Highlights • ZmUBP15 , ZmUBP16 and ZmUBP19 are specifically in response to Cd and salt stress in maize. • ZmUBP15, ZmUBP16 and ZmUBP19 are conserved in maize and localized in cell membrane. • Over-expression of ZmUBP15 , ZmUBP16 or ZmUBP19 partially rescue ub p16 -1 tolerance to Cd and salt stress in Arabidopsis. • Over-expression of ZmUBP15 , ZmUBP16 or ZmUBP19 enhance Arabidopsis tolerance to Cd stress and salt stress. Abstract Ubiquitin-Specific Protease16 (UBP16) has been described involved in cadmium stress and salt stress in Arabidopsis , however nothing is known about the functions of its homologs in maize. In this study, we investigate the functions of ZmUBP15 , ZmUBP16 and ZmUBP19 , three Arabidopsis UBP16 homologs in maize. Our results indicate that ZmUBP15 , ZmUBP16 and ZmUBP19 are ubiquitously expressed throughout plant development, and ZmUBP15, ZmUBP16 and ZmUBP19 proteins are mainly localized in plasma membrane. Complementation analyses show that over-expression of ZmUBP15 or ZmUBP16 can rescue the defective phenotype of ub p16 -1 in cadmium stress. In addition, over-expression of ZmUBP15 , ZmUBP16 or ZmUBP19 can increase the plant tolerance to cadmium stress. These results indicate that ZmUBP15 , ZmUBP16 and ZmUBP19 are required for plant to tolerance the cadmium stress. Consistent with this point, cadmium-related genes are markedly up-regulated in seedlings over-expressing ZmUBP15 , ZmUBP16 or ZmUBP19. Furthermore, our data indicate that ZmUBP15 , ZmUBP16 and ZmUBP19 partially rescue the salt-stress phenotype of ub p16 -1. Thus, our research uncover the functions of three novel maize proteins, ZmUBP15, ZmUBP16 and ZmUBP19, which are required for plants in response to cadmium stress and salt stress. [ABSTRACT FROM AUTHOR]