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.
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:The plant vascular system is essential for the enlarged plant stature and successful colonizzation the land by delivering resources throughout the plants and providing mechanical support. Despite several regulators of vascular patterning have been reported, how vascular system mediates stress resistance remain largely unknown. Here we identified a CsIND transcription factor that is specifically expressed in the xylem and phloem tissues in cucumber. Knock down of CsIND by RNAi lead to dwarf plants with enlarged or disorganized vascular systems in all aerial organs. The content of both auxin and jasmonic acid were increased in the CsIND-RNAi lines. Transcriptome profiling by RNA-Seq hints CsIND-regulated gene networks for defense response and vascular development. Biochemical analyses verified that CsIND directly binds to well-known vascular regulators including CsCCR1, CsMYB116, CsYAB5, CsBP and CsAUX, and physically interacts with dorsiventral patterning genes CsKAN2 and CsYAB5. Further, CsIND-RNAi plants displayed significantly enhanced tolerance to nitrogen dificency and resistance to cucumber downy mildew. Therefore, CsIND regulates vascular formation and resistance to biotic and abiotic stresses in cucumber, through the combinarory interactions with well-known vascular regulaors and hormone metabolism and signaling pathways.
Project description:In order to find out the genes involved in the heat shock response of cucumber, the seedlings of '9930', a North China type cucumber variety, were treated with high temperature at 42℃, and the leaves of the seedlings were taken after 0, 3 and 6 hours of treatment for transcriptome sequencing to analyze the differential expression genes of cucumber in response to high temperature stress. The results showed that compared with the control (heat treatment at 0h), there were 6 082 genes differentially expressed after heat treatment for 3 h and 6 h, of which 3245 were up-regulated and 2 388 were down-regulated. The results of enrichment analysis of GO and KEGG showed that these differentially expressed genes were mainly involved in metabolic pathway and protein synthesis pathway. Among the differentially expressed genes, there are many Hsp family genes, including Hsp20, HSP70 and Hsp90, which are up-regulated by heat stress, indicating that these genes may play a positive regulatory role in heat shock response of cucumber. In addition, many transcription factors, including AP2, MYB, WRKY, bHLH and HSF, were also induced by heat.
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:Salinity seriously reduces the yield and quality of crops. Silicon (Si) has been widely reported to have beneficial effects on plant growth and development under salt stress. However, the mechanism is still poorly understood. In an attempt to identify genes or gene networks that may be orchestrated to improve salt tolerance of cucumber plants, we profiled the RNA-seq transcriptomes of both control and salt-stressed cucumber leaves in the presence or absence of added Si. The comparative transcriptome analysis revealed that Si plays an important role in shaping the transcriptome of cucumber: the expression levels of >1,000 genes (differtially expressed genes, DEGs) were changed in response to Si treatment as compared with the control, and these genes were mainly involved in ion transport, hormone and signal transduction, biosynthesis and metabolic processes, stress and defense responses, and antioxidant activity. Under salt stress, many genes functionally associated with metabolic processes and responses to environmental stimuli were strongly up- or down-regulated in their expressions. Si treatment showed a tendency that induced the transcriptomic profile of salt-stressed cucumber back to that of the control with large majority of Na down-regulated DEGs and about half of Na up-regulated DEGs being adjusted back to CT levels. This study provides a novel insight into the mechanism for Si-mediated alleviation of salt stress in plants at the transcriptome level, and it suggests that Si may act as an elicitor to precondition cucumber plants and induce salt tolerance.
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:Discovering the mechanism by which CO2 enrichment alleviates drought stress in the roots of cucumber seedlings via proteomic analysis
Project description:Corynespora leaf spot (CSL), caused by Corynespora cassiicola, has become one of the most important foliar diseases of cultivated cucumber. However, the defense mechanisms of cucumber plants in response to C. cassiicola are still poorly understood. Here, proteins from resistant plants were analyzed using isobaric tags for relative and absolute quantification (iTRAQ). A total of 286 differentially expressed proteins were identified (P<0.05, ratio>1.2 or <0.83) at 6 and 24 h after pathogen inoculation in the resistant cucumber cultivar Jinyou 38. Some of the early responses to C. cassiicola infection were revealed, and four vital clues regarding the resistance of Cucumis sativus to cucumber CLS were discovered. First, the proteomic approach revealed the modulation of signaling pathways in resistant cucumber plants in response to C. cassiicola infection. Second, the plant immune system recognizes the pathogen and initiates the expression of basal immune response proteins, including those related to defense and stress responses, signal transduction, cell metabolism and redox regulation. Third, the common stress pathways were activated by C. cassiicola; in particular, mildew resistance locus O (MLO) proteins played a crucial role in the prevention of CLS. Fourth, the rapid activation of the carbohydrate and secondary metabolic pathways, the modification and reinforcement of cell walls, and the adjustment of the apoplectic environment to high-stress conditions were crucial in cucumber resistance to CLS disease. Overall, our data increase the knowledge of incompatible interactions between plants and pathogens and provide new insight into the contribution of molecular processes in cucumber to disease resistance.