Project description:Genotyping arrays are tools for high throughput genotyping, which is required in genome-wide association studies (GWAS). Since the first cucumber genome draft was reported, genetic maps were constructed mainly based on simple-sequence repeats (SSRs) or on combinations of SSRs and other sequence-related amplified polymorphism (SRAP). In this study we developed the first cucumber genotyping array which consisted of 32,864 single nucleotide polymorphisms (SNPs). These markers cover the cucumber genome every 2.1Kb and have parents/F1 hybridizations as a training set. The training set was validated with Fludigm technology and had 98% concordance. The application of the genotyping array was illustrated by constructed a genetic map of 600 cM in length based on recombinant inbred lines (RIL) population of a 9930XGy14 cross of which compromise of 11564 SNPs. The markers collinearity between the genetic map and genome references of the two parents estimated as R2=0.97. Moreover, this comparison supports a translocation in the beginning of chromosome 5 that occurred in the lineage of 9930 and Gy14 as well as local variation in the recombination rate. We also used the array to investigate the local allele frequencies along the cucumber genome and found specific region with segregation distortions. We believe that the genotyping array together with the training set would be a powerful tool in applications such as quantitative-trait loci (QTL) analysis and GWAS.
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: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:The carpel number (CN) is an important fruit trait affecting fruit shape, size, and internal quality in cucumber. CsCLAVATA3 (CsCLV3) was previously showed to be the simply inherited gene responsible for carpel number variation in cucumber, but the molecular mechanism of CsCLV3 regulating carpel number remains elusive. Here, we found that the expression of CsCLV3 was negatively correlated with carpel number variation in different cucumber lines. Knock down of CsCLV3 by RNAi led to increased number of petals and carpels, suggesting that CsCLV3 functions as a negative regulator for floral organ number in cucumber. WUSCHEL (WUS) has been well characterized to promote CLV3-expressing stem cell activity in a non-cell autonomous manner to regulate meristem maintenance and floral organ number. However, here we found the expression region of CsCLV3 overlaps with CsWUS in the basal domain of meristem, and CsCLV3 interact with CsWUS at the protein level through binding to the WUS-box motif. Overexpression of CsFUL1, a FRUITFULL-like MADS-box gene involved in fruit length regulation, resulted in increased number of floral organs in cucumber. Biochemical analyses indicated that CsFUL1 can directly bind to CsWUS promoter to stimulate its expression. Further, we found that auxin participates in carpel number variation in cucumber through physical interaction of AUXIN RESPONSE FACTOR 14 (CsARF14) and CsWUS. Therefore, CsFUL1 and CsARF14 are two new players in the WUS-CLV pathway in determining carpel number variation in cucumber.