Colinearity between the barley grain protein content (GPC) QTL on chromosome arm 6HS and the wheat Gpc-B1 region
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Grain Protein Content (GPC) is an important determinant of grain quality in many crops, including barley and wheat. Recently, the map-based cloning of Gpc-B1, a wheat GPC quantitative trait locus (QTL), revealed a NAC transcription factor (TtNAM-B1) that was associated with increased grain protein, zinc, and iron content. In barley, a QTL for GPC was identified in a segregating population developed from a cross between ‘Karl’ (low GPC) and ‘Lewis’ (average GPC). This QTL was mapped near marker hvm74 on chromosome 6H and was suggested as a potential orthologue for Gpc-B1 on chromosome arm 6BS. In the current study, wheat genes that were previously mapped within a 0.8 cM segment spanning the TtNAM-B1 gene were converted into barley molecular markers. These new markers, together with the barley TtNAM-B1 orthologous gene (designated HvNAM-1 hereafter) were mapped on a 0.7 cM interval encompassing the peak of the barley QTL for GPC on chromosome arm 6HS. Sequence comparison of HvNAM-1 parental alleles showed two single nucleotide polymorphisms (SNPs) that result in two amino acid differences. Analysis of the allelic variation in a wild and cultivated barley collection revealed that the Karl haplotype was present only in nine out of 147 tested accessions. The colinearity between the wheat and barley GPC regions and the low frequency of the HvNAM-1 haplotype associated with low GPC suggest that the barley NAC transcription factor is responsible for the GPC QTL on barley chromosome 6H.
KeywordsBarley Colinearity Grain protein content NAC transcription factor QTL mapping wheat
This study was supported by Research Grant No. US-3573-04C from BARD, the United States—Israel Binational Agricultural Research Foundation. A. Distelfeld is indebted to Vaadia-BARD Postdoctoral Fellowship Award No. FI-386-06. The authors wish to thank L. Beloborodov for excellent technical assistance. Barley seeds were kindly provided by the USDA-ARS, National Small Grains Germplasm Research Facility, Aberdeen, Idaho.
- Avivi L (1978) High protein content in wild tetraploid Triticum dicoccoides Korn. In: Ramanujam S (ed) Proceedings of the 5th international wheat genetics symposium, New Delhi, India. Indian Society of Genetics and Plant Breeding (ISGPB), pp 372–380Google Scholar
- Cakmak I, Torun A, Millet E, Feldman M, Fahima T, Korol AB, Nevo E, Braun HJ, Ozkan H (2004) Triticum dicoccoides: an important genetic resource for increasing zinc and iron concentration in modern cultivated wheat. Soil Sci Plant Nutr 50:1047–1054Google Scholar
- Kleinhofs A, Kilian A, Saghai Maroof MA, Biyashev RM, Hayes P, Chen FQ, Lapitan N, Fenwick A, Blake TK, Kanazin V, Ananiev E, Dahleen L, Kudrna D, Bollinger J, Knapp SJ, Liu B, Sorrells M, Heun M, Franckowiak JD, Hoffman D, Skadsen R, Steffenson B (1993) A molecular, isozyme and morphological map of the barley (Hordeum vulgare) genome. Theor Appl Genet 86:705–712CrossRefGoogle Scholar
- Yu Y, Tomkins JP, Waugh R, Frisch DA, Kudrna D, Kleinhofs A, Brueggeman RS, Muehlbauer GJ, Wise RP, Wing RA (2000) A bacterial artificial chromosome library for barley (Hordeum vulgare L.) and the identification of clones containing putative resistance genes. Theor Appl Genet 101:1093–1099CrossRefGoogle Scholar