The <scp>bZIP</scp> Transcription Factor <scp>UvbZIP14</scp> Regulates Vegetative Growth, Conidiation and Abiotic Stress Tolerance in <i>Ustilaginoidea virens</i>

ABSTRACT bZIP transcription factors play a crucial role in regulating various physiological processes in phytopathogens. Ustilaginoidea virens is known to possess 28 bZIP transcription factors; however, their biological functions remain unexplored. In this study, the function of UvbZIP14 in U . virens was investigated. The expression levels of UvbZIP14 were found to be up‐regulated after rice inoculation with U . virens . The knockout mutants and complemented strains of UvbZIP14 were generated and characterised. The knockout mutants display increased growth and decreased conidiation. Compared with the wild‐type strain, the knockout mutants exhibit reduced sensitivity to NaCl and sorbitol but increased sensitivity to CFW. There was no significant difference in the number of false smut balls in rice between the knockout and wild‐type strains. These results findings highlight the significant role of UvbZIP14 in regulating vegetative growth, conidiation and tolerance to abiotic stress in U . virens .