Transcriptome analysis of ectopic chloroplast development in green curd cauliflower (Brassica oleracea L. var. botrytis)

<p>Abstract</p> <p>Background</p> <p>Chloroplasts are the green plastids where photosynthesis takes place. The biogenesis of chloroplasts requires the coordinate expression of both nuclear and chloroplast genes and is regulated by developmental and environmental signals. Despite extensive studies of this process, the genetic basis and the regulatory control of chloroplast biogenesis and development remain to be elucidated.</p> <p>Results</p> <p>Green cauliflower mutant causes ectopic development of chloroplasts in the curd tissue of the plant, turning the otherwise white curd green. To investigate the transcriptional control of chloroplast development, we compared gene expression between green and white curds using the RNA-seq approach. Deep sequencing produced over 15 million reads with lengths of 86 base pairs from each cDNA library. A total of 7,155 genes were found to exhibit at least 3-fold changes in expression between green and white curds. These included light-regulated genes, genes encoding chloroplast constituents, and genes involved in chlorophyll biosynthesis. Moreover, we discovered that the cauliflower <it>ELONGATED HYPOCOTYL5 </it>(<it>BoHY5</it>) was expressed higher in green curds than white curds and that 2616 HY5-targeted genes, including 1600 up-regulated genes and 1016 down-regulated genes, were differently expressed in green in comparison to white curd tissue. All these 1600 up-regulated genes were HY5-targeted genes in the light.</p> <p>Conclusions</p> <p>The genome-wide profiling of gene expression by RNA-seq in green curds led to the identification of large numbers of genes associated with chloroplast development, and suggested the role of regulatory genes in the high hierarchy of light signaling pathways in mediating the ectopic chloroplast development in the green curd cauliflower mutant.</p

Salt-induced and Salt-suppressed Proteins in Tomato Leaves

Tomato (Solanum lycopersicum cv. Money Maker) seedlings at the two-leaf stage were grown in one-half strength Hoagland solution supplemented with 50 mm NaCl for 4 days, with 100 mm NaCl for 4 days, with 150 mm NaCl for 4 days, and with a final concentration 200 mm NaCl for 2 days. Solutions were refreshed every 2 days for treated and untreated seedlings. Non-treated plants were grown in nonamended one-half strength Hoagland solution. Three biological replicates (BR) were included for treated and control experiments. At the end of treatments, the uppermost three newly expanded leaves from all 12 plants in each BR were collected and bulked to extract total protein. Proteomic analysis resulted in the identification of several salt-induced and salt-suppressed proteins. Salt-induced proteins were: vacuolar H+-ATPase A1 subunit isoform (1.6-fold), germin-like protein (1.5-fold), ferredoxin-NADP (+) reductase (1.2-fold), quinone oxidoreductase-like protein (4.4-fold), heat-shock protein (4.9-fold), and pyrophosphorylase (1.7-fold). Salt-suppressed proteins were: ATPase alpha subunit (−1.5-fold) and rubisco activase (−1.4-fold). Proteins identified in this study affect cellular activities for antioxidant, stress protection, carbon fixation, and carbohydrate partitioning in young tomato leaves under salt stress

Draft Genome Sequence of New Bacillus cereus Strain tsu1

This paper reports the draft genome sequence of new Bacillus cereus strain tsu1, isolated on an agar-cellulose plate. The draft genome sequence is 5.81 Mb, revealing 5,673 coding sequences. It contains genes for cellulose-degradation and biosynthesis pathways of polyhydroxybutyrate (PHB) and 8 rRNA genes (5S, 16S, and 23S)

The Al-induced proteomes of epidermal and outer cortical cells in root apex of cherry tomato \u27LA 2710\u27

This paper reports a laser capture microdissection-tandem mass tag-quantitative proteomics analysis of Al-sensitive cells in root tips. Cherry tomato (Solanum lycopersicum var. cerasiforme ‘LA2710’) seedlings were treated under 15 μM Al3+ activity for 13 d. Root-tip longitudinal fresh frozen tissue sections of 10 μm thickness were prepared. The Al-sensitive root zone and cells were determined using histochemical analysis of root-tips and micro-sections. A procedure for collecting the Al-sensitive cells using laser capture microdissection-protein extraction-tandem mass tag-proteomics analysis was developed. Proteomics analysis of 18 μg protein/sample with three biological replicates per treatment condition identified 3879 quantifiable proteins each associated with two or more unique peptides. Quantified proteins constituted a broad range of Kyoto Encyclopedia of Genes and Genomes pathways when searched in the annotated tomato genome. Differentially expressed proteins between the Al-treated and non-Al treated control conditions were identified, including 128 Al-up-regulated and 32 Al-down-regulated proteins. Analysis of functional pathways and protein-protein interaction networks showed that the Al-down-regulated proteins are involved in transcription and translation, and the Al-up-regulated proteins are associated with antioxidant and detoxification and protein quality control processes. The proteomics data are available via ProteomeXchange with identifier PXD010459 under project title ‘LCM-quantitative proteomics analysis of Al-sensitive tomato root cells’. Significance This paper presents an efficient laser capture microdissection-tandem mass tag-quantitative proteomics analysis platform for the analysis of Al sensitive root cells. The analytical procedure has a broad application for proteomics analysis of spatially separated cells from complex tissues. This study has provided a comprehensive proteomics dataset expressed in the epidermal and outer-cortical cells at root-tip transition zone of Al-treated tomato seedlings. The proteomes from the Al-sensitive root cells are valuable resources for understanding and improving Al tolerance in plants

