Project description:BackgroundBroccoli (Brassica oleracea var. italica), a member of Cruciferae, is an important vegetable containing high concentration of various nutritive and functional molecules especially the anticarcinogenic glucosinolates. The sprouts of broccoli contain 10-100 times higher level of glucoraphanin, the main contributor of the anticarcinogenesis, than the edible florets. Despite the broccoli sprouts' functional importance, currently available genetic and genomic tools for their studies are very limited, which greatly restricts the development of this functionally important vegetable.ResultsA total of ∼85 million 251 bp reads were obtained. After de novo assembly and searching the assembled transcripts against the Arabidopsis thaliana and NCBI nr databases, 19,441 top-hit transcripts were clustered as unigenes with an average length of 2,133 bp. These unigenes were classified according to their putative functional categories. Cluster analysis of total unigenes with similar expression patterns and differentially expressed unigenes among different tissues, as well as transcription factor analysis were performed. We identified 25 putative glucosinolate metabolism genes sharing 62.04-89.72% nucleotide sequence identity with the Arabidopsis orthologs. This established a broccoli glucosinolate metabolic pathway with high colinearity to Arabidopsis. Many of the biosynthetic and degradation genes showed higher expression after germination than in seeds; especially the expression of the myrosinase TGG2 was 20-130 times higher. These results along with the previous reports about these genes' studies in Arabidopsis and the glucosinolate concentration in broccoli sprouts indicate the breakdown products of glucosinolates may play important roles in the stage of broccoli seed germination and sprout development.ConclusionOur study provides the largest genetic resource of broccoli to date. These data will pave the way for further studies and genetic engineering of broccoli sprouts and will also provide new insight into the genomic research of this species and its relatives.

Project description:Purpose: The goals of this study are to analyze the transcriptome of five time point in broccoli seed germination and sprout development and to find the putative glucosinolate metabolism genes in the stage. Methods: Total mRNA of germinated seeds, 3 day cotyledons, 7 day botyledons, 11 day cotyledons and 11 day euphyllas of wild-type broccoli were harvested. Each sample was harvested in three independent biological replicates with equal weight and subsequently pooled together for sequencing. The sequence reads that passed quality filters were de novo assembled using VELVET followed by OASES. Then the assembled unigenes were used for the abundance and functional analysis. Results: A total of ~85million 251bp reads were obtained. After de novo assembly and searching the assembled transcripts against the Arabidopsis thaliana and Nr databases, 19,441 top-hit transcripts were clustered as unigenes with an average length of 2,133bp. These unigenes were classified according to their putative functional categories. Cluster analysis of total unigenes with similar expression patterns and differentially expressed unigenes among different tissues,as well as transcription factor analysis were performed. We identified 25 putative glucosinolate metabolismgenes sharing 62.04-89.72% nucleotide sequence identity with the Arabidopsis orthologs. This established a broccoli glucosinolate metabolic pathway with high colinearity to Arabidopsis. Many of the biosynthetic and degradation genes showed higher expression after germination than in seeds; especially the expression of the myrosinaseTGG2 was 20-130 times higher.These results along with the previous reports that glucosinolate concentration decreased exponentially once after germination indicate the breakdown products of glucosinolates may play important roles in broccoli seed germination and sprout development. Conclusion: Our study provides the largest genetic resource of broccoli to date. These data will pave the way for further studies and genetic engineering of broccoli sprouts to develop functional vegetables containing high levels of the anticarcinogenic glucosinolates. They will also provide new insight into the genomic research of this species and its relatives.

Project description:Purpose: The goals of this study are to analyze the transcriptome of five time point in broccoli seed germination and sprout development and to find the putative glucosinolate metabolism genes in the stage. Methods: Total mRNA of germinated seeds, 3 day cotyledons, 7 day botyledons, 11 day cotyledons and 11 day euphyllas of wild-type broccoli were harvested. Each sample was harvested in three independent biological replicates with equal weight and subsequently pooled together for sequencing. The sequence reads that passed quality filters were de novo assembled using VELVET followed by OASES. Then the assembled unigenes were used for the abundance and functional analysis. Results: A total of ~85million 251bp reads were obtained. After de novo assembly and searching the assembled transcripts against the Arabidopsis thaliana and Nr databases, 19,441 top-hit transcripts were clustered as unigenes with an average length of 2,133bp. These unigenes were classified according to their putative functional categories. Cluster analysis of total unigenes with similar expression patterns and differentially expressed unigenes among different tissues,as well as transcription factor analysis were performed. We identified 25 putative glucosinolate metabolismgenes sharing 62.04-89.72% nucleotide sequence identity with the Arabidopsis orthologs. This established a broccoli glucosinolate metabolic pathway with high colinearity to Arabidopsis. Many of the biosynthetic and degradation genes showed higher expression after germination than in seeds; especially the expression of the myrosinaseTGG2 was 20-130 times higher.These results along with the previous reports that glucosinolate concentration decreased exponentially once after germination indicate the breakdown products of glucosinolates may play important roles in broccoli seed germination and sprout development. Conclusion: Our study provides the largest genetic resource of broccoli to date. These data will pave the way for further studies and genetic engineering of broccoli sprouts to develop functional vegetables containing high levels of the anticarcinogenic glucosinolates. They will also provide new insight into the genomic research of this species and its relatives. Wild-type broccoli mRNA profiles of seeds, 3 day cotyledons, 7 day botyledons, 11 day cotyledons and 11 day euphyllas were generated by deep sequencing, three biological replicates pooling together for each tissue, using Illumina Myseq platform.

