Project description:Transcriptome sequencing (RNA-seq) was used to sequence the leaves of Xanthoceras sorbifolia Bunge under low nitrogen, so as to analyze the resistance of Xanthoceras sorbifolia Bunge to low nitrogen.
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:We present results from deep sequencing of small RNA populations from several genotypes of soybean and demonstrate that the CHS siRNAs accumulated only in the seed coats of the yellow varieties having either the dominant I or i-i alleles and not in the pigmented seed coats with homozygous recessive i genotypes. However, the diagnostic CHS siRNAs did not accumulate in the cotyledons of genotypes with the dominant I or i-i alleles thus demonstrating the novelty of an endogenous inverted repeat region of CHS genes driving RNA silencing in trans of non-linked CHS family members in a tissue-specific manner. The phenomenon results in inhibition of a metabolic pathway by siRNAs in one tissue allowing expression of the flavonoid pathway and synthesis of secondary metabolites in other organs as the chalcone synthase small RNAs are found in the seed coats of yellow seeded soybean varieties but not in the cotyledons of the same genotype. In order to compare the population of chalcone synthase related small RNAs, we sequenced 3 to 6 million small RNAs using the Illumina Genome Analyzer from the following four soybean cultivars and tissues with specific genotypes at the I locus: Richland immature seed coats (homozygous for the dominant I allele that specifies yellow seed coat); Williams immature seed coats (homozygous for the dominant i-i allele that specifies yellow seed coat with pigmented hilum) Williams (i-i/i-i yellow) immature cotyledons (homozygous for the dominant i-i allele that specifies yellow seed coat with pigmented hilum); Williams 55 immature seed coats (a Williams isogenic line homozygous for the recessive i allele that specifics pigmented seed coats. All seed coats and cotyledons were dissected from green stage immature seeds within the fresh weight range of 50-75 mg.
Project description:To identify the important genetic resources of tea oil accumulation and quality formation in Camellia oleifera, an important woody edible oil tree native to Southern China, we have designed and customized an expression profile chip of C. oleifera with 8×60 K on the basis of transcriptome sequencing of multiple tissue samples including kernels, roots, and leaves from multiple varieties. we used the mcroarrays to determine the gene expressions in kernel development of C. oleifera elite varieties'Huashuo' , 'Huaxin' , 'Huajin' and 'Jujian' respectively. Microarray results indicated a total of 10710 gene probes showed stable differential expression in the comparation of August vs June and 9987 in the comparation of October vs August. PATHWAY enrichment results of DEGs indicated that the oil synthesis and accumulation occured in the whole kernel development of C. oleifera, but were mainly concentrated from the nutrition high-speed synthesis period to the seed mature period, which was consistent with the variation trend of oil content and fatty acide composition in C. oleifera kernel development.
Project description:Higher temperature conditions during the final stages of rice seed development (seed filling and maturation) are known to cause damage to both rice yield and rice kernel quality. Japan, especially western and central parts, has seen record high temperatures in the last decade, and the rice kernel quality has decreased; specifically a reduction the first-grade of rice has been seen. In this study, we specifically looked at the harvested rice in a town of the central Kanto-plains (Japan) during the year 2010, which saw day-time temperatures go above the critical limits ranging from 34 to 38C at the final stages of seed development and maturity to investigate high-temperature effects in the actual field condition. Three sets of dry mature rice seeds (commercial) were obtained Japan Agriculture (JA Zen-Noh) branch in Ami-town of Ibaraki prefecture in September 2010, as grade 1 (labeled as Y1), grade 2 (labeled as Y2), and grade 3 (out-of-grade, labeled as Y3). The research objective was to examine in particular alterations in gene expressions genome-wide in grade 2 (Y2) and grade 3 (Y3) seeds over the grade 1 (Y1) following the high-temperature spike using a high-throughput omic-approach DNA microarray (Agilent 4 x 44K rice oligo DNA chip) in conjunction with MapMan bioinformatics analysis. Rice seed quality analysis revealed, as expected, low quality in Y3 > Y2 over Y1, in taste, amylose, protein and fatty acid degree, but not in water content. Transcriptome profiling data revealed 124 and 373 up-regulated and 106 and 129 down-regulated genes in Y2 and Y3, respectively. Bioinformatics analysis of differentially expressed genes revealed changes in function of genes related to metabolism, including starch metabolism (e.g., alpha amylase), defense/stress response, fatty acid biosynthesis and hormones. This research provides for the first time the seed transcriptome profile for the classified low grades (2 and out-of-grade) of rice under an actual stressed environmental condition of high temperature.
Project description:Permeability is a crucial trait that affects seed longevity and is regulated by different polymers including proanthocyanidins, suberin, cutin and lignin located in the seed coat. By testing mutants in suberin transport and biosynthesis, we demonstrate the importance of this biopolymer to cope with seed deterioration. Transcriptomic analysis of cog1‐2D, a gain‐of‐function mutant with increased seed longevity, revealed the upregulation of several peroxidase genes. Reverse genetics analysing seed longevity uncovered redundancy within the seed coat peroxidase gene family, however after controlled deterioration treatment, seeds from the prx2 prx25 double and prx2 prx25 prx71 triple mutant plants presented lower germination than wild‐type plants. Transmission electron microscopy (TEM) analysis of the seed coat of these mutants showed a thinner palisade layer, but no changes were observed in proanthocyanidin accumulation or in the cuticle layer. Spectrophotometric quantification of acetyl bromide‐soluble lignin components indicated changes in the amount of total polyphenolics derived from suberin and/or lignin in the mutant seeds. Finally, the increased seed coat permeability to tetrazolium salts observed in the prx2 prx25 and prx2 prx25 prx71 mutant lines suggested that the lower permeability of the seed coats caused by altered polyphenolics is likely to be the main reason explaining their reduced seed longevity.
Project description:Thlaspi arvense (Pennycress) is an emerging feedstock for biofuel production because of its high seed oil content enriched in erucic acid. A transcriptomic and a lipidomic study were performed to analyze the dynamics of gene expression, glycerolipid content and acyl-group distribution during seed maturation. Genes involved in fatty acid biosynthesis were expressed at the early stages of seed maturation. Genes encoding enzymes of the Kennedy pathway like TaDGAT1, TaLPAT or TaGPAT increased their expression with maturation, coinciding with the increase in TAG species containing 22:1. Positional analysis showed that the most abundant TAG species contained 18:2 at sn-2 position in all maturation stages, suggesting no specificity of the TaLPAT for VLCFAs. TaDGAT2 mRNA was more abundant at the initial maturation stages, coincident with the rapid incorporation of 22:1 to TAG, suggesting a coordination between DGAT enzymes for TAG biosynthesis. Genes encoding TaPDAT1, TaLPCAT or TaPDCT, involved in acyl-editing or PC-derived DAG/TAG biosynthesis showed also higher expression at the early maturation stages, coinciding with a higher proportion of TAG species containing C18 fatty acids. These results suggested a higher contribution of these two pathways at the early stages of seed maturation. LC-MS analysis of the content and acyl-group distribution of DAG and PC pools was compatible with the acyl content in TAG at the different maturation stages. Our data point to a model in which a strong temporal coordination between pathways and isoforms in each pathway, both at the expression and acyl-group incorporation, contributes to high erucic TAG accumulation in Pennycress.