uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Differential expression of genes important for adaptation in Capsella bursa-pastoris (Brassicaceae)
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Functional Genomics.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Functional Genomics.
Department of Molecular Genetics and Microbiology, University of Florida.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Evolutionary Functional Genomics.
Show others and affiliations
2007 (English)In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 145, no 1, 160-173 p.Article, review/survey (Refereed) Published
Abstract [en]

Understanding the genetic basis of natural variation is of primary interest for evolutionary studies of adaptation. In Capsella bursa-pastoris, a close relative of Arabidopsis (Arabidopsis thaliana), variation in flowering time is correlated with latitude, suggestive of an adaptation to photoperiod. To identify pathways regulating natural flowering time variation in C. bursa-pastoris, we have studied gene expression differences between two pairs of early- and late-flowering C. bursa-pastoris accessions and compared their response to vernalization. Using Arabidopsis microarrays, we found a large number of significant differences in gene expression between flowering ecotypes. The key flowering time gene FLOWERING LOCUS C (FLC) was not differentially expressed prior to vernalization. This result is in contrast to those in Arabidopsis, where most natural flowering time variation acts through FLC. However, the gibberellin and photoperiodic flowering pathways were significantly enriched for gene expression differences between early- and late-flowering C. bursa-pastoris. Gibberellin biosynthesis genes were downregulated in late-flowering accessions, whereas circadian core genes in the photoperiodic pathway were differentially expressed between early- and late-flowering accessions. Detailed time-series experiments clearly demonstrated that the diurnal rhythm of CIRCADIAN CLOCK-ASSOCIATED1 (CCA1) and TIMING OF CAB EXPRESSIONI (TOC1) expression differed between flowering ecotypes, both under constant light and long-day conditions. Differential expression of flowering time genes was biologically validated in an independent pair of flowering ecotypes, suggesting a shared genetic basis or parallel evolution of similar regulatory differences. We conclude that genes involved in regulation of the circadian clock, such as CCA1 and TOC1, are strong candidates for the evolution of adaptive flowering time variation in C. bursa-pastoris.

Place, publisher, year, edition, pages
2007. Vol. 145, no 1, 160-173 p.
Keyword [en]
Spermatophyta, Angiospermae, Dicotyledones, Cruciferae, Capsella bursa-pastoris, Adaptation, Gene
National Category
Biological Sciences
Identifiers
URN: urn:nbn:se:uu:diva-96450DOI: 10.1104/pp.107.102632ISI: 000249285200015OAI: oai:DiVA.org:uu-96450DiVA: diva2:171026
Available from: 2007-11-15 Created: 2007-11-15 Last updated: 2017-12-14Bibliographically approved
In thesis
1. Evolution of Flowering Time in the Tetraploid Capsella bursa-pastoris (Brassicaceae)
Open this publication in new window or tab >>Evolution of Flowering Time in the Tetraploid Capsella bursa-pastoris (Brassicaceae)
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Although polyploidy is believed to be a major source of evolutionary novelty, few studies have examined the genetic basis of phenotypic variation in wild polyploids. In this thesis I have studied the genetic basis of flowering time variation in the wild tetraploid crucifer Capsella bursa-pastoris, as well as the evolutionary history of this species.

First, phylogenetic methods were employed to test hypotheses on the origin of C. bursa-pastoris. Based on DNA sequences from two chloroplast DNA loci and three independent nuclear genes, we found no support for the notion of C. bursa-pastoris as an autopolyploid of the diploid C. grandiflora, or an allopolyploid of C. grandiflora and C. rubella, even though some C. bursa-pastoris accessions shared alleles with C. rubella at nuclear loci. Using divergence population genetic methods, a larger sample of accessions and data for six duplicated nuclear genes, we found that allele sharing in sympatry was better explained by introgressive hybridization than by multiple origins of the tetraploid.

