[Show abstract][Hide abstract] ABSTRACT: In contrast to other cereals, typical barley cultivars have caryopses with adhering hulls at maturity, known as covered (hulled) barley. However, a few barley cultivars are a free-threshing variant called naked (hulless) barley. The covered/naked caryopsis is controlled by a single locus (nud) on chromosome arm 7HL. On the basis of positional cloning, we concluded that an ethylene response factor (ERF) family transcription factor gene controls the covered/naked caryopsis phenotype. This conclusion was validated by (i) fixation of the 17-kb deletion harboring the ERF gene among all 100 naked cultivars studied; (ii) two x-ray-induced nud alleles with a DNA lesion at a different site, each affecting the putative functional motif; and (iii) gene expression strictly localized to the testa. Available results indicate the monophyletic origin of naked barley. The Nud gene has homology to the Arabidopsis WIN1/SHN1 transcription factor gene, whose deduced function is control of a lipid biosynthesis pathway. Staining with a lipophilic dye (Sudan black B) detected a lipid layer on the pericarp epidermis only in covered barley. We infer that, in covered barley, the contact of the caryopsis surface, overlaid with lipids to the inner side of the hull, generates organ adhesion.
Preview · Article · Apr 2008 · Proceedings of the National Academy of Sciences
[Show abstract][Hide abstract] ABSTRACT: Cultivated barley (Hordeum vulgare L.) is well known as one of the most widely cultivated crops in the world and as an extensively studied plant species in the field of genetics. In recent years, despite its very large genome size (ca. 5,000 Mb), the research resources needed for barley genomic studies have become available, including a large number of expressed sequence tags (ESTs). These have been widely used for barley genome analyses, such as DNA marker-generation and the construction of microarrays. However, the availability of a large-insert genomic library, which is also essential for genomic studies, has been relatively limited in the barley research community. We described here the construction and characterization of a barley bacterial artificial chromosome (BAC) library, using the Japanese malting barley variety 'Haruna Nijo'. The BAC library consisted of 294,912 clones arrayed in 768 384-well microtiter plates. The average size of each cloned insert was estimated to be 115.2 kb, with approximately 0.5% of the clones lacking inserts. Chroloplast DNAs were present in about 1.7% of the library. Thus, the genomic coverage of the 'Haruna Nijo' BAC library was estimated to be about 6.6 genome-equivalents. In order to rapidly identify specific BAC clones, we developed a screening strategy that combined PCR analysis of pooled BAC DNAs with colony hybridization. Using this screening scheme, we investigated the genomic coverage of this BAC library, using 13 locus-specific ESTs and a sequence-tagged site marker. By screening the whole library with individual markers, we identified an average of 5.1 clones per marker. This screening scheme also enabled us to rapidly construct a physical contig spanning a region of approx. 190 kb around the HvBRII locus, where the mutation responsible for the semi-dwarf plant type 'uzu' is located. These results indicate that the 'Haruna Nijo' BAC library will be useful for barley genomic studies.
No preview · Article · Mar 2007 · Breeding Science
[Show abstract][Hide abstract] ABSTRACT: To elucidate the origin of naked barley, molecular variation of the marker sKT7 tightly linked to the nud locus was examined. A total of 259 (53 wild, 106 hulled domesticated, and 100 naked domesticated) barley accessions were studied. Restriction analysis of the sKT7 PCR-amplified product revealed the alleles I, II, III, and IV. All four alleles were found in wild barley, but allele IV was found only in a single accession from southwestern Iran. Hulled domesticated accessions showed alleles I, II, or III, but all naked domesticated accessions had allele IV. The distribution of allele IV in wild barley and its pervasive presence in naked domesticated lines support the conclusion that naked barley has a monophyletic origin, probably in southwestern Iran. The available results suggest two scenarios for the origin of naked barley: either directly from a wild barley with allele IV or from a hulled domesticated line with allele IV that later became extinct. Naked domesticated accessions from different regions of the world have extremely homogeneous DNA sequences at the sKT7 locus, supporting the monophyletic origin of naked barley. For allele IV, four haplotypes (IVb to IVe) were found in 30 naked accessions: IVb was predominant (66.7%) and widely distributed, while the other three haplotypes, differing by only one nucleotide at different positions relative to IVb, showed a localized distribution. The geographical distribution of the haplotypes of sKT7 allele IV suggests migration routes of naked domesticated barley in central and eastern Asia.
Preview · Article · Jun 2004 · Theoretical and Applied Genetics
[Show abstract][Hide abstract] ABSTRACT: The hulled or naked caryopsis character of barley ( Hordeum vulgare L.) is an important trait for edibility and to follow its domestication process. A single recessive gene, nud, controls the naked caryopsis character, and is located on the long arm of chromosome 7H. To develop a fine map around the nud locus efficiently, the HEGS (High Efficiency Genome Scanning) electrophoresis system was combined with amplified fragment length polymorphism (AFLP). From bulked segregant analysis of 1,894 primer combinations, 12 AFLP fragments were selected as linked markers. For mapping, an F(2 )population of 151 individuals derived from a cross between Kobinkatagi (naked type) and Triumph (hulled type) was used. Seven AFLP markers were localized near the nud region. A fine map was developed with one-order higher resolution than before, along with the seven anchor markers. Among the seven linked AFLP markers (KT1-7), KT1, KT2 and KT6 were co-dominant, and the former two were detected for their single-nucleotide polymorphisms (SNPs) in the same length of fragments after electrophoresis with the non-denaturing gels of HEGS. The nud locus has co-segregated with KT3 and KT7, and was flanked by KT2 and KT4, at the 0.3-cM proximal and the 1.2-cM distal side, respectively. Four of these AFLP markers were converted into sequence-characterized amplified region (SCAR) markers, one of which was a dominant marker co-segregating with the nud gene.
No preview · Article · Jan 2004 · Theoretical and Applied Genetics