College of Agronomy, Nanjing Agricultural University, 210095, Nanjing, PR China.
College of Agronomy, Nanjing Agricultural University, 210095, Nanjing, PR China; Jiangsu Collaborative Innovation Center for Modern Crop Production, 210095, Nanjing, PR China.
Plant Physiol Biochem. 2023 Sep;202:107967. doi: 10.1016/j.plaphy.2023.107967. Epub 2023 Aug 14.
Rice glutelin is sensitive to temperature and nitrogen, however, the regulatory mechanism of glutelin response to temperature and nitrogen is unclear. In this study, we conducted the open field warming experiment by the Free-air temperature enhancement facility and application of nitrogen during grain filling. In three-year field warming experiments, glutelin relative content was significantly increased under elevated temperature and application of nitrogen. Temperature and nitrogen and their interaction increased the glutelin accumulation rate in the early and middle grain filling stages (10-25d after flowering), but decreased the glutelin accumulation rate in the middle and late grain filling stages (25-45d after flowering). Elevated temperature promoted pro-glutelin levels whereas application of nitrogen under warming increased the amount of α-glutelin. At the transcriptional level, the expression levels of the glutelin-encoding genes and protein disulphide isomerase-like enzyme (PDIL1-1), glutelin precursor accumulation 4 (GPA4), glutelin precursor mutant 6 (GPA2), glutelin precursor accumulation 3 (GPA3) and vacuolar processing enzyme (OsVPE1) of glutelin folding, transport and accumulation-related genes were up-regulated by nitrogen under natural temperature as early as 5d after flowering. However, elevated temperature up-regulated glutelin-encoding genes before 20d after flowering, and the expression of endoplasmic reticulum chaperone (OsBip1), OsPDIL1-1, small GTPase gene (GPA1), GPA2-GPA4 and OsVPE1 were significantly increased post 20d after flowering under warming. In addition, the increase in glutelin content worsened grain quality, particularly chalkiness and eating quality. Overall, the results were helpful to understand glutelin accumulation and provide a theoretical basis for further study the relationship between rice quality and glutelin under global warming.
水稻谷蛋白对温度和氮素敏感，但谷蛋白响应温度和氮素的调控机制尚不清楚。本研究通过开顶式空气增温设施进行田间增温实验和籽粒灌浆期施氮实验，结果表明，增温与施氮均显著增加了谷蛋白相对含量。增温和施氮及其互作对花后 10-25d 和 25-45d 灌浆早期和中期的谷蛋白积累速率有促进作用，但降低了灌浆中期和后期的谷蛋白积累速率。增温促进了前谷蛋白水平，而增温施氮增加了α-谷蛋白的含量。在转录水平上，谷蛋白编码基因和蛋白二硫键异构酶样酶（PDIL1-1）、谷蛋白前体积累 4（GPA4）、谷蛋白前体突变体 6（GPA2）、谷蛋白前体积累 3（GPA3）和谷蛋白折叠、转运和积累相关基因的液泡加工酶（OsVPE1）的表达水平在花后 5d 时就被氮素上调。然而，增温在花后 20d 前上调了谷蛋白编码基因的表达，并且内质网伴侣（OsBip1）、OsPDIL1-1、小 GTPase 基因（GPA1）、GPA2-GPA4 和 OsVPE1 的表达在增温后 20d 后显著增加。此外，谷蛋白含量的增加恶化了籽粒品质，尤其是垩白度和食味品质。总体而言，本研究结果有助于了解谷蛋白的积累，并为进一步研究全球变暖下水稻品质与谷蛋白的关系提供理论依据。
