Plant Physiol, August 2000, Vol. 123, pp. 1281-1288
The Mid-Pericarp Cell Layer in Soybean Pod Walls Is a
Multicellular Compartment Enriched in Specific Lipoxygenase
Isoforms1
Wesley E.
Dubbs and
Howard D.
Grimes*
Department of Botany (W.E.D.) and School of Molecular Biosciences
(H.D.G.), Washington State University, Pullman, Washington
99164-4234
Specific lipoxygenase isoforms immunolocalize to the cytosol of a
single cell layer in the soybean (Glycine max L.) pod
wall. The cells of this layer, termed the mid-pericarp layer (MPL), are
larger than adjacent cells and are highly branched. The entire MPL
appears to form an elaborate interdigitated network within the pod
wall. A particularly striking feature of the MPL is the presence of
extensive regions of very thin, approximately 30 nm, cell wall, which
connect the cells of the MPL. It was demonstrated that after mechanical
wounding of the pod wall, 40-kD fluorescein-dextran was able to move
throughout the MPL. In addition, when pod walls are cut, an exudate
flows from the MPL that is highly enriched in lipoxygenase isoforms
(approximately 40% of the total protein). The MPL of soybean pod walls
may represent a novel multicellular compartment involved in defense of
leguminous plants.
1
This research was funded by the U.S. Department
of Agriculture National Research Initiative Competitive Grants Program
(grant nos. 9703353 and 9903498 to H.D.G.).
*
Corresponding author; e-mail grimes{at}wsu.edu; fax 509-335-1907.
© 2000 American Society of Plant Physiologists
