Trehalose Biosynthetic Genes Are Involved in the Development and Pathogenesis in the Poplar Canker Fungus <i>Cytospora chrysosperma</i>

Poplar Cytospora canker, caused by <i>Cytospora chrysosperma</i>, is one of the most destructive and widespread poplar diseases worldwide, especially in northern China. However, our current understanding of its pathogenic mechanisms remains limited. Here, we show that trehalose biosynthetic genes, such as trehalose-6-phosphate synthase 1 (<i>CcTps1</i>), trehalose-6-phosphate phosphatase (<i>CcTps2</i>), and the regulatory subunit (<i>CcTps3</i>), play important roles in the development and virulence of <i>C</i>. <i>chrysosperma</i>. The targeted deletion mutants showed reduced trehalose synthesis and were defective in hyphal growth and conidiation. Deletion of any of the three genes attenuated virulence in poplar twigs, and stronger poplar defense responses were triggered after inoculated by the mutants. Additionally, the mutants exhibited increased sensitivity to H₂O₂ and cell wall stressors. Taken together, the findings suggest that trehalose biosynthetic genes contribute to fungal development, stress responses, and full virulence in <i>C</i>. <i>chrysosperma</i>.