Project description:The gynoecium is one of the most complex organs of angiosperms specialized for seed production and dispersal, but only several genes important for ovule or embryo sac development were identified by using female sterile mutants. The female sterility in oilseed rape (Brassica napus) was before found to be related with one alien chromosome from another crucifer Orychophragmus violaceus. Herein, the developmental anatomy and comparative transcript profiling (RNA-seq) for the female sterility were performed to reveal the genes and possible metabolic pathways behind the formation of the damaged gynoecium. Using Brassica_ 95k_ unigene as the reference genome, a total of 28,065 and 27,653 unigenes were identified to be transcribed in S1 and H3, respectively, suggesting the newly initiated transcriptions in S1. Further comparison of the transcript abundance between S1 and H3 revealed that 4540 unigenes showed more than two fold expression difference. Gene ontology and pathway enrichment analysis of the Differentially Expressed Genes (DEGs) revealed that a number of important genes and metabolism pathways were involved in the development of gynoecium, embryo sac, ovule, integuments as well as the interactions between pollen and pistil. DEGs for the ovule development were detected to function in the metabolism pathways regulating brassinosteroid (BR) biosynthesis, adaxial/abaxial axis specification, auxin transport and signaling. A model was proposed to show the possible roles and interactions of these pathways for the sterile gynoecium development. The results provided new information for the molecular mechanisms behind the gynoecium development at early stage in B. napus.
Project description:Background: The fertile and sterile plants are derived from the self-pollinated offspring of the F1 hybrid between novel restorer line NR1 and Nsa CMS line in Brassica napus, which possess the identical cytoplasmic genetic material arising from Nsa CMS line. As far as the nuclear genetic background is concerned, both fertile and sterile plants have the complete set of chromosomes from Brassica napus, except one or two members of the added Sinapis arvensis chromosome pair in the fertile plant. To elucidate gene expression and regulation caused by the A and C subgenomes, the alien chromosome and cytoplasm from S. arvensis during the development of young floral buds, we performed genome-widely high-throughput transcriptomic sequencing between young floral buds of sterile and fertile plants. Results: In this study, equal amount of RNA taken from young floral buds of sterile and fertile plants were sequenced using Illumina/Solexa platform. A total of 4,415,866 and 4,244,140 raw tags were obtained in sterile plant (Ste) and fertile plant (Fer) libraries, respectively. After filtering out low quality data, a total of 2,760,574 and 2,714,441 clean tags remained from the two libraries, from which 242,163 (Ste) and 253,507 (Fer) distinct tags were obtained. To identify the genes corresponding to the distinct tags in each library, all distinct sequencing tags were annotated using all possible CATG+17-nt sequences of the genome and transcriptome of Brassica rapa and those of Brassica oleracea as the reference sequences, respectively. Many genes showed substantial differences in expression between the two libraries. In total, there were 3231 genes of B. rapa and 3371 genes of B. oleracea which were detected with significant differential expression levels. GO and pathway-based analyses were performed to determine and further understand the biological functions of differentially expressed genes (DEGs). In addition, there were 1089 specially expressed unknown tags in Fer, which were neither mapped to B. oleracea nor mapped to B. rapa, and these unique tags were presumed to arise basically from the added alien chromosome of S. arvensis. Fifteen genes were randomly selected and confirmed their expression levels by quantitative RT-PCR, fourteen of the fifteen genes showed expression patterns consistent with the digital gene expression (DGE) data. Conclusions: A number of genes were differentially expressed between the young floral buds of sterile and fertile plants. Some of these genes may be candidates for future research on CMS in Nsa line, fertility restoration and improved agronomic traits in NR1 line. Further study of the unknown tags which were specially expressed in Fer will help to dig those genes with desirable agronomic traits from wild species. mRNA profiles of fertile buds (Fer) and sterile buds (Ste) were generated by deep sequencing.
