Project description:The cucumber is one of the most important vegetables worldwide and is used as a research model for study of phloem transport, sex determination and temperature-photoperiod physiology. The shoot apex is the most important plant tissue in which the cell fate and organ meristems have been determined. In this study, a series of whole-genome small RNA, degradome and transcriptome analyses were performed on cucumber shoot apical tissues treated with high vs. low temperature and a long vs. short photoperiod.
Project description:Orchid Dendrobium Sonia (Sonia) has wide demand in floral market throughout the world due to its vibrant coloured flowers, flowering recurrence and dense inflorescence. Effects of different monochromatic light qualities (red, far-red, blue, white) on different developmental and growth responses such as seed gemination, shoot and root growth, chlorophyll and carotenoid accumulation were studied in Sonia. Asymbiotic seed germination was the highest under blue or white light (80%, p<0.001) and least under far-red (55%, p<0.001) suggesting that it could either be controlled by an exceptional novel function of Cryptochrome 1 or the blue wavelengths perceived by PHYA or PHYB in Sonia. All analyses were done in 6-months-old plants till 1 year of age. Shoot length increased significantly in white or red light (3.7-fold, 3.5-fold respectively) while was least under far-red (decreased by 1.6-fold) indicating the major regulatory role of PHYB for shoot growth. Root growth in red in Sonia was more similar to hypocotyl adventitious root (HAR) formation genetically considering PHYB transcript expression. We suggest that the root growth (HAR) under red in Sonia is partly attributed to PHYB, negatively regulated with HY5 transcription factor and positively associated with auxin biosynthesis and accumulation gene BABY BOOM (BBM2) and efflux carriers such as LIKE AUXIN RESISTANT 2 and 3 (LAX2, LAX3). Highest chlorophyll content under far-red and blue might be a hyper-response of SAR under FR light in Sonia. Taxonomic tree analysis finds Sonia closer to Phalenopsis and Dendrobium catenatum Lindl. The three phytochromes and one cryptochrome sequences which were similar to PHYA, B, C and CRY1 respectively. CRY1 was retrieved with one more isoform CRY1_X2, with all these sequences more similar to those of Oryza.sativa. Further study can clarify the indicating reason of a probable gene loss which is evident from the absence of any sequence similar to CRY2 in root RNA isolates of Dendrobium Sonia.
Project description:Shoot branching is an important agronomic trait that directly determines plant architecture and affects crop productivity. To promote crop yield and quality, axillary branches need to be manually removed during cucumber production for fresh market and thus are undesirable. Auxin is well known as the primary signal imposing for apical dominance and acts as a repressor for branching outside of the lateral buds. The TEOSINTE BRANCHED1/CYCLOIDEA /PCF (TCP) family gene BRANCHED1 (BRC1) has been shown to be the central integrator for multiple environmental and developmental factors that functions locally to inhibit shoot branching. However, no direct link has been reported between auxin and BRC1. Here, we find that cucumber BRANCHED1 (CsBRC1) is expressed in the axillary buds and displays higher expression level in cultivated cucumber than its wild ancestor. Knockdown of CsBRC1 by RNAi leads to increased bud outgrowth and reduced auxin accumulation in buds. We further show that CsBRC1 directly binds to two auxin efflux carriers PIN-FORMED (CsPIN1b and CsPIN3) and negatively regulates their expression. Ectopic expression of CsPIN1b or CsPIN3 driven by CsBRC1 promoter results in increased shoot branching. Moreover, shade induces the expression of CsBRC1 in cultivated cucumber, but not in wild ancestor, which may be partly due to the addition of two light response elements in the CsBRC1 promoter of cultivated cucumber. Therefore, our data suggest the formation of a regulatory pathway of shade-CsBRC1-auxin transport in suppressing lateral bud outgrowth during cucumber domestication.
Project description:Purpose: Next-generation sequencing (NGS) has revolutionized systems-based analysis of gene expression profiles of cucumber under short-term chilling stress. The goals of this study are to transcriptome analysis of cucumber leaves under chilling stress. Methods: mRNA profiles of seedlings exposed to an air temperature of 6°C in the absence of light at 0, 2, 6, and 12 h were generated by deep sequencing, in triplicate, using Illumina Hiseq platform. The reference genome and gene model annotation files were downloaded from the genome website (http://cucurbitgenomics.org/). An index of the reference genome was built using Bowtie v.2.2.3 and paired-end clean reads were aligned to the reference genome using TopHat v.2.0.12. qRT–PCR validation was performed using SYBR Green assays. Results: A total of 55.7 million clean reads was generated. Based on the threshold values of absolute value of log2 ratio ≥ 1 and FDR ≤ 0.05, a total of 2113 DEGs was identified at three time points (2, 6, and 12 h). A total of 30 genes was detected at all time points. The number of DEGs increased with time. In total, 100 TFs from 22 families in three subsets were detected. And 19 kinase families were identified in three subsets. The DEGs identified by RNA sequencing were confirmed by qRT-PCR analysis, indicating that the data were reliable. These findings provide information that can be useful for investigating the molecular mechanisms underlying the response to chilling stress in cucumber and other plants. Conclusions: The results presented here reveal changes in the transcriptome profile of cucumber in response to chilling stress. Exposure to a low temperature induced genes involved in hormone regulation, lipid metabolism, and photosynthesis, including NAC, WRKY, AP2/ERF, ERD, MYB as well as zinc finger TFs and protein kinases such as receptor-like protein kinase, MAPK, and CDK. Most TFs were upregulated whereas CDKs were downregulated. These findings provide information that can be useful for investigating the molecular mechanisms underlying the response to chilling stress in cucumber and other plants.
