THE PLANT CELL, Vol 1, Issue 1 73-80, Copyright © 1989 by American Society of Plant Biologists
Spatial Patterns of Gene Expression in Brassica napus Seedlings: Identification of a Cortex-Specific Gene and Localization of mRNAs Encoding Isocitrate Lyase and a Polypeptide Homologous to Proteinases
R. A. Dietrich, D. J. Maslyar, R. C. Heupel and J. J. Harada
Department of Botany, University of California, Davis, California 95616
We investigated the spatial expression of three genes that are expressed
during seed germination and postgerminative development in Brassica napus
L. using in situ hybridization procedures. Two of the mRNAs encode
isocitrate lyase and a predicted polypeptide that is homologous to cysteine
proteinases. We reported previously that the mRNAs are prevalent primarily
in cotyledons of seedlings and accumulate with similar kinetics during
postgerminative growth. Here, we show that the two mRNAs are detected in
several seedling tissues, but they display different distribution patterns
in both cotyledons and root-shoot axes. The third mRNA is abundant in
seedling axes and accumulates specifically in the ground meristem and
mature cortex of hypocotyls and roots. Distribution of the mRNA in root
meristems suggests that the gene product participates in an early event in
cortical cell differentiation. Our results provide insight into the
physiological processes that characterize seedlings.
