The seed coat-specific expression of a subtilisin-like gene, SCS1, from soybean

A seed coat-specific gene, SCS1 (Seed Coat Subtilisin I), from soybean, Gly cine max [L.] Merill, has been identified and studied. The gene belongs to a small family of genes with sequence similarity to the subtilisins, which are serine proteases. Northern blot analysis showed that SCSI RNA accumulat es to maximal levels in seed coats at 12 days post anthesis, preceding the final stages of seed coat differentiation. The SCSI RNA was not found in ot her tissues including embryos, seed pods, flowers, stems, roots or leaves. In-situ hybridization studies confirmed the temporal pattern of expression observed by Northern blot analysis and further revealed a restricted patter n of RNA accumulation in thick-walled parenchyma cells of the seed coats. T hese cells are important in the apoplastic translocation of nutrients en ro ute to the embryo from the vascular tissues. The tissue-specific subtilisin -like gene may be required for regulating the differentiation of the thick- walled parenchyma cells.