Plant branching hormone discovered

In an important breakthrough, plant biologists at The University of Queensland (UQ) have identified a hormone that plays a key role in determining the size and shape of plants.

The discovery of the hormone strigolactone could have enormous impact on the forestry and horticultural industries, and is expected to lead to the ability to custom design the shape of plants.

“Taller plants can be produced by boosting strigolactone, and bushier plants can be grown by suppressing the hormone,” UQ Associate Professor Dr Christine Beveridge said.

“In the case of fruit-producing trees where the yield comes from the branches, repression of the chemical — that is, to create more branches — can give a better harvest.”

A number of factors work together to determine plant shape and size, but the discovery of strigolactone’s role in inhibiting branch development was important, Dr Beveridge said, and paved the way for understanding the regulatory framework behind plant development.

“It is interesting that strigolactone uses a long-distance signaling process to determine plant shoot branching,” Dr Beveridge said.

“Strigolactone’s capacity to have an impact on shoot branching will be conducive to obtaining a desired shape in plants and is sure to prove beneficial in crop production.”

Dr Beveridge, who is a Future Fellow of the Australian Research Council, said in the forestry industry the hormone could be manipulated to inhibit branch production and contribute to better stem growth and wood production.

Researchers from the University of Western Australia (UWA) have detected a structurally similar chemical called karrikins in smoke that affects the sprouting of dormant seeds after fire.

Through research done under a UQ-UWA Bilateral Research Collaboration Award, a gene called MAX2 was found to control the functioning of both strigolactone and karrikins.

Dr Beveridge said despite the similarity in the structure of the two hormones and their similar response systems, karrikins did not affect shoot branching.

Current promising leads with these hormones on their chemistry and on other aspects of plant development could result in improvements in the propagation of endangered and economically important plant species and in weed eradication and reforestation.

UQ’s main commercialisation company, UniQuest, is currently working towards commercialisation opportunities for this technology.

Media: Dr Christine Beveridge, UQ School of Biological Sciences, ph +61 7 3365 7525 or Divya Parthasarathy at UQ Communications (07 3365 2049)