Project description:The I locus is a 27-kb inverted repeat cluster of chalcone synthase genes CHS1-3-4 that mediates siRNA down-regulation of CHS7 and CHS8 target mRNAs during seed development leading to yellow seed coats lacking anthocyanin pigments. Here, we report small RNA sequencing of ten stages of seed development from a few days post fertilization through maturity, revealing the amplification from primary to secondary short interfering RNAs (siRNAs) occurring during development. The young seed populations had a higher proportion of siRNAs representing the CHS1-3-4 gene family members, consistent with this region as the origin of the primary siRNAs. More intriguingly, the very young seed had a higher proportion of 22-nt CHS siRNAs than did the mid-maturation seed. We infer that the primary CHS siRNAs increase during development to levels sufficient to trigger amplification of secondary CHS siRNAs from the CHS7/8 target mRNAs, enabling the total levels of 21-nt CHS siRNAs to rise dramatically. Further, we demonstrate that the soybean system exhibits tissue-specific CHS siRNA production because primary CHS siRNA levels are not sufficient to trigger secondary amplification in tissues other than the seed coat. High-throughput sequencing using Genome Analyzer II and Illumina HiSeq 2000 was performed with two biological replicates (Some stages don't have replicate).
Project description:The I locus is a 27-kb inverted repeat cluster of chalcone synthase genes CHS1-3-4 that mediates siRNA down-regulation of CHS7 and CHS8 target mRNAs during seed development leading to yellow seed coats lacking anthocyanin pigments. Here, we report small RNA sequencing of ten stages of seed development from a few days post fertilization through maturity, revealing the amplification from primary to secondary short interfering RNAs (siRNAs) occurring during development. The young seed populations had a higher proportion of siRNAs representing the CHS1-3-4 gene family members, consistent with this region as the origin of the primary siRNAs. More intriguingly, the very young seed had a higher proportion of 22-nt CHS siRNAs than did the mid-maturation seed. We infer that the primary CHS siRNAs increase during development to levels sufficient to trigger amplification of secondary CHS siRNAs from the CHS7/8 target mRNAs, enabling the total levels of 21-nt CHS siRNAs to rise dramatically. Further, we demonstrate that the soybean system exhibits tissue-specific CHS siRNA production because primary CHS siRNA levels are not sufficient to trigger secondary amplification in tissues other than the seed coat.
Project description:Background: Pollen, the male partner in the reproduction of flowering plants, comprises either two or three cells at maturity. The current knowledge of the pollen transcriptome is limited to the model plant Arabidopsis thaliana, which has tri-cellular pollen grains at maturity. Comparative studies on pollen of other genera, particularly crop plants, are needed to understand the pollen gene networks that are subject to functional and evolutionary conservation. In this study, we used the Affymetrix Soybean GeneChip® to perform transcriptional profiling on mature bi-cellular soybean pollen. Results: Compared to the sporophyte transcriptome, the soybean pollen transcriptome revealed a restricted and unique repertoire of genes, with a significantly greater proportion of specifically expressed genes than is found in the sporophyte tissue. Comparative analysis shows that, among the 37,500 soybean unique transcripts addressed in this study, 10,299 genes (27.46%) are expressed in pollen. Of the pollen-expressed genes, about 9,489 (92.13%) are also expressed in sporophytic tissues, and 810 (7.87%) are selectively expressed in pollen. Overall, the soybean pollen transcriptome shows an enrichment of transcription factors (mostly zinc finger family proteins), cell cycle-related transcripts, signal recognition receptors, ethylene responsive factors, chromatin remodeling factors, and members of the ubiquitin proteasome proteolytic pathway. Moreover, we identify several new pollen-specific candidate genes that might play a significant role in pollen biology. Conclusion: This is the first report of a soybean pollen transcriptional profile. These data extend our current knowledge regarding regulatory pathways that govern the gene regulation and development of pollen. We also demonstrate that pollen is a rich store of regulatory proteins that are essential and sufficient for de novo gene expression. A comparison between transcription factors up-regulated in soybean and those upregulated in Arabidopsis revealed some divergence in the numbers and kinds of regulatory proteins expressed in both species.
Project description:Controlled deterioration treatment (CDT) negatively affects the seed quality and vigor during post-harvest storage. A label-free proteomic approach was utilized to understand the CDT responses in soybean seeds. Soybean seed are rich in seed-storage proteins (SSPs) constituting up to 70 to 80% of the total seed protein content. Due to the presence of these SSPs, it is very difficult to identify and/or characterize the low-abundance regulatory proteins. Availability of appropriate methods for extraction of low-abundance proteins (LAPs) are now providing a platform for the identification of novel proteins involved in the signal perception and transduction during environmental perturbations. To enrich LAPs, the extracted total seed proteins were subjected to protamine sulfate precipitation (PSP) method to deplete SSPs. Fractionated protein fractions thus prepared were analyzed for identification of differential proteins using Label-free quantitative proteomics approaches.
Project description:Ten mutants with altered seed composition traits were identified in a soybean fast neutron population (Bolon et al. 2014). These mutant lines were maintained to an advanced generation (ranging between M5 and M9) and compared to their wild-type parent (M92-220-Long) using CGH to identify the causative region/gene associated with the seed composition changes.