Abstract
Gibberellic acid (GA3) promotes corolla elongation and pigmentation in petunia flowers. We have previously shown that GA3 induces pigmentation by activating specific genes of the anthocyanin biosynthetic pathway. The aim of the present work was to examine whether GA3 induces also the expression of genes from other metabolic pathways in petunia corollas that may be associated with growth. Recently we reported the cloning of the petunia sam gene coding for S-adenosylmethionine synthetase (SAMS). In the present work we show that sam expression is induced by GA3 in both corollas and stems. The expression of the gene was correlated with corolla elongation. GA3 and the cytokinin, N-6-benzyladenine (BA) promoted corolla growth and sam expression, whereas abscisic acid (ABA) inhibited corolla elongation and repressed sam mRNA accumulation. An analysis of sam expression in stems indicated a high level in young, elongating internodes and a very low level in the mature, non-elongating stem zone. The results of the present study show that the effect of GA3 on gene expression in the corolla of petunia, is not restricted to the anthocyanin biosynthetic pathway; they also suggest a possible role for sam in GA3-induced corolla and stem elongation.
Original language | English |
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Pages (from-to) | 90-94 |
Number of pages | 5 |
Journal | Physiologia Plantarum |
Volume | 97 |
Issue number | 1 |
DOIs | |
State | Published - May 1996 |
Keywords
- Corolla growth
- Gibberellic acid
- Petunia hybrida
- S-adenosylmethionine synthetase
- Stem elongation