Project description:The effect of the number of pods on the main inflorescence (NPMIs) on seed yield in Brassica napus plants grown at high density is a topic of great economic and scientific interest. We sought to identify patterns of gene expression that are associated with inflorescence and PMI differentiation and development in Brassica napus.
Project description:High temperature stress results in yield loss and alterations to seed composition during seed filling in oilseed rape (Brassica napus). However, the mechanism underlying this heat response is poorly understood. In this study, we employed a microarray analysis with silique walls and seeds from the developing siliques (20 days after flowering) of Brassica napus that had undergone heat stress.
Project description:High temperature stress results in yield loss and alterations to seed composition during seed filling in oilseed rape (Brassica napus). However, the mechanism underlying this heat response is poorly understood. In this study, we employed a microarray analysis with silique walls and seeds from the developing siliques (20 days after flowering) of Brassica napus that had undergone heat stress. Two-condition experiment, control vs heat stress, 2 time points
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:Time course of gene expression profiles during seed development and maturation in Brassica napus were studied using Combimatrix Brassica microarray.
Project description:Gene expression profiles during seed development and fatty acid (FA) metabolism, as well as the relevant regulation, of Brassica napus were studied through multiple high-throughput genomic approaches. Serial Analysis of Gene Expression (SAGE) using seed materials obtained a total of 68,718 tags, of which 23,897 were unique and 503 tags were functionally identified, and revealed the transcriptome of approximately 35,000 transcripts in B. napus developing seeds. Further, ~22,000 independent ESTs were obtained by large-scale sequencing using immature embryos at different stages, and 8343 uni-ESTs and 3355 full-length cDNAs were identified respectively, resulting in the systemic identification of B. napus FA biosynthesis-related genes. Gene expression profiles were further studied employing cDNA chip hybridization to reveal the global regulatory network of FA metabolism in developing seeds. Together with the analysis on FA amounts and composition, it was shown that 17-21 days after pollination (DAP) was a crucial stage for transition of seed to sink tissue. High expressions of FA biosynthesis-related genes and transition of FA components are mainly at stages 21 DAP or 21-25 DAP respectively. In addition, compared to Arabidopsis, more critical roles of starch metabolism are detected for B. napus seed FA metabolism and storage components accumulation. Crucial effects of starch metabolism, carbon flux, oxidative pentose phosphate pathway (OPPP), photosynthesis, and other regulators in FA metabolism were discussed. Keywords: Brassica napus, immature seed, SAGE, EST, cDNA microarray
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: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:Illumina mRNA-Seq is comparable to microarray analysis for transcript quantification but has increased sensitivity and, importantly, the potential to distinguish between homoeologous genes in polyploids. Using a novel curing process, we adapted a reference sequence that was a consensus derived from ESTs from both Brassica A and C genomes to one containing A and C genome versions for each of the 94,558 original unigenes. We aligned reads from Brassica napus to this cured reference, finding 38% more reads mapping in resynthesised lines and 28% in natural lines. Where the A and C versions differed at single nucleotide positions, termed inter-homoeologue polymorphisms (IHPs), we were able to apportion expression in the polyploid to the A or C genome homoeologues. 43,761 unigenes contained at least one IHP, with a mean frequency of 10.5 per kb unigene sequence. 6,350 of the unigenes with IHPs were differentially expressed between homoeologous gene pairs in resynthesised B. napus. 3,212 unigenes showed a similar pattern of differential expression across a range of natural B. napus crop varieties and, of these, 995 were in common with resynthesised B. napus. Functional classification showed over-representation in gene ontology categories not associated with dosage-sensitivity.
Project description:In species with exalbuminous seeds such as crucifer oilseeds and legumes, the endosperm is eventually consumed and its space occupied by the embryo during seed development. However, the main constituent of the early developing seed is the liquid endosperm, and most of the carbon resources for the ensuing stages of seed development arrive at the embryo through the endosperm. In contrast to the extensive study of species with persistent endosperm, little is known about the global gene expression pattern in the endosperm of exalbuminous seed species. We took a multiparallel approach that combines ESTs, protein profiling and microarray analyses to look into the gene expression landscape in the endosperm of the oilseed crop Brassica napus. An EST collection of over 30,000 entries allowed us to detect close to 10,000 unisequences expressed in the endosperm. A protein profile analysis of more than 800 proteins corroborated several signature pathways uncovered by abundant ESTs. Using microarray analyses, we identified genes that are differentially or highly expressed across all developmental stages. These complementary analyses provided insight on several prominent metabolic pathways in the endosperm. We also discovered that LEC1 was highly expressed in the endosperm and that the regulatory cascade downstream of LEC1 operates in the endosperm. The endosperm EST collection and the microarray dataset provide a basic genomic resource for dissecting metabolic and developmental events important for oilseed improvement. Our findings on the featured metabolic processes and the LEC1 regulatory cascade offer new angles for investigation on the integration of endosperm gene expression with embryo development and storage product deposition in seed development. Keywords: seed development