Land plants get a large portion of their mineral nutrients through their relationship with soil fungi called arbuscular mycorrhizal (AM) symbiosis. Despite decades of research, many of the genes required to form this relationship remain elusive. A new study conducted by researchers at the Boyce Thompson Institute (BTI) has uncovered genes that plants use to form symbiotic relationships with fungi.

With the widely available genome sequences, the researchers were able to compare 50 plant genomes to identify 138 genes shared exclusively by plants capable of AM symbiosis. Armando Bravo, a BTI postdoctoral scientist worked with bioinformatics analyst Thomas York to compare the genome sequences of 34 plant species that can form symbiosis with 16 plants that cannot. Then they picked out the genes that are found only in plants that form AM symbiosis and arrived at just 138 genes. Fifteen of these were already known to play a role in AM symbiosis and Bravo tested the accuracy of seven of the unknown genes in the group by growing barrel medic with mutations in those genes and examining their ability to form a successful symbiosis. Mutations in six of these genes resulted in a faulty interaction.

Almost all staple crops form AM symbioses, and optimizing this interaction through crop breeding could improve yield and reduce the need for fertilizers.

For more details, read the news release at the BTI website.

Figure: A fungus forms a microscopic, tree-like arbuscule inside a plant root cell, which enables the fungus to transfer soil nutrients to the plant. The fungus is visualized with fluorescent compounds. (Credit: M.J. Harrison)