Seeds of Arabidopsis plants expressing dominant-negative AtSKD1 under control of the GL2 promoter show a transparent testa phenotype and a mucilage defect.

We have recently shown that overexpression of dominant-negative AtSKD1 versions under control of the trichome and non-root-hair-cell specific GL2 promoter (GL2pro) blocks trafficking of soluble cargo to the vacuole, resulting in its fragmentation and ultimately cell death. GL2pro is also active in the Arabidopsis seeds. When we inspected seeds of the dominant-negative AtSKD1 variants we found two phenotypes. The seeds display a transparent testa phenotype caused by a lack of proanthocyanidin (PA) and do not possess seed coat mucilage. Both phenotypes could be connected by cell death induced by the overexpression of dominant-negative AtSKD1.