Project description:We have used genome-wide proteomic profiling to examine leaves of hybrids for molecular phenotypes. Profiles of the proteome of maize leaves revealed hybrid-specific differences in the chloroplast and mitochondria; levels of their energy transduction complexes and ribosomes were selectively elevated 10-20% above mid-parent levels. Each of these protein machines is comprised of nuclear-encoded and organelle-encoded subunits and we refer to them as digenomic protein complexes. Expression heterosis of the organelle ribosome proteins was quantitatively predictive of growth heterosis in a set of hybrids. Ethylene biosynthetic enzyme levels were reduced in hybrids and an ethylene biosynthesis mutant in an inbred background partially phenocopied the molecular differences seen in hybrids indicating that reduced ethylene levels may play a role in maize heterosis.
Project description:Expression profiling analyses for 5 maize inbreds and 4 hybrids, chosen to represent diversity in genotypes and heterosis responses, revealed a correlation between genetic diversity and transcriptional variation. This is a companion dataset to an Affymetrix profiling experiment (GEO Series GSE10236). Keywords: Genotype comparison series Expression profiling was used to study gene expression in aerial tissue from 11-day seedlings of maize. Three biological replicates were performed for nine different genotypes; B37, B73, B84, Mo17, Oh43, B37xB73, B84xB73, Oh43xB73 and Oh43xMo17.
Project description:Expression profiling analyses for 5 maize inbreds and 4 hybrids, chosen to represent diversity in genotypes and heterosis responses, revealed a correlation between genetic diversity and transcriptional variation. This is a companion dataset to an Affymetrix profiling experiment (GEO Series GSE10236). Keywords: Genotype comparison series
Project description:This research reports the analysis of sRNAs in 14 and 7 inbred lines from a breeding population. We analyzed the contribution of sRNAs to the formation of heterosis via integrative association analysis with field data of 98 hybrids generated from the set of inbred lines. Our results indicate a contribution of sRNAs to heterosis. We were able to identify different sets of sRNAs associated with heterosis with distinct length and genome distribution patterns. Analysis of sRNA contribution to the formation of heterosis in maize by an association study in a breeding population.
Project description:we determine genome-wide binding profiles of a maize CCA1 homolog, ZmCCA1b, in maize inbreds and F1 hybrids at different times of the day. ZmCCA1b is characterized as a central clock regulator gene with evolutionarily conserved molecular and circadian functions and nonadditively expressed in F1 hybrid seedlings. ZmCCA1b binds to over 4,300 target genes in the maize genomes, of which annotation confirms energy metabolic pathways as the main output. We report that an altered temporal binding activity of ZmCCA1b in the hybrid seedlings, which increases expression of carbon fixation genes, increases carbon fixation rates and biomass, demonstrating a novel example of how circadian-regulatory networks directly contribute to growth vigor in maize hybrids. These results collectively offer new insights into clock-mediated regulation of growth vigor in hybrid plants and crops. Profiling genome-wide binding events of ZmCCA1b in the maize inbreds and F1 hybrids at ZT3, ZT9 and ZT15 using chromatin immunoprecipitation followed by deep sequencing (ChIP-seq). 2 biological replicates for each sample were used. Input DNA sample corresponding to each ChIP sample was also sequenced in parallel. We have developed a native antibody for the protein (GRMZM2G014902; epitope: residues 11-77) for the ChIP-seq study.
Project description:Heterosis is most frequently manifested by the substantially increased vigorous growth of hybrids compared with their parents. Investigating genomic variations in natural populations is essential to understand the initial molecular mechanisms underlying heterosis in plants. Here, we characterized the genomic architecture associated with biomass heterosis in 200 Arabidopsis hybrids. The genome-wide heterozygosity of hybrids makes a limited contribution to biomass heterosis, and no locus shows an obvious overdominance effect in hybrids. However, the accumulation of significant genetic loci identified in genome wide association studies (GWAS) in hybrids strongly correlates with better-parent heterosis (BPH). Candidate genes for biomass BPH fall into diverse biological functions, including cellular, metabolic, and developmental processes and stimulus-responsive pathways. Important heterosis candidates include WUSCHEL, ARGOS, and some genes that encode key factors involved in cell cycle regulation. Interestingly, transcriptomic analyses in representative Arabidopsis hybrid combinations reveal that heterosis candidate genes are functionally enriched in stimulus-responsive pathways, including responses to biotic and abiotic stimuli and immune responses. In addition, stimulus-responsive genes are repressed to low-parent levels in hybrids with high BPH, whereas middle-parent expression patterns are exhibited in hybrids with no BPH. Our study reveals a genomic architecture for understanding the molecular mechanisms of biomass heterosis in Arabidopsis, in which the accumulation of the superior alleles of genes involved in metabolic and cellular processes improve the development and growth of hybrids, whereas the overall repressed expression of stimulus responsive genes prioritizes growth over responding to environmental stimuli in hybrids under normal conditions.
