Copy
Issue 3
July 2014

In this issue:

New markers for powdery mildew resistance loci in barley:

  • QTL on 5H (resistance sources Denar and CLE210)

  • mlo9 and mlo11

90k wheat SNP array published in Plant Biotechnology Journal and featured in Ground Cover

Using the 90K wheat SNP array to develop low-cost single marker assays for QTL: the first of a series of technology tips to be published in this newsletter.

 

Contact Us


Diane Mather
T +61 8 8313 7156
E diane.mather@adelaide.edu.au

Ken Chalmers
T +61 8313 6812
E ken.chalmers@adelaide.edu.au

www.markers.net.au







Markers for powdery mildew resistance from Denar and CLE210 barley
 

AWBMMP-GA has developed markers (uah6 and uah7) that map near QTL on chromosome 5H and that distinguish two sources of powdery mildew resistance (Denar from the Czech Republic and CLE210 from Uruguay) from all Australian barley varieties that AWBMMP-GA has tested.  The QTL were mapped based on adult-plant symptoms in the populations CLE210/Baudin and Denar/Baudin. Although the QTL mapped at the same position in both populations, the Denar allele seems more broadly effective (trials in both WA and Queensland) than the CLE210 allele (effective in WA trials but not in a Queensland trial). 

Members of the Australian cereal breeding and pre-breeding community can access primer sequences and assay protocols, by logging in to our project website.  CLICK HERE to login or to request a userid. Once you have logged in, click on MARKER RESOURCES.

Breeding organisations can contact Diane Mather  (diane.mather@adelaide.edu.au, 08 8313 7156) to request seed of selected CLE210/Baudin and/or Denar/Baudin lines for use as parents in crossing.
 
[PROJECT: UA00143]

Functional markers for mlo-9 and mlo-11

The Mlo gene of barley has multiple recessive (mlo) alleles for resistance against powdery mildew. Although these alleles exhibit some negative pleiotropic effects (increased susceptibility to some other fungal pathogens, necrotic leaf spotting and reduced grain yield) they are of interest because they confer durable broad spectrum resistance.
 
The mlo-11 allele, which was discovered in Ethiopian barley landraces, has been  deployed in a number of barley varieties in Europe, some of which have been released in Australia (GrangeR, Henley, Westminster). The mlo-9 allele, which was originally developed by EMS mutagenesis in the barley cultivar Diamant, has been  deployed in a number of barley varieties in Europe, including Alexis and Barke. 

AWBMMP-GA has developed a dominant KASP assay (uah7) that detects tandem repeats in the mlo-11 allele and a co-dominant KASP assay (uah8) that detect the functional SNP in the mlo-9 allele. 

Members of the Australian cereal breeding and pre-breeding community can access primer sequences and assay protocols, by logging in to our project website.  CLICK HERE to login or to request a userid. Once you have logged in, click on MARKER RESOURCES.
 
[PROJECT: UA00143]

90k SNP array publication

Since the  last issue of this newsletter, the following paper was published:

Wang, S, Wong, D, Forrest, K, Allen, A, Chao, S, Huang, B, Maccaferri, M,  Salvi, S, Cattivelli, L; Mastrangelo, A, Stephen, S,  Barker, G, Wieseke, R, Pileske, J, International Wheat Genome Sequencing Consortium, Lillemo, M, Mather, D, Appels, R, Dolferus, R,  Brown-Guedira, G,  Korol, A, Akhunova, A, Feuillet, C, Salse, J, Morgante, M, Pozniak, C, Luo, MC, Dvorak, J, Morell, M, Dubcovsky, J, Ganal, M, Tuberosa, R, Lawley, C, Mikoulitch, I, Cavanagh, C, Edwards, K, Hayden, M & Akhunov, E (2014) Characterization of polyploid wheat genomic diversity using a high-density 90,000 SNP array. Plant Biotechnology Journal DOI: 10.1111/pbi.12183

This work was also featured in a recent issue of GRDC's Ground Cover. 

Using the 90K wheat SNP array to develop low-cost single marker assays for QTL


Numerous pre-breeders are using the wheat 90K Infinium SNP chip, based on 90,000 gene-based markers,  to fine-map QTL and identify tightly linked markers. Here, the DAV00127 'next-gen technology project' describes how this can be accomplished quickly and at low cost.

To refine a QTL region, a researcher can selectively genotype individual lines from a segregating mapping population (e.g. 12 resistant lines and 12 susceptible lines).  The inclusion of multiple populations segregating for the QTL in different genetic backgrounds (or even unrelated germplasm with known phenotypes) can be used to increase recombination in the region to help delineate a minimal genomic segment for the QTL. SNPs identified to flank the QTL (and SNPs spanning the QTL at regular intervals, which can be identified using comparative genomics) can be converted to low-cost single marker assays such as KASP markers.

The resulting single-marker assays can be applied to future work including selection of informative recombinants for development of future crosses, the genotyping of future populations to further refine the QTL interval, and to reduce phenotyping costs (which is especially important for traits that are difficult to phenotype, such as PHS, LMA, frost and drought tolerance)  by allowing the selection of the most informative recombinant lines.

[PROJECT: DAV00127]

This newsletter:

Several times a year, the Australian Wheat and Barley Molecular Marker Program informs user groups about recent discoveries, new marker and new technologies. To avoid being a nuisance to those who are not interested, we only send the newsletter to those who subscribe. If you know someone who might be interested, please suggest that they visit www.markers.net.au and click on NEWSLETTER.

Copyright © 2014 Australian Wheat and Barley Molecular Marker Program, All rights reserved.