Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


A new source of maize hybrid vigor

Steve Moose, an associate professor of maize functional genomics at the University of Illinois and his graduate student Wes Barber think they may have discovered a new source of heterosis, or hybrid vigor, in maize. They have been looking at small RNAs (sRNAs), a class of double-stranded RNA molecules that are 20 to 25 nucleotides in length.
“Hybrid vigor” refers to the increased vigor or general health, resistance to disease, and other superior qualities arising from the crossbreeding of genetically different plants. “We’ve always known that there’s a genetic basis for this heterosis,” said Moose. “Charles Darwin noticed it and commented that corn was particularly dramatic.”

Scientists have been debating the sources of hybrid vigor since the early 1900s when Mendel’s laws were rediscovered. Many of them disagreed with the model that prevailed from the 1920s to the 1950s, which linked heterosis to a single gene or to the interaction of several genes. “It seemed that the whole genome was involved,” said Moose.

The discovery of DNA in 1953 eventually caused a paradigm shift in the way people looked at hybrid vigor but, Moose said, there was no unifying theory. Even as new genetic technologies were developed, the genes did not seem to explain everything.

“We thought that maybe it’s the rest of the genome, the remaining 85 percent of the corn genome, that’s important,” said Moose.

sRNAs were originally found in 1998 in roundworms. Researchers studying virus resistance in plants then began to notice them and observed that the way that they function is very different from the functioningof protein-coding genes.

“Every time we have a breakthrough in our knowledge of genetics, people have looked to see if that breakthrough brings any insight into the mystery of the hybrid vigor,” said Moose. “That’s what we’ve done with the small RNAs.”

“When you think about what small RNAs do, they participate in regulating growth and they tell other genes what to do,” he continued. “So they have the two properties that we know fit what has been described (about heterosis) even though we do not have an explanation. We would argue that, while they are part of the explanation, they may not be the whole explanation.”

Moose and Barber sampled small RNAs from the seedling shoot and the developing ear of maize hybrids, two tissues that grow rapidly and program growth, to investigate how the small RNA profiles of these hybrids differed from those of their parents. In collaboration with associate professor of crop sciences Matt Hudson, they analyzed what they described as a “deluge” of data.

“There were 50 million data points, but we whittled it down to the most important ones,” said Barber.

They found that differences are due mainly to hybrids inheriting distinct small interfering RNAs (siRNAs), a subset of sRNAs, from each parent. The siRNAs interfere with gene expression. They also found that hybridization does not create new siRNAs, but hybrids have a more complex siRNA population than their parents because they inherit distinct siRNAs from both parents.

Moreover, the differences in parental siRNAs originated primarily from repeats, which are the result of retrotransposon activity. Retrotransposons are elements that move around and amplify themselves within a genome.

“This is a new source of genetic diversity that people had overlooked,” said Barber.

“We are not saying that genes are not important,” said Moose. “”But probably the way corn properties are altered in the hybrid situation is mediated by the small RNAs in addition to the genes.”

Moose and Barber hope that their work might provide more insight into how to decide which inbred maize lines to cross. “We don’t want to alter how the plant grows, but if we can tweak it to do whatever it already does either faster or more, that could be an advantage,” said Moose.

The article describing this work, “Repeat Associated Small RNAs Vary Among Parents and Following Hybridization in Maize” by Wesley T. Barber, WeiZhang, Hlaing Win, Kranthi K. Varala, Jane E. Dorweiler, Matthew E. Hudson, and Stephen P. Moose was published in the June 26, 2012, issue of Proceedings of the National Academy of Science.
News Writer
Susan Jongeneel, 217-333-3291
News Source
Steve Moose, 217-244-6308

Susan Jongeneel | EurekAlert!
Further information:

Further reports about: RNA crop science hybrid vigor small RNA small interfering RNA

More articles from Agricultural and Forestry Science:

nachricht Forest Management Yields Higher Productivity through Biodiversity
14.10.2016 | Technische Universität München

nachricht Farming with forests
23.09.2016 | University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES)

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: Novel light sources made of 2D materials

Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.

So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...

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...

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

Prototype device for measuring graphene-based electromagnetic radiation created

28.10.2016 | Power and Electrical Engineering

Gamma ray camera offers new view on ultra-high energy electrons in plasma

28.10.2016 | Physics and Astronomy

When fat cells change their colour

28.10.2016 | Life Sciences

More VideoLinks >>>