UCR Biochemist Daniel R. Gallie led the research, funded by the U.S. Department of Agriculture, the National Science Foundation and the California Agricultural Experiment Station. The findings will be published in the December issue of The Plant Journal in a paper titled ACC Synthase Expression Regulates Leaf Performance and Drought Tolerance in Maize.
Ethylene is vital in regulation of plant responses to environmental stresses, such as flooding and drought, and to attack by pathogens. But often, ethylene initiates leaf death in response to adverse conditions, sacrificing less essential parts of a plant to protect the growing tip, responsible for producing flowers, the reproductive organs of plants. Gallie said that he and his research team have examined the role of ethylene during plant growth and development since 1997.
In the most recent study, conducted by UCR researchers and Pioneer Hi-Bred International, an Iowa-based developer and supplier of seed to farmers, the authors targeted ACC synthase, an enzyme required for the production of ethylene, screening thousands of plants for naturally occurring mutants that were deficient in the enzyme.
The researchers isolated several such plants, and one in particular that produced substantially lower levels of the hormone. Leaves from this mutated plant remained functional and maintained photosynthetic function longer than non-altered plants.
In addition, the plants were more resistant to the effects of adverse environmental conditions. Surprisingly, by reducing the level of ethylene, all the leaves of the altered plants contained higher levels of chlorophyll and leaf protein, and functioned better than control leaves.