Orthologous receptor kinases quantitatively affect the host status of barley to leaf rust fungi
byWang Y, Blilou I
Wang Y, Subedi S, de Vries H, Doornenbal P, Vels A, Hensel G, Kumlehn J, Johnston PA, Qi X, Blilou I, Niks RE† and Krattinger SG†(2019)Orthologous receptor kinases quantitatively affect the host status of barley to leaf rust fungi. Nature Plants 5: 1129-1135.
Global food security depends on cereal crops with durable disease
resistance. Most cereals are colonized by rust fungi, which are
pathogens of major significance for global agriculture.
Cereal rusts display a high degree of host specificity and one rust
species or forma specialis generally colonizes only one cereal host.
Exploiting the non-host status and transferring non-host resistance
genes between cereal crop species has been proposed as a strategy for
durable rust resistance breeding. The molecular determinants that define
the host status to rusts, however, are largely unknown. Here, we show
that orthologous genes at the Rphq2 locus for quantitative leaf rust resistance from cultivated barley and Rph22 from wild bulbous barley affect the host status to leaf rusts. Both genes encode lectin receptor-like kinases. We transformed Rphq2 and Rph22
into an experimental barley line that has been bred for susceptibility
to non-adapted leaf rusts, which allowed us to quantify resistance
responses against various leaf rust species. Rphq2 conferred a
much stronger resistance to the leaf rust of wild bulbous barley than to
the leaf rust adapted to cultivated barley, while for Rph22 the
reverse was observed. We hypothesize that adapted leaf rust species
mitigate perception by cognate host receptors by lowering ligand
recognition. Our results provide an example of orthologous genes that
connect the quantitative host with non-host resistance to cereal rusts.
Such genes provide a basis to exploit non-host resistance in molecular