Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


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


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:

More articles from Life Sciences:

nachricht Gene therapy shows promise for treating Niemann-Pick disease type C1
27.10.2016 | NIH/National Human Genome Research Institute

nachricht 'Neighbor maps' reveal the genome's 3-D shape
27.10.2016 | International School of Advanced Studies (SISSA)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

How nanoscience will improve our health and lives in the coming years

27.10.2016 | Materials Sciences

OU-led team discovers rare, newborn tri-star system using ALMA

27.10.2016 | Physics and Astronomy

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

More VideoLinks >>>