December 6, 2017

Scientists at the U.S Department of Energy's Oak Ridge National Laboratory (ORNL) have identified a common set of genes that enable different drought-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.

For more details about this study, read the ORNL News.