Project description:Glucosinolates are the biochemical compounds that provide defense to plants against pathogens and herbivores. In this study, the relative expression level of 48 glucosinolate biosynthesis genes was explored in four morphologically-different cabbage inbred lines by qPCR analysis. The content of aliphatic and indolic glucosinolate molecules present in those cabbage lines was also estimated by HPLC analysis. The possible association between glucosinolate accumulation and related gene expression level was explored by principal component analysis (PCA). The genotype-dependent variation in the relative expression level of different aliphatic and indolic glucosinolate biosynthesis genes is the novel result of this study. A total of eight different types of glucosinolates, including five aliphatic and three indolic glucosinolates, was detected in four cabbage lines. Three inbred lines BN3383, BN4059 and BN4072 had no glucoraphanin, sinigrin and gluconapin detected, but the inbred line BN3273 had these three aliphatic glucosinolate compounds. PCA revealed that a higher expression level of ST5b genes and lower expression of GSL-OH was associated with the accumulation of these three aliphatic glucosinolate compounds. PCA further revealed that comparatively higher accumulation of neoglucobrassicin in the inbred line, BN4072, was associated with a high level of expression of MYB34 (Bol017062) and CYP81F1 genes. The Dof1 and IQD1 genes probably trans-activated the genes related to biosynthesis of glucoerucin and methoxyglucobrassicin for their comparatively higher accumulation in the BN4059 and BN4072 lines compared to the other two lines, BN3273 and BN3383. A comparatively higher progoitrin level in BN3273 was probably associated with the higher expression level of the GSL-OH gene. The cabbage inbred line BN3383 accounted for the significantly higher relative expression level for the 12 genes out of 48, but this line had comparatively lower total glucosinolates detected compared to the other three cabbage lines. The reason for the genotypic variation in gene expression and glucosinolate accumulation is a subject of further investigation.

Project description:BackgroundWucai (Brassica campestris L. ssp. chinensis var. rosularis Tsen) is a variant of nonheading Chinese cabbage (Brassica campestris L.), which is one of the major vegetables in China. Cytoplasmic male sterility (CMS) has been used for Wucai breeding in recent years. However, the underlying molecular mechanism of Wucai CMS remains unclear. In this study, the phenotypic and cytological features of Wucai CMS were observed by anatomical analysis, and a comparative transcriptome analysis was carried out to identify genes related to male sterility using Illumina RNA sequencing technology (RNA-Seq).ResultsMicroscopic observation demonstrated that tapetum development was abnormal in the CMS line, which failed to produce fertile pollen. Bioinformatics analysis detected 4430 differentially expressed genes (DEGs) between the fertile and sterile flower buds. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to better understand the functions of these DEGs. Among the DEGs, 35 genes (53 DEGS) were implicated in anther and pollen development, and 11 genes were involved in pollen cell wall formation and modification; most of these showed downregulated expression in sterile buds. In addition, several genes related to tapetum development (A6, AMS, MS1, MYB39, and TSM1) and a few genes annotated to flowering (CO, AP3, VIN3, FLC, FT, and AGL) were detected and confirmed by qRT-PCR as being expressed at the meiosis, tetrad, and uninucleate microspore stages, thus implying possible roles in specifying or determining the fate and development of the tapetum, male gametophyte and stamen. Moreover, the top four largest transcription factor families (MYB, bHLH, NAC and WRKY) were analyzed, and most showed reduced expression in sterile buds. These differentially expressed transcription factors might result in abortion of pollen development in Wucai.ConclusionThe present comparative transcriptome analysis suggested that many key genes and transcription factors involved in anther development show reduced gene expression patterns in the CMS line, which might contribute to male sterility in Wucai. This study provides valuable information for a better understanding of CMS molecular mechanisms and functional genome studies in Wucai.

Dataset Information

Identification of metabolic QTLs and candidate genes for glucosinolate synthesis in Brassica oleracea leaves, seeds and flower buds.

Publications

Identification of metabolic QTLs and candidate genes for glucosinolate synthesis in Brassica oleracea leaves, seeds and flower buds.

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