Heterotrimeric G proteins regulate nitrogen-use efficiency in rice.

Area of Science:

• Plant genetics
• Agricultural science
• Molecular biology

Background:

• Sustainable agriculture necessitates enhancing crop nutrient-use efficiency.
• Nitrogen-use efficiency (NUE) is a critical trait in rice (Oryza sativa).
• A major quantitative trait locus for NUE, qNGR9, was previously identified.

Purpose of the Study:

• To identify the gene underlying the rice nitrogen-use efficiency quantitative trait locus qNGR9.
• To investigate the role of DEP1 in nitrogen response and rice domestication.
• To elucidate the molecular mechanism of DEP1 in regulating nitrogen signaling.

Main Methods:

• Gene identification and allelic analysis of DEP1.
• Genetic diversity analysis of DEP1 in rice subspecies.
• Protein-protein interaction studies using yeast two-hybrid and in vivo assays.
• Phenotypic analysis of rice plants with different DEP1 alleles under varying nitrogen levels.

Main Results:

• The qNGR9 locus is synonymous with the DENSE AND ERECT PANICLES 1 (DEP1) gene.
• Different DEP1 alleles exhibit varying responses to nitrogen, indicating artificial selection during rice domestication.
• The dominant dep1-1 allele promotes nitrogen-insensitive growth, enhanced nitrogen uptake, and improved yield under moderate nitrogen fertilization.
• DEP1 interacts with G protein subunits RGA1 (Gα) and RGB1 (Gβ), modulating nitrogen signaling.

Conclusions:

• The DEP1 gene plays a crucial role in regulating nitrogen signaling and utilization in rice.
• The plant G protein complex is integral to nitrogen signal transduction.
• Modulating heterotrimeric G protein activity presents a viable strategy for sustainable increases in rice grain yield.