The SlDOF3.4-SlCDF4 module improves tomato growth under low-nitrogen conditions

Area of Science:

• Plant Biology
• Molecular Biology
• Agricultural Science

Background:

• DNA-binding with one finger (DOF) proteins are crucial plant-specific transcription factors (TFs) involved in growth and nitrogen metabolism.
• The specific roles of DOF TFs in tomato's response to nitrogen deficiency are not well understood.

Purpose of the Study:

• To investigate the function of the DOF gene SlDOF3.4 in tomato under low nitrogen (LN) conditions.
• To elucidate the regulatory mechanisms of SlDOF3.4 in nitrogen assimilation and jasmonic acid (JA) biosynthesis.

Main Methods:

• Gene overexpression and knockout in tomato (Solanum lycopersicum).
• Dual-luciferase reporter assays to assess promoter binding activity.
• Analysis of nitrogen assimilation and JA biosynthesis gene expression.
• Phenotypic analysis under low nitrogen conditions.

Main Results:

• Overexpression of SlDOF3.4 improved tomato seedling growth, root length, and biomass under LN conditions.
• SlDOF3.4 interacts with SlCDF4, and both bind to the promoters of SlGS (nitrogen assimilation) and SlLOXD (JA biosynthesis) genes.
• Co-expression enhanced promoter binding, and LN upregulated nitrogen assimilation and JA biosynthesis genes in overexpressing plants.
• SlCDF4 knockout impaired LN growth, partially rescued by methyl jasmonate treatment.

Conclusions:

• SlDOF3.4 and SlCDF4 cooperatively regulate nitrogen assimilation and JA biosynthesis in tomato.
• These DOF TFs play a significant role in tomato's adaptation to low nitrogen environments.
• Findings offer insights into improving crop nitrogen use efficiency and stress tolerance.