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.
Project description:Through a two-year field experiment, G70×GDH11 with strong heterosis and K326×GDH11 with weak heterosis were screened out. Transcriptome analyses revealed that 80.89% and 57.28% of the differentially expressed genes (DEGs) in the strong and weak heterosis combinations exhibited an overdominant expression pattern, respectively. The genes that up-regulated the overdominant expression in the strong heterosis hybrids were significantly enriched in the ion homeostasis. Genes involved in K+ transport (KAT1/2, GORK, AKT2 and KEA3), activity regulation complex (CBL-CIPK5/6), and vacuole (TPKs) genes were overdominant expressed in strong heterosis hybrids, which contributed to K+ homeostasis and heterosis in tobacco leaves.
Project description:Based our serial analysis of gene expression (SAGE) data from an elite Chinese super-hybrid rice (LYP9) and its parental cultivars (93-11 and PA64s) in three major tissue types at three different developmental stages, we obtained a much more comprehensive view of genes that related to rice heterosis and analyzed the potential effects of gene-expression difference on the heterosis of rice.These heterotic expression genes among different genotypes provided new avenues for exploring the molecular mechanisms underlying heterosis, including variable gene expression patterns. Keywords: Heterosis study by SAGE
Project description:Heterosis has long been exploited for crop breeding; however, the genetic mechanisms, particularly the initial establishment of heterosis during the early vegetative growth phase, remain elusive. The biggest challenge for that is to exclude noise genes from the identified heterosis-related candidates. Herein, we use nutrient-deficient hybrid with no measurable growth heterosis as control to filter potential background noise differentially expressed genes In this dataset, we compared the differentially expressed genes in both heterotic and non-heterotic hybrid. After filtering these irrelevant genes, only 336 differentially expressed genes (DEGs), which is significantly lower than those of previous reports, were identified as heterosis-related genes in a super hybrid rice of Liang-You-Pei-Jiu (LYP9) at early-tillering stage
Project description:we compared the change of transcritome between the parents and their F1 hybrids showing different heterosis level and obtained the potential index for predicting the heterosis level between rice parental lines.
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:Heterosis occurs where F1 offspring display superior characteristics to the parents. Heterosis is usually considered to result from crosses of genetically distinct (e.g. homozygous inbred) parents producing heterozygous F1 offspring. Most mechanistic models for heterosis require genetically heterozygous F1 hybrid offspring harbouring allelic diversity. Epigenetic or dosage models for heterosis could allow for heterosis effects in F1 offspring that display no allelic diversity with their parents. Reciprocal inter-ploidy crosses between diploid (2x) and tetraploid (4x) lines in the same genetic background generates genetically identical F1 triploids (3x). Such reciprocal F1 triploids differ according to whether the additional chromosome set is either maternally (maternal excess) or paternally inherited (paternal excess). Biomass accumulation and abiotic stress tolerance between the parental (2x and 4x) and reciprocal F1 triploid (3x) offspring of Arabidopsis thaliana accession C24 reveals a strong parental genome-dosage induced heterosis in the paternal-excess triploid F1 plants. In these F1 triploids, the circadian clock related genes CCA1 and TOC1, and the growth factors PIF4 and PIF5, display different expression levels compared to the non-heterotic maternal excess F1 triploid siblings. Whole transcriptome profiling reveals a paternal genome dosage effect on gene expression levels with strong enrichment for dysregulated abiotic stress-related genes in the paternal excess F1 triploids. This study demonstrates that heterosis can be triggered without allelic diversity in F1 triploid plants. Heterosis without heterozygosity in plants can be induced via an epigenetic “chromosome imprinting” like parental genome dosage effect requiring paternal transmission of an additional chromosome set
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: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.