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ID 62369
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Taketa, Shin Institute of Plant Science and Resources, Okayama University Kaken ID researchmap
Hattori, Momoko Institute of Plant Science and Resources, Okayama University
Takami, Tsuneaki Institute of Plant Science and Resources, Okayama University
Himi, Eiko Institute of Plant Science and Resources, Okayama University
Sakamoto, Wataru IInstitute of Plant Science and Resources, Okayama University
Abstract
The albino lemma 1 (alm1) mutants of barley (Hordeum vulgare L.) exhibit obvious chlorophyll-deficient hulls. Hulls are seed-enclosing tissues on the spike, consisting of the lemma and palea. The alm1 phenotype is also expressed in the pericarp, culm nodes and basal leaf sheaths, but leaf blades and awns are normal green. A single recessive nuclear gene controls tissue-specific alm1 phenotypic expression. Positional cloning revealed that the ALM1 gene encodes a Golden 2-like (GLK) transcription factor, HvGLK2, belonging to the GARP subfamily of Myb transcription factors. This finding was validated by genetic evidence indicating that all 10 alm1 mutants studied had a lesion in functionally important regions of HvGLK2, including the three alpha-helix domains, an AREAEAA motif and the GCT box. Transmission electron microscopy revealed that, in lemmas of the alm1.g mutant, the chloroplasts lacked thylakoid membranes, instead of stacked thylakoid grana in wild-type chloroplasts. Compared with wild type, alm1.g plants showed similar levels of leaf photosynthesis but reduced spike photosynthesis by 34%. The alm1.g mutant and the alm1.a mutant showed a reduction in 100-grain weight by 15.8% and 23.1%, respectively. As in other plants, barley has HvGLK2 and a paralog, HvGLK1. In flag leaves and awns, HvGLK2 and HvGLK1 are expressed at moderate levels, but in hulls, HvGLK1 expression was barely detectable compared with HvGLK2. Barley alm1/Hvglk2 mutants exhibit more severe phenotypes than glk2 mutants of other plant species reported to date. The severe alm1 phenotypic expression in multiple tissues indicates that HvGLK2 plays some roles that are nonredundant with HvGLK1.
Keywords
chloroplast
GLK2
Hordeum vulgare
photosynthesis
spike
thylakoid
Note
This is an Accepted Manuscript of an article published by Oxford University Press.
This fulltext is available in Jan. 2022.
Published Date
2021-1-13
Publication Title
Plant and Cell Physiology
Volume
volume62
Issue
issue3
Publisher
Oxford University Press (OUP)
Start Page
447
End Page
457
ISSN
1471-9053
Content Type
Journal Article
language
English
OAI-PMH Set
岡山大学
Copyright Holders
© 2021 Japanese Society of Plant Physiologists
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isVersionOf https://doi.org/10.1093/pcp/pcab001
Funder Name
Japan Society for the Promotion of Science
Oohara Foundation
助成番号
16K07556