Project description:Background: The fertile and sterile plants are derived from the self-pollinated offspring of the F1 hybrid between novel restorer line NR1 and Nsa CMS line in Brassica napus, which possess the identical cytoplasmic genetic material arising from Nsa CMS line. As far as the nuclear genetic background is concerned, both fertile and sterile plants have the complete set of chromosomes from Brassica napus, except one or two members of the added Sinapis arvensis chromosome pair in the fertile plant. To elucidate gene expression and regulation caused by the A and C subgenomes, the alien chromosome and cytoplasm from S. arvensis during the development of young floral buds, we performed genome-widely high-throughput transcriptomic sequencing between young floral buds of sterile and fertile plants. Results: In this study, equal amount of RNA taken from young floral buds of sterile and fertile plants were sequenced using Illumina/Solexa platform. A total of 4,415,866 and 4,244,140 raw tags were obtained in sterile plant (Ste) and fertile plant (Fer) libraries, respectively. After filtering out low quality data, a total of 2,760,574 and 2,714,441 clean tags remained from the two libraries, from which 242,163 (Ste) and 253,507 (Fer) distinct tags were obtained. To identify the genes corresponding to the distinct tags in each library, all distinct sequencing tags were annotated using all possible CATG+17-nt sequences of the genome and transcriptome of Brassica rapa and those of Brassica oleracea as the reference sequences, respectively. Many genes showed substantial differences in expression between the two libraries. In total, there were 3231 genes of B. rapa and 3371 genes of B. oleracea which were detected with significant differential expression levels. GO and pathway-based analyses were performed to determine and further understand the biological functions of differentially expressed genes (DEGs). In addition, there were 1089 specially expressed unknown tags in Fer, which were neither mapped to B. oleracea nor mapped to B. rapa, and these unique tags were presumed to arise basically from the added alien chromosome of S. arvensis. Fifteen genes were randomly selected and confirmed their expression levels by quantitative RT-PCR, fourteen of the fifteen genes showed expression patterns consistent with the digital gene expression (DGE) data. Conclusions: A number of genes were differentially expressed between the young floral buds of sterile and fertile plants. Some of these genes may be candidates for future research on CMS in Nsa line, fertility restoration and improved agronomic traits in NR1 line. Further study of the unknown tags which were specially expressed in Fer will help to dig those genes with desirable agronomic traits from wild species.
Project description:Alien chromosome substitution lines are vital germplasm for breeding and genetic mapping. Previously, a whole set of nine Brassica rapa-oleracea monosonic alien addition lines (MAALs, C1-C9) was established in the background of natural B. napus genotype “Oro”, after the restituted B. rapa (RBR) for Oro was realized. Herein, a monosomic substitution line with one alien C1 chromosome (Cs1) in the RBR complement was selected in the progenies of MAAL C1 and RBR, by the PCR amplification of specific gene markers and fluorescence in situ hybridization. Cs1 exhibited the whole plant morphology similar to RBR except for the defective stamens without fertile pollen grains, but it produced some seeds and progeny plants carrying the C1 chromosome at high rate besides those without the alien chromosome after pollination by RBR. The viability of the substitution and its progeny for the restituted B. rapa diploid further elucidated the functional compensation between the chromosome pairs with high homoeology. To reveal the impact of such aneuploidy on genome-wide gene expression, the transcriptomes of MAAL C1, Cs1 and euploid RBR were analyzed. Compared to RBR, Cs1 had sharply reduced gene expression level across chromosome A1, demonstrating the loss of one copy of A1 chromosome. Both additional chromosome C1 in MAAL and substitutional chromosome C1 in Cs1 caused not only cis-effect but also prevalent trans-effect differentially expressed genes. A dominant gene dosage effects prevailed among low expressed genes across chromosome A1 in Cs1, and moreover, dosage effects for some genes potentially contributed to the phenotype deviations. Our results provided novel insights into the transcriptomic perturbation and gene dosage effects on phenotype in chromosome substitution related to one naturally evolved allopolyploid.
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: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:This study aimed to evaluate the effects of UV-B wavelength regions (< 300 nm) in canola plants (Brassica napus L.). Agilent One-Color Gene Expression Microarray analysis was conducted using an Agilent-022520 Brassica napus 4x44K Array.
Project description:Time course of gene expression profiles during seed development and maturation in Brassica napus were studied using Combimatrix Brassica microarray.
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