Project description:Trichomes are the hair-like structures that are widely present on the surface of aerial organs and function in plant defense against biotic and abiotic stresses. Previous studies focus on the single cell trichomes in Arabidopsis and cotton, or multicellular glandular trichomes in tomato, but the developmental process and molecular mechanisms controlling multicellular non-glandular trichome development are largely neglected. Here, we extensively characterized the fruit trichome (spine) development in wild type cucumber and in a tiny branched hair (tbh) mutant that contains a spontaneous mutation and has hairless foliage and smooth fruit surface. Our data indicated that cucumber trichome was multicellular and non-glandular, with no branches or endoreduplication. Further, the major feature of cucumber trichome development was spine base expansion. Transcriptome profiling through Digital Gene Expression indicated that meristem-related genes and transcription factors were implicated in the fruit spine development, and polarity regulators were upregulated during spine base expansion. qRT-PCR verified the reliability of our RNA-SEQ data, and in situ hybridization confirmed the enriched expression of meristem regulators CUP-SHAPED COTYLEDON3 (CUC3) and STM (SHOOT MERISTEMLESS) , as well as the abaxial identity gene KANADI (KAN) in cucumber fruit spine. Together, our results suggest a distinct regulatory pathway involving meristem genes and polarity regulators in multicellular trichome development in cucumber. Using Digital Gene Expression technology to compare the genome-wide gene expression profiles in the fruit spines of wild type cucumber and the tbh mutant, as well as the fruit spines on fruits of 0.5cm and 1.6cm long, repectively. Two biological repelicates were generated for each tissue.
Project description:Trichomes are the hair-like structures that are widely present on the surface of aerial organs and function in plant defense against biotic and abiotic stresses. Previous studies focus on the single cell trichomes in Arabidopsis and cotton, or multicellular glandular trichomes in tomato, but the developmental process and molecular mechanisms controlling multicellular non-glandular trichome development are largely neglected. Here, we extensively characterized the fruit trichome (spine) development in wild type cucumber and in a tiny branched hair (tbh) mutant that contains a spontaneous mutation and has hairless foliage and smooth fruit surface. Our data indicated that cucumber trichome was multicellular and non-glandular, with no branches or endoreduplication. Further, the major feature of cucumber trichome development was spine base expansion. Transcriptome profiling through Digital Gene Expression indicated that meristem-related genes and transcription factors were implicated in the fruit spine development, and polarity regulators were upregulated during spine base expansion. qRT-PCR verified the reliability of our RNA-SEQ data, and in situ hybridization confirmed the enriched expression of meristem regulators CUP-SHAPED COTYLEDON3 (CUC3) and STM (SHOOT MERISTEMLESS) , as well as the abaxial identity gene KANADI (KAN) in cucumber fruit spine. Together, our results suggest a distinct regulatory pathway involving meristem genes and polarity regulators in multicellular trichome development in cucumber.
Project description:Purpose: Cucumber (Cucumis sativus L.) is an economically important vegetable crop worldwide, and cucumber fruit spine density has an important impact on the commercial value. However, little is known about the regulatory mechanism for the fruit spine formation.In this study, the transcriptome analyses of ovaries and pericarps from numerous-spine parent and few-spine parent were conducted to identify the gene regulatory networks involved in the formation and development of numerous fruit spines in cucumber. Methods: Cucumber mRNA profiles of ovaries and pericarps from numerous-spine parent and few-spine parent were generated by deep sequencing, in triplicate, using Illumina HiSeq 4000. Then, clean data (clean reads) were obtained by removing reads containing adapters, reads containing poly-N sequences and low-quality reads from the raw data. Simultaneously, the Q20, Q30 and GC contents of the clean data were calculated. All of the downstream analyses were based on the high-quality clean data. Clean paired-end reads were mapped to the reference genome using TopHat v2.0.12 (Trapnell et al. 2012). Then, the FPKM (fragments per kilobase of transcript sequence per million base pairs sequenced) value of each gene was calculated to estimate gene expression levels (Trapnell et al. 2010). Genes with an adjusted P-value < 0.05 identified by DESeq were assigned as differentially expressed genes(DEGs). Results: We generated 42.96-57.53 million raw reads from each library, and 39.85-54.02 million clean reads were obtained after the removal of low-quality reads and adapter sequences. Among the clean reads, 79.03-80.94% were mapped to the gene database . Based on the KEGG database, pathway enrichment analysis was performed to identify significantly enriched metabolic pathways or signal transduction pathways in DEGs. Plant hormone signal transduction was significantly enriched in up-regulated genes in both F_6DBF compared with M_6DBF and F_0DAA compared with M_0DAA. Conclusions: Based on the transcriptome analysis, we excavated possible biological regulatory networks involved in the formation and development of numerous fruit spines in cucumber. This work will promote the exploration of molecular mechanisms that regulate cucumber fruit spine density.
