AUTHOR=Tu Debao , Jiang Yang , Salah Akram , Xi Min , Cai Mingli , Cheng Bo , Sun Xiaosong , Cao Cougui , Wu Wenge 

TITLE=Variation of rice starch structure and physicochemical properties in response to high natural temperature during the reproductive stage

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1136347

DOI=10.3389/fpls.2023.1136347

ISSN=1664-462X

ABSTRACT=Climate warming affects rice growth at different phenological stages, thereby increasing rice chalkiness and protein, and reducing eating and cooking quality (ECQ). The structural and physicochemical properties of rice starch played important roles in determining rice quality. However, the differences of their response to the high temperature during reproductive stage have been rarely studied. In the present study, they were evaluated and compared between two contrasting natural temperature field conditions, namely high seasonal temperature (HST) and low seasonal temperature (LST), during the reproductive stage of rice in 2017 and 2018. Compared with LST, the HST significantly deteriorated rice quality, including the increased grain chalkiness, setback, consistence and pasting temperature, and the reduced taste values. HST considerably reduced the total starch and increased protein content. Likewise, HST significantly reduced short amylopectin chains (degree of polymerization (DP) <12), and increased long amylopectin chains (DP>12) and relative crystallinity. The starch structure, total starch content and protein content explained 91.4%, 90.4% and 89.2% of the total variations in pasting properties, taste value and grain chalkiness degree, respectively. In conclusion, we suggested that rice quality variations were closely associated with changes in chemical composition content (total starch and protein content) and the starch structure in response to HST. These results indicated that we should improve the resistance of rice to high temperature during reproductive stage to improve rice starch fine structure and quality in further breeding and practice.