greatly reduced which was similar to 6X and 33X RCSC with very little effect on normal cells which similar to 1X RCSC. RCSC fractions increased nuclear and cytoplasmic ROS vs. both untreated and inflammatory control. Analysis of four fractions by mass spectrometry identified 4-deoxyphloridzin, 5'-methoxycurcumin, piceid and lupeol as candidate compounds which are likely to be responsible for the antiproliferative, anti-inflammatory and immune-regulating properties of RCSC. CONCLUSION: RCSC and its fractions showed anti-inflammatory activity on inflamed colon epithelial cells. Downstream target candidate genes which are likely to mediate RCSC effects were identified. Candidate compounds responsible for the antiproliferative and anti-inflammatory activity of RCSC and its fractions provide possible drug targets.

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.

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.

Mycorrhiza and heavy metal resistant bacteria enhance growth, nutrient uptake and alter metabolic profile of sorghum grown in marginal soil.

The main challenge for plants growing in nutrient poor, contaminated soil is biomass reduction, nutrient deficiency and presence of heavy metals. Our aim is to overcome these challenges using different microbial combinations in mining-impacted soil and focus on their physiological and biochemical impacts on a model plant system, which has multiple applications. In the current study, sorghum BTx623 seedlings grown in mining-impacted soil in greenhouse were subjected to plant growth promoting bacteria (PGPB or B) alone, PGPB with arbuscular mycorrhizal fungi (My), My alone and control group with no treatment. Root biomass and uptake of most of the elements showed significant increase in all treatment groups in comparison with control. Mycorrhiza group showed the best effect followed by My + B and B groups for uptake of majority of the elements by roots. On the contrary, biomass of both shoot and root was more influenced by B treatment than My + B and My treatments. Metabolomics identified compounds whose levels changed in roots of treatment groups significantly in comparison to control. Upregulation of stearic acid, sorbitol, sebacic acid and ferulic acid correlated positively with biomass and uptake of almost all elements. Two biochemical pathways, fatty acid biosynthesis and galactose metabolism, were regulated in all treatment groups. Three common pathways were upregulated only in My and My + B groups. Our results suggest that PGPB enhanced metabolic activities which resulted in increase in element uptake and sorghum root biomass whether accompanied with mycorrhiza or used solely.

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.