Project description:Arabidopsis thaliana shows hybrid vigour (heterosis) in progeny of crosses between Col and C24 accessions (1). Hybrid vigour was evident as early as the mature seeds and in the seedlings 3 days after sowing (DAS). At 3 DAS genes encoding chloroplast-located proteins were significantly overrepresented (187) among the 724 genes which have greater than mid parent values of expression in the hybrid. Many of these genes are involved in chlorophyll biosynthesis and photosynthesis. The rate of photosynthesis was constant per unit leaf area in parents and hybrids. Larger cell sizes in the hybrids were associated with more chloroplasts per cell, more total chlorophyll and more photosynthesis. The increased transcription of the chloroplast-targeted genes was restricted to the 3 to 7 DAS period. At 10 DAS only 118 genes had expression levels different from the expected mid parent value in the hybrid and only 12 of these genes were differentially expressed at 3 DAS. The early increase in activity of genes involved in photosynthesis and the associated phenomena of increase in cell size and number through development, leading to larger leaf areas of all leaves in the hybrid, suggest a central role for increased photosynthesis in the production of the heterotic biomass. In support of this correlation we found that an inhibitor of photosynthesis eliminated heterosis and higher light intensities enhanced both photosynthesis and heterosis. In hybrids with low level heterosis (Ler x Col) chloroplast-targeted genes were not upregulated and leaf areas were only marginally increased. Whole plants in Col, C24, and their F1 hybrids with two replications
Project description:Arabidopsis thaliana shows hybrid vigour (heterosis) in progeny of crosses between Col and C24 accessions (1). Hybrid vigour was evident as early as the mature seeds and in the seedlings 3 days after sowing (DAS). At 3 DAS genes encoding chloroplast-located proteins were significantly overrepresented (187) among the 724 genes which have greater than mid parent values of expression in the hybrid. Many of these genes are involved in chlorophyll biosynthesis and photosynthesis. The rate of photosynthesis was constant per unit leaf area in parents and hybrids. Larger cell sizes in the hybrids were associated with more chloroplasts per cell, more total chlorophyll and more photosynthesis. The increased transcription of the chloroplast-targeted genes was restricted to the 3 to 7 DAS period. At 10 DAS only 118 genes had expression levels different from the expected mid parent value in the hybrid and only 12 of these genes were differentially expressed at 3 DAS. The early increase in activity of genes involved in photosynthesis and the associated phenomena of increase in cell size and number through development, leading to larger leaf areas of all leaves in the hybrid, suggest a central role for increased photosynthesis in the production of the heterotic biomass. In support of this correlation we found that an inhibitor of photosynthesis eliminated heterosis and higher light intensities enhanced both photosynthesis and heterosis. In hybrids with low level heterosis (Ler x Col) chloroplast-targeted genes were not upregulated and leaf areas were only marginally increased.
Project description:This SuperSeries is composed of the following subset Series: GSE24494: cgh_colvsc24_chr4-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE24831: cgh_colvsc24_wg-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE24835: cgh_colvscvi_wg-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE25049: h3k4me2_c24_chr4-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE25050: h3k27me3_colxcvi-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE25051: h3k27me3_cvi-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE25052: h3k27me3_col(cvi)-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE25053: h3k4me2_colxcvi-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE25054: h3k4me2_cvi-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE25056: h3k4me2_col(cvi)-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE25057: h3k27me3_colxc24-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE25058: h3k27me3_c24-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE25059: h3k27me3_col(c24)-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE25060: h3k4me2_colxc24_chr4-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions GSE25061: h3k4me2_col_chr4-Analysis of epigenomic changes in hybrids Arabidopsis thaliana Col-0, C24 and Cvi accessions Refer to individual Series
