Plant caspase-like proteins: from function identification to application in winter rapeseed genetic breeding

Plant programmed cell death (PCD) shares striking similarities with animal apoptosis in both morphological and biochemical characteristics, yet plant genomes lack genuine orthologs of animal caspases. Instead, plants have evolved a category of caspase-like proteins that are functionally analogous but lack sequence homology with animal caspases. This review systematically summarizes recent advances in the research of major plant caspase-like proteins, including metacaspases, vacuolar processing enzymes (VPEs), saspases, phytaspases, the proteasomal β subunit PBA1, and cathepsin B. These proteins play pivotal regulatory roles in PCD triggered during plant development, senescence, biotic and abiotic stresses, and exhibit distinctive substrate specificities, activation mechanisms, and regulatory networks. Furthermore, focusing on winter rapeseed, this review discusses the application potential of caspase-like proteins in genetic breeding, such as enhancing stress resistance by modulating their activities, optimizing yield-related traits, and improving biotechnological breeding platforms including microspore embryogenesis. Despite challenges including functional redundancy, spatiotemporal regulation, and species-specific divergence, caspase-like proteins serve as core nodes in the PCD regulatory network and provide valuable targets for crop improvement. This review offers a systematic reference for further understanding the molecular mechanisms of plant PCD and its application in crop breeding.