Influence of sulfur on transcriptomic variation of genes involved in arsenic metabolism in rice grains
ABSTRACT: We performed Illumina sequencing to acquire the differentially expressed genes induced by arsenate and sulfur treatments. We found that sulfur (S) application reduced As concentration of rice grains harvested at 20 days after anthesis (DAA). By contrast with the control, the expression of 1001 genes were found to be significantly changed, 46 genes up-regulated and 954 genes down-regulated in the 20As grains. 1169 genes expressed significantly differently between the samples of control and 20As+120S, with 16 genes up-regulated and 1153 genes down-regulated. Among the differentially expressed genes (DEGs) regulated by As and S treatment, there were 10 DEGs encoding phosphate transporter, and 24 DEGs encoding aquaporin transporter. Some genes involved in As detoxification, such as ABC transporter, glutathione S-transferase and phytochelatin synthase were up-regulated by sulfur treatment. The results provide an insight into the molecular basis of how sulfur application regulates As accumulation in rice grains. Arsenic (As) was artificially added to soil with 20 mg/kg As (Na2AsO4.12H2O, 20As), another treatment was 20As+120S, sulfur (S) were supplied artificially with 120 mg/kg (Na2S2O3•5H2O) to the As-added soil (20As+120S).
Project description:Detailed information: Rice (*Oryza sativa* L. cv. Nipponbare) is a drought-susceptible species which is well suited for studies of abiotic stress response because of the comprehensive bioinformatics resource available. By withholding water from the entire root system of young rice plants, or half the root system only, it was possible to infer the relative impact of signals arriving from roots growing in wet and dry soil on the shoot proteome. The global proteome of shoots had 685 proteins in common to all three drought treatments but there were major shifts in abundance of individual proteins within 16 functional categories. The dominant changes were analyzed more deeply. First, we investigated transport and cell component organization, where some proteins were up-regulated by drought but many more down-regulated. Proteins involved in protein metabolism were up-regulated in general by drought when they were responsible for protein degradation but those involved in protein synthesis were down-regulated when water was withheld. Stress-related proteins behaved very consistently by increasing in droughted plants but notably some proteins were most abundant when roots of the same plant were growing in both wet and dry soil. This suggests that drought signals are complex interactions and not simply the additive effect of water supply to the roots. Changes in carbohydrate-processing proteins were consistent with the passive accumulation of soluble sugars in shoots under drought, with hydrolysis of sucrose and starch synthesis both enhanced. Data analysis information: The result raw files were converted to mzXML format and processed through the global proteome machine (GPM) software (version 2.1.1) of the X!Tandem algorithm (freely available at http://www.thegpm.org). The 16 gel fractions were processed serially for each experiment and the output files were generated as non-redundant, merged files with protein identifications with log (e) values less than -1, for each individual gel fraction. A protein database compiled from NCBI *O*. *sativa* with 26938 protein sequences (August 2011) was used in GPM to search the tandem mass spectra; the database also included common trypsin and human peptide contaminants. False discovery rates (FDR) were evaluated by searching against a reversed sequence database. Search parameters included MS and MS/MS tolerances of +2 Da and +0.2 Da, carbamidomethylation of cysteine as fixed modifications, oxidation of methionine as variable modifications and tolerance of two missed tryptic cleavages and K/R-P cleavages.
Project description:Cadmium (Cd)-contamination in soil has been becoming a major environmental problem in China. Ramie, a fiber crop, was frequently proposed to be used as the crop for phytoremediation of Cd-contaminated farmlands. However, high level Cd accumulation can cause a great inhibition of growth in ramie. To understand the potential mechanism for this phenomenon, the ramie genes involved in the Cd stress response were identified using Illumina pair-end sequencing in two Cd-stressed plants (CdS1 and CdS2) and two control plants (CO1 and CO2) in this study. Approximately 48.7, 51.6, 41.2, and 47.1 million clean sequencing reads generated from the libraries of CO1, CO2, CdS1, and CdS2, respectively, were De novo assembled to yield 56,932 non-redundant unigenes. A total of 26,686 (46.9%) genes were annotated for their function. Comparison of gene expression levels between CO and CdS ramie revealed 155 differentially expressed genes (DEGs). Sixteen DEGs was further confirmed their expression difference by real-time quantitative PCR (qRT-PCR). Among these 16 DEGs, 2 genes encoding GA2-oxidase which is a major enzyme for deactivating bioactive gibberellins (GAs) were found with a markedly up-regulated expression, which is possibly responsible for the growth inhibition of Cd-stressed ramie. Pathway enrichment analysis revealed that a pathway (Cutin, suberine and wax biosynthesis) was markedly enriched by DEGs. The discovery of these Cd stress-responsive genes and pathways will be helpful for further understanding the mechanism of Cd-stressed response and improving the ability of Cd stress tolerance in ramie. A total of four samples, two replicates of control plants (CO1 and CO2) and two replicates of cadmium-stressed plants (CdS1 and CdS2) were used for RNA-seq.