The genetic basis of flowering time variation was examined using three approaches. A gene expression microarray study revealed that early- and late-flowering accessions differ in circadian rhythm, as well as in the gibberellin pathway affecting flowering time. Second, two QTL (Quantitative Trait Loci) for flowering time map to duplicated linkage groups. Third, polymorphisms at the candidate genes CRYPTOCHROME1 (CRY1), in one of the QTL regions, and FLOWERING LOCUS C (FLC) are associated with natural flowering time variation. Different FLC splice site polymorphisms are associated with flowering time in samples from Western Eurasia and China. The CRY1 association is only found in Europe, where alleles introgressed from C. rubella have an effect on flowering time. In conclusion, duplicated genes, introgressive hybridization and splicing variation may all have played a role in the evolution of flowering time variation in C. bursa-pastoris.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2007. 40 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 367
Keyword
Biology, flowering time, homoeolog, hybridization, introgression, microarray, multiple origins, polyploid, QTL, Biologi
Identifiers
urn:nbn:se:uu:diva-8311 (URN)978-91-554-7024-1 (ISBN)
Public defence
2007-12-07, Lindahlsalen, EBC, Norbyvägen 18, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2007-11-15 Created: 2007-11-15 Last updated: 2009-10-30Bibliographically approved
2. Studies on Natural Variation and Evolution of Photoperiodism in Plants
Open this publication in new window or tab >>Studies on Natural Variation and Evolution of Photoperiodism in Plants
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Photoperiodism refers to the organism’s ability to detect and respond to seasonal changes in the daily duration of light and dark and thus constitutes one of the most significant and complex examples of the interaction between the organism and its environment. This thesis attempts to describe the prevalence of variation in a photoperiodic response, its adaptive value, and its putative genetic basis in a common cruciferous weed, Capsella bursa-pastoris (Brassicaceae). Furthermore, the thesis presents a first comprehensive comparative overview of the circadian clock mechanism in an early land plant, Physcomitrella patens (Bryophyta), thus providing insights into the evolution of the plant circadian system.

In an introductory survey of global gene expression changes among early- and late flowering accessions of C. bursa-pastoris we found an enrichment of genes involved in photoperiodic response and regulation of the circadian clock. Secondly, by phenotyping circadian rhythm variation in a worldwide sample of accessions with known flowering time, we detected robust latitudinal clines in flowering time and circadian period length, which constitute strong indications of local adaptation to photoperiod in the shaping of flowering time variation in this species. In an attempt to elucidate putative genetic causes for the correlated variation between circadian rhythm and flowering time, we found that sequence variation and diverged expression in components regulating light input to the clock, PHYTOCHROME B (PHYB) and DE-ETIOLATED 1 (DET1) make them strong candidate genes. Finally, we present a comparative study of circadian network topology in the moss P. patens. Phylogenetic analyses and time series expression studies of putative clock homologues indicated that several core clock genes present in vascular plants appeared to be lacking in the moss. Consequently, while the clock mechanism in higher plants constitutes at least a three-loop system of interacting components, the moss clock appears to comprise only a single loop.

We conclude that C. bursa-pastoris is a highly suitable model system for the further elucidation of the molecular variation that influences adaptive change in natural plant populations. Furthermore, we believe that the continuing study of the seemingly less complex circadian network of P. patens not only can provide insights into the evolution of the plant circadian system, but also may help to clarify some of the remaining issues of the circadian clock mechanism in higher plants.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2010. 37 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 718
Keyword
photoperiodism, circadian, flowering time, natural variation, evolution, Caspella bursa-pastoris, Physcomitrella patens
Research subject
Biology with specialization in Evolutionary Functional Genomics
Identifiers
urn:nbn:se:uu:diva-119269 (URN)978-91-554-7730-1 (ISBN)
Public defence
2010-04-09, Zootissalen, Evolutionsbiologiskt centrum (EBC), Villavägen 9, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2010-03-17 Created: 2010-02-24 Last updated: 2010-03-17Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Slotte, TanjaHolm, KarlLagercrantz, UlfLascoux, Martin

Search in DiVA

By author/editor
Slotte, TanjaHolm, KarlLagercrantz, UlfLascoux, Martin
By organisation
Evolutionary Functional Genomics
In the same journal
Plant Physiology
Biological Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 559 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf