"Crop seeds provide nearly 70 to 80 percent of calories and 60 to 70 percent of all proteins consumed by the human population," said Z. Jeff Chen, the D.J. Sibley Centennial Professor in Plant Molecular Genetics at The University of Texas at Austin. "Seed production is obviously very important for agriculture and plant evolution."
Chen and his colleagues, including David Baulcombe at the University of Cambridge, provide the first genetic evidence that seed development is controlled by maternally inherited "small interfering RNAs," or siRNAs.
They published their research April 3 in the journal PNAS.
SiRNAs are known to control a number of aspects of growth and development in plants and animals. The researchers used Arabidopsis, a rapidly growing flowering plant in the mustard family, for the study.
In this case, the researchers found that the siRNAs influence the development of a seed's endosperm, which is the part of the seed that provides nutrients to the developing plant embryo, much like the placenta in mammals. The endosperm is also the source for most of the nutritional content of the seed for humans and animals.
Despite the importance of the endosperm, little has been known about the molecular mechanisms that govern its growth.
In flowering plant seeds, the embryo is formed by fusion of one paternal and one maternal genome, while the endosperm combines one paternal and two maternal genomes. This process of embryo and endosperm formation is known as "double fertilization."
The scientists found that when a female plant with a duplicate genome (known as a tetraploid) is crossed with a male plant with a normal genome (called a diploid), not only is there an increase in the maternal genome in their offspring's seed endosperm, but there is also an associated increase in maternal siRNAs.
Those maternal siRNAs decrease the expression of genes that lead to larger endosperm growth, meaning that the siRNAs create smaller seeds.
"Now we understand that siRNAs play a large role in sensing maternal and paternal genome imbalance and controlling seed development, and that maternal control is important," said Chen.
The researchers are working to find out how exactly siRNAs regulate gene expression in the endosperm and embryo and how they control seed size. These new findings will enable scientists to develop biotechnological tools for improving seed production and crop yield.
But Chen cautioned that "bigger isn't always better." In fact, in his experiments, seeds lacking the control of the maternally inherited siRNAs grew so large that they collapsed.
Chen's research is funded by the National Science Foundation Genetic Mechanisms program. It was also the result of a Fulbright Award he received to do research with Baulcombe, a Royal Society research professor, at Cambridge. Baulcombe is widely recognized for his pioneering and seminal research discovering the role of siRNAs in gene silencing in plants.
Z. Jeff Chen | EurekAlert!
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences