Selection and Gene Flow Shape Genomic Islands that Control Floral Guides
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PROVIDER: PRJNA486455 | ENA |
REPOSITORIES: ENA
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Project description:Genomes of closely-related species or populations often display localized regions of enhanced relative sequence divergence, termed genomic islands. It has been proposed that these islands arise through selective sweeps and/or barriers to gene flow. Here, we genetically dissect a genomic island that controls flower color pattern differences between two subspecies of Antirrhinum, A.m.striatum and A.m.pseudomajus, and relate it to clinal variation across a natural hybrid zone. We show that selective sweeps likely raised relative divergence at two tightly-linked MYB-like transcription factors, leading to distinct flower patterns in the two subspecies. The two patterns provide alternate floral guides and create a strong barrier to gene flow where populations come into contact. This barrier affects the selected flower color genes and tightly linked loci, but does not extend outside of this domain, allowing gene flow to lower relative divergence for the rest of the chromosome. Thus, both selective sweeps and barriers to gene flow play a role in shaping genomic islands: sweeps cause elevation in relative divergence while heterogeneous gene flow flattens the surrounding “sea”, making the island of divergence stand out. By showing how selective sweeps establish alternative adaptive phenotypes that lead to barriers to gene flow, our study sheds light on possible mechanisms leading to reproductive isolation and speciation.
2018-08-18 | GSE118621 | GEO
Project description:Genomes of closely-related species or populations often display localized regions of enhanced relative sequence divergence, termed genomic islands. It has been proposed that these islands arise through selective sweeps and/or barriers to gene flow. Here, we genetically dissect a genomic island that controls flower color pattern differences between two subspecies of Antirrhinum majus, A.m.striatum and A.m.pseudomajus, and relate it to clinal variation across a natural hybrid zone. We show that selective sweeps likely raised relative divergence at two tightly-linked MYB-like transcription factors, leading to distinct flower patterns in the two subspecies. The two patterns provide alternate floral guides and create a strong barrier to gene flow where populations come into contact. This barrier affects the selected flower color genes and tightly-linked loci, but does not extend outside of this domain, allowing gene flow to lower relative divergence for the rest of the chromosome. Thus, both selective sweeps and barriers to gene flow play a role in shaping genomic islands: sweeps cause elevation in relative divergence, while heterogeneous gene flow flattens the surrounding "sea," making the island of divergence stand out. By showing how selective sweeps establish alternative adaptive phenotypes that lead to barriers to gene flow, our study sheds light on possible mechanisms leading to reproductive isolation and speciation.
| S-EPMC6205484 | biostudies-literature
Project description:CpG islands shape the epigenome landscape.
| PRJNA419733 | ENA
Project description:Universally accepted landmark stages are necessary to highlight key events in tomato reproductive development. In this study, we provide a description of floral and fruit development in a red-fruited closely related wild relative of tomato, Solanum pimpinellifolium accession LA1589. We use established and propose new landmarks as the framework for the characterization of the tomato fruit shape gene SUN in fruit development. SUN controls fruit shape predominantly after fertilization and its effect reaches a maximum at 8 days post anthesis coinciding with fruit landmark 4 representing the globular embryo stage of seed development. We also analyzed gene expression profiles of floral buds 10 days before anthesis (floral landmark 7), anthesis-stage flowers (floral landmark 10 and fruit landmark 1), and 5 days post anthesis fruit (fruit landmark 3). The expression profiles of the NILs that differ at sun showed that 34 genes were differentially expressed and most of them at a less than 2-fold difference. However, many genes were differentially expressed between the developmental times points, including many genes involved in phytohormone biosynthesis or signaling as well as organ identity and patterning of tomato fruit. Three biological replicates were conducted with three sets of LA1589 sun NILs that differ at sun growing during different time periods resulting in 3 time points x 2 genotypes x 3 replicates = 18 array hybridizations.
2010-05-18 | E-GEOD-15453 | biostudies-arrayexpress
Project description:Floral guides are signal patterns that lead pollinators to floral rewards after they have located the flower, and increase foraging efficiency and pollen transfer. Patterns of several floral signalling modalities, particularly colour patterns, have been identified as being able to function as floral guides. Floral temperature frequently shows patterns that can be used by bumblebees for locating and recognising the flower, but whether these temperature patterns can function as a floral guide has not been explored. Furthermore, how combined patterns (using multiple signalling modalities) affect floral guide function has only been investigated in a few modality combinations. We assessed how artificial flowers induce behaviours in bumblebees when rewards are indicated by unimodal temperature patterns, unimodal colour patterns or multimodal combinations of these. Bees visiting flowers with unimodal temperature patterns showed an increased probability of finding rewards and increased learning of reward location, compared to bees visiting flowers without patterns. However, flowers with contrasting unimodal colour patterns showed further guide-related behavioural changes in addition to these, such as reduced reward search times and attraction to the rewarding feeder without learning. This shows that temperature patterns alone can function as a floral guide, but with reduced efficiency. When temperature patterns were added to colour patterns, bees showed similar improvements in learning reward location and reducing their number of failed visits in addition to the responses seen to colour patterns. This demonstrates that temperature pattern guides can have beneficial effects on flower handling both when alone or alongside colour patterns.
