The petunia homologue of tomato gast1: transcript accumulation coincides with gibberellin-induced corolla cell elongation

Abstract

Gibberellins (GAs) regulate petunia corolla pigmentation and elongation. To study this hormone's effect at the molecular level, we used the tomato gast1 gene as a probe to isolate a gibberellin-induced gene (gip) from petunia corollas. The deduced sequence of gip exhibited 82% identity with GAST1 protein and contained a short, highly hydrophobic N-terminal region. High levels of gip expression were detected in elongating corollas and young stem intemodes. When detached corollas were grown in vitro in sucrose medium, gip expression was strongly induced by gibberellic acid (GA3). GA3-induced gip expression in corollas was inhibited by abscisic acid (ABA). The expression of the gene was also induced by GA3 in detached young stem segments. Sucrose was not essential for GA-induced gip expression in corollas but enhanced its effect. In stems, on the other hand, sucrose inhibited the effect of the hormone. The results of the present work support the possible role of gip in GA-induced corolla and stem elongation.

Snakin-1, a Peptide from Potato That Is Active Against Plant Pathogens

“…Sequences are (a) RC153 from Ricinus communis (EMBL accession no. T24153); (b) N37340 from Arabidopsis thaliana (Newman et al 1994); (c) Os0951 from rice (Sasaki et al 1994); (d) PHGIPl from petunia (Ben-Nissan and Weiss 1996); (e) GASTl from tomato (Shi et al 1992); (f,g,i,j) GASA2,3,4,1 from A. thaliana (Herzog et al 1995); (h) RSIl from tomato (Taylor and Scheuring 1994); and (KIS) kistrin from the Malayan pit viper (Adler et al 1991). Identical residues are shaded and the numbers of identical residues (id/63) are indicated.…”

“…Leaves were sprayed with solutions of hormones that have been implicated in plant-pathogen interactions, such as methyl jasmonate (50 uM), ethylene (ethephon 0.03 g/liter), and abscisic acid (100 uM), inducers of systemic acquired resistance, such as salicylic acid (5 mM) and isonicotinic acid (0.6 mM), and hormones that have been shown to affect steady-state levéis of mRNAs encoding some SN1 homologues in other plant species (Shi et al 1992;Herzog et al 1995;Ben-Nissan and Weiss 1996), such as indolacetic acid (20 uM) and GA (100 uM). In none of these treatments was induction of the SN1 mRNA observed.…”

“…The amino acid sequence of snakin-1 has some motifs in common with hemotoxic, desintegrin-like snake venoms and is homologólas to deduced amino acid sequences corresponding to a family of plant cDNAs of unknown fimction, some of which are induced by gibberellic acid (GA) in mutants deficient in this hormone (Shi et al 1992;Herzog et al 1995;Ben-Nissan and Weiss 1996), whereas one of them has been found to be expressed during lateral root differentiation (Taylor and Scheuring 1994).…”

One new kind of phytohormonal signaling integrator: Up-and-coming GASA family genes

“…Most of the GASA proteins are located in the cell wall, suggesting their function may relate to the cell wall extension or cell division. Existing research results show that GASA protein involved in promoting 9,18,23,45 or inhibiting 27,46 cell elongation and cell division 11,19,24,32 and other developmental processes, such as flowering time regulation.…”

TheGibberellic Acid Stimulated-LikeGene Family in Maize and Its Role in Lateral Root Development

“…A variety of results from different plant species suggest that GAST-like genes are mainly involved in cell elongation and cell division. Expression data and mutant analyses in petunia (Petunia hybrida), for example, have suggested that the Gibberellic Acid Induced Petunia1 (GIP1) gene is involved in the elongation of the stem and the corolla (Ben-Nissan and Weiss, 1996;Ben-Nissan et al, 2004). Similarly, expression of tomato GAST1 has been associated with stem elongation (Shi et al, 1992), although plants either over-or underexpressing GAST1 did not display an altered phenotype (Shi and Olszewski, 1998).…”