Modifiers of genetic dominance at the Arabidopsis self-incompatibility locus retain proto-miRNA features and act through non-canonical gene silencing pathways
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE249508 | GEO | 2023/12/07
REPOSITORIES: GEO
Similar Datasets
Project description:Self-incompatibility (SI) in flowering plants is a common mechanism that prevents self-fertilization and promotes outcrossing. In Brassicaceae, the locus controlling SI is highly diverse and dozens of distinct alleles are organized in a complex dominance hierarchy: the gene controlling SI specificity in pollen always shows monoallelic expression in heterozygote individuals, and this is achieved through the action of sRNA precursors that resemble miRNAs, although the mechanism behind this remains elusive. Here, we engineered Arabidopsis thaliana lines expressing components of the Arabidopsis halleri SI system and used a reverse genetics approach to pinpoint the pathways underlying the function of these sRNA precursors. We showed that they trigger a robust decrease in transcript abundance of the recessive pollen SI genes, but not through the canonical transcriptional or post transcriptional gene silencing pathways. Furthermore, we observed that single sRNA precursors are typically processed into hundreds of sRNA molecules, with distinct sizes, abundance levels and ARGONAUTE loading preferences. This heterogeneity closely resembles that of proto-miRNAs, the evolutionary ancestors of miRNAs. Our results suggest that these apparent arbitrary features, which are often associated with lack of effects in gene expression, are crucial in the context of the SI dominance hierarchy since they allow one sRNA precursor of a given allele to repress multiple other (more recessive) alleles. This study not only provides an in-depth characterization of the molecular features underlying complex dominance interactions, but also constitutes a unique example of how specific evolutionary constraints shape the progression of sRNA precursors within the proto-miRNA – miRNA evolutionary continuum.
2023-12-07 | GSE249506 | GEO
Project description:Self-incompatibility (SI) in flowering plants is a common mechanism that prevents self-fertilization and promotes outcrossing. In Brassicaceae, the locus controlling SI is highly diverse and dozens of distinct alleles are organized in a complex dominance hierarchy: the gene controlling SI specificity in pollen always shows monoallelic expression in heterozygote individuals, and this is achieved through the action of sRNA precursors that resemble miRNAs, although the mechanism behind this remains elusive. Here, we engineered Arabidopsis thaliana lines expressing components of the Arabidopsis halleri SI system and used a reverse genetics approach to pinpoint the pathways underlying the function of these sRNA precursors. We showed that they trigger a robust decrease in transcript abundance of the recessive pollen SI genes, but not through the canonical transcriptional or post transcriptional gene silencing pathways. Furthermore, we observed that single sRNA precursors are typically processed into hundreds of sRNA molecules, with distinct sizes, abundance levels and ARGONAUTE loading preferences. This heterogeneity closely resembles that of proto-miRNAs, the evolutionary ancestors of miRNAs. Our results suggest that these apparent arbitrary features, which are often associated with lack of effects in gene expression, are crucial in the context of the SI dominance hierarchy since they allow one sRNA precursor of a given allele to repress multiple other (more recessive) alleles. This study not only provides an in-depth characterization of the molecular features underlying complex dominance interactions, but also constitutes a unique example of how specific evolutionary constraints shape the progression of sRNA precursors within the proto-miRNA – miRNA evolutionary continuum.
2023-12-07 | GSE249507 | GEO
Project description:Modifiers of genetic dominance at the Arabidopsis self-incompatibility locus retain proto-miRNA features and act through non-canonical gene silencing pathways
| PRJNA1049406 | ENA
Project description:Modifiers of genetic dominance at the Arabidopsis self-incompatibility locus retain proto-miRNA features and act through non-canonical gene silencing pathways - BSAS data
| PRJNA1049411 | ENA
Project description:Modifiers of genetic dominance at the Arabidopsis self-incompatibility locus retain proto-miRNA features and act through non-canonical gene silencing pathways - AGO-IP data
| PRJNA1049412 | ENA
Project description:The self-incompatibility (SI) system of the Brassicaceae is based on allele-specific interactions among haplotypes of the S locus. In all tested self-incompatible Brassicaceae, the S haplotype encompasses two linked genes, one encoding the S-locus receptor kinase (SRK), a transmembrane kinase displayed at the surface of stigma epidermal cells, and the other encoding its ligand, the S-locus cysteine-rich (SCR) protein, which is localized in the pollen coat. Transfer of the two genes to self-fertile Arabidopsis thaliana allowed the establishment of robust SI in several accessions, indicating that the signaling cascade triggered by this receptor-ligand interaction and the resulting inhibition of "self" pollen by the stigma have been maintained in extant A. thaliana. Based on studies in Brassica species, the membrane-tethered kinase MLPK, the ARM repeat-containing U-box protein ARC1, and the exocyst subunit Exo70A1 have been proposed to function as components of an SI signaling cascade. Here we tested the role of these molecules in the SI response of A. thaliana SRK-SCR plants. We show that the A. thaliana ARC1 ortholog is a highly decayed pseudogene. We also show that, unlike reports in Brassica, inactivation of the MLPK ortholog AtAPK1b and overexpression of Exo70A1 neither abolish nor weaken SI in A. thaliana SRK-SCR plants. These results do not support a role for these molecules in the SI response of A. thaliana.
