Project description:Using high-throughput RNA sequencing, we developed a spatiotemporal transcriptome atlas for seed development of eight maize inbred lines based on 144 samples from the middle to late stages of grain development. A total of 26,747 genes with FPKM value more than 1 at least one sample were found to be involved in programming grain development. Global comparisons of genes expression highlighted the fundamental transcriptomic reprogramming and the phases of development. Coexpression analysis provided further insight into the dynamic reprogramming of the transcriptome by revealing functional transitions during maturation. Combined with grain moisture content and grain dehydration rate of different developmental time points of eight maize inbred lines, we captured a large number of genes related to grain moisture content and grain dehydration rate, which should help elucidate key mechanisms and regulatory networks that underlie grain dehydration during maize grain development. These results provide a comprehensive understanding of which biological processes are involved in the regulation of moisture variety of maize grain, the general principles of which provide a new perspective on improving maize grain dehydration characteristics. Meanwhile, this study provides a valuable resource for understanding the genetic regulation of maize grain development.
Project description:Purpose: To identify the potential genes that regulate seed germination speed in maize, we performed a time-series transcriptome analysis with two inbred maize lines (72-3 fast germination, F9721 slow germination) during the seed germination and compared the differentially expressed genes (DEGs) in transcriptome with genes identified by GWAS Methods: Methods: mRNA profiles of two maize inbred lines 72-3 and F9721 showing divergent seed germination at six stages during germination were generated by deep sequencing, in triplicate, using Illumina Hiseq2500. The sequence reads that passed quality filters were analyzed at the gene level. Hisat2 was used to align clean reads to maize B73 reference genome, and HTSeq was used to count transcript abundance. DESeq2 models were used to compare DEGs at each germination stage within or between samples Results: Comparative transcriptome study identified 12 hours after imbibition (HAI) as the critical stage responsible for the variation of germination speed. The DEGs between 72-3 and F9721 were mainly enriched in metabolic pathways, biosynthesis of secondary metabolites, oxidoreductase activity pathways, hormone signal transduction, and amino acid transporter activity pathways Conclusions: Combined with evidence from gene expression data, GWAS, and gene synteny with other model species, we finally anchored three genes as the likely candidate genes regulating germination speed in maize
Project description:To acknowledge the molecular mechanisms underlying maize salt tolerance, two maize inbred lines, including salt-tolerant 8723 and salt-sensitive P138, were used in this study. Comparative proteomics of seedling roots from two maize inbred lines under 180 mM salt stress for 10 days was performed by the isobaric tags for relative and absolute quantitation (iTRAQ) approach. We obtained a total of 336237 spectra. 30616 peptides and a total of 7505 proteins were identified with 1% FDR. A total of 7505 differentially expressed proteins (DEPs) were identified. 626 DEPs were identified in line 8723 under salt stress, among them, 378 up-regulated and 248 down-regulated. 473 DEPs were identified in P138, of which 212 were up-regulated and 261 were down-regulated. Venn diagram analysis showed that 17 DEPs were up-regulated and 12 DEPs were down-regulated in the two inbred lines. In addition, 8 DEPs were up-regulated in line 8723 but down-regulated in P138, 6 DEPs were down-regulated in line 8723 but up-regulated in P138. In salt-stressed 8723, the DEPs were primarily associated with phenylpropanoid biosynthesis, starch and sucrose metabolism, and the MAPK signaling pathway. Intriguingly, the DEPs were only associated with the nitrogen metabolism pathway in P138. Compared to P138, the root response to salt stress in 8723 could maintain stronger water retention capacity, osmotic regulation ability, synergistic effects of antioxidant enzymes, energy supply capacity, signal transduction, ammonia detoxification ability, lipid metabolism, and nucleic acid synthesis. Based on the proteome sequencing information, changes in the abundance of 8 DEPs were correlated with the corresponding mRNA levels. Our results from this study may elucidate some details of salt tolerance mechanisms and salt tolerance breeding of maize.
