Editor's Summary

11 September 2008

Branching out: new class of plant hormones inhibits branch formation

For many years the textbooks recognized five 'classic' plant hormones: auxin, gibberellins, ethylene, cytokinin and abscisic acid. To these can be added the brassinosteroids, nitric oxide and jasmonates, among others, as phytohormones or plant growth regulators. Shoot branching is regulated by hormones, with both auxin and cytokinin playing a part. But the existence of mutants with enhanced branching in several species suggested a third factor was involved, a novel plant hormone released from the roots that prevents excessive shoot branching. Two groups now identify a class of chemical compounds called strigolactones — or one of their derivatives — as that missing hormone. Strigolactones are found in root exudates and are reduced in the branching mutants; external application of these chemicals inhibits shoot branching in the mutants.

News and ViewsPlant biology: Hormones branch out

Evidence points to the existence of a hitherto uncharacterized type of hormone that controls different aspects of plant growth and interaction. The hunt for that hormone is heating up.

Harry Klee


ArticleStrigolactone inhibition of shoot branching

Victoria Gomez-Roldan, Soraya Fermas, Philip B. Brewer, Virginie Puech-Pagès, Elizabeth A. Dun, Jean-Paul Pillot, Fabien Letisse, Radoslava Matusova, Saida Danoun, Jean-Charles Portais, Harro Bouwmeester, Guillaume Bécard, Christine A. Beveridge, Catherine Rameau & Soizic F. Rochange


ArticleInhibition of shoot branching by new terpenoid plant hormones

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