Identification of stress-responsive genes in an indica rice (Oryza sativa L.) using ESTs generated from drought-stressed seedlings

The impacts of drought on plant growth and development limit cereal crop production worldwide. Rice (Oryza sativa) productivity and production is severely affected due to recurrent droughts in almost all agroecological zones. With the advent of molecular and genomic technologies, emphasis is now placed on understanding the mechanisms of genetic control of the drought-stress response. In order to identify genes associated with water-stress response in rice, ESTs generated from a normalized cDNA library, constructed from drought-stressed leaf tissue of an indica cultivar, Nagina 22 were used. Analysis of 7794 cDNA sequences led to the identification of 5815 rice ESTs. Of these, 334 exhibited no significant sequence homology with any rice ESTs or full-length cDNAs in public databases, indicating that these transcripts are enriched during drought stress. Analysis of these 5815 ESTs led to the identification of 1677 unique sequences. To characterize this drought transcriptome further and to identify candidate genes associated with the drought-stress response, the rice data were compared with those for abiotic stress-induced sequences obtained from expression profiling studies in Arabidopsis, barley, maize, and rice. This comparative analysis identified 589 putative stress-responsive genes (SRGs) that are shared by these diverse plant species. Further, the identified leaf SRGs were compared to expression profiles for a drought-stressed rice panicle library to identify common sequences. Significantly, 125 genes were found to be expressed under drought stress in both tissues. The functional classification of these 125 genes showed that a majority of them are associated with cellular metabolism, signal transduction, and transcriptional regulation

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

Peer reviewe

Mutational, proteomic and metabolomic analysis of a plant growth promoting copper-resistant Pseudomonas spp.

Pseudomonas sp. TLC6-6.5-4 is a multiple metal resistant plant growth-promoting bacteria isolated from copper-contaminated lake sediments. In this study, a comprehensive analysis of genes involved in copper resistance was performed by generating a library of transposon (Tn5) mutants. Two copper-sensitive mutants with significant reduction in copper resistance were identified: CSM1, a mutant disrupted in trpA gene (tryptophan synthase alpha subunit), and CSM2, a mutant disrupted in clpA gene (ATP-dependent Clp protease). Proteomic and metabolomic analyses were performed to identify biochemical and molecular mechanisms involved in copper resistance using CSM2 due to its lower minimum inhibitory concentration compared with CSM1 and the wild type. Proteomic analysis revealed that disruption of Clp protease gene up-regulated molecular chaperones and down-regulated the expression of enzymes related to tRNA modification, whereas metabolomic analysis showed that amino acid and oligosaccharide transporters that are part of ATP-binding cassette (ABC) transporters pathways were down-regulated. Further, copper stress altered metabolic pathways including the tricarboxylic acid cycle, protein absorption and glyoxylate metabolism. © 2012 Federation of European Microbiological Societies

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

Comparative metabolic profiling of vetiver (Chrysopogon zizanioides) and maize (Zea mays) under lead stress

© 2017 Elsevier Ltd Lead (Pb) contamination of residential soils in United States is attributed to use of Pb based paints prior to 1978 and their deterioration and accumulation in surface soils. Exposure to Pb due to ingestion and inhalation of Pb laden soil and dust causes neurological disorders, renal disorders, developmental and behavioral problems, particularly in children under the age of six. Vetiver grass is one of the leading choices for Pb remediation due to its ability to hyperaccumulate Pb, in addition to high biomass. In order to understand the effect of Pb on vetiver metabolic pathways, we compared the global metabolic changes in vetiver with that of maize, a Pb susceptible plant under Pb stress. Vetiver showed massive increase in levels of key metabolites in response to Pb, including amino acids, organic acids and coenzymes. Maize showed very modest increase in some of the same metabolites, and no change in others. The results provide the first indication of the difference in metabolic response of the hyperaccumulator, vetiver to lead stress as compared to maize

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

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

Detection of genetic variability using random amplified polymorphic DNA markers in some accessions of moringa oleifera Lam. from northern Nigeria

To investigate genetic variability in Moringa oleifera Lam., 75 accessions from the Sudan and Guinea savanna zones in Nigeria were taxonomically analysed using Random Amplified polymorphic DNA (RAPD) markers. The electrophoresis bands were analysed using NTSYSpc software and the result of their matrices indicated different variability in the accessions. High degrees of polymorphism (74%) among the accessions were observed in terms of genetic relationship and were grouped into five clusters. This high variability can be utilised for mapping out breeding strategies in the production of cultivars with better yield of M. oleifera to meet the pressing needs of these multi-purpose crop to our growing populations

Autoimmune-like pulmonary disease in association with parvovirus B19 - A clinical, morphologic, and molecular study of 12 cases

Parvovirus B19, the agent responsible for fifth disease, has been emerging as a significant pathogenetic factor in various acute vasculitic syndromes such as Wegener's granulomatosis, Henoch-Schonlein purpura, and Kawasaki disease. It has also been implicated in more chronic vasculopathic syndromes, specifically in the context of scleroderma and dermatomyositis. The basis of this association is likely multifactorial; implicated mechanisms include the virus's affinity for endothelium, resulting in a state of neoantigenicity through varied mechanisms as well as the induction of tumor necrosis factor alpha, a factor involved in the propagation of ANCA-positive vasculitic syndromes. The authors present a series of 12 patients with interstitial lung disease including idiopathic pulmonary fibrosis, scleroderma-associated pulmonary fibrosis, lymphocytic interstitial pneumonitis, and septal capillaritis. In all cases there was evidence of chronic parvovirus B19 infection based on serologic assessment and the isolation of B19 DNA on lung samples in all patients. Furthermore, in two cases there was in situ localization of B19 RNA and tumor necrosis factor alpha to endothelium and stromal cells. On pathologic examination, there were varying degrees of both septal fibrosis and inflammation along with evidence of septal capillary injury. In those cases categorized as representing either sclerodema or idiopathic pulmonary fibrosis, the immunofluorescent studies showed evidence of anti-endothelial cell antibody formation. The ANCA-associated syndromes were, as expected, negative by fluorescent analysis. Significantly elevated factor VIII levels, a standard serologic index of endothelial cell injury, were seen in four of the six patients tested. The antiphospholipid profile revealed antiphospholipids in 7 of the 1 I patients tested. This report highlights a possible causal role for parvovirus B19 in the pathogenesis of select pulmonary disorders