Cohesin cofactor dispensable during the meiotic division but playing an important role in DNA repair by homologous recombination (HR) probably by helping SMC5/SMC6 complex (PubMed:26648949). Regulator of sister chromatid cohesion in mitosis which may stabilize cohesin complex association with chromatin (PubMed:26648949). May couple sister chromatid cohesion during mitosis to DNA replication (By similarity). Cohesion ensures that chromosome partitioning is accurate in both meiotic and mitotic cells and plays an important role in DNA repair (PubMed:26648949). Required for proximal-distal cell cycle-driven leaf growth in both lamina and petiole (PubMed:24946828). Interacts with the cohesin complex. Weak impact on meiosis such as formation of some chromosome bridges at late anaphase I and telophase I in forming pollen, but severe effects on development, fertility, somatic homologous recombination (HR) and DNA repair, especially in plants lacking PDS5A, PDS5B, PDS5C, PDS5D and PDS5E (PubMed:26648949). Altered two-dimensional leaf shape leading to compact rosettes and roundish leaves due to lower cell number in both the lamina and the petiole explaining the macroscopic reduction in lamina and petiole length (PubMed:24946828). Belongs to the PDS5 family.