Breakthrough Research On Ocean Algae Could Lead To Freeze- And Drought-Resistant Crops, Says UF/IFAS Scientist

June 25, 1997

GAINESVILLE—A University of Florida professor reports finding “the missing link” in how tiny ocean algae produce a chemical substance that influences cloud formation in the atmosphere. The breakthrough research could help explain global climate changes and make it possible to develop agricultural crops that resist freeze, drought and salt water damage.

Andrew Hanson, a plant biochemist, molecular biologist and eminent scholar with UF’s Institute of Food and Agricultural Sciences, describes the research in the June 26 issue of the international scientific journal Nature. His article explains how marine algae produce dimethylsulfonio-propionate (DMSP), which is converted into dimethylsulfide (DMS), a sulfur gas that helps clouds form in the atmosphere.

He said researchers have been interested in unraveling the mysteries of DMSP for more than 30 years.

“Until now, we simply did not know how marine algae made DMSP,” Hanson said. “In terms of a scientific breakthrough, we have established the biochemistry of how algae convert the common compound methionine — which is found in all algae — into DMSP. That’s the new finding and it opens the door for future research on global climate changes and improved agricultural crops.”

The Nature article reports on how Hanson and collaborating scientists identified the four steps by which marine algae make DMSP. Most of the algae used in their research were collected along the east coast of Florida in Flagler County.

Hanson said algae produce DMSP to protect themselves from the negative effects of high salinity and freezing. DMSP also is formed in some higher plants that are tolerant to drought, freeze and salt stress.

When the DMS sulfur gas in ocean water enters the atmosphere by sea-air exchange, the gas is oxidized into sulfuric acid, Hanson said. Tiny sulfuric acid particles then help promote the formation of clouds which block and reflect heat energy from the sun back into space. This has a cooling effect on the earth.

“We now have a clearer picture of how marine algae help control world climate. Since DMS gas from algae is linked to cloud formation, its role in global heating and cooling could be critical. We don’t know how future trends in world climate will affect marine algae, but we do know there is a feedback effect operating.

“With global warming, will the algae make more DMS to increase cloud formation and help cool the planet, or will they make less DMS? We really don’t know at this point,” Hanson said.

“If we can use genetic engineering to transfer the capacity to make this compound from these simple marine organisms into commercial agricultural crops, we should be able to confer a useful degree of drought, freeze and salt tolerance to these plants,” he said. “Citrus, for example, would be a particularly good target because it is quite sensitive to freezing and has no DMSP or any related compounds itself.

“That’s why we are now working on finding the enzymes and cloning the genes we need to achieve the resistance we want in crops,” he said. “The research published in Nature is the first major step toward that goal.”

Hanson, whose UF/IFAS laboratory leads the $500,000 national research project that involves three other universities, attributed the breakthrough to “a very strong collaborative effort between my laboratory and colleagues at Michigan State University, Purdue University and Rutgers University.”

Hanson credited Douglas Gage at Michigan State for his expertise in mass spectrometry, David Rhodes at Purdue for computer modeling and Thomas Leustek from Rutgers who worked with Hanson as a visiting scientist in the UF/IFAS Department of Horticultural Sciences.

The research project is supported by grants from the National Science Foundation in Washington, D.C., and the Office of Naval Research and by the C.V. Griffin Senior Foundation Inc. in Howie-In-The-Hills. The Griffin foundation provided funding to establish Hanson’s UF eminent scholar position and to support his research.