. Energy News .

Stronger corn? Take it off steroids, make it all female
by Brian Wallheimer
West Lafayette IN (SPX) Dec 07, 2011

A mutant of maize that cannot produce brassinosteroids develops feminized sex organs with female kernels growing where male tassel flowers would normally occur. (Purdue University photo/Burkhard Schulz)

A Purdue University researcher has taken corn off steroids and found that the results might lead to improvements in that and other crops.

Burkhard Schulz, an assistant professor of horticulture and landscape architecture, wanted to understand the relationship between natural brassinosteroids - a natural plant steroid hormone - and plant architecture, specifically plant height. Schulz said corn could benefit by becoming shorter and sturdier, but the mechanisms that control those traits are not completely understood.

"It is essential to change the architecture of plants to minimize how much land we need to produce food and fuels," said Schulz, whose findings are published in the early online version of the Proceedings of the National Academy of Sciences.

"If you can find a natural mutation or mechanism that gives you what you need, you are much better off than using transgenic techniques that could be difficult to get approval for."

Schulz found that when maize loses the ability to produce brassinosteroids, it becomes a dwarf, as he suspected. But another feature caught him off guard: The plants without the naturally occurring steroids could not make male organs - they had kernels where the tassels should be.

That could be a cost-saving discovery for the seed industry. Hybrid seed producers must painstakingly remove the male pollen-producing tassels from each plant so that they do not pollinate themselves. Schulz said maize plants that produce only female organs would eliminate the detasseling step.

"This would be the perfect mutation for hybrid seed production," Schulz said. "There is no way these plants could produce pollen because they do not have male flowers."

Schulz used a multistep process to determine brassinosteroids' role in height and, later, sex determination. He wanted to ensure that light and the addition of gibberelic acid, a hormone that promotes cell growth and elongation, would not eliminate the dwarfism.

Schulz gathered known mutants of maize with short mesocotyls, the first node on a corn stalk. He suspected that even dwarf plants that produced brassinosteroids would have elongated mesocotyls if grown in the dark as they stretched for light, a trait typical of all brassinosteroid mutants. He also added gibberellic acid to the plants to ensure that a deficiency of that hormone was not causing the dwarfism.

The dwarf plants that did not grow in the dark or with the addition of the gibberellic acid were compared to regular maize plants that had been dwarfed by subjecting them to a chemical that disrupts the creation of brassinosteroids. Both exhibited short stalks with twisted leaves and showed the feminization of the male tassel flower.

Schulz then used information that was already known from the research plant Arabidopsis about genes that control brassinosteroid production. He found the same genes in the maize genome.

In the dwarf maize plants, those genes were mutated, disrupting the biosynthesis of the steroids. A chemical analysis showed that the compounds produced along the pathway of gene to steroid were greatly diminished in the maize dwarfs.

Cloning of the gene revealed that an enzyme of the brassinosteroid pathway was defective in the mutant plants. A related enzyme in humans has been reported as essential for the production of the sex steroid hormone testosterone. Mutations in this enzyme in humans also resulted in feminization.

While Schulz expected brassinosteroids to affect plant height, he said he did not expect those steroids to affect sex determination.

"We don't know if this is a special case for corn or if this is generally the same in other plants," he said. "If it is the same in other plants, it should be useful for creating plants or trees in which you want only males or females."

Gurmukh Johal, a professor of botany and plant pathology and collaborator on the research, identified the mutant used in the research, nana plant1, years ago. He said better understanding the steroid-production pathways could be important to strengthening maize plants and increasing yields.

"Maize produces too much pollen and it actually wastes a lot of energy on that," Johal said. "This implies that by using this gene or the pathway it controls, we could manipulate the plants to improve their quality."

Schulz said he would look at other plants, such as sorghum, to determine if the same genes and pathways control sex determination and height.

The project was an international collaboration with George Chuck from the Plant Gene Expression Center at the University of California Berkeley, Shozo Fujioka of RIKEN Advanced Science Institute in Japan, Sunghwa Choe of Seoul National University in South Korea, and Devi Prasad Potluri of Chicago State University.

Related Links
Purdue University
Farming Today - Suppliers and Technology

Get Our Free Newsletters Via Email
Buy Advertising Editorial Enquiries


. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Using Radiation to Sterilize Light Brown Apple Moth
Lanham MD (SPX) Dec 07, 2011
A new study published in the Journal of Economic Entomology shows that radiation can be used to effectively sterilize the light brown apple moth (LBAM), an insect pest found in Australia, New Zealand, California, Hawaii, Sweden, and the British Isles. The light brown apple moth, Epiphyas postvittana (Walker), feeds on apples, pears, stonefruits, citrus, grapes, berries and many other plant ... read more

NASA Satellite Confirms Sharp Decline in Pollution from US Coal Power Plants

China launches remote-sensing satellite Yaogan XIII

Texas Drought Visible in New National Groundwater Maps

APL Proposes First Global Orbital Observation Program

China launches 10th satellite for independent navigation system

Authorities Gauge Impact of Europe's Galileo Navigation Satellite System

Russia's Glonass-M satellite put into orbit

ITT Exelis and Chronos develop offerings for the Interference, Detection and Mitigation market

Ecologists fume as Brazil Senate OKs forestry reform

Palm planters blamed for Borneo monkey's decline

Madagascar fishermen protect mangroves to save jobs

Mozambique's new forests may not be as green as they seem

US Navy in big biofuel purchase

E. Coli Bacteria Engineered to Eat Switchgrass and Make Transportation Fuels

OSU study questions cost-effectiveness of biofuels and their ability to cut fossil fuel use

Mast from classic racing yacht holds one of the keys to sustainable biofuels

Enecsys and SMTC Partner to Build Next-Gen Solar Energy Conversion Technology

SolarStrong moves forward without government backing

Could CIGS hold the key to solar manufacturers' survival?

Oerlikon Solar Initiative Could See Lower Module Production Costs

Mortenson Construction Completes Elk Wind Project

Enel: More new wind capacity in Iberia

AREVA Wind M5000-135 offshore turbine evolves proven M5000 platform

New Bladed link to offshore code checking tools

Four trapped miners found dead in China: Govt

Five rescued from collapsed Chinese mine

Coal mine collapse traps 12 in China

Death toll in China mine blast rises to 34

Filipino drug trafficker executed in China: Philippines

China arrests 600 in huge child trafficking bust

Wife of Australian jailed in China has cancer

Fear of fire stalks Hong Kong's cubicle dwellers


The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement