Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A new source of maize hybrid vigor

29.06.2012
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:
http://www.illinois.edu

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

More articles from Agricultural and Forestry Science:

nachricht Alkaline soil, sensible sensor
03.08.2017 | American Society of Agronomy

nachricht New 3-D model predicts best planting practices for farmers
26.06.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

NASA Protects its super heroes from space weather

17.08.2017 | Physics and Astronomy

Spray-on electric rainbows: Making safer electrochromic inks

17.08.2017 | Materials Sciences

Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

17.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>