Project description:mRNA expression profiling of the embryo, endosperm (micropylar, peripheral, chalazal), and seed coat (outer, inner, chalazal, chalazal proliferating tissue) of the developing Brassica napus seed. Tissues were isolated using laser microdissection (LMD) from Brassica napus seeds at the globular, heart, and mature green stages of seed development.
Project description:We profiled the gene regulatory landscape of Brassica napus reproductive development using RNA sequencing. Comparative analysis of this nascent allotetraploid across the plant lifecycle revealed the contribution of each subgenome to plant reproduction. Global mRNA profiling across reproductive development revealed lower accumulation of C subgenome transcripts relative to the A subgenome. Subgenome-specific transcriptional networks identified distinct transcription factor families enriched in each of the A and C subgenome in early seed development. Analysis of a tissue specific transcriptome of early seed development revealed transcription factors predicted to be regulators encoded by the A subgenome are expressed primarily in the seed coat whereas regulators encoded by the C subgenome were expressed primarily in the embryo. Whole genome transcription factor networks identified BZIP11 as an essential regulator of early B. napus seed development. Knockdown of BZIP11 using RNA interference resulted in knockdown of predicted target genes, and a reproductive-lethal phenotype. Our data indicate that subgenome bias are characteristic features of the B. napus seed throughout its development, and that such bias might not be universal across the embryo, endosperm, and seed coat of the developing seed. We also find that examining transcriptional networks spanning both the A and C genomes of the whole B. napus seed can identify valuable targets for seed development research. We suggest that-omics level approaches to studying gene regulation in B. napus can benefit from both broad and high-resolution analyses.
Project description:Seed coat colour is determined by the type of pigment deposited in the seed coat cells. It is related to important agronomic traits of seeds, such as seed dormancy, longevity, oil content, protein content and fibre content. In Brassica napus, inheritance of seed coat colour is related to maternal effects and pollen effects (xenia effects). In this research, we isolated a mutation of yellow seeded B. napus controlled by a single Mendelian locus with pollen effect. Microcopy of transverse sections of the mature seed shows pigment is deposited only in the epidermal cells, the first cell layer of seed coat. By Illumina Hiseq 2000 sequencing technology, a total of 12 G clean data, 116x coverage of coding sequences of B. napus, was achieved from 26-day old brown and yellow seeds. It was assembled into 172,238 independent transcripts and 55,637 unigenes by Trinity. A total of 150 orthologous genes of Arabidopsis transparent testa (TT) genes were mapped in silico to 19 chromosomes of B. napus. Only 49 of the TT orthologous genes are transcripted in seeds. However transcription of all the orthologs was independent of the embryonal control of seed coat colour. Of all the Trinity-assembled unigenes, only 55 genes were found to be differentially expressed between the brown seeds and yellow mutant. Among them 50 were up-regulated and 5 were down-regulated in the yellow seeds as compared to the brown counterpart. By KEGG classification, 14 metabolic pathways were enriched significantly. Of these, 5 pathways: phenylpropanoid biosynthesis, cyanoamino acid metabolism, plant hormone signal transduction, metabolic pathways and biosynthesis of secondary metabolites, were related with seed coat pigmentation. Free amino acid quantification showed that Ala and Phe were produced at higher levels in the embryo of yellow seeds as compared to brown seeds. This increase was not observed in the seed coat. Moreover, the excess amount of free Ala was exactly twice that of Phe in the 26-day embryo of yellow seeds. Pigment indispensable substrate chalcone is synthesized from two molecules of Ala and one molecule of Phe. The correlation between accumulation of Ala and Phe and disappearance of pigment in the yellow seeded mutant indicate that embryonal control of seed coat colour is related with Phe and Ala metabolism in the embryo of B. napus.
