Abstract
Extracellular proteins play various functions in plants. Xylogen, an arabinogalactan protein (AGP) which is isolated from Zinnia mesophyll cell culture, is an extracellular arabinogalactan protein that promotes tracheary element differentiation. Xylogen is secretory protein whose membrane localization is supposed to be regulated by its C-terminus glycosylphosphatidylinositol (GPI)-anchor. In Arabidopsis, AtXYP2 is likely to be the ortholog of Zinnia xylogen. To understand the secretion and localization mechanisms of AtXYP2, we generated transgenic plants harboring GFP-fused AtXYP2 gene under the AtXYP2 promoter, and analyzed intracellular localization. In the root of transgenic plants, GFP signal was observed in the immature xylem and the procambium. Its subcellular localization differed dependently on differentiation stages. Together with the results using organelle marker and mutants of vesicular transportation, we will discuss on regulation of subcellular localization of xylogen.
