Tissue specific expression of cell wall proteins of seedlings of Prosopis chilensis during development and wound stress

Four cell wall proteins of seedling cotyledons of Prosopis chilensis were characterized by SDS-polyacrylamide gel electrophoresis. The molecular masses of these proteins were 180, 126, 107 and 63 kDa. All of them immuno-crossreacted with polyclonal antibodies raised against extensin from soybean seed coats. Immuno-dot blot analysis demonstrated that the minimum expression of cotyledonary cell wall proteins was 48 h after seed imbibition, while 24 h after wound stress the expression of these wall proteins increased four-fold. Tissue immuno-prints and immuno-histochemistry showed that the proteins are expressed in the cell wall of all tissues. However, the epidermis and vascular bundles of cotyledons, hypocotyls and roots, and the living cells surrounding the wounded areas highly expressed the wall proteins. When the primary roots of the seedlings were injured by performing cuts with razor blades, the seedlings achieved a growth three times faster than control seedlings and secondary roots developed in sites close to the injuries. Immuno-histochemistry of secondary roots revealed that the root tips and the area of the cortical tissue of the primary roots being pressed by the the emerging root tip, highly expressed the cell wall proteins.