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Matsushima R, Hisano H, Galis I, Miura S, Crofts N, Takenaka Y, Oitome NF, Ishimizu T, Fujita N, Sato K. FLOURY ENDOSPERM 6 mutations enhance the sugary phenotype caused by the loss of ISOAMYLASE1 in barley. Theor Appl Genet 2023; 136:94. [PMID: 37010621 PMCID: PMC10070237 DOI: 10.1007/s00122-023-04339-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 03/02/2023] [Indexed: 06/19/2023]
Abstract
Barley double mutants in two genes involved in starch granule morphology, HvFLO6 and HvISA1, had impaired starch accumulation and higher grain sugar levels than either single mutant. Starch is a biologically and commercially important glucose polymer synthesized by plants as semicrystalline starch granules (SGs). Because SG morphology affects starch properties, mutants with altered SG morphology may be useful in breeding crops with desirable starch properties, including potentially novel properties. In this study, we employed a simple screen for mutants with altered SG morphology in barley (Hordeum vulgare). We isolated mutants that formed compound SGs together with the normal simple SGs in the endosperm and found that they were allelic mutants of the starch biosynthesis genes ISOAMYLASE1 (HvISA1) and FLOURY ENDOSPERM 6 (HvFLO6), encoding starch debranching enzyme and CARBOHYDRATE-BINDING MODULE 48-containing protein, respectively. We generated the hvflo6 hvisa1 double mutant and showed that it had significantly reduced starch biosynthesis and developed shrunken grains. In contrast to starch, soluble α-glucan, phytoglycogen, and sugars accumulated to higher levels in the double mutant than in the single mutants. In addition, the double mutants showed defects in SG morphology in the endosperm and in the pollen. This novel genetic interaction suggests that hvflo6 acts as an enhancer of the sugary phenotype caused by hvisa1 mutation.
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Affiliation(s)
- Ryo Matsushima
- Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki, Okayama, 710-0046, Japan.
| | - Hiroshi Hisano
- Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki, Okayama, 710-0046, Japan
| | - Ivan Galis
- Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki, Okayama, 710-0046, Japan
| | - Satoko Miura
- Department of Biological Production, Akita Prefectural University, Akita, 010-0195, Japan
| | - Naoko Crofts
- Department of Biological Production, Akita Prefectural University, Akita, 010-0195, Japan
| | - Yuto Takenaka
- College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Naoko F Oitome
- Department of Biological Production, Akita Prefectural University, Akita, 010-0195, Japan
| | - Takeshi Ishimizu
- College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Naoko Fujita
- Department of Biological Production, Akita Prefectural University, Akita, 010-0195, Japan
| | - Kazuhiro Sato
- Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki, Okayama, 710-0046, Japan
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