Study of Pear Resistance to Multiple Pathogens Through Mediation of JA/SA Signaling Pathways

Background: Apples and pears, as important economic fruit crops, are frequently threatened by various diseases, including Valsa canker. Given the numerous advantages of disease resistance breeding, the identification of key resistance genes is particularly important. This study aimed to identify the “Duli-G03” (<i>Pyrus betulifolia</i>) resistance gene <i>PbeZFP3</i> and clarify its regulatory mechanism in disease resistance via JA/SA pathways, providing a theoretical basis for resistant breeding. Results: In this study, we identified a C2H2-type transcription factor, <i>PbeZFP3</i>, in the <i>Valsa</i> canker-resistant rootstock “Duli-G03”. Expression analysis revealed that <i>PbeZFP3</i> is induced by both <i>Valsa pyri</i> (<i>Vp</i>) and <i>Vp</i> metabolites (<i>Vp</i>M). Transient expression in pear and apple fruits and stable expression in suspension cells confirmed that PbeZFP3 positively regulates <i>Valsa</i> canker resistance. Meanwhile, PbeZFP3 not only enhances the resistance of “Duli-G03” cells to <i>Botrytis cinerea</i> infection, but may also act as a negative regulator against <i>Colletotrichum fructicola</i>. The overexpression of <i>PbeZFP3</i> in “Duli-G03” significantly upregulated the expression of genes related to jasmonic acid (JA) and salicylic acid (SA) signaling. Conclusions: These findings demonstrate that the jasmonic acid (JA) and salicylic acid (SA) signaling pathways are involved in the enhanced <i>Valsa</i> canker resistance conferred by <i>PbeZFP3</i> overexpression. A deeper understanding of this host resistance mechanism will provide theoretical support for breeding strategies aimed at developing disease-resistant fruit trees.