Development of a laser capture microscope-based single-cell-type proteomics tool for studying proteomes of individual cell layers of plant roots

Single-cell-type proteomics provides the capability to revealing the genomic and proteomics information at cell-level resolution. However, the methodology for this type of research has not been well-developed. This paper reports developing a workflow of laser capture microdissection (LCM) followed by gel-liquid chromatography-tandem mass spectrometry (GeLC-MS/MS)-based proteomics analysis for the identification of proteomes contained in individual cell layers of tomato roots. Thin-sections (~10-μm thick, 10 sections per root tip) were prepared for root tips of tomato germinating seedlings. Epidermal and cortical cells (5000–7000 cells per tissue type) were isolated under a LCM microscope. Proteins were isolated and then separated by SDS–polyacrylamide gel electrophoresis followed by in-gel-tryptic digestion. The MS and MS/MS spectra generated using nanoLC-MS/MS analysis of the tryptic peptides were searched against ITAG2.4 tomato protein database to identify proteins contained in each single-cell-type sample. Based on the biological functions, proteins with proven functions in root hair development were identified in epidermal cells but not in the cortical cells. Several of these proteins were found in Al-treated roots only. The results demonstrated that the cell-type-specific proteome is relevant for tissue-specific functions in tomato roots. Increasing the coverage of proteomes and reducing the inevitable cross-contamination from adjacent cell layers, in both vertical and cross directions when cells are isolated from slides prepared using intact root tips, are the major challenges using the technology in proteomics analysis of plant roots

Differential Root Proteome Expression in Tomato Genotypes with Contrasting Drought Tolerance Exposed to Dehydration

A comparative proteomics study using isobaric tags for relative and absolute quantitation (iTRAQ) was performed on a mesophytic tomato (Solanum lycopersicum) cultivar and a dehydration-resistant wild species (Solanum chilense) to identify proteins that play key roles in tolerance to water deficit stress. In tomato ‘Walter’ LA3465, 130 proteins were identified, of which 104 (80%) were repressed and 26 (20%) were induced. In S. chilense LA1958, a total of 170 proteins were identified with 106 (62%) repressed and 64 (38%) induced. According to their putative molecular functions, the differentially expressed proteins belong to the following subgroups: stress proteins, gene expression, nascent protein processing, protein folding, protein degradation, carbohydrate metabolism, amino acid and nucleotide metabolism, lipid metabolism, signal transduction, and cell cycle regulation. Based on changes in protein abundance induced by the dehydration treatment, cellular metabolic activities and protein biosynthesis were suppressed by the stress. In S. chilense, dehydration treatment led to elevated accumulation of proteins involved in post-transcriptional gene regulation and fidelity in protein translation including prefoldin, which promotes protein folding without the use of adenosine-5′-triphosphate (ATP), several hydrophilic proteins, and calmodulin in the calcium signal transduction pathway. Those protein changes were not found in the susceptible tomato, ‘Walter’. Within each functional protein group, proteins showing opposite changes (dehydration induced vs. repressed) in the two species were identified and roles of those proteins in conferring tolerance to water deficit stress are discussed. Information provided in this report will be useful for selection of proteins or genes in analyzing or improving dehydration tolerance in tomato cultivars

Proteome profile changes during poly-hydroxybutyrate intracellular mobilization in gram positive Bacillus cereus tsu1

Bacillus cereus is a bacterial species which grows efficiently on a wide range of carbon sources and accumulates biopolymer poly-hydroxybutyrate (PHB) up to 80% cell dry weight. PHB is an aliphatic polymer produced and stored intracellularly as a reservoir of carbon and energy, its mobilization is a key biological process for sporulation in Bacillus spp. Previously, B. cereus tsu1 was isolated and cultured on rapeseed cake substrate (RCS), with maximum of PHB accumulation reached within 12 h, and depleted after 48 h. Fore-spore and spore structure were observed after 24 h culture

Comparative Proteomics of Root Apex and Root Elongation Zones Provides Insights into Molecular Mechanisms for Drought Stress and Recovery Adjustment in Switchgrass

