Research Progress on the Effect of Nitrogen on Rapeseed between Seed Yield and Oil Content and Its Regulation Mechanism

Abstract

Rapeseed (Brassica napus L.) is one of the most important oil crops in China. Improving the oil production of rapeseed is an important way to ensure the safety of edible oil in China. Oil production is an important index that reflects the quality of rapeseed and is determined by the oil content and yield. Applying nitrogen is an important way to ensure a strong and stable yield. However, the seed oil content has been shown to be reduced in most rapeseed varieties after nitrogen application. Thus, it is critical to screen elite germplasm resources with stable or improved oil content under high levels of nitrogen, and to investigate the molecular mechanisms of the regulation by nitrogen of oil accumulation. However, few studies on these aspects have been published. In this review, we analyze the effect of nitrogen on the growth and development of rapeseed, including photosynthetic assimilation, substance distribution, and the synthesis of lipids and proteins. In this process, the expression levels of genes related to nitrogen absorption, assimilation, and transport changed after nitrogen application, which enhanced the ability of carbon and nitrogen assimilation and increased biomass, thus leading to a higher yield. After a crop enters the reproductive growth phase, photosynthates in the body are transported to the developing seed for protein and lipid synthesis. However, protein synthesis precedes lipid synthesis, and a large number of photosynthates are consumed during protein synthesis, which weakens lipid synthesis. Moreover, we suggest several research directions, especially for exploring genes involved in lipid and protein accumulation under nitrogen regulation. In this study, we summarize the effects of nitrogen at both the physiological and molecular levels, aiming to reveal the mechanisms of nitrogen regulation in oil accumulation and, thereby, provide a theoretical basis for breeding varieties with a high oil content.

Phenotype, Biomass, Carbon and Nitrogen Assimilation, and Antioxidant Response of Rapeseed under Salt Stress

“…The previous study demonstrated that seed oil was synthesized through triacylglycerols including several metabolic pathways, such as the Calvin cycle, C assimilation, and starch metabolism [ 45 ]. In contrast, seed protein synthesis was associated with N uptake, transportation, and lipid synthesis [ 46 ]. The stronger inhibition of salt stress on C assimilation than on N assimilation led to a concentration effect for N, resulting in an increase in N content.…”

Effects of antibiotics on secondary metabolism and oxidative stress in oilseed rape seeds

“…Rapeseed, a Brassica plant of the Cruciferae family, is the third largest oilseed crop in the world and the largest in China, with the oil, vegetable, and owers used as food, tea, and fertilizer. China has approximately 20% of the word's rapeseed production area (USDA FAS, 2023) and produces 5.2 million t of high-quality edible oil annually, accounting for about 50% of domestic edible vegetable oil (Zhu et al, 2023). As a fertilizer-dependent crop, oilseed rape has higher nutrient requirements for nitrogen, phosphorus and other nutrients than crops such as wheat and soybean (Fang et al, 2023).…”