LA JOLLA, CAThe seeds sprouting in your spring garden may still be struggling to reach the sun. If so, they are consuming a finite energy pack contained within each seed. Once those resources are depleted, the plant cell nucleus must be ready to switch on a "green" photosynthetic program. Researchers at the Salk Institute for Biological Studies recently showed a new way that those signals are relayed.
In a study published in the May 24, 2011, issue of the journal Current Biology, a team led by Joanne Chory, Ph.D., professor and director of the Plant Molecular and Cellular Biology Laboratory, and including postdoctoral fellows, Jesse Woodson, Ph.D., and Juan Perez-Ruiz, Ph.D., identify a signaling factor sent by plant chloroplasts to turn on photosynthesis-related genes. Their finding may help achieve greater crop yields and better plant health.
"When a seedling establishes a photosynthetic lifestyle, it needs to activate several thousand genes in the nucleus," says Chory, also a Howard Hughes Medical Institute investigator and holder of the Howard H. and Maryam R. Newman Chair in Plant Biology. "One of the signals to do this comes from the organelle in charge of photosynthesis, called the chloroplast. In this study we identified this signaling molecule as heme."
Although in plants and animals most genes reside in the nucleus, small DNA rings of genes are found in other cellular venues such as energy-producing mitochondria. Plant chloroplasts, whose primary function is to turn light and carbon dioxide into energy and carbohydrates required for growth, also contain genes that regulate photosynthesis-related factors encoded in the plant cell nucleus.
"The Chory lab previously identified mutations in five genes in Arabidopsis thaliana plants that were unable to synthesize molecules such as chlorophyll or respond to signals generated by intermediates of the chlorophyll biosynthetic pathway," explains Woodson, the s
|Contact: Kat Kearney|