Further Characterization of Expression of Auxin-Induced Genes in Tobacco (Nicotiana tabacum) Cell-Suspension Cultures

Abstract

Plant hormones are known to have pleiotropic effects on growth and development. For example, the naturally occurring auxin, IAA, influences cell division, cell elongation, and differentiation. A variety of early events (time scale: seconds to hours) preceding the biological response to auxin has been described (Brummell and Hall, 1987). However, the specificity of these early responses and their significance for the occurrence of the biological response are in general far from clear. For instance, the stimulation of proton extrusion and the hyperpolarization of the plasma membrane potential are well-described rapid auxin effects. Recently, however, it was shown that both growth-promoting auxins and growth-inactive structural analogs were capable of inducing these processes (Felle et al., 1991; Peters and Felle, 1991), demonstrating that stimulation of the proton pump is a rather unspecific effect of auxin, although the activation of the H+-ATPase is indispensable for the occurrence of cell elongation.During the past few years, a number of research groups, including our own, have studied early effects of auxins on the induction of specific proteins and mRNAs (for recent reviews, see Guilfoyle, 1986;Theologis, 1986; Key, 1989).

ocs element promoter sequences are activated by auxin and salicylic acid in Arabidopsis.

“…The auxin transport inhibitor NPA inhibits the transport of auxin to the roots and is thought to result in a build-up of auxin in the aerial parts ofthe plant (ref. 36 The expression of the auxin-responsive tobacco CNT/GNT genes are also induced by SA (28). Since the promoters of these genes contain potential ocs element-like sequences, we investigated if ocs element sequences are also activated by SA.…”

“…In a number of cases the expression of the auxin-responsive GST genes is also inducible by other stimuli such as heavy metals, wounding, and salicylic acid (SA) (see ref. 28 and references within). SA is a disease-resistance signal in plants; exogenous application of SA stimulates resistance to a variety of lesioninducing pathogens (29,30).…”

Expression and RNA Splicing of the Maize Glutathione S-Transferase Bronze2 Gene Is Regulated by Cadmium and Other Stresses

“…We show that Bz2 is strongly and rapidly induced by cadmium and to a lesser extent by arsenite, ABA, and auxin (very weakly). Other GST genes have been shown to be induced by cadmium, including the soybean GmGST26-A gene (Czarnecka et al, 1988;Hagen et al, 1988), the tobacco NT103, NT107, and NT114 genes (van der Zaal et al, 1991;Boot et al, 1993), and the parA GSTs (Takahashi et al, 1991). In addition, protein levels of the wheat GST25 and GST26 increase in the presence of cadmium (Mauch and Dudler, 1993).…”

Cloning and Characterization of a Glutathione S-Transferase That Can Be Photolabeled with 5-Azido-indole-3-acetic Acid

“…In some cases, expression of these genes is also regulated by heavy metals (Hagen et al, 1988) or salicylic acid (Boot et al, 1993).…”