Amino acid content in rice grains is affected by high temperature during the early grain-filling period

Abstract

Amino acid content in grains is an important nutritional quality trait in rice. High temperature can affect rice quality by accelerating grain filling. However, there is limited information available on the influence of high temperature on amino acid content in rice grains, especially under natural conditions. In this study, grain-filling traits and amino acid content in the grain of two rice cultivars (Luliangyou 996 and Lingliangyou 268) were compared between two years (2016 and 2017) with contrasting temperatures during the early grain-filling period under field conditions. Average daily mean temperature during the period of 0–5 days after full heading in 2016 (30.1 °C) was 5.4 °C higher than that in 2017. Initial, maximum, and mean grain-filling rates were 42–307% higher in 2016 than in 2017 for Luliangyou 996 and Lingliangyou 268. The time taken to reach the maximum grain-filling rate and active grain-filling duration were 6.3–10.7 d shorter in 2016 compared to 2017 for Luliangyou 996 and Lingliangyou 268. Grain weight was equal to or significantly higher in 2016 than in 2017 for Luliangyou 996 and Lingliangyou 268. N accumulation and N content in the grain were significantly lower in 2016 than in 2017 for both cultivars. The grain contents of all detected amino acids, except for methionine in Luliangyou 996, were significantly lower in 2016 than in 2017. Our study suggests that high temperature during the early grain-filling period can result in an accelerated grain-filling process, reduced N accumulation and content in rice grains, and consequently reduced amino acid content in the grain.

Comparative Quantitative Proteomic Analysis Reveals Differentially Expressed Proteins Involved in Grain-Filling Rate of Rice at the Early Ripening Stage

“…Seed development in rice is a complex biological process that directly impact potential yield and is regulated by complex regulatory networks involving several transcription factors [40].In the current study, two rice cultivars, i.e., Xiangzaoxian 24 and Xiangzaoxian 42, that possess contrasting phenotypes in grain lling rate during the early ripening period were employed in identi cation of grain lling differentially expressed proteins. Determination coe cients (R 2 ) of the grain-lling process in Xiangzaoxian 24 and Xiangzaoxian 42 cultivars as tted by the logistic regression were 0.991 and 0.987, respectively, suggesting that the logistic regression is a reliable analysis to t the grain-lling process in rice which is consistent with previous reports [5,41]. The cultivar Xiangzaoxian 42 exhibited a grain-lling rate during the period of 0-3 days after full heading that is 2-times higher than that of the cultivar Xiangzaoxian 24 as estimated by the logistic regression, indicating the appropriacy of cultivars selection for quantitative proteomic analysis.…”

“…Two rice cultivars, i.e., Xiangzaoxian 24 and Xiangzaoxian 42, provided by the Nongfeng Seed Industry Co., Ltd., Changsha, China exhibited contrasting phenotypes in grain lling during the early ripening period were used in the current study. The cultivar Xiangzaoxian 24 exhibited a slower grain lling compared to the cultivar Xiangzaoxian 42 during the early ripening period [5,41]. The randomized complete-block design with three replicates with a plot size of 40 m 2 were implemented in carrying out a eld experiment growing the two cultivars in Yongan (28°09′ N, 113°37′ E, 43 m asl), Hunan Province, China, in the early rice-growing season in 2018.…”

Genome-wide association study reveals that different pathways contribute to grain quality variation in sorghum (Sorghum bicolor)

“…Also, amino acids are crucial for seed development and germination as well as plant stress response. To date, the amino acid metabolism pathways have been well studied, and key genes regulating these pathways have been identified in Arabidopsis [10,11], tomato [12], soybeans [13], rice [14] and maize [15]. Among the well characterized genes are Opaque-2 (O2), floury-2 and high-lysine, whose mutants have high lysine concentrations [15].…”

Proteomic Profiling Reveals Differentially Expressed Proteins Associated with Amylose Accumulation During Rice Grain Filling

“…Rice is considered a staple food for more than half of the world's population, therefore improving rice quality and productivity is essential to overcome the rapid population growth and meet the economic development and to ensure sustainable human food [1]. Cooking and eating properties of rice grains are the main factors that in uence consumer choice of preferred types of rice [2].…”