Modulation of Gibberellins Protects Plants from Environmental Stresses

Plant hormones, including gibberellins (GAs), regulate plant growth and development from germination to death. Several plant growth regulators (PGRs) interfere with the endogenous balance of hormones. Triazoles, which have both fungitoxic and PGR effects, reduce plant height and protect plants from various environmental stresses and it is proposed that their primary action is mediated by a reduction of GAs and a shift in the hormonal balance which is beneficial to the plant. Protection of plants by the triazole from apparently unrelated stresses is associated with increased antioxidant potential. Both the phenotypic and stress protective effects of triazoles are negated by GAs. Studies using near-isogenic lines of normal and dwarf barley indicate that modulation of GA is an effective way inducing stress tolerance in plants. Modulation of GA levels with chemicals, classical or molecular genetics could form the basis for novel crop protection strategies.