Integrated Genome-Scale Analysis Identifies Novel Genes and Networks Underlying Senescence in Maize

Area of Science:

• Plant Biology
• Genetics
• Agronomy

Background:

• Crop senescence impacts yield and nutritional quality, with premature senescence reducing yield and delayed senescence (stay-green) having mixed effects.
• Limited information exists on the genetic basis of senescence in maize (Zea mays) and other cereal crops.

Purpose of the Study:

• To elucidate the genetic architecture of senescence and stay-green traits in maize.
• To identify candidate genes and understand molecular mechanisms underlying senescence regulation.

Main Methods:

• Systematic characterization of natural variation in maize senescence.
• Transcriptome analysis and coexpression network construction for senescing and stay-green lines.
• Genome-wide association study (GWAS) to identify candidate senescence-related genes.

Main Results:

• Sixty-four candidate genes were identified via GWAS, with 14 linked to senescence processes like proteolysis and sugar signaling.
• Eight GWAS candidates, including a trehalose-6-phosphate synthase and NAC transcription factor, were supported by coexpression networks for stay-green.
• Source-sink communication and cell wall activity were identified as critical for stay-green traits.

Conclusions:

• The study provides a foundation for understanding and manipulating maize senescence for improved carbon yield, nutrition, and stress tolerance.
• Candidate genes identified offer targets for breeding enhanced stay-green traits in maize and other cereals.