Switchgrass plants were grown in a Sandwich tube system to induce gradual drought stress by withholding watering. After 29 days, the leaf photosynthetic rate decreased significantly, compared to the control plants which were watered regularly. The drought-treated plants recovered to the same leaf water content after three days of re-watering. The root tip (1cm basal fragment, designated as RT1 hereafter) and the elongation/maturation zone (the next upper 1 cm tissue, designated as RT2 hereafter) tissues were collected at the 29th day of drought stress treatment, (named SDT for severe drought treated), after one (D1W) and three days (D3W) of re-watering. The tandem mass tags mass spectrometry-based quantitative proteomics analysis was performed to identify the proteomes, and drought-induced differentially accumulated proteins (DAPs). From RT1 tissues, 6156, 7687, and 7699 proteins were quantified, and 296, 535, and 384 DAPs were identified in the SDT, D1W, and D3W samples, respectively. From RT2 tissues, 7382, 7255, and 6883 proteins were quantified, and 393, 587, and 321 proteins DAPs were identified in the SDT, D1W, and D3W samples. Between RT1 and RT2 tissues, very few DAPs overlapped at SDT, but the number of such proteins increased during the recovery phase. A large number of hydrophilic proteins and stress-responsive proteins were induced during SDT and remained at a higher level during the recovery stages. A large number of DAPs in RT1 tissues maintained the same expression pattern throughout drought treatment and the recovery phases. The DAPs in RT1 tissues were classified in cell proliferation, mitotic cell division, and chromatin modification, and those in RT2 were placed in cell wall remodeling and cell expansion processes. This study provided information pertaining to root zone-specific proteome changes during drought and recover phases, which will allow us to select proteins (genes) as better defined targets for developing drought tolerant plants. The mass spectrometry proteomics data are available via ProteomeXchange with identifier PXD017441

Identification of Proteins for Salt Tolerance Using a Comparative Proteomics Analysis of Tomato Accessions with Contrasting Salt Tolerance

Tomato (Solanum lycopersicum) has a wide variety of genotypes differing in their responses to salinity. This study was performed to identify salt-induced changes in proteomes that are distinguishable among tomatoes with contrasting salt tolerance. Tomato accessions [LA4133 (a salt-tolerant cherry tomato accession) and ‘Walter’ LA3465 (a salt-susceptible accession)] were subjected to salt treatment (200 mm NaCl) in hydroponic culture. Salt-induced changes in the root proteomes of each tomato accession were identified using the isobaric tags for relative and absolute quantitation (iTRAQ) method. In LA4133, 178 proteins showed significant differences between salt-treated and non-treated control root tissues (P ≤ 0.05); 169 proteins were induced (1.3- to 5.1-fold) and nine repressed (–1.7- to –1.3-fold). In LA3465, 115 proteins were induced (1.3- to 6.4-fold) and 23 repressed (–2.5- to –1.3-fold). Salt-responsive proteins from the two tomato accessions were involved in the following biological processes: root system development and structural integrity; carbohydrate metabolism; adenosine-5′-triphosphate regeneration and consumption; amino acid metabolism; fatty acid metabolism; signal transduction; cellular detoxification; protein turnover and intracellular trafficking; and molecular activities for regulating gene transcription, protein translation, and post-translational modification. Proteins affecting diverse cellular activities were identified, which include chaperonins and cochaperonins, heat-shock proteins, antioxidant enzymes, and stress proteins. Proteins exhibiting different salt-induced changes between the tolerant and susceptible tomato accessions were identified, and these proteins were divided into two groups: 1) proteins with quantitative differences because they were induced or repressed by salt stress in both accessions but at different fold levels; and 2) proteins showing qualitative differences, where proteins were induced in one vs. repressed or not changed in the other accession. Candidate proteins for tolerance to salt and secondary cellular stresses (such as hypo-osmotic stress and dehydration) were proposed based on findings from the current and previous studies on tomato and by the use of the Arabidopsis thaliana protein database. Information provided in this report will be very useful for evaluating and breeding for plant tolerance to salt and/or water deficit stresses

Genome Structure of Bacillus cereus tsu1 and Genes Involved in Cellulose Degradation and Poly-3-Hydroxybutyrate Synthesis

In previous work, we reported on the isolation and genome sequence analysis of Bacillus cereus strain tsu1 NCBI accession number JPYN00000000. The 36 scaffolds in the assembled tsu1 genome were all aligned with B. cereus B4264 genome with variations. Genes encoding for xylanase and cellulase and the cluster of genes in the poly-3-hydroxybutyrate (PHB) biosynthesis pathway were identified in tsu1 genome. The PHB accumulation in B. cereus tsu1 was initially identified using Sudan Black staining and then confirmed using high-performance liquid chromatography. Physical properties of these PHB extracts, when analyzed with Raman spectra and Fourier transform infrared spectroscopy, were found to be comparable to the standard compound. The five PHB genes in tsu1 (phaA, phaB, phaR, phaC, and phaP) were cloned and expressed with TOPO cloning, and the recombinant proteins were validated using peptide mapping of in-gel trypsin digestion followed by mass spectrometry analysis. The recombinant E. coli BL21 (DE3) (over)expressing phaC was found to accumulate PHB particles. The cellulolytic activity of tsu1 was detected using carboxymethylcellulose (CMC) plate Congo red assay and the shift towards low-molecular size forms of CMC revealed by gel permeation chromatography in CMC liquid culture and the identification of a cellulase in the secreted proteome