Small RNAs serve as a genetic buffer against genomic shock in Arabidopsis interspecific hybrids and allopolyploids
Ontology highlight
ABSTRACT:
ORGANISM(S): Arabidopsis arenosa x Arabidopsis thaliana Arabidopsis thaliana Arabidopsis suecica Arabidopsis arenosa
PROVIDER: GSE15443 | GEO | 2009/07/31
SECONDARY ACCESSION(S): PRJNA115805
REPOSITORIES: GEO
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Project description:MicroRNAs (miRNAs) and small interfering RNAs (siRNAs) are produced in diverse species and control gene expression and epigenetic regulation. Although physiological and developmental roles of miRNAs and siRNAs have been extensively studied in plants and animals, expression diversity and evolution of miRNAs and siRNAs in closely related species are poorly understood. Here we report comprehensive analyses of miRNA expression and siRNA distribution in two closely related species (Arabidopsis thaliana and A. arenosa), a natural allotetraploid (A. suecica), and two resynthesized allotetraploid lines (F1 and F7) derived from A. thaliana and A. arenosa. The siRNA populations present in A. thaliana were maintained in resynthesized allotetraploids and A. suecica. Although miRNA sequences were highly conserved, their expression patterns were highly variable between the allotetraploids and their progenitors. Significantly, many miRNAs were nonadditively expressed in the allotetraploids relative to the parents and preferentially degraded A. thaliana or A. arenosa targets. Stable inheritance of parental siRNAs in allopolyploids helps maintain genome stability in response to M-bM-^@M-^\genomic shockM-bM-^@M-^], whereas expression diversity of miRNAs and their target preference lead to interspecies variation in gene expression, growth, and development. NOTE: sff files unavailable for Samples AaL and F1L. 10 samples examined: Arabidopsis thaliana leaf, flower, Arabidopsis arenosa leaf and flower, F1 synthetic allopolyploid leaf and flower, F7 synthetic allopolyploid leaf and flower, Arabidopsis suecica leaf and flower. To determine small RNA profiles in Arabidopsis allotetraploids and their progenitors, we made 10 small RNA libraries from rosette leaves (L) and flower buds (F) in five lines, A. thaliana, A. arenosa, Allo(F1), Allo733(F7), and A. suecica. To examine expression of small RNAs among related species and their hybrids, we employed miRNA microarrays and compared small RNA levels.
2009-07-30 | E-GEOD-15443 | biostudies-arrayexpress
Project description:Changes in genome structure and gene expression have been documented in both resynthesized and natural allopolyploids that contain two or more divergent genomes. The underlying mechanisms for rapid and stochastic changes in gene expression are unknown. Arabidopsis suecica is a natural allotetraploid derived from the extant species A. thaliana and A. arenosa. Here we report that reduced DNA methylation in met1-RNAi A. suecica lines altered the expression of ~200 genes encoding transposons, centromeric and heterochromatic RNAs, and predicted proteins. Reduced DNA methylation occurred frequently in promoter regions of the upregulated genes but not of the repressed genes and led to increased mobility of En/Spm-like transposons in met1-RNAi A. suecica lines. Compared to A. arenosa centromeres, A. thaliana centromeres were hypermethylated, which correlates with higher levels of small RNA accumulation in A. thaliana centromeres than that in A. arenosa centromeres. Derepression of the genes examined was primarily derived from A. thaliana subgenome, and A. arenosa genes are less affected by methylation defects. Moreover, non-CG (CC) methylation in the promoter region of A. thaliana At2g23810 was maintained in resynthesized allotetraploids, and the methylation spread within the promoter region in natural A. suecica, leading to silencing of At2g23810, which was demethylated and reactivated in met1-RNAi A. suecica lines. We suggest that a subset of A. thaliana and A. arenosa genes are differentially methylated in natural allopolyploids, and some A. thaliana genes including centromeres are subjected to transcriptional repression and genome-specific RNA-mediated DNA methylation in Arabidopsis allopolyploids. Keywords: gene expression in reduced DNA methylation lines in Arabidopsis allotetraploids
2008-03-30 | GSE9512 | GEO
Project description:Gene-expression divergence between species shapes morphological evolution, but the molecular basis is largely unknown. Here we show cis- and trans-regulatory elements and chromatin modifications on gene-expression diversity in genetically tractable Arabidopsis allotetraploids. In Arabidopsis thaliana and Arabidopsis arenosa, both cis and trans with predominant cis-regulatory effects mediate gene-expression divergence. The majority of genes with both cis- and trans-effects are subjected to compensating interactions and stabilizing selection. Interestingly, chromatin modifications correlate with cis - and trans -regulation. In F1 allotetraploids, Arabidopsis arenosa trans factors predominately affect allelic expression divergence. Arabidopsis arenosa trans factors tend to upregulate Arabidopsis thaliana alleles, whereas Arabidopsis thaliana trans factors up- or down-regulate Arabidopsis arenosa alleles. In resynthesized and natural allotetraploids, trans effects drive expression of both homoeologous loci into the same direction. We provide evidence for natural selection and chromatin regulation in shaping gene-expression diversity during plant evolution and speciation. Examination of gene expression in 5 tetraploid Arabidopsis using mRNA-seq
