PLANT PHYSIOLOGY , Vol 112, Issue 1 53-59, Copyright © 1996 by American Society of Plant Biologists
|
DEVELOPMENT AND GROWTH REGULATION |
Influence of Auxin and Gibberellin on in Vivo Protein Synthesis during Early Pea Fruit Growth
R. van Huizen, J. A. Ozga and D. M. Reinecke
Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada, T6G 2P5
Developing pea fruits (Pisum sativum L.) offer a unique opportunity to
study growth and development in a tissue that is responsive to both
gibberellins (GAs) and auxin (4-chloroindole-3-acetic acid[4-CI-IAA]). To
begin a molecular analysis of the interaction of GAs and auxins in pea
fruit development, in vivo labeling with [35S]methionine coupled with
two-dimensional gel electrophoresis were used to characterize de novo
synthesis of proteins during gibberellic acid (GA3)-, 4-CI-indoleacetic
acid-, and seed-induced pea pericarp growth. The most significant and
reproducible polypeptide changes were observed between molecular weights of
20 and 60. Comparing about 250 de novo synthesized proteins revealed that
seed removal changed the pattern substantially. We identified one class of
polypeptides that was uniquely seed induced and five classes that were
affected by hormone treatment. The latter included 4-CI-IAA-induced,
GA3-induced, GA3- and 4-CI-IAA-induced, 4-CI-IAA-repressed, and GA3- and
4-CI-IAA-repressed polypeptides. Similar patterns of protein expression
were associated with both hormone treatments; however, changes unique to
GA3 or 4-CI-IAA treatment also indicate that the effects of GA3 and
4-CI-IAA on this process are not equivalent. In general, application of
4-CI-IAA plus GA3 replaced the seed effects on pericarp protein synthesis,
supporting our hypothesis that both hormones are involved in pea pericarp
development.
