Transcriptome analysis of the roots at early and late seedling stages using Illumina paired-end sequencing and development of EST-SSR markers in radish.
ABSTRACT The tuberous root of radish is an important vegetable, but insufficient transcriptomic and genomic data are currently available to understand the molecular mechanisms underlying tuberous root formation and development. High-throughput transcriptomic sequencing is essential to generate a large transcript sequence data set for gene discovery and molecular marker development. In this study, a total of 107.3 million clean reads were generated using Illumina paired-end sequencing technology. De novo assembly generated 61,554 unigenes with an average length of 820 bp. Based on a sequence similarity search with known proteins or nucleotides, 85.51 % (52,634), 90.18 % (55,507) and 54 % (33,242) consensus sequences showed homology with sequences in the Nr, Nt and Swiss-Prot databases, respectively. Of these annotated unigenes, 21,109 and 17,343 unigenes were assigned to gene ontology categories and clusters of orthologous groups, respectively. A total of 27,809 unigenes were assigned to 123 pathways in the Kyoto Encyclopedia of Genes and Genomes database. Analysis of transcript differences between libraries from the early and late seedling developmental stages demonstrated that starch and sucrose metabolism and phenylpropanoid biosynthesis may be the dominant metabolic events during tuberous root formation and plant hormones probably play critical roles in regulation of this developmental process. In total, 14,641 potential EST-SSRs were identified among the unigenes, and 12,733 primer pairs for 2,511 SSR were obtained. Summarily, this study gave us a clue to understand the radish tuberous root formation and development, and also provided us with a valuable sequence resource for novel gene discovery and marker-assisted selective breeding in radish. KEY MESSAGE: De novo assembled and characterized the radish tuberous root transcriptome; explored the mechanism of radish tuberous root formation; development of EST-SSR markers in radish.
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ABSTRACT: Liriodendron chinense (Hemsl.) Sarg is an endangered species and occupies a pivotal position in phylogenetic studies of flowering plants, while its genomic resources are limited. In this study, we performed transcriptome sequencing for L. chinense petals and leaves using the Illumina paired-end sequencing technique. Approximately 17.02-Gb clean reads were obtained, and de novo assembly generated 87,841 unigenes, with an average length of 778bp. Of these, there were 65,535 (74.61 %) unigenes with significant similarity to publically available plant protein sequences. There were 3,386 genes identified as significant differentially expressed between petals and leaves, among them 2,969 (87.68 %) were up-regulated and 417 (12.31 %) down-regulated in petals. Metabolic pathway analysis revealed that 25 unigenes were predicted to be responsible for the biosynthesis of carotenoids, with 7 genes differentially expressed between these two tissues. This report is the first to identify genes associated with carotenoid biosynthesis in Liriodendron and represents a valuable resource for future genomic studies on the endangered species L. chinense.Gene 11/2013; · 2.20 Impact Factor
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ABSTRACT: Radish (Raphanus sativus L.), is an important root vegetable crop worldwide. Glucosinolates in the fleshy taproot significantly affect the flavor and nutritional quality of radish. However, little is known about the molecular mechanisms underlying glucosinolate metabolism in radish taproots. The limited availability of radish genomic information has greatly hindered functional genomic analysis and molecular breeding in radish. In this study, a high-throughput, large-scale RNA sequencing technology was employed to characterize the de novo transcriptome of radish roots at different stages of development. Approximately 66.11 million paired-end reads representing 73,084 unigenes with a N50 length of 1,095 bp, and a total length of 55.73 Mb were obtained. Comparison with the publicly available protein database indicates that a total of 67,305 (about 92.09% of the assembled unigenes) unigenes exhibit similarity (e --value <= 1.0e-5) to known proteins. The functional annotation and classification including Gene Ontology (GO), Clusters of Orthologous Group (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the main activated genes in radish taproots are predominately involved in basic physiological and metabolic processes, biosynthesis of secondary metabolite pathways, signal transduction mechanisms and other cellular components and molecular function related terms. The majority of the genes encoding enzymes involved in glucosinolate (GS) metabolism and regulation pathways were identified in the unigene dataset by targeted searches of their annotations. A number of candidate radish genes in the glucosinolate metabolism related pathways were also discovered, from which, eight genes were validated by T-A cloning and sequencing while four were validated by quantitative RT-PCR expression profiling. The ensuing transcriptome dataset provides a comprehensive sequence resource for molecular genetics research in radish. It will serve as an important public information platform to further understanding of the molecular mechanisms involved in biosynthesis and metabolism of the related nutritional and flavor components during taproot formation in radish.BMC Genomics 11/2013; 14(1):836. · 4.40 Impact Factor
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ABSTRACT: Transcriptomic data of C. roseus offering ample sequence resources for providing better insights into gene diversity: large resource of genic SSR markers to accelerate genomic studies and breeding in Catharanthus . Next-generation sequencing is an efficient system for generating high-throughput complete transcripts/genes and developing molecular markers. We present here the transcriptome sequencing of a 26-day-old Catharanthus roseus seedling tissue using Illumina GAIIX platform that resulted in a total of 3.37 Gb of nucleotide sequence data comprising 29,964,104 reads which were de novo assembled into 26,581 unigenes. Based on similarity searches 58 % of the unigenes were annotated of which 13,580 unique transcripts were assigned 5016 gene ontology terms. Further, 7,687 of the unigenes were found to have Cluster of Orthologous Group classifications, and 4,006 were assigned to 289 Kyoto Encyclopedia of Genes and Genome pathways. Also, 5,221 (19.64 %) of transcripts were distributed to 81 known transcription factor (TF) families. In-silico analysis of the transcriptome resulted in identification of 11,004 SSRs in 26.62 % transcripts from which 2,520 SSR markers were designed which exhibited a non-random pattern of distribution. The most abundant was the trinucleotide repeats (AAG/CTT) followed by the dinucleotide repeats (AG/CT). Location specific analysis of SSRs revealed that SSRs were preferentially associated with the 5'-UTRs with a predicted role in regulation of gene expression. A PCR validation of a set of 48 primers revealed 97.9 % successful amplification, and 76.6 % of them showed polymorphism across different Catharanthus species as well as accessions of C. roseus. In summary, this study will provide an insight into understanding the seedling development and resources for novel gene discovery and SSR development for utilization in marker-assisted selective breeding in C. roseus.Plant Cell Reports 02/2014; · 2.51 Impact Factor