Project description:Heterosis, or hybrid vigor, has been exploited in agriculture to deliver increases in crop yields for over a century, yet the molecular basis is not well understood We have studied the transcriptomes of 15 day old seedlings from intraspecific Arabidopsis hybrids with varying levels of heterosis and their parental lines in order to identify drivers of heterosis. The patterns of altered gene expression in the hybrids point to a reduction in basal defense levels that could reflect the antagonism between plant immunity and plant growth. Associated with this theme are changes to the salicylic acid and auxin regulated networks which are known to control abiotic and biotic defense responses as well as being important regulators of plant growth. Increased auxin response correlates with the heterotic phenotype of greater leaf cell numbers, whereas reduced salicylic acid levels and response promotes increased leaf cell size in hybrids involving C24. By manipulating salicylic acid levels in each of our hybrid systems, we can alter levels of heterosis, promote additional growth in the hybrids, and generate increased growth in the parents, especially C24. Aerial tissues of 15 days after sowing seedlings from C24, Ler, Col and their reciprocal hybrid offspring. In total 7 biological replicates for both the C24 and Ler parents, 2 biological replicates for Col, 10 biological replicates for C24/Ler and 4 biological replicates for both C24/Col and Col/Ler were sequenced and analysed. Each replicated consisted of a pools of 5-15 seedlings (see publication for more details)
Project description:Hybrid breeding is of economic importance in agriculture for increasing yield, yet the basis of the heterosis is not well understood. In Arabidopsis, crosses between different accessions produce hybrids with varied levels of heterosis relative to parental phenotypes in biomass. In all hybrids the advantages of the F1 hybrid is lost in the F2 for both phenotypic uniformity and yield gain. Success in generating F5/F6 Hybrid Mimic from the cross between C24 and Landsberg erecta (Ler) demonstrated that the large plant phenotype of the F1 hybrids can be stabilized. Hybrid Mimics selection was applied to Wassilewskija (Ws)/Ler and Col/Ler hybrids. The two hybrids showing different levels of heterosis. At 30 DAS, the Col/Ler hybrid generated Hybrid Mimics with rosette diameter and fresh weight equivalent to the F1 hybrid; Ws/Ler Hybrid Mimics outperformed the F1 hybrids in both the rosette size and biomass. Transcriptome analysis revealed up-regulation of cell wall biosynthesis and expansion genes could be a common pathway in increased size in Arabidopsis hybrids and Hybrid Mimics. Intercross of two independent Hybrid Mimic lines can further increase the biomass gain. Our results encourage the use of Hybrid Mimics for breeding and for investigating the molecular basis of heterosis.
Project description:a2e_heterosis - h3k4me2_colxc24_chr4 - Arabidopsis thaliana accessions (Col-0, C24 and Cvi) and their hybrid were used to investigate the dynamics of the epigenome after intraspecific hybridization between - H3K4me2 profiling in ColxC24 hybrids
Project description:a2e_heterosis - h3k27me3_colxc24 - Arabidopsis thaliana accessions (Col-0, C24 and Cvi) and their hybrid were used to investigate the dynamics of the epigenome after intraspecific hybridization between - H3K27me3 profiling in ColxC24 hybrids
Project description:a2e_heterosis - h3k4me2_colxcvi - Arabidopsis thaliana accessions (Col-0, C24 and Cvi) and their hybrid were used to investigate the dynamics of the epigenome after intraspecific hybridization between - H3K4me2 profiling in ColxCvi hybrids
Project description:a2e_heterosis - h3k27me3_colxcvi - Arabidopsis thaliana accessions (Col-0, C24 and Cvi) and their hybrid were used to investigate the dynamics of the epigenome after intraspecific hybridization between - H3K27me3 profiling in ColxCvi hybrids
Project description:Despite of the paramount importance of heterosis in agriculture, the molecular mechanisms underlying heterosis remain elusive. Recent studies in Arabidopsis suggested possible involvement of DNA methylation in heterosis. We tested this hypothesis genetically by crossing homozygous mutants in DNA methylation-related genes in the Columbia (Col) ecotype with homozygous mutants in the same DNA methylation-related genes in the C24 ecotype. When genes in the RNA-directed DNA methylation (RdDM) pathway were mutated, the resultant F1 hybrids did not show appreciable loss of best parent heterosis (BPH) performances in early seedling growth. In contrast, mutations in the putative chromatin remodeling protein DECREASE OF DNA METHYLATION 1 (DDM1) caused ddm1-Col like growth pattern of ddm1-F1 hybrids, a mid-parent heterosis (MPH) performance. To understand the underlying molecular mechanisms, we compared the transcriptomes of the parental plants and reciprocal F1 hybrids in the wild type and ddm1 mutant backgrounds, and identified 183 non-additively expressed (NAE) genes, which were functionally enriched in defense response, a group of genes negatively associated with plant size. Interestingly, for the expression levels of the NAE genes, WT-F1 hybrids were enriched in the Golden Ration between mid-parent values (MPVs) and Col parents in WT, but ddm1-F1 hybrids were comparable to ddm1-Col parent in ddm1 mutant, which explained the MPH performance of ddm1-F1 hybrids. DNA methylation analyses revealed only one third of the NAE genes with highly methylated promoters whose expression is negatively associated with DNA methylation of promoters, strongly suggesting that DDM1 regulates heterosis by multiple epigenetic modifications.