A Century of Gibberellin Research

From the report «A Century of Gibberellin Research», from Peter Hedden and Valerie Sponsel, published in the Journal of Plant Growth Regulation.

The review from Hedden and Sponsel traces the history of gibberellin research from the discovery in 19th century to know.

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The origins of gibberellin research can be traced to the late 19th century in Japan with the demonstration that a disease of rice that produced symptoms of excessive seedling elongation and infertility, among others, was the result of fungal infection. The symptoms of the disease including overgrowth of the seedling and sterility were later shown to be due to secretions of the fungus Gibberella fujikuroi (now reclassified as Fusarium fujikuroi).

The profound effect of gibberellins on plant growth and development, particularly growth recovery in dwarf mutants of maize and pea and induction of bolting and flowering in some rosette species, prompted speculation that these fungal metabolites were endogenous plant growth regulators, because these effects could also be obtained with plant extracts. And this was confirmed by chemical characterisation in the late 1950s.

Gibberellins are now known to be present in vascular plants, and some fungal and bacterial species. The biosynthesis of gibberellins in plants and the fungus has been largely resolved in terms of the pathways, enzymes, genes and their regulation. The proposal that gibberellins act in plants by removing growth limitation was confirmed by the demonstration that they induce the degradation of the growth-inhibiting DELLA proteins. The mechanism by which this is achieved was clarified by the identification of the gibberellin receptor from rice in 2005. Current research on gibberellin action is focussed particularly on the function of DELLA proteins as regulators of gene expression.

As conclusion since the first experiments in the late 1950s, the chemistry, biochemistry and genetics of GA biosynthesis have been resolved to a considerable extent. Nevertheless, a few unsolved questions remain.