Cornell University geneticist Ray Wu, a pioneer in genetic engineering who developed pest-, drought- and salinity-resistant rice strains that are poised for widespread use throughout the world, died of cardiac arrest Feb. 10 at Cayuga Medical Center in Ithaca, N.Y. He was 79.
The new strains have the potential to sharply increase the supply of rice, which is the staple food for more than half the world's population.
"Where rice is grown, everyone knows Ray Wu," said Cornell geneticist Susan McCouch. "He made enormous contributions to the development of rice transformation systems that are widely used to address crop production constraints throughout the rice-growing world."
In 1970, Wu developed the first method for determining the nucleotide sequence of DNA. His technique was adopted and made more efficient by Frederick Sanger, who received the 1980 Nobel Prize in Chemistry for his efforts.
During the 1980s, Wu pioneered techniques for transferring foreign genes into rice. In one study, he inserted into rice a potato gene for a protein called proteinase inhibitor II. The rice then produced the protein, which interferes with the digestive process of the pink stem borer, a common rice pest.
In a second study, he inserted a barley gene that enabled rice plants to produce a protein that makes them salt- and drought-resistant so they can grow in salty soil and recover quickly from dry conditions.
A third study increased the tolerance of rice for drought, salt and heat by introducing the bacterial gene for a sugar called trehalose.
Special promoters were inserted along with the gene so that the sugar is produced only when the rice plants need it.
Wu said the technology could easily be extended to a variety of other grain crops to improve their output.
The strains of rice produced by Wu are now being cross-bred with commercial rice varieties in countries to introduce these desirable traits into widely used strains. The resultant varieties could be in commercial use within as few as five years, McCouch said.
Wu also founded the China-United States Biochemistry and Molecular Biology Examination and Application program, which during the 1980s brought more than 400 top Chinese students to the U.S. for graduate study. That program produced more than 100 faculty members for Chinese universities.