2012-05-31 | E-GEOD-29687 | biostudies-arrayexpress
Project description:Gene-expression divergence between species shapes morphological evolution, but the molecular basis is largely unknown. Here we show cis- and trans-regulatory elements and chromatin modifications on gene-expression diversity in genetically tractable Arabidopsis allotetraploids. In Arabidopsis thaliana and Arabidopsis arenosa, both cis and trans with predominant cis-regulatory effects mediate gene-expression divergence. The majority of genes with both cis- and trans-effects are subjected to compensating interactions and stabilizing selection. Interestingly, chromatin modifications correlate with cis - and trans -regulation. In F1 allotetraploids, Arabidopsis arenosa trans factors predominately affect allelic expression divergence. Arabidopsis arenosa trans factors tend to upregulate Arabidopsis thaliana alleles, whereas Arabidopsis thaliana trans factors up- or down-regulate Arabidopsis arenosa alleles. In resynthesized and natural allotetraploids, trans effects drive expression of both homoeologous loci into the same direction. We provide evidence for natural selection and chromatin regulation in shaping gene-expression diversity during plant evolution and speciation.
2012-05-31 | GSE29687 | GEO
Project description:Polyploidy or whole genome duplication (WGD) provides raw genetic materials for sequence and expression evolution of duplicate genes. However, the mode and tempo of expression divergence between WGD duplicate genes in closely relates species and recurrent allopolyploids are poorly understood. Arabidopsis is a suitable system for testing the hypothesis that duplicate genes increase expression diversity and regulatory networks. In Arabidopsis, WGD occurred more than once prior to the split between Arabidopsis thaliana and Arabidopsis arenosa, and both natural and human-made allotetraploids are available. Comparative genomic hybridization analysis indicated that single-copy and duplicate genes after WGD were well preserved in A. thaliana and A. arenosa. Analysis of gene expression microarrays showed that duplicate genes generally had higher levels of expression divergence between two closely related species than single-copy genes. The proportion of the progenitors' duplicate genes that were nonadditively expressed in the resynthesized and natural allotetraploids was significantly higher than that of single-copy genes. Duplicate genes related to environmental stresses tended to be differentially expressed, and multi-copy duplicate genes were likely to diverge expression between progenitors and in the allotetraploids. Compared to single-copy genes, duplicate genes tend to contain TATA boxes and less DNA methylation in the promoter regions, facilitating transcriptional regulation by binding transcription factors and/or cis-and trans- acting proteins. The data suggest an important role of WGD duplicate genes in modulating diverse and novel gene expression changes in response to external environmental cues as well as internal genetic turmoil such as recurrent polyploidy events.
2008-11-20 | GSE9513 | GEO
Project description:Arabidopsis is a suitable system for testing the hypothesis that duplicate genes accelerate evolution of expression diversity among species diverged from shared whole genome duplications (WGDs) and recurrent events of WGD. In Arabidopsis, at least 9 species split after WGD of the common ancestor and new allotetraploids were formed in nature and can be resynthesized between closely related species. Using genomic and gene expression microarrays, we detected WGD duplicate and single-copy genes preserved in A.thaliana and A.arenosa in addition to change of gene expression levels among those species. We found that even conserved duplicate genes show higher levels of expression divergence between two closely related species than single-copy genes. The proportion of the progenitors’ duplicate genes that were nonadditively expressed in the resynthesized and natural allotetraploids was significantly higher than that of single-copy genes. This results show that WGD duplicate genes provide expression variegation in response to recurring polyploidy as well as among species diverged from common WGD. Duplicate genes related to external stresses tended to be differentially expressed in allopolyploids and among their progenitors. Moreover, multiple-copy duplicate genes are likely to change expression between species and in the resynthesized and natural allotetraploids. Compared to single-copy genes, duplicate genes are less likely to be methylated in the promoter regions, facilitating transcriptional regulation by binding transcription factors and/or cis-and trans- acting proteins. Our results suggest that highly retained duplicate genes are important source for developing species specific expression level and novel expression regulation to adapt to environmental changes including subsequent polyploidy.