Project description:Serial Analysis of Gene Expression (LongSAGE) was applied for gene expression profiling in seeds of oilseed rape (Brassica napus ssp. napus). The usefulness of this technique for detailed expression profiling in a non-model organism was demonstrated for the highly complex, neither fully sequenced nor annotated genome of B. napus by applying a tag-to-gene matching strategy based on Brassica ESTs and the annotated proteome of the closely related model crucifer A. thaliana. Transcripts from 3,094 genes were detected at two time-points of seed development, 23 days and 35 days after pollination (DAP). Differential expression in about 10 % of all matched genes, with a total abundance of 44 %, showed a shift from gene expression involved in diverse developmental processes including cell proliferation and seed coat formation at 23 DAP to more focussed metabolic processes including storage protein accumulation and lipid deposition at 35 DAP. The most abundant transcripts at 23 DAP were coding for diverse protease inhibitor proteins and proteases, including cysteine proteases involved in seed coat formation and a number of lipid transfer proteins involved in embryo pattern formation. At 35 DAP, transcripts encoding napin, cruciferin and oleosin storage proteins were most abundant. Over both time-points, 18.6 % of A. thaliana genes were matched by Brassica ESTs detected by LongSAGE tags in antisense orientation. This suggests a strong involvement of antisense transcript expression in regulatory processes during B. napus seed development. Seeds from 2 developmental stages of B. napus were used to construct 2 LongSAGE libraries, 23 days after pollination (23 DAP) and 35 days after pollination (35 DAP). Biological replicates and confirmation: Cloning of tag-amplified RT-PCR products, Real-time RT-PCR
Project description:Serial Analysis of Gene Expression (LongSAGE) was applied for gene expression profiling in seeds of oilseed rape (Brassica napus ssp. napus). The usefulness of this technique for detailed expression profiling in a non-model organism was demonstrated for the highly complex, neither fully sequenced nor annotated genome of B. napus by applying a tag-to-gene matching strategy based on Brassica ESTs and the annotated proteome of the closely related model crucifer A. thaliana. Transcripts from 3,094 genes were detected at two time-points of seed development, 23 days and 35 days after pollination (DAP). Differential expression in about 10 % of all matched genes, with a total abundance of 44 %, showed a shift from gene expression involved in diverse developmental processes including cell proliferation and seed coat formation at 23 DAP to more focussed metabolic processes including storage protein accumulation and lipid deposition at 35 DAP. The most abundant transcripts at 23 DAP were coding for diverse protease inhibitor proteins and proteases, including cysteine proteases involved in seed coat formation and a number of lipid transfer proteins involved in embryo pattern formation. At 35 DAP, transcripts encoding napin, cruciferin and oleosin storage proteins were most abundant. Over both time-points, 18.6 % of A. thaliana genes were matched by Brassica ESTs detected by LongSAGE tags in antisense orientation. This suggests a strong involvement of antisense transcript expression in regulatory processes during B. napus seed development.
Project description:Time course of gene expression profiles during seed development and maturation in Brassica napus were studied using Combimatrix Brassica microarray. The time course expression of 90K Brassica napus EST contigs were measured at 8 developing seed stages of 10, 15, 20, 25, 30, 35, 40 and 45 DAF (days after flowering) using single color microarray
Project description:We present an atlas of global gene expression covering embryo and seed coat development in B. rapa, B. nigra, B. oleracea, B. juncea, B. napus and B. carinata, providing insights into the evolution of gene expression in embryogenesis and seed development of brassica species.
