Comparative Physiological and Transcriptomic Characterisation of Two Japonica Rice Cultivars Under Low Nitrogen...

Area of Science:

• Agricultural Science
• Plant Physiology
• Molecular Biology

Background:

• Nitrogen (N) is crucial for rice, but inefficient use causes environmental issues.
• Low N Use Efficiency (NUE) in rice threatens agricultural sustainability.
• Understanding N response mechanisms is vital for developing efficient rice cultivars.

Purpose of the Study:

• Compare physiological and transcriptomic root profiles of two rice cultivars under normal and low nitrogen (LN) conditions.
• Investigate genotypic differences in root development and N response mechanisms.
• Identify molecular insights for breeding N-efficient rice.

Main Methods:

• Comparative analysis of root physiological traits and enzymatic activities (NR, GS) under normal and LN treatments.
• Transcriptomic profiling to identify differentially expressed genes (DEGs) in response to LN stress.
• KEGG pathway analysis to determine the functions of DEGs.

Main Results:

• Low nitrogen (LN) suppressed root growth and affected root enzymatic activities in both cultivars.
• Cultivar HJ753 demonstrated higher NITRATE REDUCTASE (NR) and GLUTAMINE SYNTHETASE (GS) activity than DJ8 under both N conditions.
• Over 5000 DEGs were identified, mainly involved in DNA replication, N metabolism, and plant hormone signaling, with genotype-specific patterns observed.

Conclusions:

• Significant genotypic differences exist in rice root development and N response under LN stress.
• Molecular insights into N metabolism and utilization pathways provide a basis for breeding N-efficient rice.
• This research supports the development of sustainable rice cultivation practices through improved NUE.