Scientists can now explore the role of PLAT proteins in symbiosis, potentially exploiting them to create more efficient nitrogen-fixing legumes.
Legume plants like soybean and alfalfa have the unique capacity to fix nitrogen directly from the air. This means they can produce their own fertilizer, potentially reducing the amount of synthetic chemicals used in agriculture and reducing pollution to rivers and streams. This environmentally important process involves a symbiosis between legume plant roots and special bacteria known as rhizobia.
Scientists have searched for many years for the genes that control molecular communication between legumes and rhizobia. In the scientific journal New Phytologist, University of Minnesota Plant Pathology researchers Diana Trujillo and Nevin Young, and Minnesota Supercomputing Institute analyst Kevin Silverstein reported a novel strategy to discover legume-rhizobial communication genes using bioinformatic data-mining of legume genome sequences.
“Genomics and bioinformatic data-mining are dramatically expanding our ability to explore biological traits like symbiosis and nitrogen-fixation,” said Young. “Discovering the key role of PLAT proteins in legumes is just one example. Our group and others around the world are now investigating the central players, potentially extending the capacity for nitrogen fixation — and self-fertilization — to non-legume crops like cereals.”
The research team searched for signaling proteins that are uniquely expanded in the genomes of just one or a few legume species. Among the gene families they found were genes known as nodule-specific PLAT (polycystin‐1, lipoxygenase, alpha toxin) proteins, which seem to interact with lipids within cells. When these genes were knocked out using the technique of CRISPR gene editing, the root nodules where symbiosis occurs were much smaller and unable to fix nitrogen. These results demonstrate that PLAT proteins play a key role in nodulation and symbiosis.
With this knowledge, scientists can now explore the role of PLAT proteins in symbiosis, potentially exploiting them to create more efficient nitrogen-fixing legumes. Scientists can also extend the new data-mining strategy developed by the team to discover other genes important in symbiosis and nitrogen fixation as well as other crop processes.
Research was supported by the National Science Foundation Plant Genome Program and the Minnesota Agricultural Experiment Station.