Project description:MicroRNAs (miRNAs) are important post-transcriptional regulators of plant development and seed formation. In Brassica napus, an important edible oil crop, valuable lipids are synthesized and stored in specific seed tissues during embryogenesis. The miRNA transcriptome of B. napus is currently poorly characterized, especially at different seed developmental stages. This work aims to describe the miRNAome of developing seeds of B. napus by identifying plant-conserved and novel miRNAs and comparing miRNA abundance in mature versus developing seeds. A total of 62 miRNA families were detected through a computational analysis of a large number of reads obtained from deep sequencing two small RNA and two RNA-seq libraries of (i) pooled immature developing stages and (ii) mature B. napus seeds. Among these miRNA families, 17 families are currently known to exist in B. napus; additionally, 32 families not reported in B. napus but conserved in other plant species were identified by alignment with known plant mature miRNAs. The contigs from the assembled mRNA-seq data allowed for a search for putative new precursors and led to the identification of 13 novel miRNA families. Differential expression between the libraries was determined through a statistical analysis of normalized miRNA reads and revealed several miRNAs and isomiRNAs that were more abundant during the developing stages. The predicted miRNA target genes encode a broad range of proteins related to seed development and energy storage. This work presents a comprehensive study of the miRNA transcriptome of B. napus seeds and will provide a basis for future research on more targeted studies of individual miRNAs and their functions in embryogenesis, seed maturation and lipid accumulation in B. napus. RNA profiles in 2 different seed libraries (mature seeds and a pool of developing seed stages) of Brassica napus by deep sequencing (Illumina HiSeq2000).
Project description:MicroRNAs (miRNAs) are important post-transcriptional regulators of plant development and seed formation. In Brassica napus, an important edible oil crop, valuable lipids are synthesized and stored in specific seed tissues during embryogenesis. The miRNA transcriptome of B. napus is currently poorly characterized, especially at different seed developmental stages. This work aims to describe the miRNAome of developing seeds of B. napus by identifying plant-conserved and novel miRNAs and comparing miRNA abundance in mature versus developing seeds. A total of 62 miRNA families were detected through a computational analysis of a large number of reads obtained from deep sequencing two small RNA and two RNA-seq libraries of (i) pooled immature developing stages and (ii) mature B. napus seeds. Among these miRNA families, 17 families are currently known to exist in B. napus; additionally, 32 families not reported in B. napus but conserved in other plant species were identified by alignment with known plant mature miRNAs. The contigs from the assembled mRNA-seq data allowed for a search for putative new precursors and led to the identification of 13 novel miRNA families. Differential expression between the libraries was determined through a statistical analysis of normalized miRNA reads and revealed several miRNAs and isomiRNAs that were more abundant during the developing stages. The predicted miRNA target genes encode a broad range of proteins related to seed development and energy storage. This work presents a comprehensive study of the miRNA transcriptome of B. napus seeds and will provide a basis for future research on more targeted studies of individual miRNAs and their functions in embryogenesis, seed maturation and lipid accumulation in B. napus. microRNA profiles in 2 different seed libraries (mature seeds and a pool of developing seed stages) of Brassica napus by deep sequencing (Illumina HiSeq2000).
Project description:MicroRNAs (miRNAs) are important post-transcriptional regulators of plant development and seed formation. In Brassica napus, an important edible oil crop, valuable lipids are synthesized and stored in specific seed tissues during embryogenesis. The miRNA transcriptome of B. napus is currently poorly characterized, especially at different seed developmental stages. This work aims to describe the miRNAome of developing seeds of B. napus by identifying plant-conserved and novel miRNAs and comparing miRNA abundance in mature versus developing seeds. A total of 62 miRNA families were detected through a computational analysis of a large number of reads obtained from deep sequencing two small RNA and two RNA-seq libraries of (i) pooled immature developing stages and (ii) mature B. napus seeds. Among these miRNA families, 17 families are currently known to exist in B. napus; additionally, 32 families not reported in B. napus but conserved in other plant species were identified by alignment with known plant mature miRNAs. The contigs from the assembled mRNA-seq data allowed for a search for putative new precursors and led to the identification of 13 novel miRNA families. Differential expression between the libraries was determined through a statistical analysis of normalized miRNA reads and revealed several miRNAs and isomiRNAs that were more abundant during the developing stages. The predicted miRNA target genes encode a broad range of proteins related to seed development and energy storage. This work presents a comprehensive study of the miRNA transcriptome of B. napus seeds and will provide a basis for future research on more targeted studies of individual miRNAs and their functions in embryogenesis, seed maturation and lipid accumulation in B. napus.