Abstract
Late blight caused by
Phytophthora infestans
greatly constrains potato production. Many
Resistance (R)
genes were cloned from wild
Solanum
species and/or introduced into potato cultivars by breeding. However, individual
R
genes have been overcome by
P. infestans
evolution; durable resistance remains elusive. We positionally cloned a new
R
gene,
Rpi-amr1,
from
Solanum americanum
, that encodes an NRC helper-dependent CC-NLR protein.
Rpi-amr1
confers resistance in potato to all 19
P. infestans
isolates tested. Using association genomics and long-read RenSeq, we defined eight additional
Rpi-amr1
alleles from different
S. americanum
and related species.Despite only ~90% identity between Rpi-amr1 proteins, all confer late blight resistance but differentially recognize
Avramr1
orthologs and paralogs. We propose that
Rpi-amr1
gene family diversity assists detection of diverse paralogs and alleles of the recognized effector, facilitating durable resistance against
P. infestans
.