Cellular localization of soybean storage protein mRNA in transformed tobacco seeds

Abstract

We transformed tobacco plants with a soybean .beta.-gonglycinin gene that encodes the 1.7-kilobase .beta.-subunit mRNA. We showed that the .beta.-conglycinin mRNA accumulates and decays during tobacco seed development and that .beta.-conglycinin mRNA is undetectable in the tobacco leaf. We utilized in situ hybridization to localize .beta.-conglycinin mRNA within the tobacco seed. .beta.-Conglycinin mRNA is not detectable within the endosperm but is localized within specific embryonic cell types. The highest concentration of .beta.-conglycinin mRNA is found in cotyledon storage parenchyma cells. We conclude that sequences required for embryo expression, temporal control, and cell specificity are linked to the .beta.-conglycinin gene, and that factors regulating .beta.-conglycinin gene expression are compartmentalized within analogous soybean and tobacco seed regions.