| 1. |
- Chardon, Fabien, et al.
(författare)
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Leaf Fructose Content Is Controlled by the Vacuolar Transporter SWEET17 in Arabidopsis
- 2013
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 23:8, s. 697-702
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Tidskriftsartikel (refereegranskat)abstract
- In higher plants, soluble sugars are mainly present as sucrose, glucose, and fructose [1]. Sugar allocation is based on both source-to-sink transport and intracellular transport between the different organelles [2,3] and depends on actual plant requirements [4]. Under abiotic stress conditions, such as nitrogen limitation, carbohydrates accumulate in plant cells [5]. Despite an increasing number of genetic studies [6, 7], the genetic architecture determining carbohydrate composition is poorly known. Using a quantitative genetics approach, we determined that the carrier protein SWEET17 is a major factor controlling fructose content in Arabidopsis leaves. We observed that when SWEET17 expression is reduced, either by induced or natural variation, fructose accumulates in leaves, suggesting an enhanced storage capacity. Subcellular localization of SWEET17-GFP to the tonoplast and functional expression in Xenopus oocytes showed that SWEET17 is the first vacuolar fructose transporter to be characterized in plants. Physiological studies in planta provide evidence that SWEET17 acts to export fructose out of the vacuole. Overall, our results suggest that natural variation in leaf fructose levels is controlled by the vacuolar fructose transporter SWEET17. SWEET17 is highly conserved across the plant kingdom; thus, these findings offer future possibilities to modify carbohydrate partitioning in crops.
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| 2. |
- Platt, Alexander, et al.
(författare)
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The Scale of Population Structure in Arabidopsis thaliana
- 2010
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 6:2, s. e1000843-
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Tidskriftsartikel (refereegranskat)abstract
- The population structure of an organism reflects its evolutionary history and influences its evolutionary trajectory. It constrains the combination of genetic diversity and reveals patterns of past gene flow. Understanding it is a prerequisite for detecting genomic regions under selection, predicting the effect of population disturbances, or modeling gene flow. This paper examines the detailed global population structure of Arabidopsis thaliana. Using a set of 5,707 plants collected from around the globe and genotyped at 149 SNPs, we show that while A. thaliana as a species self-fertilizes 97% of the time, there is considerable variation among local groups. This level of outcrossing greatly limits observed heterozygosity but is sufficient to generate considerable local haplotypic diversity. We also find that in its native Eurasian range A. thaliana exhibits continuous isolation by distance at every geographic scale without natural breaks corresponding to classical notions of populations. By contrast, in North America, where it exists as an exotic species, A. thaliana exhibits little or no population structure at a continental scale but local isolation by distance that extends hundreds of km. This suggests a pattern for the development of isolation by distance that can establish itself shortly after an organism fills a new habitat range. It also raises questions about the general applicability of many standard population genetics models. Any model based on discrete clusters of interchangeable individuals will be an uneasy fit to organisms like A. thaliana which exhibit continuous isolation by distance on many scales.
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