Project description:RNA-seq reads from the selfing species Arabidopsis thaliana were produced from flowers to study the consequences of the transition from the ancestral state (outcrossing) to the derived state (selfing). This was done in the context of examining another species in the Arabidopsis genus (A. lyrata) and another species pair (Capsella rubella versus Capsella grandiflora, which are selfing and outcrossing, respectively). These samples were generated to complement part of this larger study. Briefly, the shift from outcrossing to selfing is common in flowering plants, but neither the genomic consequences nor the speed with which they appear are well understood. An excellent model for understanding the evolution of self fertilization is provided by Capsella rubella, which became self-compatible <200,000 years ago. We present a reference genome for the species, and compare RNA expression and polymorphism patterns between C. rubella and its outcrossing progenitor C. grandiflora. There is a clear shift in the expression of genes associated with flowering phenotypes; a similar shift is seen in the related genus Arabidopsis, where self-fertilization evolved about 1 million years ago. DNA sequence polymorphisms distinguishing the two Capsella species reveal rapid genome-wide relaxation of purifying selection in C. rubella but without a concomitant change in transposable element abundance. Overall, we document that the transition to selfing may be typified by shifts in expression for genes that function in pollen and flower development, along with a measurable reduction of purifying selection.
Project description:Convergent evolution, the independent evolution of similar traits in different species under similar environmental pressures, is widespread across many taxa. In plants, a key example is the repeated evolution of floral traits associated with the transition from outcrossing to self- fertilization, often resulting in the “selfing syndrome” (e.g., reduced flower size, loss of scent, and altered reproductive strategies). However, potentially overlooked changes concern the pollen coat, which plays a role in different aspects of outcrossing strategy. To investigate this, we compared pollen morphology and proteomes between selfing and outcrossing species in the 2 Arabidopsis and Capsella genera, representing three independent selfing transitions. Pollen coat area diminished with the age of the selfing transition, with significant reductions in A. thaliana and Capsella rubella, but not in A. lyrata (recent transition, no selfing syndrome). Moreover, differentially expressed pollen coat proteins, primarily related to pathogen response, were shared across selfer-outcrosser contrasts more than expected by chance. However, similar functions appeared in random outcrosser-outcrosser comparisons, suggesting additional drivers beyond mating system transitions. Overall, our findings reveal convergent evolution of pollen coat morphology and protein composition following selfing transitions, while highlighting pathogen response as a key factor driving the fast evolution of pollen coat protein independently of the mating system.
Project description:RNA-seq reads from the outcrossing species Arabidopsis lyrata were produced from flowers to study the consequences of the transition from the ancestral state (outcrossing) to the derived state (selfing) that is observed in the sister species Arabidopsis thaliana. This was done in the context of examining another species pair (Capsella rubella versus Capsella grandiflora, which are selfing and outcrossing, respectively). These samples were generated to complement part of this larger study. Briefly, the shift from outcrossing to selfing is common in flowering plants, but neither the genomic consequences nor the speed with which they appear are well understood. An excellent model for understanding the evolution of self fertilization is provided by Capsella rubella, which became self-compatible <200,000 years ago. We present a reference genome for the species, and compare RNA expression and polymorphism patterns between C. rubella and its outcrossing progenitor C. grandiflora. There is a clear shift in the expression of genes associated with flowering phenotypes; a similar shift is seen in the related genus Arabidopsis, where self-fertilization evolved about 1 million years ago. DNA sequence polymorphisms distinguishing the two Capsella species reveal rapid genome-wide relaxation of purifying selection in C. rubella but without a concomitant change in transposable element abundance. Overall, we document that the transition to selfing may be typified by shifts in expression for genes that function in pollen and flower development, along with a measurable reduction of purifying selection.
Project description:RNA-seq reads from the selfing species Arabidopsis thaliana were produced from flowers to study the consequences of the transition from the ancestral state (outcrossing) to the derived state (selfing). This was done in the context of examining another species in the Arabidopsis genus (A. lyrata) and another species pair (Capsella rubella versus Capsella grandiflora, which are selfing and outcrossing, respectively). These samples were generated to complement part of this larger study. Briefly, the shift from outcrossing to selfing is common in flowering plants, but neither the genomic consequences nor the speed with which they appear are well understood. An excellent model for understanding the evolution of self fertilization is provided by Capsella rubella, which became self-compatible <200,000 years ago. We present a reference genome for the species, and compare RNA expression and polymorphism patterns between C. rubella and its outcrossing progenitor C. grandiflora. There is a clear shift in the expression of genes associated with flowering phenotypes; a similar shift is seen in the related genus Arabidopsis, where self-fertilization evolved about 1 million years ago. DNA sequence polymorphisms distinguishing the two Capsella species reveal rapid genome-wide relaxation of purifying selection in C. rubella but without a concomitant change in transposable element abundance. Overall, we document that the transition to selfing may be typified by shifts in expression for genes that function in pollen and flower development, along with a measurable reduction of purifying selection. As part of a cross-species comparison of gene expression, RNA-seq data was generated in biological replication (2 replicates) from Arabidopsis thaliana at the floral stage. In total, two samples (biological replicates) were used. The reference strain was used for the experments (strain Col-0). Resulting data about gene expression was used as part of a larger study. The Capsella rubella and Capsella grandiflora data are included in GEO Series GSE45518.
Project description:Deep sequencing of the 5' ends of uncapped, polyA-enriched mRNA from two biological replicate samples from Arabidopsis thaliana inflorescences, as well as two biological replicates of Arabidopsis lyrata inflorescences. These data were used to experimentally identify sliced microRNA targets from the two species.
Project description:Arabidopsis thaliana and Arabidopsis lyrata are two closely related Brassicaceae species, which are used as models for plant comparative biology. They differ by lifestyle, predominant mating strategy, ecological niches and genome organization. In order to explore molecular basis of specific traits, we performed RNA-sequencing of vegetative rosettes from both species. Additionally, we sequenced apical meristems and inflorescences of A. lyrata that allow for intra-specific transcriptome comparison in several major developmental stages. Please view also related dataset GSE69077 (RNA-sequencing of heat stressed A. lyrata and A. thaliana plants).
Project description:RNA-seq reads from the outcrossing species Arabidopsis lyrata were produced from flowers to study the consequences of the transition from the ancestral state (outcrossing) to the derived state (selfing) that is observed in the sister species Arabidopsis thaliana. This was done in the context of examining another species pair (Capsella rubella versus Capsella grandiflora, which are selfing and outcrossing, respectively). These samples were generated to complement part of this larger study. Briefly, the shift from outcrossing to selfing is common in flowering plants, but neither the genomic consequences nor the speed with which they appear are well understood. An excellent model for understanding the evolution of self fertilization is provided by Capsella rubella, which became self-compatible <200,000 years ago. We present a reference genome for the species, and compare RNA expression and polymorphism patterns between C. rubella and its outcrossing progenitor C. grandiflora. There is a clear shift in the expression of genes associated with flowering phenotypes; a similar shift is seen in the related genus Arabidopsis, where self-fertilization evolved about 1 million years ago. DNA sequence polymorphisms distinguishing the two Capsella species reveal rapid genome-wide relaxation of purifying selection in C. rubella but without a concomitant change in transposable element abundance. Overall, we document that the transition to selfing may be typified by shifts in expression for genes that function in pollen and flower development, along with a measurable reduction of purifying selection. As part of a cross-species comparison of gene expression, RNA-seq data was generated in biological replication (2 replicates) from Arabidopsis lyrata at the floral stage. In total, two samples (biological replicates) were used. The reference strain was used for the experments (strain MN47). Resulting data about gene expression was used as part of a larger study. The Capsella rubella and Capsella grandiflora data are included in GEO Series GSE45518.