Project description:Methylation of chromosomal DNA in animals and plants is a fundamental mechanism of epigenetic regulation, and the maize genome, with its diverse complement of transposons and repeats, is a paradigm for transgenerational mechanisms such as paramutation and imprinting. We have determined the genome-wide cytosine methylation map of two maize inbred lines, B73 and Mo17, at high coverage and at single nucleotide resolution. Transposon methylation is highest in CG (65%) and CHG (50%) contexts (where H = A, C or T), while methylation in CHH (5%) contexts is guided by 24nt small interfering RNA (siRNA), and not by 21-22nt siRNA. We have found that CG (8%) methylation seems to deter insertion of Mutator transposons into exons, while CHH and CHG methylation at splice donor and acceptor sites strongly inhibits RNA splicing. Methylation differences between parents are inherited in recombinant inbred lines, but methylation switches, guided by siRNA, are widespread and persist for up to 8 generations. These differences influence splicing, and recurrent switching suggest that paramutation is much more common than previously supposed, and may contribute to heterosis. Our results provide a comprehensive high resolution resource for maize genome methylation, as well as a map of recurrent transgenerational epigenetic shifts (paramutation) in the two most commonly used inbred maize lines. Genome-wide cytosine methylation map in 2 maize strains by bisulfite sequencing, and RNA and small RNA profiles in the same tissue using Illumina platform.
Project description:Two maize inbred lines, DAN3130 and JI63, with different patterns of folate accumulation and different total folate contents in mature kernels were used to investigate the transcriptional regulation of folate metabolism during late stages of kernel formation by comparative transcriptome analysis; The fresh kernel samples of each inbred line were collected on DAP 24, DAP 35 days, respectively. Mature kernel samples were harvested after all the plants turned yellow. Three biological replicates of each sample were collected, and total RNA with high quality was pooled and sent for sequencing. Total RNA of high quality was pooled for transcriptome analysis, and raw RNA-seq data of DAP 24, DAP35 and mature kernels for both two inbred lines were obtained. The folate accumulation during DAP 24 to mature kernels could be controlled by circumjacent pathways of folate biosynthesis, such as pyruvate metabolism, glutamate metabolism and serine/glycine metabolism. In addition, the folate variation between these two inbred lines was related to those genes among folate metabolism, such as genes in the pteridine branch, ρ-ABA branch, serine/THF/5-M-THF cycle and the conversion of tetrahydrofolate monoglutamate to tetrahydrofolate polyglutamate; The findings provided insight into folate accumulation mechanisms during maize kernel formation to promote folate biofortification.
Project description:Profiles of primary metabolites in the shoots of juvenile maize inbred lines in the Goodman association panel were analyzed by GC-TOFMS to identify genetic components associated with metabolic control and plant performance. The samples also include those from landrace lines and maize wild relatives.
Project description:We explored the gene expression profiles of developing maize kernel by RNA sequencing. Our purpose was to explore the sequence diversity across the inbred lines, especially in the gene regions, and to discover the gene regulatory networks employed in immature maize kernels.
Project description:This SuperSeries is composed of the following subset Series:; GSE8174: Cis-transcriptional variation in maize inbred lines B73 and Mo17 leads to additive expression - Seedling data; GSE8176: Cis-transcriptional variation in maize inbred lines B73 and Mo17 leads to additive expression - Immature ear data; GSE8179: Cis-transcriptional variation in maize inbred lines B73 and Mo17 leads to additive expression - Embryo data Experiment Overall Design: Refer to individual Series
Project description:High temperature is increasingly becoming one of the prominent environmental factors affecting the growth and development of maize (Zea mays L.). Therefore, it is critical to identify key genes and pathways related to heat stress (HS) tolerance in maize. Here, we identified a heat-resistant (Z58D) and heat-sensitive (AF171) maize inbred lines at seedling stage. Transcriptomic analysis identified 3,006 differentially expressed genes (DEGs) in AF171 and 4,273 DEGs in Z58D under HS treatments, respectively. Subsequently, GO enrichment analysis showed that shared upregulated genes in AF171 and Z58D involved in response to HS, protein folding, abiotic and temperature stimulus pathway. Moreover, the comparison between the two inbred lines under HS showed that response to heat and response to temperature stimulus significantly overrepresented for the 1,234 upregulated genes. Furthermore, commonly upregulated genes in Z58D and AF171 had higher expression level in Z58D than AF171. In addition, maize inbred CIMBL55 had been verified to be more tolerant than B73 and commonly upregulated genes had higher expression level in CIMBL55 than B73 under HS. The consistent results indicated that heat-resistant inbred lines may coordinate the remarkable expression of genes in order to recover from HS. Additionally, 35 DEGs were conserved among 5 inbred lines by a comparative transcriptomic analysis. Most of them were more pronounced in Z58D than AF171 at expression level. Those candidate genes may confer thermotolerance in maize.
Project description:we used mass spectrometto perform an integrated analysis of proteome e in an association panel consisting of 98 maize inbred lines.