Beschreibung:
<jats:title>Summary</jats:title><jats:p>
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<jats:list-item><jats:p>Arabidopsis vacuoles harbor, besides sugar transporter of the <jats:styled-content style="fixed-case">TMT</jats:styled-content>‐type, an early response to dehydration like 6 (<jats:styled-content style="fixed-case">ERDL</jats:styled-content>6) protein involved in glucose export into the cytosol. However, the mode of transport of <jats:styled-content style="fixed-case">ERDL</jats:styled-content>6 and the plant's feedback to overexpression of its activity on essential properties such as, for example, seed germination or freezing tolerance, remain unexplored.</jats:p></jats:list-item>
<jats:list-item><jats:p>Using patch‐clamp studies on vacuoles expressing <jats:italic>At<jats:styled-content style="fixed-case">ERDL</jats:styled-content>6</jats:italic> we demonstrated directly that this carrier operates as a proton‐driven glucose exporter.</jats:p></jats:list-item>
<jats:list-item><jats:p>Overexpression of <jats:italic>Bv</jats:italic><jats:styled-content style="fixed-case">IMP</jats:styled-content>, the closest sugar beet (<jats:italic>Beta vulgaris</jats:italic>) homolog to <jats:italic>At</jats:italic><jats:styled-content style="fixed-case">ERDL</jats:styled-content>6, in Arabidopsis leads surprisingly to impaired seed germination under both conditions, sugar application and low environmental temperatures, but not under standard conditions.</jats:p></jats:list-item>
<jats:list-item><jats:p>Upon cold treatment, <jats:italic>Bv</jats:italic><jats:styled-content style="fixed-case">IMP</jats:styled-content> overexpressor plants accumulated lower quantities of monosaccharides than the wild‐type, a response in line with the reduced frost tolerance of the transgenic Arabidopsis plants, and the fact that cold temperatures inhibits <jats:italic>Bv<jats:styled-content style="fixed-case">IMP</jats:styled-content></jats:italic> transcription in sugar beet leaves. With these findings we show that the tight control of vacuolar sugar import and export is a key requisite for cold tolerance and seed germination of plants.</jats:p></jats:list-item>
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