Optimization of Nitrogen Application and Root Biomass Modulates 2-Acetyl-1-Pyrroline Biosynthesis in Fragrant Rice

Area of Science:

• Agricultural Science
• Plant Physiology
• Biochemistry

Background:

• The rice root system is crucial for nutrient uptake and adaptation to environmental changes.
• Optimized nitrogen (N) supply enhances 2-acetyl-1-pyrroline (2-AP) biosynthesis in fragrant rice, but mechanisms linking N, root development, and aroma are unclear.

Purpose of the Study:

• To investigate the impact of root restriction and nitrogen availability on 2-AP biosynthesis in fragrant rice.
• To elucidate the physiological mechanisms underlying 2-AP accumulation in response to root morphology and nitrogen status.

Main Methods:

• A pot experiment using two fragrant rice cultivars under varying nitrogen regimes (0, 1.5, 3.0 g N/pot) and root growth conditions (root-restricted vs. root-unrestricted).
• Analysis of 2-AP content, root biomass, nitrogen metabolism, and photosynthetic physiology.
• Structural equation modeling and random forest analysis to determine key influencing factors.

Main Results:

• Root restriction increased 2-AP content by 22.90% while reducing root biomass by 50%.
• Nitrogen treatments increased 2-AP content in both root-restricted and unrestricted conditions compared to nitrogen-free conditions.
• Nitrogen metabolism and photosynthetic physiology were identified as significant direct or indirect drivers of 2-AP accumulation.

Conclusions:

• Root morphology and nitrogen availability interact to modulate 2-AP biosynthesis in fragrant rice.
• Physiological changes, particularly during maturation, play a substantial role in 2-AP synthesis.
• This study enhances theoretical understanding of aroma formation in scented rice cultivars.