Dissociates RAD51 from nucleoprotein filaments formed on dsDNA. Could be involved in the turnover of RAD51 protein-dsDNA filaments. Addition of RAD54 overcomes inhibition of DNA strand exchange by RAD51 bound to substrate dsDNA. Species preference in the RAD51 dissociation and DNA strand exchange assays underlines the importance of specific RAD54-RAD51 interactions. RAD51 is unable to release dsDNA upon ATP hydrolysis, leaving it stuck on the heteroduplex DNA product after DNA strand exchange (By similarity). Involved in DNA repair and mitotic recombination (PubMed:17227544, PubMed:16547115, PubMed:18430956). Functions in the homologous recombinational DNA repair (RAD52) pathway (PubMed:17227544, PubMed:16547115, PubMed:18430956). Required for synthesis-dependent strand annealing (SDSA) during double-strand break repair (PubMed:22860689). Facilitates geminiviral replication (e.g. geminivirus mungbean yellow mosaic virus (MYMV) and tomato leaf curl virus (ToLCV)). Interacts with RAD51 (PubMed:17227544, PubMed:18430956). Binds to the geminivirus mungbean yellow mosaic virus (MYMV) and to the tomato leaf curl virus (ToLCV) replication-associated proteins (PubMed:22171001). Expressed ubiquitously, with the highest levels of expression in flower buds. Present in flower buds (at protein level). Induced by gamma-irradiation and by heavy ion irradiation (PubMed:17227544, PubMed:22683605). Induced by the genotoxic formaldehyde (FA) (PubMed:20399886). Accumulates in aerial part of low-energy-ion irradiated dormant plant seeds, thus revealing an abscopal mutagenic effect (PubMed:21557702). Increased sensitivity to gamma-irradiation and to the cross-linking reagent cisplatin (PubMed:17227544). Reduced efficiency of somatic homologous recombination (HR) (PubMed:17227544, PubMed:16547115). Reduced synthesis-dependent strand annealing (SDSA) frequency (PubMed:22860689). Impaired geminiviral replication (e.g. tomato leaf curl virus (ToLCV)) (PubMed:22171001). Belongs to the SNF2/RAD54 helicase family.