Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Pod corn develops leaves in the inflorescences

25.04.2012
A leaf gene active in the maize cob causes leaves to grow in the male and female inflorescences
In a variant of maize known as pod corn, or tunicate maize, the maize kernels on the cob are not ‘naked’ but covered by long membranous husks known as glumes. According to scientists from the Max Planck Institute for Plant Breeding Research in Cologne and Friedrich Schiller University in Jena, this variant arises from the activity of a leaf gene in the maize cob that is not usually active there. Thus, pod corn is not a wild ancestor of maize, but a mutant that forms leaves in the wrong place.

Pod corn has a spectacular appearance that has fascinated naturalists for two centuries. In this maize variant, the kernels are wrapped in fine glumes which look like thin paper in their dried form and resemble a leaf sheath. The male flowers, which are arranged in a panicle at the end of the stem axis, are also surrounded by long glumes, and sometimes even develop kernels that can otherwise only be found in the cob. The pod corn leaves resemble those of the normal maize plant. Pod corn had a ritual significance for some Native American tribes and can therefore be found throughout the American continent.

The putatitive significance of pod corn for the domestication of maize has long been a matter of controversy. Some scientists believed pod corn to be a wild, precursor of the varieties with naked kernels common today. Others disagreed with this view – and they were right, as we now know. The wild ancestor of today’s common maize varieties is not pod corn but the unimpressive sweet grass teosinte.

Heinz Saedler, Günter Theißen and their colleagues have now discovered how the spectacular appearance of pod corn arises. Their findings reveal that this variant has nothing to do with the domestication of maize, but is a mutant that forms leaves in the wrong place. Genetic experiments from the 1950s provided important inspiration for the research. “We knew from the old crossing experiments that the mutation must consist of at least two genetic components that can be inherited separately. If just one component is inherited, the glumes that surround the kernels in this mutant are significantly smaller and less conspicuous than the glumes in mutants with both components. However, they are not as tiny as the glumes found in common maize plants in which the kernels sit naked on the cob,” explains Heinz Saedler from the Max Planck Institute for Plant Breeding Research.

The researchers succeeded in showing that the components in question are two copies of the same gene which are located in tandem on chromosome 4. Although the gene itself is intact in pod corn, the region that controls the transcription of the gene is damaged. As a result of this defect, spatial control of gene activity in the right plant organs is lost. Therefore, in its mutated form, this gene is also active in the cob and not only in the growing leaves. “The gene contains the information for a transcription factor. Through its ectopic activity in the male and female inflorescence, it controls a set of so called ‘target genes’ and hence a programme in the glumes that is normally reserved for leaf development and should not be active in the inflorescence. As a result of this erroneous activity, the glumes assume a leaf-like growth pattern and grow until the kernels are completely covered,” says Günter Theißen from the University of Jena.

These findings also explain the existence of pod corn with smaller glumes. “The extent of this phenotype depends on whether there are one or two copies of the damaged gene on the chromosome and whether the plant is homozygous or heterozygous for this gene,” says Theißen. “If one gene copy is present, the effect on the leaf development programme is only half as strong as it is in one with two copies. Therefore this genetic effect is additive. The gene dosage decides, on the strength of the mutant phenotype.” Theißen and his colleagues were also able to show that the mutated gene belongs to an entire family of developmental control genes known as the MADS-box gene family. Other representatives of this family control other development processes in the plant.
Contact
Professor em. Dr. Heinz Saedler
Max Planck Institute for Plant Breeding Research
Phone: +49 22 150-620
Email: saedler@­mpiz-koeln.mpg.de
Contact
Professor Dr. Günter Theißen
Friedrich-Schiller-Universität
Phone: +49 36 4194-9550
Email: guenter.theissen@­uni-jena.de

Original publication
Luzie U. Wingen, Thomas Münster, Wolfram Faigl, Wim Deleu, Hans Sommer, Heinz Saedler, Günter Theißen
Molecular genetic basis of pod corn (Tunicate maize)
PNAS 2012; online publication, April 18, 2012, doi:10.1073/pnas.1111670109

Professor em. Dr. Heinz Saedler | EurekAlert!
Further information:
http://www.mpg.de/5755791/pod_corn_leaves_inflorescences

More articles from Agricultural and Forestry Science:

nachricht Raiding the rape field
23.05.2018 | Julius-Maximilians-Universität Würzburg

nachricht New technique reveals details of forest fire recovery
17.05.2018 | DOE/Brookhaven National Laboratory

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

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...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
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

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Could a particle accelerator using laser-driven implosion become a reality?

24.05.2018 | Physics and Astronomy

Hot cars can hit deadly temperatures in as little as one hour

24.05.2018 | Health and Medicine

Complementing conventional antibiotics

24.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>