Project description:Nitrogen is the most important mineral nutrient of plant. As a worldwide and economically important vegetable, cucumber (Cucumis sativus L.) has a strong nitrogen-dependence. We took whole transcriptome sequencing approach to compare the gene expression profiles of cucumber leaves and roots grown under sufficient or insufficient nitrate supply. Analysis of the transcriptome data revealed that the root and leaf adapt different response mechanisms to long-term nitrogen deficiency. Photosynthesis and carbohydrate biosynthetic process were pronouncedly and specifically reduced in leaf, while the ion transport function, cell wall and phosphorus-deficiency response function seem systematically down-regulated in root. Genes in nitrogen uptake and assimilation are decreased in root, but some are increased in leaf under nitrogen deficiency. Several lines of evidence suggest that the altered gene expression networks support the basic cucumber growth and development likely through successful nitrogen remobilization involving in the induced expression of genes in ABA and ethylene pathways. cucumber leaf and root mRNA of 28-day after sowing nitrogen deficiency and sufficiency deep sequencing, using Illumina HiSeq 2000
Project description:Background. Ovary culture has been a useful way to generate double haploid (DH) plant in cucumber (Cucumis sativus L.). However, the rate of embryo induction and the ability for induced embryo to grow into normal embryo are quite low. Moreover, the s mechanism of cucumber embryogenesis remains ambiguous. In this study, the molecular basis for cucumber embryogenesis was explored to set up basis for a more efficient ovary culture method. Differentially expressed genes during embryogenesis process, including the early stages of embryo formation, embryo maturation and shoot formation, were investigated using transcriptomic sequencing. Methods. Based on the cytological observation of cucumber ovary culture, the ovary culture can be divided into three stages:early embryo development, embryo maturation (from pre-embryos to cotyledon embryos) and the shoot formation stage. six key time points were selected for transcriptome sequencing and analysis. Results. We firstly conducted cytological observations which suggest that cell enlargement is the symbol for gametophytes to switch to sporophyte development pathway during early embryogenesis stage. In this stage, RNA-seq revealed 3468 up-regulated genes, including hormone signal transduction genes, hormone response genes and stress-induced genes. The reported embryogenesis-related genes BBM, HSP90 and AGL were also actively expressed during this stage. The total 480 genes that function in protein complex binding, microtubule binding, tetrapyrrole binding, tubulin binding and other microtubule activities were continuously up-regulated during the embryo maturation stage, indicating that the cytoskeleton structure was continuously being built and maintained by the action of microtubule-binding proteins and enzyme modification during embryo development. In shoot formation stage, 1383 genes were up-regulated, which were mainly enriched in phenylpropanoid biosynthesis, plant hormone signal transduction, phenylalanine metabolism, and starch and sucrose metabolism. The shoot formation stage might be regulated by 6 transcription factors that contained a B3 domain, 9 genes in the AP2/ERF family and 2 genes encoded WUS homologous domain proteins. Conclusions. These findings offer a valuable framework for explaining the transcriptional regulatory mechanism underlying embryogenesis during cucumber ovary culture.
Project description:Previous study we have reported the cucumber TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) family gene BRANCHED1 (CsBRC1) as a main transcription factor functions to regulate shoot branching. Here, we found CsBRC1 (CsTCP18b in this study) had a paralogous gene CsTCP18a. To investigate whether the function of CsTCP18a was same as CsTCP18b, we carried out biochemical experiments and genetic transformation. The Real-Time PCR and in situ hybridization showed that CsTCP18a displayed different expression patterns in cucumber compared with CsTCP18b. Ectopic expression of CsTCP18a in Arabidopsis tcp18 (brc1) mutants resulted in a decreased number of rosette branches and rosette leaves, whereas silencing CsTCP18a in cucumber only led to a deformed true leaf of seedling without influencing the shoot branching. RNA-seq analysis of wild-type plants and CsTCP18a-RNAi lines implicated that CsTCP18a regulated early leaf development of cucumber through affecting the transcripts of auxin and cytokinin related genes. Further studies indicated that CsTCP18a could directly interact with CsTCP10 and CsTCP18b in vitro and in vivo. Therefore, our data suggested that CsTCP18a had functional redundancy with CsTCP18b in inhibiting axillary buds outgrowth, and it could also regulate leaf development during cucumber seedling.
Project description:Transcriptomes of Dinoroseobacter shibae DSM16493 wild type and clpX knockout mutant were recorded under white and blue light and in dark.
Project description:The widely used white light-emitting diodes (LED) deliver higher levels of blue light than do conventional domestic light sources. The high intensity of blue component is the main source of concern about the health risks of LED with respect to their light-toxicity to the retina. White LED light with higher correlated color temperature (CCT) is more likely to cause retinal injury in mice, significantly reducing the number of ONL nuclei, however apoptosis pathway may not be the only mechanism. We used the Affymetrix GeneChip (Mouse Genome 430 2.0) to describe the different influence on gene expression of mouse retina under white LED light with different CCT.
Project description:Nitrogen is the most important mineral nutrient of plant. As a worldwide and economically important vegetable, cucumber (Cucumis sativus L.) has a strong nitrogen-dependence. We took whole transcriptome sequencing approach to compare the gene expression profiles of cucumber leaves and roots grown under sufficient or insufficient nitrate supply. Analysis of the transcriptome data revealed that the root and leaf adapt different response mechanisms to long-term nitrogen deficiency. Photosynthesis and carbohydrate biosynthetic process were pronouncedly and specifically reduced in leaf, while the ion transport function, cell wall and phosphorus-deficiency response function seem systematically down-regulated in root. Genes in nitrogen uptake and assimilation are decreased in root, but some are increased in leaf under nitrogen deficiency. Several lines of evidence suggest that the altered gene expression networks support the basic cucumber growth and development likely through successful nitrogen remobilization involving in the induced expression of genes in ABA and ethylene pathways.