Project description:Plasma membrane NADPH oxidases (NOXs) are major producers of reactive oxygen species (ROS) in plant cells under normal growth and stress conditions. Rice NOXs have multiple homologs but their functional mechanisms are largely unknown. We used microarrays to detail the global gene expression profiles in rice wild-type (WT, Dongjin) and a mutant osnox2 which loss the functions of OsNOX2 protein under drought and identified distinct classes of genes between the two type rice plants under both normal growth and drought stressed conditions. The youngest fully expanded leaves from 2.5-month-old WT and osnox2 plants (three replicates each), grown under normal growth (soil moisture, 47.3%) and drought conditions (soil moisture, 8.5%), were used for RNA extraction and hybridization on Affymetrix microarrays. Control: normal growth condition; Drought: drought stress condition.
Project description:Rice in tropical and sub-tropical areas is often subjected to cold stress at the seedling stage resulting in poor growth and yield loss. In general, japonica rice has stronger cold tolerance (CT) than indica rice. However, several favorite alleles for CT exist in indica rice and can be used to enhance CT under japonica background. Genome-wide gene expression profiling is the efficient way to decipher the molecular genetic mechanism of CT enhancement and provide valuable information for the CT improvement in rice molecular breeding. In this study, the transcriptome of a CT introgressed line (IL) K354 and its recurrent parent C418 under cold stress were comparatively analyzed to explore the possible CT enhancement mechanism of K354.Totally 3184 differentially expressed genes (DEGs) including 195 transcription factors were identified in both lines under cold stress, about half of them were commonly regulated, which were involved in the major cold responsive pathways including OsDREB1s regulon. The K354-specific cold-induced DEGs were mainly related to stimulus response, cellular cell wall organization, and microtubule-based movement process compared with commonly cold-induced DEGs by GO analysis. Moreover, 296 constitutive DEGs with significantly different transcription level between C418 and K354 were detected under both control and cold stress conditions. K354-specific cold-regulated and constitutive DEGs jointly account for the CT improvement of K354. Pathway analysis unraveled up-regulation of starch and sucrose metabolism in both genotypes and presumably weaker defense response to stress in K354 than C418 under cold stress. Candidate genes prediction based on previous putative CT genetic networks revealed genotype-dependent CT enhancement mechanism in CT IL K354 vs recurrent parent C418, including Sir2, OsFAD7, OsWAK112d, and PCD related genes, etc.We propose a hypothesis of the CT enhancement mechanism in rice based on the results in present study. Firstly, a number of cold-regulated genes are able to express constitutively at high level or absent under control condition for standing by the arrival of cold stress. Next, under cold stress slower perception of stress signal from the more cold-tolerant membrane can postpone the activation of defensive system which may have possible negative effects on rice growth. Then, PCD will be launched to sacrifice a few cells for maintaining the basal growth of most cells. Finally, the protective responses on multiple aspects of cold damage will be postponed because of delayed several cold-defensive pathways (i.e. OsDREB1C regulon). It might explain why the recovery capacity of K354 from cold stress to control condition is stronger than C418. The CT enhancement mechanism can be regarded as the possible way to improve CT of japonica rice using indica germplasm in rice breeding program. In this study, the specific gene expression patterns of two genotypes (C418 and K354) at 2h, 6h, 12h, 24h and 48h during cold stress treatment (4 C) and control were characterized by using the Affymetrix rice microarray platform.
Project description:We investigated changes in gene expression in rice plants exposed to RDV to gain some insight into the fundamental physiological and biochemical changes that are induced by viral infection, in the hope of finding clues that might help to control the viral disease. An analysis, using microarrays, of gene expression in rice plants infected with Rice dwarf virus revealed significant decreases in levels of expression of genes that are involved in the formation of cell walls, reflecting the stunted growth of diseased plants. The expression of plastid-related genes was also suppressed, as anticipated from the white chlorotic appearance of infected leaves. By contrast, the expression of defense- and stress-related genes was enhanced after viral infection. Experiment Overall Design: To reduce experimental variations, three sets of ten seedlings were harvested from RDV-infected and mock-inoculated plants 9 dpi. Then we pooled leaves from multiple plants as the source of RNA, and employed three sets of microarrays (GSM119715, GSM119718 and GSM119719) using RNAs from different sources and one set of dye-swapping microarrays (GSM119715 and GSM119717).
Project description:To investigate plant-fungus interactions in early stage of infection, we analyzed response of rice against Magnaporthe grisea infection deficient mutants. In M. grisea, Mgb1 and Mst12 are essential for development of infection structures. Deletion of MGB1 results in defect in appresorium formation, and MST12, in penetration peg development. Analysis of gene expression profiles in rice by microarray revealed the mutant-specific and R gene dependent gene expression, strongly suggesting that gene-for-gene interaction commences before the penetration into rice cell. Experiment Overall Design: Agilent rice oligo microarray was used to investigate the gene expression profiling in rice plants infected with Guy11, Mgb1 and Mst12. Total RNAs were isolated from fourth leaves at 24 and 48 hpi. Agilent rice DNA chips were used according to the manufacture’s protocol. After hybridization, arrays were scanned using an Agilent Microarray Scanner, and Feature Extraction version 9.1 was used for image analysis and data extraction. Signal intensities derived from inoculated leaved were compared with that of mock-inoculated leaves. In each treatment, the experiment was performed independently three times.
