Published in:
The Plant Journal, 67 (2011) 6, Seite 960-970
Language:
English
DOI:
10.1111/j.1365-313x.2011.04648.x
ISSN:
0960-7412;
1365-313X
Origination:
Footnote:
Description:
<jats:title>Summary</jats:title><jats:p>In cells, anthocyanin pigments are synthesized at the cytoplasmic surface of the endoplasmic reticulum, and are then transported and finally accumulated inside the vacuole. In <jats:italic>Vitis vinifera</jats:italic> (grapevine), two kinds of molecular actors are putatively associated with the vacuolar sequestration of anthocyanins: a glutathione‐<jats:italic>S</jats:italic>‐transferase (GST) and two MATE‐type transporters, named anthoMATEs. However, the sequence of events by which anthocyanins are imported into the vacuole remains unclear. We used <jats:italic>MYBA1</jats:italic> transformed hairy roots as a grapevine model tissue producing anthocyanins, and took advantage of the unique autofluorescence of anthocyanins to study their cellular trafficking. In these tissues, anthocyanins were not only visible in the largest vacuoles, but were also present at higher concentrations in several vesicles of different sizes. In the cell, small vesicles actively moved alongside the tonoplast, suggesting a vesicular trafficking to the vacuole. Subcellular localization assays revealed that anthoMATE transporters were closely related with these small vesicles, whereas GST was localized in the cytoplasm around the nucleus, suggesting an association with the endoplasmic reticulum. Furthermore, cells in hairy roots expressing <jats:italic>anthoMATE</jats:italic> antisense did not display small vesicles filled with anthocyanins, whereas in hairy roots expressing <jats:italic>GST</jats:italic> antisense, anthocyanins were accumulated in vesicles but not in the vacuole. This suggests that in grapevine, anthoMATE transporters and GST are involved in different anthocyanin transport mechanisms.</jats:p>