Table 1 Major functional categories of senescence-associated genes*

Macromolecule degradation

Breakdown of proteins, nucleic acids, lipids and polysaccharides

Cysteine proteases, ubiquitin-related genes, RING finger proteins, nucleases, lipases/acylhydrolases, phospholipases, glucanases, β-glucosidase, pectinesterases, and polygalacturonase

Nutrient recycling

Transport of peptides, amino acids, sugars, purines, pyrimidines and ions

Oligopeptide transporters, ammonium transporter purine and pyrimidine transporters, glutamine synthetase and glutamate synthase, sugar transporters (MFSs), and ABC transporters

Defense and cell rescue mechanisms

Abiotic and biotic stress, and oxidative stress

Metallothionein, glutathione S-transferase, protein similar to jasmonate-inducible protein, glutathione peroxidase, and cold-regulated protein COR6.6

Transcriptional regulation

Transcription factors

Zinc finger proteins, basic helix-loop-helix proteins, bZIP proteins, HMG-box proteins and transcription factors of the WRKY, NAC, AP2, MYB, HB, TCP and GRAS families

Signal transduction

Protein phosphorylation and dephosphorylation

Receptor-like kinases, components of MAP kinase signal cascades, phosphatases and phospholipases, calcium-binding EF-hand protein RD20, calcium-dependent protein kinases, and cytoskeleton-associated proteins