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Temporal, spatial and hormonal regulation of the S ‐adenosylmethionine synthetase gene in petunia
Author(s) -
Izhaki Anat,
Shosevov Oded,
Weiss David
Publication year - 1996
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1996.tb00483.x
Subject(s) - petunia , abscisic acid , biology , gibberellic acid , gene , gene expression , elongation , regulation of gene expression , botany , anthocyanin , microbiology and biotechnology , biochemistry , germination , materials science , ultimate tensile strength , metallurgy
Gibberellic acid (GA 3 ) promotes corolla elongation and pigmentation in petunia flowers. We have previously shown that G.A 3 induces pigmentation by activating specific genes of the anthocyanin biosynthetic pathway. The aim of the present work was to examine whether GA 3 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 (SAM‐S). In the present work we show that sam expression is induced by GA 3 in both corollas and stems. The expression of the gene was correlated with corolla elongation. GA 3 and the cylokinin, 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 GA 3 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 GA 3 ‐induced corolla and stem elongation.