Comparative transcriptomics reveal distinct anthracnose immune pathways in resistant and susceptible <scp> <i>Camellia oleifera</i> </scp> clones

BACKGROUND: Camellia oleifera is an important woody-oil crop in China. Camellia anthracnose caused by fungal species in the genus Colletotrichum severely affects the oil yield and quality. Disease-resistant Ca. oleifera clones have been developed while the molecular mechanism underlying anthracnose resistance remains unclear. This study aimed to uncover the key genes and regulatory networks mediating anthracnose resistance among different Ca. oleifera clones. RESULTS: Comparative transcriptomic analysis of a highly-resistant Ca. oleifera clone (ChangLin 18) and a susceptible clone (ChangLin 40) revealed that host resistance to anthracnose is associated with rapid ROS accumulation, hypersensitive response (HR), and activation of defense-related pathways. These findings demonstrated differentially expressed genes enriched in signal transduction, hormone response, and redox regulation. Weighted gene co-expression network analysis (WGCNA) highlighted a core regulatory module comprising MYB and bHLH transcription factors and the hub gene CASP. Functional validation via transient silencing of Casparian Strip genes (CASP) in Nicotiana benthamiana impaired root development and increased susceptibility to anthracnose. CONCLUSION: Disease resistance in Ca. oleifera arises from a multi-layered defense network integrating ROS homeostasis, hormone signaling, and transcriptional regulation. Our study identified the functionally validated CASP gene, as well as candidate MYB and bHLH transcription factors, as key regulators of anthracnose resistance. These findings offer valuable targets for advancing molecular breeding and sustainable disease control strategies in Ca. oleifera. © 2026 Society of Chemical Industry.