| S-EPMC7073333 | biostudies-literature
Project description:Paired End WGS Illumina reads of A. m. striatum and A.m.pseudomajus supporting Tavares et al (2018) Selection and gene flow shape genomic islands that control floral guides.
| PRJEB28287 | ENA
Project description:Several pathways conferring environmental flowering responses in Arabidopsis converge on developmental processes that mediate floral transition in the shoot apical meristem. Many characterized mutations disrupt these environmental responses, but downstream developmental processes have been more refractory to mutagenesis. We constructed a quintuple mutant impaired in several environmental pathways and showed that it possesses severely reduced flowering responses to changes in photoperiod and ambient temperature. RNA-seq analysis of the quintuple mutant showed that the expression of genes encoding gibberellin biosynthesis enzymes and transcription factors involved in the age pathway correlates with flowering. Mutagenesis of the quintuple mutant generated two late-flowering mutants, quintuple ems 1 (qem1) and qem2. The mutated genes were identified by isogenic mapping and transgenic complementation. The qem1 mutant was an allele of ga20ox2, confirming the importance of gibberellin for flowering in the absence of environmental responses. By contrast, the qem2 mutation is in CHROMATIN REMODELING 4 (CHR4), which has not been genetically implicated in floral induction. Using co-immunoprecipitation, RNA-seq and ChIP-seq, we show that CHR4 interacts with transcription factors involved in floral meristem identity and affects expression of key floral regulators. We conclude that CHR4 mediates the response to endogenous flowering pathways in the inflorescence meristem to promote floral identity.
2020-03-02 | PXD016457 | Pride
Project description:Universally accepted landmark stages are necessary to highlight key events in tomato reproductive development. In this study, we provide a description of floral and fruit development in a red-fruited closely related wild relative of tomato, Solanum pimpinellifolium accession LA1589. We use established and propose new landmarks as the framework for the characterization of the tomato fruit shape gene SUN in fruit development. SUN controls fruit shape predominantly after fertilization and its effect reaches a maximum at 8 days post anthesis coinciding with fruit landmark 4 representing the globular embryo stage of seed development. We also analyzed gene expression profiles of floral buds 10 days before anthesis (floral landmark 7), anthesis-stage flowers (floral landmark 10 and fruit landmark 1), and 5 days post anthesis fruit (fruit landmark 3). The expression profiles of the NILs that differ at sun showed that 34 genes were differentially expressed and most of them at a less than 2-fold difference. However, many genes were differentially expressed between the developmental times points, including many genes involved in phytohormone biosynthesis or signaling as well as organ identity and patterning of tomato fruit.
2009-05-21 | GSE15453 | GEO
Project description:We conducted micro-array analysis to quantify the global transcriptome variations in floral organs of a male and female tree allowing for identification of sex-linked transcripts. We used RNA samples from male floral buds in August and female floral buds in Spetemeber. Bud scale were removed. While the sampling time differed, the developmental stage of the floral organs was similar between the male and female.
2011-12-29 | GSE29336 | GEO
Project description:Floral nectar is a rich secretion produced by nectaries offered as an attractive reward to pollinators. Floral nectaries secrete an aqueous solution largely composed of sugars and amino acids as well as an array of proteins called nectarins. These provide one of the main mechanisms of floral defense in Nicotiana nectar. Due to its composition, floral nectar provides an ideal source of nutrients for specialized microorganisms that can change the nectar composition. Understanding of floral defenses and the role of nectar proteins is essential to predict the impacts in microbial growth, nectar composition, and relationships between plants and pollinators. In order to deepen knowledge about Nicotiana spp. nectar proteins, we used LC-MS/MS-based comparative proteomic analysis to identify 22 proteins from Petunia hybrida, 35 proteins from Datura stramonium, and 144 proteins from 23 different species of Nicotiana. GO enrichment analysis and secretory signal peptide prediction demonstrated that defense/stress was the largest group of proteins in nectars with differential abundance and distribution throughout genus Nicotiana. The Nicotiana spp. proteome consisted of 105 exclusive proteins such as lipid transfer proteins (LTPs), Nectar Redox Cycle proteins, proteases inhibitors (PI), and PR-proteins. Analysis by taxonomic sections demonstrated that LTPs were the most abundant group of proteins in the nectar of Undulatae and Noctiflora sections while nectarins were more abundant proteins in Rusticae, Suaveolens, Polydicliae, and Alata sections. Peroxidases (Pox) and chitinases (Chit) were exclusive to P. hybrida nectar, while D. stramonium proteome had only seven unique proteins. Significant differences were identified between the proteome of taxonomic sections providing relevant insights into the group of proteins related to defense/stress associated with Nectar Redox Cycle, antimicrobial proteins and signaling pathways. The activity of floral nectar proteins is suggested impact the microbial growth. The knowledge about these proteomes provides significant insights into the diversity of proteins secreted in the nectars and the array of mechanisms used by Nicotiana spp. in its floral defense.
2020-01-08 | PXD014760 | Pride