Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The evolution of food plants: Genetic control of grass flower architecture

23.01.2006


Ramosa2 determines cell fate in branch meristems of maize



Scientists are interested in understanding genetic control of grass inflorescence architecture because seeds of cereal grasses (e.g. rice, wheat, maize) provide most of the world’s food. Grass seeds are borne on axillary branches, whose branching patterns dictate most of the variation in form seen in the grasses. Maize produces two types of inflorescence; the tassel (male pollen-bearing flowers) and the ear (female flowers and site of seed or kernel development). The tassel forms from the shoot apical meristem after the production of a defined number of leaves, whereas ears form at the tips of compact axillary branches. Normal maize ears are unbranched, and tassels have long branches only at their base.

Many different genes control the architecture as well as the nutrient content in cereal grasses. The ramosa2 (ra2) mutant of maize has increased branching of inflorescences relative to wild type plants, with short branches replaced by long, indeterminate ones, suggesting that the ra2 gene plays an important role in controlling inflorescence architecture. A recent publication in The Plant Cell (Bortiri et al.) reports that ra2 encodes a putative transcription factor, or protein that controls the expression of other genes. Scientists involved in the study were Esteban Bortiri, George Chuck, and Sarah Hake of the USDA Plant Gene Expression Center and University of California at Berkeley and colleagues Erik Vollbrecht of Iowa State University, Torbert Rocheford of the University of Illinois, and Rob Martienssen of Cold Spring Harbor Laboratory in New York.


The group found that the ra2 gene is transiently expressed early in development of the maize inflorescence. Analysis of gene expression in a number of different mutant backgrounds placed ra2 function upstream of other genes that regulate branch formation. The early expression of ra2 suggests that it functions in regulating the patterning of stem cells in axillary meristems.

Said Dr. Hake, "we think that ra2 is critical for shaping the initial steps of inflorescence architecture in the grass family, because the ra2 expression pattern is conserved in other grasses including rice, barley, and sorghum".

Perspective: Branching Out: The ramosa Pathway and the Evolution of Grass Inflorescence Morphology

In an accompanying Current Perspective Essay, Paula McSteen of The Pennsylvania State University discusses the ramosa pathway in the context of the evolution of plant development.

"The grasses are a premier model system for evolution of development studies in higher plants: there is tremendous diversity in inflorescence morphology, the phylogeny is well understood and many species are genetically transformable so hypotheses can be tested. Maize in particular is an excellent model system for studying selection as it was domesticated from its wild ancestor teosinte a mere 10,000 years ago. Because transcription factors control many developmental processes, it is common to find that diversification of morphology between closely related organisms has involved changes in how transcription factors are regulated or how transcription factors interact with their target genes. An understanding of the ramosa pathway in the grass family will be important in understanding the evolution of the grasses and furthermore will provide an understanding of the mechanisms of evolution of development."

Dr. McSteen commented "because ra2 has increased branching it might have the potential to lead to increased seed number and yield in some cereal grasses. This might not be true for maize because of the structure of the ear, but one can imagine that a ra2 mutant of barley, rice or sorghum might have more branches, and thus produce more seed".

Nancy Eckardt | EurekAlert!
Further information:
http://www.aspb.org
http://www.aspb.org/pressreleases/TPC039032.pdf
http://www.plantcell.org/

More articles from Life Sciences:

nachricht Lethal combination: Drug cocktail turns off the juice to cancer cells
12.12.2018 | Universität Basel

nachricht Smelling the forest – not the trees
12.12.2018 | Universität Konstanz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Lethal combination: Drug cocktail turns off the juice to cancer cells

A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.

The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...

Im Focus: New Foldable Drone Flies through Narrow Holes in Rescue Missions

A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.

Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...

Im Focus: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

 
Latest News

New discoveries predict ability to forecast dementia from single molecule

12.12.2018 | Health and Medicine

CCNY-Yale researchers make shape shifting cell breakthrough

12.12.2018 | Physics and Astronomy

Pain: Perception and motor impulses arise in the brain independently of one another

12.12.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>