© 1996 Heron Publishing—Victoria, Canada
Characterization of seed storage proteins in Populus and their homology with Populus vegetative storage proteins
Tannis Beardmore (1), Suzanne Wetzel (2), Darwin Burgess (3) and Pierre J. Charest (3)
1. Canadian Forest Service, P.O. Box 4000, Regent St. South, Fredericton, NB, E3B 5P7, Canada / 2. Canadian Forest Service, P.O. Box 490, 1219 Queen St. E., Sault Ste. Marie, ON, P6A 5M7, Canada / 3. Canadian Forest Service, P.O. Box 2000, Chalk River, ON, K0J 1J0, Canada / Received March 16, 1995
Summary
We investigated the synthesis and accumulation of vegetative storage proteins (VSPs) in poplar plantlets and the homology
between poplar seed storage proteins (SSPs) and VSPs. One-dimensional SDS polyacrylamide gel electrophoresis confirmed that
both seed and vegetative storage proteins contained two predominant polypeptides of MW 32 and 36 kDa, but the subunit composition
of the polypeptides differed. The 32- and 36-kDa polypeptides were highly abundant in basal leaves, stems, and roots of poplar
plantlets. The 36-kDa subunit was synthesized in all plantlet tissues examined, but the 32-kDa subunit was not, suggesting
that the 36-kDa polypeptide is a precursor of the 32-kDa polypeptide. The 36- and 32-kDa polypeptides of both SSPs and VSPs
were glycosylated and both were found to be albumins. In addition, both polypeptides cross-reacted with a VSP antibody. Protein
fingerprint patterns generated with two different proteolytic enzymes were identical for the 36-kDa polypeptide isolated from
seeds or from stem tissue. Our study provides evidence that poplar SSPs and VSPs exhibit homology, and that expression is
neither tissue-specific nor regulated solely by photoperiod.
Keywords:
Alnus crispa, electrophoresis, Larix × eurolepis, poplar, protein fingerprint, Salix microstycha.
