Physicochemical properties and molecular mechanisms of different resistant starch subtypes in rice

Cheng Liang; Haoyang Xu; Hui You; Ouling Zhang; Yiman Han; Qingyu Li; Yungao Hu; Xunchao Xiang

doi:10.3389/fpls.2023.1313640

Physicochemical properties and molecular mechanisms of different resistant starch subtypes in rice

Front Plant Sci. 2024 Jan 8:14:1313640. doi: 10.3389/fpls.2023.1313640. eCollection 2023.

Authors

Cheng Liang^{1

2}, Haoyang Xu^{1

2}, Hui You^{1

2}, Ouling Zhang^{1

2}, Yiman Han^{1

2}, Qingyu Li³, Yungao Hu^{1

2}, Xunchao Xiang^{1

2}

Affiliations

¹ Lab of Plant Molecular Genetics and Breeding, Southwest University of Science and Technology, Mianyang, China.
² Rice Research Institute, Southwest University of Science and Technology, Sichuan, Mianyang, China.
³ School of Medicine, Tsinghua University, Beijing, China.

Abstract

Resistant starch (RS) can help prevent diabetes and decrease calorie intake and that from plants are the main source of mankind consumption. Rice is many people's staple food and that with higher RS will help health management. A significantly positive correlation exists between apparent amylose content (AAC) of rice and its RS content. In this study, 72 accessions with moderate or high AAC were selected to explore the regulatory mechanisms and physicochemical properties on different proceeding types of rice RS. RS in raw milled rice (RSm), hot cooked rice (RSc), and retrogradation rice (RSr) showed a wide variation and distinct controlling mechanisms. They were co-regulated by Waxy (Wx), soluble starch synthase (SS) IIb and SSI. Besides that, RSm was also regulated by SSIIa and SSIVb, RSc by granule-bound starch synthase (GBSS) II and RSr by GBSSII and Pullulanase (PUL). Moreover, Wx had significant interactions with SSIIa, SSI, SSIIb and SSIVb on RSm, but only the dominant interactions with SSIIb and SSI on RSc and RSr. Wx was the key factor for the formation of RS, especially the RSc and RSr. The genes had the highest expression at 17 days after flowering and were beneficial for RS formation. The longer the chain length of starch, the higher the RS3 content. RSc and RSr were likely to be contained in medium-size starch granules. The findings favor understanding the biosynthesis of different subtypes of RS.

Keywords: gene expression patterns; gene interaction; resistant starch; rice (Oryza sativa L.); starch granule properties; targeted-gene association study.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was financially supported by the Major Science and Technology Project “the Breeding of Green and Efficient Super Rice Varieties” of “14th Five-year Plan” Biological Breeding of Sichuan Province (Grant No.2022ZDZX0012); the Key Research & Development program of Sichuan Province, China (Grant No. 2019YFN0019).