The AP2/ERF transcription factor family plays pivotal roles in plant growth, stress responses, and defense mechanisms, yet its diversity in camphor trees remains underexplored. This study identified 154 AP2/ERF genes in the Camphora officinarum genome, with over 80% belonging to the ERF subfamily, a distribution consistent with other angiosperms. Synteny analysis revealed that tandem and segmental duplications were key drivers of family expansion, suggesting adaptive diversification under ecological pressures. Structural analysis showed that the majority of ERF/RAV subfamily genes possess a single-exon structure, whereas AP2 subfamily genes display muti-exon structures, indicating divergent evolutionary trajectories and potential functional versatility via alternative splicing. Promoter analyses detected numerous hormone- and stress-responsive elements, linking these genes to abscisic acid, auxin, gibberellin signaling, and pathogen defense. Further expression profiling during stem development showed that approximately 60% of CoAP2/ERF genes were constitutively expressed across 17 expression trends, suggesting roles in basal development and stage-specific processes (e.g., lignification). Under Epicoccum poaceicola infection, 23 CoAP2/ERF genes were differentially expressed. Among them, upregulated ERF homologs related to RAP2.2/2.3 suggested roles in hypoxia and antimicrobial responses, while downregulation of ERF5 homologs indicated a growth–defense trade-off, whereby developmental processes are suppressed to prioritize pathogen resistance. Overall, this study deciphers the genomic architecture and structural diversity of CoAP2/ERF genes, along with expression dynamics of these genes in development and biotic stress adaptation of camphor trees. These findings provide critical insights into transcriptional regulation of development and stress responses in camphor trees and establish a theoretical basis for molecular breeding and biotechnological strategies aimed at improving stress resilience in woody plants.

To investigate the influence of seasonal dynamics on the endophytic fungal community of Camphora bodinieri with citral chemotype, we employed standardized sampling and high-throughput sequencing to analyze the diversity, composition, and structure of endophytic fungi across different seasons. A total of 1825 Amplicon Sequence Variants (ASVs) were obtained, belonging to 12 phyla, 43 classes, 104 orders, 239 families, 449 genera, and 663 species. Among them, 23 ASVs were shared across all four seasons, suggesting the presence of a core fungal community. The number of season-specific ASVs was highest in autumn (730), followed by summer (336), spring (325), and winter (202). The results showed that season significantly affected the Shannon (F_3,9 = 5.927, p = 0.016) and Simpson (F_3,9 = 4.892, p = 0.026) indices, with the diversity and species richness of endophytic fungi being highest in autumn and lowest in winter. Across different tissues, the similarity of endophytic fungal communities between leaves and stems was comparatively higher than that with roots. Furthermore, different fungal taxa exhibited differential distribution patterns along temperature–moisture gradients. This study explored the seasonal diversity of endophytic fungi in C. bodinieri with citral chemotype, providing a theoretical basis for understanding host–endophyte interactions.

This study aimed to investigate the inhibitory effects and mechanisms of essential oil and its endophytic fungi of Camphora bodinieri with citral chemotype (CBCC) against Rhizoctonia solani, the causal agent of rice sheath blight. The antifungal activity was assessed by measuring the inhibition rate at various concentrations. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe ultrastructural changes in the pathogen. For the CBCC bodinieri essential oil treatment group, the MIC was 1.0 μL/mL, and the inhibition rate reached 100%, showing a concentration-dependent effect (0.0625–1.0 μL/mL, inhibition rate 29.02–100%). Electron microscopy showed that the essential oil caused severe damage to hyphal cell membranes, cytoplasmic agglutination, and organelle disintegration, whereas the endophytic fungi caused only local shrinkage and partial deformation. Both the CBCC essential oil and the endophytic fungi exhibit antifungal activity. They are promising candidates for the biological control of rice sheath blight and have potential for development as biofungicides.