Barley Grain with Adhering Hulls Is Controlled by an ERF Family Transcription Factor Gene Regulating a Lipid Biosynthesis Pathway

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 105; no. 10; pp. 4062 - 4067
• Main Authors: Taketa, Shin, Amano, Satoko, Tsujino, Yasuhiro, Sato, Tomohiko, Saisho, Daisuke, Kakeda, Katsuyuki, Nomura, Mika, Suzuki, Toshisada, Matsumoto, Takashi, Sato, Kazuhiro, Kanamori, Hiroyuki, Kawasaki, Shinji, Takeda, Kazuyoshi
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 11.03.2008; National Acad Sciences
• Subjects: Arabidopsis; Azo Compounds; Barley; Biological Sciences; Botany; Cells; Cereals; Cloning, Molecular; Cultivars; Edible Grain - metabolism; Epidermis; Gene Expression Regulation, Plant; Genes; Genes, Plant; Genetic loci; Genetic Variation; Grains; Hordeum - cytology; Hordeum - genetics; Hordeum - metabolism; Hordeum vulgare; Lipids; Lipids - analysis; Lipids - biosynthesis; Molecular Sequence Data; Mutation; Naphthalenes; Pericarp; Permeability; Plant domestication; Plant Proteins - genetics; Plant Proteins - metabolism; Plants; Sequence Analysis, DNA; Studies; Transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism
• DOI: 10.1073/pnas.0711034105
• ISSN: 0027-8424

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.