PAP5 — Hordeum vulgare subsp. vulgare

Summary

HORVU.MOREX.R3.2HG0103220 (HvPAP5, also known as HvSAG12) on barley chromosome 2H encodes a papain-like cysteine peptidase belonging to the peptidase C1A family, with thiol endopeptidase activity and proteinase-activated receptor binding. The gene is associated with programmed cell death in cell development, floral organ senescence, and proteolysis, and responds to multiple hormones including ethylene, cytokinin, auxin, and gibberellin, as well as to sugars (glucose, fructose, sucrose) and UV-B. It is linked to the mevalonate and methylerythritol phosphate pathways, defence response to fungi, and protein breakdown. The product localises to senescence-associated vacuoles, lysosomes, protein storage vacuoles, and the ER lumen. Associations include grain filling period, photosynthetic rate, leaf senescence, seed yield, nitrogen remobilisation, drought resistance, and flooding tolerance. Studies of related genes in other species link the family to developmental senescence, cadmium-induced programmed cell death, and bacterial resistance.