Metabolic and co-expression network-based analyses associated with nitrate response in rice

Area of Science:

• Plant Molecular Biology
• Crop Physiology
• Metabolomics

Background:

• Understanding nitrogen use efficiency (NUE) in crops is vital for agricultural sustainability.
• Gene expression and metabolic reprogramming are key responses to nitrogen (N) availability.
• Rice (Oryza sativa) is a major food crop, making its N response critical.

Purpose of the Study:

• To investigate molecular and metabolic responses to varying nitrogen conditions in rice.
• To identify key genes and metabolic pathways involved in nitrogen use efficiency.
• To differentiate responses to acute N reduction versus chronic N limitation.

Main Methods:

• Weighted gene co-expression network analysis (WGCNA) of gene expression data.
• Metabolic profiling of leaf and root tissues under different nitrogen regimes.
• Comparative analysis across sufficient, limiting, and shifting N conditions.

Main Results:

• Identified 18 gene co-expression clusters, with four significantly correlated to limiting/reducing nitrate treatments.
• Enriched Gene Ontology (GO) terms include nucleoside/nucleotide binding, defense response, and kinase activity.
• Metabolic profiling revealed distinct leaf responses to N reduction vs. limitation, involving N assimilation compounds and amino acids.

Conclusions:

• Gene co-expression and metabolic profiling highlight the importance of signal transduction in N response.
• Regulation of nitrogen mobilization is a key component of plant adaptation to N limitation.
• Findings deepen understanding of N responses and N use in crops, aiding NUE improvement.