Scientists cloned the gene WAX2 after they discovered a fast-wilting mutant of Arabidopsis, a commonly used experimental plant. The gene is directly associated with the synthesis of the protective layer of plants, called the cuticle, and its contained waxes, according to the study published in the May issue of The Plant Cell.

The difference in the mutant Arabidopsis when compared to a wild-type, or normal, plant is the plants' ability to retain water. This is apparently because the mutation, called wax2, has a different cuticle structure than found in a plant that has the normal gene, WAX2.

"If we can alter the expression of the WAX2 gene, we might be able to produce a cuticle that is thicker or more rigid so that it's less permeable to water loss," said Matt Jenks, associate professor of horticulture and landscape architecture.

Manipulating what the gene does or when it is turned on could result in plants better able to survive in arid conditions.

Jenks and his research team isolated more than 20 mutant Arabidopsis plants that showed alterations in the amount of wax they produced. Of these, only a few lost water more quickly than the wild type.

"The mutant wax2 was the most drought susceptible," Jenks said. "Unlike previously described wax mutants, removal of the WAX2 gene product causes dramatic alteration in the cuticle membrane, and the plant no longer is able to prevent water loss."

Jenks said he believes that when the cuticle membrane structure is changed because of the wax2 malfunction of the WAX2 gene, the protective wax within the cuticle membrane is displaced, affecting transpiration. Transpiration is how plants emit waste matter though their leaf surfaces.

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Contact: Susan A. Steeves
ssteeves@aes.purdue.edu
765-496-7481
Purdue University
21-May-2003