Loss-of-function of SSIIa and SSIIIa confers high resistant starch content in rice endosperm.

Autor: Yang H; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China., Dong X; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. Electronic address: dongxb503@ibcas.ac.cn., Chai Y; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China., Cui S; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China., Tian L; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China., Zhang J; Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China., Qu LQ; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: lqqu@ibcas.ac.cn.
Jazyk: angličtina
Zdroj: Carbohydrate polymers [Carbohydr Polym] 2025 Jan 15; Vol. 348 (Pt B), pp. 122871. Date of Electronic Publication: 2024 Oct 15.
DOI: 10.1016/j.carbpol.2024.122871
Abstrakt: Rice (Oryza sativa L.) endosperm accumulates huge amounts of starch. Rice starch is highly digestible, potentially enhancing the occurrence of blood sugar- and intestine-related diseases such as type 2 diabetes. Resistant starch (RS) is hardly digestible in small intestine but can be converted into beneficial short-chain fatty acids in large intestine, potentially reducing the incidence of these diseases. However, it is still difficult to produce a high RS rice variety. Here, we report that simultaneous deficiency of soluble starch synthases IIa and IIIa confers high RS content in rice endosperm. The ssIIa ssIIIa exhibited higher RS content than did the ssIIIa ssIIIb, a mutant reported currently to have remarkably higher RS content than parental ssIIIa, under our experimental conditions. Loss-of-function of SSIIa and SSIIIa significantly elevated the activity of granule-bound starch synthase I and thus content of amylose. Furthermore, total lipid content increased in mutant seeds, implying that intermediate metabolites spilled out from starch biosynthesis into lipid biosynthesis. The increased amylose content and improved lipid synthesis coordinately contributed to high RS content in mutant seeds. These results further reveal the molecular mechanism of RS occurrence in rice endosperm and provide a critical genetic resource for breeding higher RS rice cultivars.
Competing Interests: Declaration of competing interest The authors declare that they have no potential conflict of interests.
(Copyright © 2024 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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