Scientists at the U.S Department of Energy's Oak Ridge National Laboratory
(ORNL) have identified a common set of genes that enable different
drougth-resistant plants to survive in semi-arid conditions. The discovery
could play a significant role in bioengineering and creating energy crops
that are tolerant to water deficits.

The scientists are studying a variety of drought-resistant plants to unlock
the mystery of crassulacean acid metabolism or CAM photosynthesis. The
research team sequenced the genome of Kalanchoë fedtschenkoi, an emerging
model for CAM genomics research because of its relatively small genome and
amenability to genetic modification. The team investigated and compared the
genomes of K. fedtschenkoi, Phalaenopsis equestris (orchid) and Ananas
comosus (pineapple) using ORNL's Titan supercomputer.

They identified 60 genes that exhibited convergent evolution in CAM species,
including convergent daytime and nighttime gene expression changes in 54
genes, as well as protein sequence convergence in six genes. The team
discovered a novel variant of phosphoenolpyruvate carboxylase, or PEP, an
important "worker" enzyme responsible for the nighttime fixation of carbon
dioxide into malic acid, which is then converted back to carbon dioxide for
photosynthesis during the day.

[www.ornl.gov]
ate-evolution-water-use-efficient-crops