HbSNAP33 and HbSYP4 enhanced the resistance to Colletotrichum gloeosporioides in rubber tree

The rubber tree, the primary source of natural rubber, faces increasing threats from anthracnose, a disease caused by Colletotrichum gloeosporioides that can lead to significant yield losses. Vesicle trafficking, regulated by SNARE proteins, is essential to plant immunity; however, the role of the SNARE family in rubber tree defense remains unclear. In this study, 117 SNARE genes were identified within the rubber tree genome. Among them, HbSNAP33 and HbSYP4 were highlighted as key regulators, showing strong induction during pathogen infection. Functional analysis revealed that overexpressing these genes in transgenic tobacco significantly enhanced resistance, limiting pathogen spread and increasing defensive reactive oxygen species (ROS) production. Further investigation demonstrated that this resistance is linked to the activation of the salicylic acid (SA) signaling pathway, as evidenced by the upregulation of NbPR1 and NbPR2. Notably, HbSNAP33 and HbSYP4 exhibited distinct regulatory effects on immune pathways. HbSNAP33 activated not only SA signaling but also jasmonic acid (JA) signaling, pattern-triggered immunity (PTI), and effector-triggered immunity (ETI), while HbSYP4 predominantly enhanced SA-associated basal defenses. This study provides the first comprehensive genomic insight into the rubber tree SNARE gene family and clarifies the mechanisms by which HbSNAP33 and HbSYP4 enhance anthracnose resistance via SA-mediated defenses. These genes offer promising targets for the molecular breeding of disease-resistant rubber trees.