| S-EPMC3207705 | biostudies-literature
Project description: Not available
| S-EPMC11291619 | biostudies-literature
Project description:Potato is the third most important staple food crop. To address challenges associated with global food security, a hybrid potato breeding system, aimed at converting potato from a tuber-propagated tetraploid crop into a seed-propagated diploid crop through crossing inbred lines, is under development. However, given that most diploid potatoes are self-incompatible, this represents a major obstacle which needs to be addressed in order to develop inbred lines. Here, we report on a self-compatible diploid potato, RH89-039-16 (RH), which can efficiently induce a mating transition from self-incompatibility to self-compatibility, when crossed to self-incompatible lines. We identify the S-locusinhibitor (Sli) gene in RH, capable of interacting with multiple allelic variants of the pistil-specific S-ribonucleases (S-RNases). Further, Sli gene functions like a general S-RNase inhibitor, to impart SC to RH and other self-incompatible potatoes. Discovery of Sli now offers a path forward for the diploid hybrid breeding program.
| S-EPMC8260799 | biostudies-literature
Project description:Self-incompatibility (SI) is the flowering plant reproductive system in which self pollen tube growth is inhibited, thereby preventing self-fertilization. SI has evolved independently in several different flowering plant lineages. In all Brassicaceae species in which the molecular basis of SI has been investigated in detail, the product of the S-locus receptor kinase (SRK) gene functions as receptor in the initial step of the self pollen-rejection pathway, while that of the S-locus cysteine-rich (SCR) gene functions as ligand. Here we examine the hypothesis that the S locus in the Brassicaceae genus Leavenworthia is paralogous with the S locus previously characterized in other members of the family. We also test the hypothesis that self-compatibility in this group is based on disruption of the pollen ligand-producing gene. Sequence analysis of the S-locus genes in Leavenworthia, phylogeny of S alleles, gene expression patterns, and comparative genomics analyses provide support for both hypotheses. Of special interest are two genes located in a non-S locus genomic region of Arabidopsis lyrata that exhibit domain structures, sequences, and phylogenetic histories similar to those of the S-locus genes in Leavenworthia, and that also share synteny with these genes. These A. lyrata genes resemble those comprising the A. lyrata S locus, but they do not function in self-recognition. Moreover, they appear to belong to a lineage that diverged from the ancestral Brassicaceae S-locus genes before allelic diversification at the S locus. We hypothesize that there has been neo-functionalization of these S-locus-like genes in the Leavenworthia lineage, resulting in evolution of a separate ligand-receptor system of SI. Our results also provide support for theoretical models that predict that the least constrained pathway to the evolution of self-compatibility is one involving loss of pollen gene function.
| S-EPMC3653793 | biostudies-literature
Project description:Although the transition to selfing in the model plant Arabidopsis thaliana involved the loss of the self-incompatibility (SI) system, it clearly did not occur due to the fixation of a single inactivating mutation at the locus determining the specificities of SI (the S-locus). At least three groups of divergent haplotypes (haplogroups), corresponding to ancient functional S-alleles, have been maintained at this locus, and extensive functional studies have shown that all three carry distinct inactivating mutations. However, the historical process of loss of SI is not well understood, in particular its relation with the last glaciation. Here, we took advantage of recently published genomic resequencing data in 1,083 Arabidopsis thaliana accessions that we combined with BAC sequencing to obtain polymorphism information for the whole S-locus region at a species-wide scale. The accessions differed by several major rearrangements including large deletions and interhaplogroup recombinations, forming a set of haplogroups that are widely distributed throughout the native range and largely overlap geographically. "Relict" A. thaliana accessions that directly derive from glacial refugia are polymorphic at the S-locus, suggesting that the three haplogroups were already present when glacial refugia from the last Ice Age became isolated. Interhaplogroup recombinant haplotypes were highly frequent, and detailed analysis of recombination breakpoints suggested multiple independent origins. These findings suggest that the complete loss of SI in A. thaliana involved independent self-compatible mutants that arose prior to the last Ice Age, and experienced further rearrangements during postglacial colonization.
| S-EPMC5850868 | biostudies-literature