Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NC State Geneticists Study Origin, Evolution of "Sticky" Rice

23.10.2002


When tested in iodine, grains of non-glutinous rice turn black (left), while glutinous rice remains unstained.


A study by two North Carolina State University geneticists traces the origin and evolution of a genetic mutation that long ago led to the creation of a type of rice known as glutinous, or "sticky," rice.

The molecular genetic research leads researchers to believe that glutinous rice - which differs from non-glutinous, or common, rice on account of a mutation in its Waxy gene that suppresses the formation of a starch called amylose - most likely originated a single time in Southeast Asia. Further, DNA evidence - namely the lower-than-expected genetic variability in the Waxy gene - suggests that early domesticators of glutinous rice liked its adhesive quality and wanted to preserve that particular trait.

Dr. Michael Purugganan, associate professor of genetics, and Dr. Kenneth Olsen, post-doctoral research associate in genetics, publish their findings in the Oct. 23 edition of Genetics.



To learn more about the origin and evolution of sticky rice, the researchers studied 105 glutinous and non-glutinous samples of rice donated from the multitudinous stock kept by the International Rice Research Institute in Los Banos, Philippines.

Rice contains two starches: amylose and amylopectin. Glutinous rice lacks amylose; in fact, it is the lack of amylose that gives it its sticky composition. Non-glutinous rice - what you’d find if you cooked up a name-brand package of rice from the grocery store, for example - contains up to 30 percent amylose; the result is rice with grains that separate.

Glutinous rice is the staple food in some areas in Southeast Asia, including parts of Laos, Thailand and Cambodia, the researchers say. Sticky rice has also migrated north to become an important part of the diet in places like China and Japan. Used primarily in a number of desserts - rice cakes, for example - sticky rice has achieved important cultural standing in East and Southeast Asia.

But Asian folklore diverges on the origin of glutinous rice, Purugganan says. He found both a Laotian Buddhist legend charting the existence of glutinous rice to about 1,100 years ago and Chinese folklore that indicated the existence of glutinous rice more than 2,000 years ago.

"Since no one really knows where glutinous rice came from, we wanted to find its origin using molecular means," Purugganan says. "We also wanted to find out the number of times the mutation in the Waxy gene that suppresses amylose, which produces glutinous rice, arose during rice domestication. And, we wanted to see if the Waxy gene showed evidence of selection by early Asian farmers."

Performing genetic sequencing of these samples at NC State’s Genome Research Laboratory, Purugganan and Olsen assembled a "gene tree," or network that represents patterns of genetic differences among the DNA sequences, Olsen explains.

Using the gene tree, the researchers found that sticky rice’s genetic mutation maps to a single mutation on the gene tree, suggesting that the mutation occurred a single time rather than more than once, Olsen says. Looking at the geographic locations of the rice DNA sequences that are direct ancestors of the mutation, the researchers found fairly strong evidence that Southeast Asia was the geographic origin of sticky rice. This squares with the fact that sticky rice is a staple in some parts of Southeast Asia.

"This type of research really opens up the window of not only how crops originate, but also how specific features evolve," Purugganan says. Olsen adds, "This is one of the first times that anyone has looked within a crop species at the evolutionary and geographical origins of important domestication traits in crops."

Purugganan and Olsen now plan to study other genes involved in starch synthesis in rice.

Research funding for the study of the origin and evolution of glutinous rice was provided
by the Alfred P. Sloan Foundation.

Dr. Michael Purugganan | North Carolina State University

More articles from Life Sciences:

nachricht More genes are active in high-performance maize
19.01.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht How plants see light
19.01.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>