Project description:Heterosis is most frequently manifested by the substantially increased vigorous growth of hybrids compared with their parents. Investigating genomic variations in natural populations is essential to understand the initial molecular mechanisms underlying heterosis in plants. Here, we characterized the genomic architecture associated with biomass heterosis in 200 Arabidopsis hybrids. The genome-wide heterozygosity of hybrids makes a limited contribution to biomass heterosis, and no locus shows an obvious overdominance effect in hybrids. However, the accumulation of significant genetic loci identified in genome wide association studies (GWAS) in hybrids strongly correlates with better-parent heterosis (BPH). Candidate genes for biomass BPH fall into diverse biological functions, including cellular, metabolic, and developmental processes and stimulus-responsive pathways. Important heterosis candidates include WUSCHEL, ARGOS, and some genes that encode key factors involved in cell cycle regulation. Interestingly, transcriptomic analyses in representative Arabidopsis hybrid combinations reveal that heterosis candidate genes are functionally enriched in stimulus-responsive pathways, including responses to biotic and abiotic stimuli and immune responses. In addition, stimulus-responsive genes are repressed to low-parent levels in hybrids with high BPH, whereas middle-parent expression patterns are exhibited in hybrids with no BPH. Our study reveals a genomic architecture for understanding the molecular mechanisms of biomass heterosis in Arabidopsis, in which the accumulation of the superior alleles of genes involved in metabolic and cellular processes improve the development and growth of hybrids, whereas the overall repressed expression of stimulus responsive genes prioritizes growth over responding to environmental stimuli in hybrids under normal conditions.
Project description:Expression profiling analyses for 5 maize inbreds and 4 hybrids, chosen to represent diversity in genotypes and heterosis responses, revealed a correlation between genetic diversity and transcriptional variation. The majority of differentially expressed genes in each of the different hybrids exhibited additive expression patterns, and ~25% exhibited statistically significant non-additive expression profiles. Among the non-additive profiles, ~80% exhibited hybrid expression levels between the parental levels, ~20% exhibited hybrid expression levels at the parental levels and ~1% exhibited hybrid levels outside the parental range. These findings indicate that the frequencies of additive and non-additive expression patterns are very similar across a range of hybrid lines. Keywords: Genotype comparison series
Project description:Many animal and plant species exhibit increased growth rates, reach larger sizes and, in the cases of crops and farm animals, produce higher yields when bred as hybrids between genetically differing strains, a phenomenon known as hybrid vigour or heterosis. Despite the importance of heterosis, and its extensive genetic analysis, there has been little understanding of its molecular basis. We aimed to determine whether characteristics of the leaf transcriptome, as an indicator of the innate functional genetic architecture of a plant line, could be used as markers to predict heterosis and the performance of hybrids, a methodology we term Association Transcriptomics. Relationships between transcript abundance of specific genes and the values of heterosis and heterosis-dependent traits were identified and mathematical models were constructed that relate gene expression characteristics in inbred lines of Arabidopsis thaliana and maize with vegetative biomass and for grain yield, respectively, in corresponding hybrids.
Project description:Heterosis, also known as hybrid vigor, has been extensively utilized to increase productivity in crop, yet the underlying molecular mechanisms remain largely elusive. Recent studies have reported that in addition to mRNA transcription, epigenetic variations in DNA methylation, small RNAs and histone modifications also contribute to heterosis. However, the operative mode of post-transcriptional regulation on gene expression such as RNA m6A methylation and translational efficiency in heterosis has never been explored. In this study, we generated transcriptome-wide profiles of mRNA abundance, m6A methylation, and translational efficiency from the maize (Zea mays) F1 hybrid B73×Mo17 and its two parental lines B73 and Mo17 to ascertain contributions of each regulatory layer to heterosis at the seedling stage. We documented that although the global abundance and the distribution configuration of m6A maintained unchanged, a greater number of genes have gained m6A modification in hybrid compared to parent lines. m6A modification and translational efficiency exhibited greater variations between hybrid and parents as compared with observed variation of mRNA abundance. In hybrid, the vast majority of genes with m6A modification exhibited non-additive expression pattern, the percentage of which was exceedingly higher than that of differential genes at mRNA abundance and translation efficiency levels. Non-additive genes involved in different biological processes were hierarchically coordinated by discrete combinations of three regulatory layers. These findings suggest that transcriptional and post-transcriptional regulations on gene expression adopt divergent approaches to participate in the formation of heterosis in hybrid. Overall, the integrated multi-omics analysis provides a valuable portfolio for interpreting transcriptional and post-transcriptional regulation on gene expression in maize hybrid, and pave new avenues for exploring molecular mechanisms underlying hybrid vigor.