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The basic leucine zipper (bZIP) transcription factor (TF) family, one of the largest and the most diverse TF families, is widely distributed across the eukaryotes. It has been described that the bZIP TFs play diverse roles in development, nutrient utilization, and various stress responses in fungi. However, little is known of the bZIP members in <i>Cytospora chrysosperma</i>, a notorious plant pathogenic fungus, which causes canker disease on over 80 woody plant species. In this study, 26 bZIP genes were systematically identified in the genome of <i>C. chrysosperma</i>, and two of them (named <i>CcbZIP05</i> and <i>CcbZIP23</i>) significantly down-regulated in <i>CcPmk1</i> deletion mutant (a pathogenicity-related mitogen-activated protein kinase) were selected for further analysis. Deletion of <i>CcbZIP05</i> or <i>CcbZIP23</i> displayed a dramatic reduction in fungal growth but showed increased hypha branching and resistance to cell wall inhibitors and abiotic stresses. The <i>CcbZIP05</i> deletion mutants but not <i>CcbZIP23</i> deletion mutants were more sensitive to the hydrogen peroxide compared to the wild-type and complemented strains. Additionally, the <i>CcbZIP23</i> deletion mutants produced few pycnidia but more pigment. Remarkably, both <i>CcbZIP05</i> and <i>CcbZIP23</i> deletion mutants were significantly reduced in fungal virulence. Further analysis showed that <i>CcbZIP05</i> and <i>CcbZIP23</i> could regulate the expression of putative effector genes and chitin synthesis-related genes. Taken together, our results suggest that <i>CcbZIP05</i> and <i>CcbZIP23</i> play important roles in fungal growth, abiotic stresses response, and pathogenicity, which will provide comprehensive information on the <i>CcbZIP</i> genes and lay the foundation for further research on the bZIP members in <i>C. chrysosperma</i>.