2008-11-20 | GSE13468 | GEO
Project description:An allopolyploid formation consists of the two processes of hybridisation and chromosome doubling. Hybridisation makes a different genome combined in the same cell, and genome M-bM-^@M-^\shockM-bM-^@M-^] and instability occur during this process, whereas chromosome doubling results in doubling and reconstructing the genome dosage. Recent studies have demonstrated that small RNAs, mainly siRNAs and miRNAs, play an important role in maintaining the genome reconstruction and stability. However, to date, little is known regarding the role of small RNAs during the process of wide hybridisation and chromosome doubling, which is essential to elucidate the mechanism of polyploidisation. Therefore, the genetic and DNA methylation alterations and changes in the siRNA and miRNA were assessed during the formation of an allodiploid (genome: AB) and its allotetraploid (genome: AABB) between Brassica rapa (M-bM-^YM-^@) and Brassica nigra (M-bM-^YM-^B) in the present study.The phenotypic analysis exhibited that the allotetraploid had high heterosis compared with their parents and the allodiploid. The methylation-sensitive amplification polymorphism (MSAP) analysis indicated that the proportion of changes in the methylation pattern of the allodiploid was significantly higher than that found in the allotetraploid, while the DNA methylation ratio was higher in the parents than the allodiploid and allotetraploid. The high-throughput sequencing results obtained for the small RNAs showed that the expression levels of miRNAs increased in the allodiploid and allotetraploid compared with the parents, and the expression levels of siRNAs increased and decreased compared with the parents B. rapa and B. nigra, respectively. Moreover, the percentages of miRNAs increased with an increase in the polyploidy levels, but the percentages of siRNAs and DNA methylation alterations decreased with an increase in the polyploidy levels. Furthermore, 320 known and 52 novel miRNAs were obtained from the parents in both the allodiploid and allotetraploid. However, quantitative real-time polymerase chain reaction (qRT PCR) analysis showed that the expression levels of the targets genes were negatively corrected with the expressed miRNAs.The study showed that siRNAs and DNA methylation play an important role in maintaining the genome stability in the formation of an allotetraploid. The miRNAs regulate gene expression and induce the phenotype variation, which may play an important role in the occurrence of heterosis in the allotetraploid. The findings of this study may provide new information for elucidating that the allotetraploids have a growth advantage over the parents and the allodiploids. High throughput sequence of the parents (Brassica rapa and Brassica nigra) and their hybrids (allodiploid and allotetraploid)
2014-09-30 | E-GEOD-61872 | biostudies-arrayexpress
Project description:An allopolyploid formation consists of the two processes of hybridisation and chromosome doubling. Hybridisation makes a different genome combined in the same cell, and genome “shock” and instability occur during this process, whereas chromosome doubling results in doubling and reconstructing the genome dosage. Recent studies have demonstrated that small RNAs, mainly siRNAs and miRNAs, play an important role in maintaining the genome reconstruction and stability. However, to date, little is known regarding the role of small RNAs during the process of wide hybridisation and chromosome doubling, which is essential to elucidate the mechanism of polyploidisation. Therefore, the genetic and DNA methylation alterations and changes in the siRNA and miRNA were assessed during the formation of an allodiploid (genome: AB) and its allotetraploid (genome: AABB) between Brassica rapa (♀) and Brassica nigra (♂) in the present study.The phenotypic analysis exhibited that the allotetraploid had high heterosis compared with their parents and the allodiploid. The methylation-sensitive amplification polymorphism (MSAP) analysis indicated that the proportion of changes in the methylation pattern of the allodiploid was significantly higher than that found in the allotetraploid, while the DNA methylation ratio was higher in the parents than the allodiploid and allotetraploid. The high-throughput sequencing results obtained for the small RNAs showed that the expression levels of miRNAs increased in the allodiploid and allotetraploid compared with the parents, and the expression levels of siRNAs increased and decreased compared with the parents B. rapa and B. nigra, respectively. Moreover, the percentages of miRNAs increased with an increase in the polyploidy levels, but the percentages of siRNAs and DNA methylation alterations decreased with an increase in the polyploidy levels. Furthermore, 320 known and 52 novel miRNAs were obtained from the parents in both the allodiploid and allotetraploid. However, quantitative real-time polymerase chain reaction (qRT PCR) analysis showed that the expression levels of the targets genes were negatively corrected with the expressed miRNAs.The study showed that siRNAs and DNA methylation play an important role in maintaining the genome stability in the formation of an allotetraploid. The miRNAs regulate gene expression and induce the phenotype variation, which may play an important role in the occurrence of heterosis in the allotetraploid. The findings of this study may provide new information for elucidating that the allotetraploids have a growth advantage over the parents and the allodiploids.
