Brassica S-Proteins Accumulate in the Intercellular Matrix along the Path of Pollen Tubes in Transgenic Tobacco Pistils

A tobacco plant transformed with a Brassica oleracea SLG-22 gene was analyzed by immunocytochemical methods to determine the localization of the transgene-encoded protein product. Immunolabeling was observed in the pistil along the path followed by pollen tubes after pollination. S-antigen accumulated in the intercellular matrix of the transmitting tissue of the style and its continuation in the basal portion of the stigma and outside a few special cells of the placental epidermis of the ovary. This pattern of S-antigen distribution closely resembles that described for the S-associated glycoproteins of self-incompatible Nicotiana alata and differs from its distribution in B. oleracea.