Scientists Discover Critical Immune Component in Barley

Many valuable cereal crops come from the same grass family, Poaceae, including barley, wheat, rice, and maize. Scientists have been working to better understand the molecular mechanisms behind this lineage's survival to ensure that these plants continue to flourish and feed the world in years to come.

Grasses have evolved into the thriving varieties they are today while diseases that infect them evolved alongside them. The Pucciniales, an order of fungal pathogens that cause rust diseases includes stripe rust, Puccinia striiformis, which is present in all major wheat-growing areas of the world.

P. striiformis is an adaptable pathogen. However, while wheat stripe rust has been endemic in Australia for more than 60 years, it has not adapted to infect barley despite both crops being grown in the same regions, and the source of this resistance has remained unclear. The Matthew Moscou group at The Sainsbury Laboratory (TSL) identified three resistance (R) gene loci designated Rps6, Rps7, and Rps8, contributing to barley's non-adapted resistance to wheat stripe rust. To better understand the role of these R genes in barley, the group fine-mapped Rps8 to a region on chromosome 4H, which encompasses a presence/absence variation across diverse barley accessions, and found that Rps8-mediated resistance to wheat stripe rust is conferred by a receptor kinase (Pur1) and a Poales-specific Exo70 (Exo70FX12). The group says this is an exciting discovery in plant immunity and cereal evolution. This information will allow scientists to transfer wheat stripe rust immunity traits to another variety.

For more details, read the news article on the TSL website.