2014-09-30 | GSE61872 | GEO
Project description:Polyploidy provides evolutionary and morphological novelties in many plants and some animals. However, the role of genome dosage and composition in gene expression changes remains poorly understood. Here, we generated a series of resynthesized Arabidopsis tetraploids that contain 0-4 copies of Arabidopsis thaliana and Arabidopsis arenosa genomes and investigated ploidy and hybridity effects on gene expression. Allelic expression can be defined as dosage dependent (expression levels correlate with genome dosages) or otherwise as dosage independent. Here, we show that many dosage-dependent genes contribute to cell cycle, photosynthesis, and metabolism, whereas dosage-independent genes are enriched in biotic and abiotic stress responses. Interestingly, dosage-dependent genes tend to be preserved in ancient biochemical pathways present in both plant and nonplant species, whereas many dosage-independent genes belong to plant-specific pathways. This is confirmed by an independent analysis using Arabidopsis phylostratigraphic map. For A. thaliana loci, the dosage-dependent alleles are devoid of TEs and tend to correlate with H3K9ac, H3K4me3, and CG methylation, whereas the majority of dosage-independent alleles are enriched with TEs and correspond to H3K27me1, H3K27me3, and CHG (H = A, T, or C) methylation. Furthermore, there is a parent-of-origin effect on nonadditively expressed genes in the reciprocal allotetraploids especially when A. arenosa is used as the pollen donor, leading to metabolic and morphological changes. Thus, ploidy, epigenetic modifications, and cytoplasmic-nuclear interactions shape gene expression diversity in polyploids. Dosage-dependent expression can maintain growth and developmental stability, whereas dosage-independent expression can facilitate functional divergence between homeologs (subfunctionalization and/or neofunctionalization) during polyploid evolution.
2015-05-19 | GSE50715 | GEO
Project description:Genome-wide analysis of gene expression has documented differential gene expression between closely related species in plants or animals and nonadditive gene expression in hybrids and allopolyploids compared to the parents. In Arabidopsis, 15-43% of genes are expressed differently between the related species, A. thaliana and A. arenosa, and the majority of them are nonadditvely expressed (differently from mid-parent value) in allotetraploids relative to the parents. The gene expression variation is associated with transcriptional and posttranscriptional mechanisms. Although transcriptional regulation by epigenetic mechanisms plays a role in nonadditive gene expression, the effects of posttranscriptional regulation on nonadditive gene expression is largely unknown. Here we reported a comprehensive genome-wide analysis of mRNA decay in Arabidopsis allotetraploids using oligo gene microarrays. Among ~26,000 annotated genes on the arrays, over 1% of genes showed a rapid decay rate with an estimated half-life of less than 60 min, and these genes are known as genes with unstable transcripts (GUTs). Interestingly, 30% of GUTs matched the nonadditively expressed genes, and their expression levels were significantly negatively correlated. These nonadditively expressed GUTs are highly enriched with a 2-8-fold increase compared to the proportion of all genes in the Gene Ontology (GO) classifications in response to stress, abiotic and biotic stimulus, signal transduction, and transcription. The data are consistent with the enrichment of nonadditvely-expressed genes in those categories in allopolyploids of Arabidopsis, wheat and cotton. Interestingly, the GUTs include some key transcription factors including circadian clock regulators, suggesting a mechanism for rapid response to light signalling and clock regulation in allotetraploids. These data collectively suggest an important role of mRNA stability in nonadditive expression of homoeologous genes in allopolyploids. A total of 8 slides were used for comparison (0 min vs. 120 min), including two biological and four technical replications. Each biological replication consists of two technical replications (four slides) that were hybridized with reverse-labeled probes.
2011-09-15 | E-GEOD-26065 | biostudies-arrayexpress