Project description:Poplars are known to be highly tolerant species to boron toxicity and accumulation. However, genes and molecular networks responsible in boron toxicity tolerance have not been investigated yet. Therefore, we performed a pot experiment with 20 black poplar clones collected from the vicinity of boron mines and polluted areas to investigate its potential role in phytoremediation and to select the most boron toxicity tolerant genotype. Trees were treated with irrigation water containing seven elevated boron concentrations from 0 to 160 ppm. Then a microarray based comparative transcriptome profiling was conducted to identify boron toxicity regulated genes responsible in defence responses of black poplar. The results of the study indicated that black poplar is quite suitable for phytoremediation of boron pollution. It could resist 15 ppm soil B content and < 1600 mg/kg boron accumulation in leaves which are highly toxic concentrations for almost all agricultural plants. Transcriptomics results of study revealed totally 1625 and 1419 altered probe sets under boron toxicity in leaf and root tissues, respectively. The highest induction were recorded for the probes sets annotated to tyrosine aminotransferase, ATP binding cassette transporters, glutathione S transferases and metallochaperone proteins. Strong up regulation of these genes attributed to internal excretion of boron into the cell vacuole and existence of detoxification processes in black poplar. Many candidate genes functional in signalling, gene regulation, antioxidation, boron uptake, transport and detoxification processes were also identified in the current study. This is the first transcriptomic study identifying boron toxicity regulated poplar genes and their potential role in boron toxicity tolerance. Total RNA used in microarray experiment was isolated from the leaves and roots of black poplar clone; N.92.237 which accumulated the highest amount of boron its tissues. Total RNA used in the microarray experiment was isolated from leaves and roots of three black poplar saplings grown in ~ 2 ppm (control) and ~ 15 ppm (toxic) soil B contents. RNA isolation was made according to Lithium chloride precipitation method described in Chang et al. (1993). These three isolated RNAs (biological replicates) for each tissue loaded onto three Affymetrix poplar Gene Chips (technical replicates). Totally, 12 GeneChips (2 tissues × 2 different B treatment × 3 biological replicates) were used for transcriptional analysis.
Project description:Methionine sulfoxide reductases catalyze the reduction of MetSO back to the correct Met residue. Previously, the gene of Capsicum annuum methionine sulfoxide reductase B2 was isolated and CaMSRB2-overexpressing tomato shows enhanced growth, which may trigger increased resistance to the pathogens. To assess the role of this enzyme in rice, we generated transgenic lines under the control of the rice Rab21 (responsive to ABA protein 21) promoter with/without Bar marker gene. Several physiological tests such as MV and Fv/Fm, indicators of an oxidative stress-inducing agent and a potential maximal PSII quantum yield, respectively strongly suggested CaMSRB2 confers drought tolerance to rice. Using 3′-tiling microarray covering the whole rice genes, we carried out genome-wide expression analyses with CaMsrB2-transformed rice (Oryza sativa L. cv. ILMI). Rice was grown in port for six weeks and treated with drought by water withholding for two days. A total of 15 chips were used for the microarray experiment. RNA was extracted from plants just before and 2 days after the duration of water withdrawal for the control and the comparison, respectively. Experiments were performed with three or two biological replicates.
Project description:Near-isogenic lines TW16-4 and TW16-69 were developed from the cross between TN1 (recurrent parent susceptible to RTSV) and Utri Merah (donor parent resistant to RTSV). TW16-4 is susceptible to RTSV, whereas TW16-69 is resistant to RTSV based on a serolog. Experiment Overall Design: Comparison between RTSV and mock-infected rice. Biological replicates: 2 control (mock), 2 RTSV-infected, independently grown and harvested at 7 days after inoculation (DAI). Each sample was prepared using leaf tissues pooled from 5 plants grown under the same conditions.
Project description:Recently, we found a dioecious plant Populus cathayana males possess a greater tolerance to enhanced UV-B radiation than do females. To carry this work forward, comparative transcriptome analyses were carried out. Similar to previous studies, a set of conserved functions and pathways related to UV-B stress were detected in males and females, regardless of the sex. In addition, sex-specific responses via transcriptome remodeling were also detected as shown in the changes of sex-related gene expression occurred in some pathways. For example, a lot of differentially expressed genes (DEGs) involved in amino acid metabolism were mainly up-regulated in males, but down-regulated in females. Moreover, we found some DEGs expressed predominantly or exclusively in one sex, which may directly contribute to sex-related physiological responses. 4 samples examined: (i) males exposure to decreased solar UV-B radiation (MC); (ii) females exposure to decreased solar UV-B radiation (FC); (iii) males exposure to ambient solar UV-B radiation (MU); and (iv) females exposure to ambient solar UV-B radiation (FU). Nine plants of each sex were exposed to each treatment, and RNA samples from the 9 individuals were pooled with equal proportion.