Query (optional)   in Class  All Allele Author Colleague Collection Assembly Gene Gene Class Gene Product Germplasm Image Journal Keyword Library Locus Map Map Data Marker Pathology Polymorphism Probe Protein QTL Rearrangement Reference Sequence Species Trait Trait Study Two Point Data  

---

GrainGenes Reference Report: TPJ-38-215

[Submit comment/correction]

Reference	TPJ-38-215
Title	A single-amino acid substitution in the sixth leucine-rich repeat of barley MLA6 and MLA13 alleviates dependence on RAR1 for disease resistance signaling
Journal	Plant Journal
Year	2004
Volume	38
Pages	215-226
Author	Halterman DA Wise RP
Abstract	Summary: Interactions between barley and the powdery mildew pathogen, Blumeria graminis f. sp. hordei, (Bgh) are determined by unique combinations of host resistance genes, designated Mildew-resistance locus (Ml), and cognate pathogen avirulence genes. These interactions occur both dependent and independent of Rar1 (required for Mla12 resistance) and Sgt1 (Suppressor of G-two allele of skp1), which are differentially required for diverse plant disease-resistance pathways. We have isolated two new functional Mla alleles, Rar1-independent Mla7 and Rar1-dependent Mla10, as well as the Mla paralogs, Mla6-2 and Mla13-2. Utilizing the inherent diversity amongst Mla-encoded proteins, we identified the only two amino acids exclusively conserved in RAR1-dependent MLA6, MLA10, MLA12, and MLA13 that differ at the corresponding position in RAR1-independent MLA1 and MLA7. Two- and three-dimensional modeling places these residues on a predicted surface of the sixth leucine-rich repeat (LRR) domain at positions distinct from those within the beta-sheets hypothesized to determine resistance specificity. Site-directed mutagenesis of these residues indicates that RAR1 independence requires the presence of an aspartate at position 721, as mutation of this residue to a structurally similar, but uncharged, asparagine did not alter RAR1 dependence. These results demonstrate that a single-amino acid substitution in the sixth MLA LRR can alter host signaling but not resistance specificity to B. graminis
External Databases	Pubmed: 15078326
Keyword	[ Hide all but 1 of 45 ] amino apr arabidopsis asparagine aspartate avirulence avirulence gene barley blumeria blumeria graminis crystal structure disease divergent selection diversity domain essential component f-sp hordei gene graminis hordei host host-resistance leucine-rich repeat locus mildew modeling mutagenesis mutation pathogen plant defenses plant disease resistance powdery mildew powdery mildew resistance rar1 signaling repeat resistance resistance gene resistance gene evolution resistance specificity site-directed mutagenesis specificity substitution surface transposable element unique

GrainGenes is a product of the Agricultural Research Service of the US Department of Agriculture.