Plant biologist seeks molecular differences between rice and its mimic

Dec 19, 2006

Red rice sounds like a New Orleans dish or a San Francisco treat. But it's a weed, the biggest nuisance to American rice growers, who are the fourth largest exporters of rice in the world. And rice farmers hate the pest, which, if harvested along with domesticated rice, reduces marketability and contaminates seed stocks.

Complicating matters is the fact that red rice and cultivated rice are exactly the same species, so an herbicide cannot be developed that seeks out only red rice. It would kill cultivated rice, too.

But now a plant evolutionary biologist at Washington University in St. Louis has been funded by the National Science Foundation (NSF) at $1.12 million for two years to perform genetic studies on red rice to understand molecular differences between the two that someday could provide the basis for a plan to eradicate the weed. The particular NSF program funding the research is the Plant Genome Comparative Sequencing Program.

Kenneth M. Olsen, Ph.D., Washington University assistant professor of biology in Arts & Sciences, believes that gene flow is one factor that has been at work.

"We are looking for candidate genes that underlie particular traits that differ between the two," said Olsen. "Knowing more about the traits could help in potentially controlling the weed. We have a key advantage in this research in that we know the complete cultivated rice genome, so it's fairly easy to target genes of interest."

Olsen and his colleagues, Ana Caicedo, Ph.D., of the University of Massachusetts, and Yulin Jia, Ph.D., of the United States Department of Agriculture National Rice Research Center, will test at least two hypotheses. One is that red rice is rice that's gone feral, or gone bad.

"In this scenario, you have a sort of selection favoring the weedy version of the crop that out-competes the crop itself," he said. "That's called de-domestication."

Another possibility, which is not mutually exclusive, is that weedy rice was introduced into the Americas from Asia, where weedy hybrids of the cultivated species and the wild species occur. These weedy strains then took hold in U.S. soils and began contaminating the U.S. cultivated species.

Meet the candidates

Olsen says that the weed has many characteristics of a wild species.

"By looking at candidate genes and those genes surrounding them we can test the hypotheses of the origins of traits and see if the traits have been introduced by hybridization of weedy and wild species, or, conversely, we can look at the molecular level to see if the de-domestication phenomenon is going on."

To control red rice infestations, growers often will rotate crops away from rice to soybeans, for instance. And there are cultivation techniques that can eliminate most of the threat, although another nasty feature of the weed is its dormancy – its seed can lie viable in soils for up to 20 years. There also is a great amount of variation in different red rice strains. Some look remarkably like cultivated rice and behave like cultivated rice. The plants are as tall as cultivated rice and flower at the same time. These "crop mimics" are difficult to spot.

Olsen hopes understanding trait differences can lead to eradication of red rice.

"We're looking for anything that exploits the difference between the crop and the weed and the way that the weed grows versus the way that the crop grows," he said. "That's the way to eradicate it."

Source: Washington University in St. Louis

Explore further: Blue mussels not yet the bellwether of NE coastal environment

add to favorites email to friend print save as pdf

Related Stories

Obama recommends extended wilderness zone in Alaska

8 hours ago

US President Barack Obama said Sunday he would recommend a large swath of Alaska be designated as wilderness, the highest level of federal protection, in a move likely to anger oil proponents.

NASA craft set to beam home close-ups of Pluto

8 hours ago

Nine years after leaving Earth, the New Horizons spacecraft is at last drawing close to Pluto and on Sunday was expected to start shooting photographs of the dwarf planet.

Navy wants to increase use of sonar-emitting buoys

10 hours ago

The U.S. Navy is seeking permits to expand sonar and other training exercises off the Pacific Coast, a proposal raising concerns from animal advocates who say that more sonar-emitting buoys would harm whales and other creatures ...

Uganda seizes massive ivory and pangolin haul

10 hours ago

Ugandan wildlife officers have seized a huge haul of elephant ivory and pangolin scales, representing the deaths of hundreds of endangered animals, police said Sunday.

Recommended for you

Population genomics unveil seahorse domain

13 hours ago

In a finding vital to effective species management, a team including City College of New York biologists has determined that the lined seahorse (Hippocampus erectus) is more a permanent resident of the we ...

Researchers develop new potato cultivar

16 hours ago

Dakota Ruby is the name of a new potato cultivar developed by the NDSU potato breeding project and released by the North Dakota Agricultural Experiment Station. Dakota Ruby has bright red skin, stores well and is intended ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.