Fine mapping and chromosome walking towards the Ror1 locus in barley (Hordeum vulgare L.)

Item Type:	Article
Title:	Fine mapping and chromosome walking towards the Ror1 locus in barley (Hordeum vulgare L.)
Creators Name:	Acevedo-Garcia, J. and Collins, N.C. and Ahmadinejad, N. and Ma, L. and Houben, A. and Bednarek, P. and Benjdia, M. and Freialdenhoven, A. and Altmüller, J. and Nürnberg, P. and Reinhardt, R. and Schulze-Lefert, P. and Panstruga, R.
Abstract:	KEY MESSAGE: The Ror1 gene was fine-mapped to the pericentric region of barley chromosome 1HL. Recessively inherited loss-of-function alleles of the barley (Hordeum vulgare) Mildew resistance locus o (Mlo) gene confer durable broad-spectrum disease resistance against the obligate biotrophic fungal powdery mildew pathogen Blumeria graminis f.sp. hordei. Previous genetic analyses revealed two barley genes, Ror1 and Ror2, that are Required for mlo-specified resistance and basal defence. While Ror2 was cloned and shown to encode a t-SNARE protein (syntaxin), the molecular nature or Ror1 remained elusive. Ror1 was previously mapped to the centromeric region of the long arm of barley chromosome 1H. Here, we narrowed the barley Ror1 interval to 0.18 cM and initiated a chromosome walk using barley yeast artificial chromosome (YAC) clones, next-generation DNA sequencing and fluorescence in situ hybridization. Two non-overlapping YAC contigs containing Ror1 flanking genes were identified. Despite a high degree of synteny observed between barley and the sequenced genomes of the grasses rice (Oryza sativa), Brachypodium distachyon and Sorghum bicolor across the wider chromosomal area, the genes in the YAC contigs showed extensive interspecific rearrangements in orientation and order. Consequently, the position of a Ror1 homolog in these species could not be precisely predicted, nor was a barley gene co-segregating with Ror1 identified. These factors have prevented the molecular identification of the Ror1 gene for the time being.
Keywords:	Powdery Mildew, Yeast Artificial Chromosome, Barley Chromosome, Barley Gene, Yeast Artificial Chromosome Clone
Source:	Theoretical and Applied Genetics
ISSN:	0040-5752
Publisher:	Springer
Volume:	126
Number:	12
Page Range:	2969-2982
Date:	December 2013
Official Publication:	https://doi.org/10.1007/s00122-013-2186-6
PubMed:	View item in PubMed

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