A pathogen-induced putative NAC transcription factor mediates leaf rust resistance in barley

Abstract

Leaf rust, caused by Puccinia hordei, is one of the most widespread and damaging foliar diseases affecting barley. The barley leaf rust resistance locus Rph7 has been shown to have unusually high sequence and haplotype divergence. In this study, we isolate the Rph7 gene using a fine mapping and RNA-Seq approach that is confirmed by mutational analysis and transgenic complementation. Rph7 is a pathogen-induced, non-canonical resistance gene encoding a protein that is distinct from other known plant disease resistance proteins in the Triticeae. Structural analysis using an AlphaFold2 protein model suggests that Rph7 encodes a putative NAC transcription factor with a zinc-finger BED domain with structural similarity to the N-terminal DNA-binding domain of the NAC transcription factor (ANAC019) from Arabidopsis. A global gene expression analysis suggests Rph7 mediates the activation and strength of the basal defence response. The isolation of Rph7 highlights the diversification of resistance mechanisms available for engineering disease control in crops.

The wheat stripe rust resistance gene YrNAM is Yr10

“…In conclusion, the current evidence indicates that Yr10 is YrNAM , a gene with Triticeae NAC-BED domain (TNB) domain architecture similar to that reported for barley leaf rust resistance gene Rph7 8 Together, these genes represent a different class of R proteins. We propose the simplification of two separate gene identities conferring a common specificity to a single designation, Yr10 , for the benefit of the wider winter cereal research community.…”

“…YrNAM encodes a non-canonical resistance protein with a NAM (No Apical Meristem) domain and a ZnF (Zinc Finger)-BED domain at the N and C termini, respectively 5 . It is structurally similar to Rph7 , a leaf rust resistance gene in barley containing NAC transcription factor (TF) and ZnF-BED domains 8 . Together YrNAM and Rph7 represent a different class of R proteins, which we propose be designated as Triticeae NAC-BED domain (TNB) proteins.…”

Pangenome characterization and analysis of the NAC gene family reveals genes for Sclerotinia sclerotiorum resistance in sunflower (Helianthus annuus)

“…Overexpression of the eggplant ( Solanum melongena ) transcription factor S mNAC suppresses resistance to bacterial wilt pathogen Ralstonia solanacearum [ 77 ]. Analysis suggests a putative NAC transcription factor Rph7 in barley ( Hordeum vulgare ) mediates the activation and strength of the basal defense response to leaf rust pathogen Puccinia hordei [ 78 ]. The rice OsNAC30 mutant lines showed markedly reduced susceptibility to Xanthomonas oryzae pv.…”