Cellular localization of soybean storage protein mRNA in transformed tobacco seeds

Abstract

We transformed tobacco plants with a soybean β-conglycinin gene that encodes the 1.7-kilobase β-subunit mRNA. We showed that the β-conglycinin mRNA accumulates and decays during tobacco seed development and that β-conglycinin mRNA is undetectable in the tobacco leaf. We utilized in situ hybridization to localize β-conglycinin mRNA within the tobacco seed. β-Conglycinin mRNA is not detectable within the endosperm but is localized within specific embryonic cell types. The highest concentration of β-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 β-conglycinin gene, and that factors regulating β-conglycinin gene expression are compartmentalized within analogous soybean and tobacco seed regions.