RT Journal Article
SR Electronic
T1 A pathogen-induced putative NAC transcription factor mediates leaf rust resistance in barley
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.11.30.518475
DO 10.1101/2022.11.30.518475
A1 Chunhong Chen
A1 Matthias Jost
A1 Megan A. Outram
A1 Dorian Friendship
A1 Sambasivam Periyannan
A1 Jan Bartoš
A1 Kateřina Holušová
A1 Peng Zhang
A1 Dhara Bhatt
A1 Davinder Singh
A1 Evans Lagudah
A1 Robert Park
A1 Peter Dracatos
YR 2022
UL http://biorxiv.org/content/early/2022/12/01/2022.11.30.518475.abstract
AB Leaf rust, caused by Puccinia hordei, is one of the most widespread and damaging foliar diseases affecting barley (Hordeum spp.). The barley leaf rust resistance locus Rph7, located on the short arm of chromosome 3H, confers defence at all growth stages and was previously shown to have unusually high sequence and haplotype divergence. Earlier, four candidate genes for Rph7 were reported and, despite an in-depth comparative sequence analysis and haplotypic characterisation, the causal gene could not be resolved. Here, we successfully cloned Rph7 utilising a fine mapping approach in combination with an RNA-Seq based expression analysis. We identified three up-regulated and pathogen-induced genes with presence/absence variation (PAV) at this locus. Sequence analysis of chemically induced Rph7 knockout mutant lines identified multiple independent non-synonymous variants, including a premature stop codon in a single non-canonical resistance gene that encodes a 302-amino acid protein. Progeny from four independent transgenic lines segregated for the expected avirulent Rph7 infection type in response to several avirulent P. hordei pathotypes, however, all plants were susceptible to a single virulent pathotype confirming the specificity. Structural analysis using an AlphaFold2 protein model suggests that Rph7 encodes a putative NAC transcription factor, as it shares structural similarity to ANAC019 from Arabidopsis, with a C-terminal BED domain. A global gene expression analysis suggests Rph7 is involved in the activation of basal defence.Competing Interest StatementThe authors have declared no competing interest.