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)geneloci 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.

[www.tsl.ac.uk]