Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UCSD Biologists Solve Plant Growth Hormone Enigma

03.07.2006
Gardeners and farmers have used the plant hormone auxin for decades, but how plants produce and distribute auxin has been a long-standing mystery. Now researchers at the University of California, San Diego have found the solution, which has valuable applications in agriculture.

The study, published in the July 1 issue of the journal Genes and Development, describes the discovery of a whole family of auxin genes, and shows that each gene is switched on at a distinct location in the plant. Contrary to the current thinking in the field, the research shows that the patterns in which auxin is produced in the plant influence development, a finding that can be applied to improving crops.


Electron microscope image of the female portion of a normal (left) and auxin-deficient (right) flower. Credit: Yunde Zhao, UCSD

“The auxin field dates back to Charles Darwin, who first reported that plants produced a substance that made them bend toward light,” said Yunde Zhao, an assistant professor of biology at UCSD. “But until now, the auxin genes have been elusive. Our discovery of these genes and the locations where auxin is produced in the plant can be applied to agricultural problems, such as how to make seedless fruit or plants with stronger stems.”

Applying auxin to plants can have many different effects. For example, it can promote root development in cuttings, stimulate fruit development in the absence of fertilization or, in excess, kill weeds. However, this study is the first to show what happens in a plant when auxin production is turned off.

The researchers identified a family of 11 genes (YUCCA 1-11) that are involved in the synthesis of auxin. In Arabidopsis—a small plant favored by biologists because it is easy to manipulate genetically—Zhao’s team inactivated combinations of the YUCCA genes and studied the effects of the inactivations on plant growth and development.

“Plant biologists have wanted to do this experiment for a long time, but only recently have new genetic tools such as ‘reverse genetics’ and ‘activation tagging’ made it possible,” explained Youfa Cheng, a postdoctoral fellow working with Zhao. “Even with the advances in technology, it took about three years to produce plants lacking at least four of the 11 YUCCA genes.”

Disrupting one YUCCA gene did not have any obvious effects. Therefore, there is overlap in the functions of the genes in this family. However, when two or more YUCCA genes were inactivated, the plants had developmental defects. The defects, including flowers with missing or misshapen parts, or deformations in the tissues that transport water and nutrients throughout the plant, differed depending on which combinations of genes were deleted.

The researchers say that this finding was surprising because most people in the field thought that where auxin was made did not really matter. The widely held view was that auxin could just be transported wherever it was needed. Not so, because turning auxin off in specific tissues of the plant led to defects in those tissues, while the rest of the plant appeared normal.

“Knowing which auxin genes are activated when should make it possible to modify plant development,” said Zhao. “It wouldn’t require adding any new genes to the plant, just changing when the appropriate auxin genes were on or off could alter growth. For example, to make seedless tomatoes, one could activate auxin in the floral organs before fertilization has taken place.”

Applying auxin to the flowers by hand can also induce seedless tomatoes, or other seedless fruit, but this method is too tedious to be useful for commercial purposes. Seedless fruits would not just be novelty items. For example, Zhao points out that seeds significantly increase the effort and waste involved in producing tomato sauce.

“This study is a real tour de force,” commented Martin Yanofsky, a professor of biology at UCSD, who was not one of the authors of the study. “People have been trying to figure out auxin for decades. By carefully inactivating the genes for auxin synthesis one by one, the team was able to show how the localized production of auxin controls the architecture of a plant.”

Xinhua Dai, a research associate working with Zhao, also contributed to the study. This research was supported by the National Institutes of Health.

Media Contact: Sherry Seethaler, (858) 534-4656

Comment: Yunde Zhao, (858), 822-2670

Sherry Seethaler | EurekAlert!
Further information:
http://www.ucsd.edu

More articles from Life Sciences:

nachricht Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>