Project description:Cucumber (Cucumis sativus L.) fruit is a type of fleshy fruit that is harvested immaturely. Early fruit development directly determines the final fruit length and diameter, and consequently the fruit yield and quality. Different cucumber varieties display huge variations of fruit length, but how fruit length is determined at the molecular level remains poorly understood. To understand the genes and gene networks that regulate fruit length in cucumber, high throughout RNA-seq data were used to compare the transcriptomes of early fruit from two near isogenic lines with different fruit lengths. 3955 genes were found to be differentially expressed, among which 2368 genes were significantly up-regulated and 1587 down-regulated in the line with long fruit. Microtubule and cell cycle related genes were dramatically activated in the long fruit, and transcription factors were implicated in the fruit length regulation in cucumber. Thus, our results built a foundation to dissect the molecular mechanism of fruit length control in cucumber, a key agricultural trait of significant economic importance.
Project description:Cucumber (Cucumis sativus L.) fruit is a type of fleshy fruit that is harvested immaturely. Early fruit development directly determines the final fruit length and diameter, and consequently the fruit yield and quality. Different cucumber varieties display huge variations of fruit length, but how fruit length is determined at the molecular level remains poorly understood. To understand the genes and gene networks that regulate fruit length in cucumber, high throughout RNA-seq data were used to compare the transcriptomes of early fruit from two near isogenic lines with different fruit lengths. 3955 genes were found to be differentially expressed, among which 2368 genes were significantly up-regulated and 1587 down-regulated in the line with long fruit. Microtubule and cell cycle related genes were dramatically activated in the long fruit, and transcription factors were implicated in the fruit length regulation in cucumber. Thus, our results built a foundation to dissect the molecular mechanism of fruit length control in cucumber, a key agricultural trait of significant economic importance. Comparative analysis of fruit from two near-isogenic lines, 408 (long fruit) and 409 (short fruit), was employed to discover genes and networks that regulate the fruit length. Two biological replicates were used from each line.
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:Cucumber (Cucumis sativus L.) is an important vegetable crop bearing fleshy pepo fruits that harvested immature. The fruit length is one of the most important agricultural traits that directly determine the fruit yield and affects fruit quality, but the regulatory mechanism of fruit length variation remains elusive. Here we found a FRUITFULL-like MADS-box gene CsFUL1 functions as a key repressor for fruit length regulation in cucumber. The expression of CsFUL1 is highly enriched in male flowers and fruits, and negatively correlated with fruit length in different cucumber lines. Notably, a key SNP in CsFUL1 was selected during cucumber domestication for long fruit. Ectopic expression of CsFUL1 was unable to rescue the indehiscent fruit phenotype of ful-1 in Arabidopsis. Overexpression of CsFUL1 resulted in increased floral organs and reduced fruit length, whereas knockdown of CsFUL1 led to elongated fruit in cucumber. Transcriptome and biochemical analyses showed that CsFUL1 regulates fruit length through two pathways: one by inhibiting the PIN-FORWED (PIN1/7)-mediated auxin transport and thus downregulates auxin related genes in the fruit, and the other by forming a tetramer with other MADS-box genes to repress the CsSUP-mediated cell division and cell expansion. In addition, we found that CsFUL1 promotes locule number variation through the classical CsWUS-CsCLV pathway. Our findings uncover the regulatory commonality and specificity during development of different fruit types, and provide an important candidate gene to customize fruit length during cucumber breeding.
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.
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: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:To identify the differentially expressed genes(DEGs) in the ventral and dorsal of cucumber bending fruits,cucumber bending fruit mRNA profiles of 2-day-old ventral and dorsal were generated by deep sequencing. After removing the low quality reads, the total number of clean reads in two library were 27.07 million and16.52 million, accounted for 85.21% and 80.71% of total reads .We identified a total of 4313 sequences differentially expressed in ventral and dorsal of bending fruit with a 2-fold or greater change and P < 0.01 , the Dorsal (D2) served as a control, in which 2351 up-regulated genes and 1962 down-regulated genes.For up-regulated genes, protein kinase activity, ethylene mediated signaling pathway, regulation of cell shape, auxin polar transport were significantly enriched, whereas down-regulated genes, the functional classes photosynthesis, oxidation reduction, response to auxin stimulus were significantly enriched. Moreover, among DEGs related to ethylene, we identified an ERF/AP2 gene CsERF025 that was significant difference in the dorsal and ventral of cucumber. up-regulation of CsERF025 in cucumber promoted fruit bendng and Increased the fruit bending angle, suggesting that CsERF025 plays an important role in cucumber bending fruit.
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:Fruit length is a key domestication trait that affects crop yield and appearance quality. Cucumber fruits vary from 5~60 cm in length. Despite multiple fruit length QTLs have been identified, the underlying genes and regulatory mechanisms are poorly understood. Map-based cloning identified a nonsynonymous SNP (G to A) in CRABS CLAW (CsCRC) confers the major effect fruit length QTL FS5.2. CsCRCA is a rare allele only exist in Xishuangbanna cucumber with round fruits. Construction of near-isogenic line (NIL) of CsCRCA led to 34~39% reduction in fruit length. Introduction of CsCRCG into the NIL rescued the short-fruit phenotype, and knockdown of CsCRCG resulted in reduced fruit length and decreased cell size. RNA-seq results showed that an auxin responsive protein CsARP1 expressed decreased in CsCRC-RNAi lines. Further, an auxin responsive protein Further, CsARP1 is the downstream target gene of CsCRCG, instead of CsCRCA. Knockout of CsARP1 produced decreased fruit length with smaller cells. Hence, our work suggested that CsCRCG positively regulates fruit elongation through transcriptional activation of CsARP1 and thus enhanced cell expansion. Utilization of CsCRC alleles provides a new strategy to manipulate fruit length in cucumber breeding.