Refine
Has Fulltext
- no (6) (remove)
Year of publication
- 2004 (6) (remove)
Document Type
- Article (6)
Language
- English (6)
Is part of the Bibliography
- yes (6)
Institute
- Institut für Biochemie und Biologie (6) (remove)
Heterosis has been widely used in agriculture to increase yield and to broaden adaptability of hybrid varieties and is applied to an increasing number of crop species. We performed a systematic survey of the extent and degree of heterosis for dry biomass in 63 Arabidopsis accessions crossed to three reference lines (Col-0, C24, and Nd). We detected a high heritability (69%) for biomass production in Arabidopsis. Among the 169 crosses analyzed, 29 exhibited significant mid-parent-heterosis for shoot biomass. Furthermore, we analyzed two divergent accessions, C24 and Col-0, the F-1 hybrids of which were shown to exhibit hybrid vigor, in more detail. In the combination Col-0/C24, heterosis for biomass was enhanced at higher light intensities; we found 51% to 66% mid-parent-heterosis at low and intermediate light intensities (60 and 120 mumol m(-2) s(-1)), and 161% at high light intensity (240 mumol m(-2) s(-1)). While at the low and intermediate light intensities relative growth rates of the hybrids were higher only in the early developmental phase (0-15 d after sowing [DAS]), at high light intensity the hybrids showed increased relative growth rates over the entire vegetative phase (until 25 DAS). An important finding was the early onset of heterosis for biomass; in the cross Col-0/C24, differences between parental and hybrid lines in leaf size and dry shoot mass could be detected as early as 10 DAS. The widespread occurrence of heterosis in the model plant Arabidopsis opens the possibility to investigate the genetic basis of this phenomenon using the tools of genetical genomics
Microarray transcript profiling and RNA interference are two new technologies crucial for large-scale gene function studies in multicellular eukaryotes. Both rely on sequence-specific hybridization between complementary nucleic acid strands, inciting us to create a collection of gene-specific sequence tags (GSTs) representing at least 21,500 Arabidopsis genes and which are compatible with both approaches. The GSTs were carefully selected to ensure that each of them shared no significant similarity with any other region in the Arabidopsis genome. They were synthesized by PCR amplification from genomic DNA. Spotted microarrays fabricated from the GSTs show good dynamic range, specificity, and sensitivity in transcript profiling experiments. The GSTs have also been transferred to bacterial plasmid vectors via recombinational cloning protocols. These cloned GSTs constitute the ideal starting point for a variety of functional approaches, including reverse genetics. We have subcloned GSTs on a large scale into vectors designed for gene silencing in plant cells. We show that in planta expression of GST hairpin RNA results in the expected phenotypes in silenced Arabidopsis lines. These versatile GST resources provide novel and powerful tools for functional genomics
In a screen for potential mediators of brassinosteroid (BR) effects, the EXORDIUM (EXO) protein was identified as a regulator of BR-responsive genes. The EXO gene was characterized as a BR-up-regulated gene. EXO overexpression under the control of the 35SCaMV promoter resulted in increased transcript levels of the BR-up-regulated KCS1, Exp5, delta-TIP, and AGP4 genes, which likely are involved in the mediation of BR-promoted growth. 35S::EXO lines grown in soil or in synthetic medium showed increased vegetative growth in comparison to wild-type plants, resembling the growth phenotype of BR-treated plants. Thus, the EXO protein most likely promotes growth via the modulation of gene expression patterns. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved