Unmethyl-esterified homogalacturonan and extensins seal Arabidopsis graft union.

To the best of our knowledge, this is the first report on the composition and structure of the extracellular material that gets deposited on the surface of graft union during Arabidopsis grafting. The results showed that unmethyl-esterified homogalacturonan and extensins are together involved in the adhesion of scion and stock, as well as taking part in sealing the graft union. The extracellular material is of importance not only due to the potential pectin-extensin interaction but also due to its origin. The findings presented here implicate a need for studies with biochemical approach for a detailed analysis of the composition and structure of the extracellular material.