Project description:Cucumber fruit wart composed of spine and tubercule is an important appearance quality trait, which affects product classification and market value of cucumber fruit. Although several key genes for initiation and development of spine and tubercule have been cloned, their underlying mechanisms and relationships have not been well studied. Here, we identified a cucumber basic Helix-Loop-Helix (bHLH) gene CsHEC2 that was strongly expressed in spines and tubercules of cucumber peel. Knockout lines obtained using CRISPR/Cas9 technology were used to explore the biological function of CsHEC2. Compared with the wild type, the Cshec2 mutants resulted in reduced density of wart, and decreased cytokinin accumulation in fruit peel compared to wild type. To comprehensively analyze the regulatory network, RNA sequencing (RNA-seq) experiments were conducted on female buds at 7 days before anthesis (DBA). Transcriptomic data analysis showed that 293 and 1295 genes were up- and down-regulated in Cshec2 mutants relative to WT, respectively. Several sets of genes for cytokinin biosynthesis and metabolism were expressed differently, which explained the decrease of cytokinin in Cshec2 mutants. Our results suggested that CsHEC2 is very likely to regulate the initiation of fruit wart by affecting cytokinin pathway.
Project description:Cucumber (Cucumis sativus L.) is an economically important vegetable cultivated all over the world. Grafting can produce bloomless or sparse-bloom cucumber, which is welcomed by increasing consumers. Bloom granule is tine glandular hair, which is hard and rare studied on its formation and related genes. Mutifunctional RNA-seq is a recently developed analytical approach for transcriptome profiling via high-throughput sequencing and has been recently applied to a wide variety of organisms, which provide us reliable technical means detect bloom formation and related genes. In this study, we chose a cucumber inbred line (Shannong No.5) and two pumpkin rootstock lines as materials, and constructed four tested cucumbers, grew plants in “Yamazaki cucumber nutrient solution formula” prepared by deionized water, treated plants with or without 1.7mM potassium silicate 2 hours before collecting pericarp. Each treatment were duplicated twice.16 cDNA libraries were constructed from pericarp of a cucumber inbred line (own-rooted cucumber), C/C (self-grafted cucumber), M/C (More bloom, cucumber grafted onto “3225” rootstock) and L/C(Less bloom, cucumber grafted onto “3212” rootstock). We obtained 17,215,769~17,529,047 high quality reads, and 18,804~19,358 genes from each sample. All reads can be mapped to the cucumber genome (Version 2). By RPKM comparing, we got 38 comparing combinations with differentially expressed genes (DEGs), obtained 38 significantly expressed combinations by FDR≤0.001 and the absolute value of log2Ratio≥1 as the thresholds. These results suggest that there are many differences and genes expression mode among effects of grafting or added silicon. This study addresses a preliminary analysis and offers a foundation for future genomic research in the bloom formation of cucumber.
Project description:We compared organ specific chloroplast gene expression in cucumber between fully developed leaves (12th counting from the bottom of plant) and growing tips, female flowers, young leaves, young fruits (3-5 cm long). We have also characterized chloroplast gene transcription in cucumber etiolated seedlings in comparison to mature cucumber leaves.
Project description:Cucumber is an important vegetable crop worldwide, which is mainly propagated by seed. The successful occurrence of double fertilization is the premise of seed production in angiosperms. Cucumber ALC homolog (CsALC) displayed a novel and positive function in pollen tube emergence process, and regulated female fertility by promoting CsRALF4/19 function during pollen tube guidance in cucumber.
Project description:Cucumber (Cucumis sativus L.) is one of the most important fruit vegetable crops and is widely grown worldwide (FAO STAT 2016, http://faostat3.fao.org). Astringency greatly affects the flavor quality of cucumber fruits and can be irritating due to the unpleasant oral sensation it causes. However, there are no available report addressing the molecular mechanisms driving the development of cucumber fruit astringency at the transcriptome level. A few relatively basic research efforts have been carried out in our previous studies. In this study, genome-wide analysis of gene expression in the highly astringent cucumber inbred line ‘YB’ was performed using RNA-seq. The aims of this research were to identify the genes responsible for fruit astringency development and to provide new insights into the mechanism underlying the synthesis of astringent compounds in cucumber fruits.