The NAC Transcription Factor SlNAP2 Enhances Tomato Resistance to Ralstonia solanacearum

Bacterial wilt caused by Ralstonia solanacearum is a devastating soil‐borne disease threatening tomato production with limited control strategies. NAC transcription factors play vital roles in plant stress responses, but their function in tomato resistance to bacterial wilt remains unclear. Our previous investigation revealed that SlNAP2 expression is markedly induced following R. solanacearum infection. Here, subcellular localization confirmed SlNAP2 is localized in the nucleus and possesses transcriptional activation activity. Functional analysis revealed that SlNAP2 overexpression enhanced resistance to bacterial wilt, whereas a CRISPR/Cas9 knockout increased susceptibility. Physiological and biochemical assays demonstrated that SlNAP2 alleviates pathogen‐induced reactive oxygen species (ROS) accumulation by enhancing the activities of superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonia‐lyase (PAL), and polyphenol oxidase (PPO), while reducing malondialdehyde (MDA) content. Hormonal profiling indicated SlNAP2 negatively regulates the jasmonic acid (JA) pathway but positively modulates the salicylic acid (SA) pathway: overexpression lines displayed decreased JA levels along with downregulated expression of JA signaling‐related genes ( SlMYC2 , SlCOI1 , SlJAZ , and SlAOS ), and increased SA levels accompanied by upregulated expression of SA pathway genes ( SlNPR1 , SlTGA , SlPR1 , and SlICS1 ). Molecular interaction assays confirmed that SlNAP2 physically interacts with SlMYC2 in vivo and in vitro and specifically binds to the SlMYC2 promoter. However, dual‐luciferase reporter assays indicated SlNAP2 does not directly activate SlMYC2 transcription. In summary, SlNAP2 positively regulates tomato resistance to bacterial wilt by enhancing antioxidant defense, coordinately modulating JA and SA signaling pathways, and maintaining ROS homeostasis. This study provides new insights into the functional mechanisms of NAC transcription factors in plant immunity.