Scientists at the Department of Energy's Oak Ridge National Laboratory
(ORNL) have uncovered the genetic and metabolic mechanisms that allow
certain plants to conserve water and thrive in semi-arid climates. Semi-arid
plants, such as agave, have survived in areas with little or no rainfall by
developing a specialized mode of photosynthesis called crassulacean acid
To understand CAM photosynthesis, the research team compared the molecular
traits of agave with Arabidopsis, which uses a more common photosynthetic
process. The team evaluated genetic behavior that signals stomatal movement
in each plant over the same 24-hour period. They found that the timing of
daytime against nighttime stomatal activity varied significantly between
agave and Arabidopsis. The research also identified the genetic and
metabolic mechanisms that signal CAM plants to open and close their stomata.
Understanding the timing of these signals will be key to transferring CAM
processes into crops such as rice, corn, poplar, and switchgrass.
Gerald Tuskan, ORNL Corporate Fellow and coauthor, said "The transfer of CAM
molecular machinery into energy crops would facilitate their deployment onto
marginal lands and would simultaneously reduce competition with food crops."