Background The camphor tree (Cinnamomum camphora) is a valuable source of essential oils rich in monoterpenes and sesquiterpenes, which exhibit antibacterial, antioxidant, and insecticidal properties. The AP2/ERF transcription factor family is known for its roles in regulating secondary metabolite biosynthesis and stress responses in plants. However, the functions and regulatory mechanisms of AP2/ERF transcription factors in camphor tree remain largely unexplored. Results A total of 154 unique AP2/ERF genes were identified in the camphor tree genome and classified into four subfamilies (RAV, AP2, ERF, and DREB), among which the ERF subfamily comprises 75 members and represents the largest. The physicochemical properties of the proteins were diverse, with predicted nuclear localization. Phylogenetic analysis revealed distinct clustering patterns consistent with their subfamily classification. Gene structure analysis showed variation in exon-intron organization among subfamilies. A total of 5,910 cis-acting elements were identified in the promoters, with MeJA-responsive and stress responsiveness elements being most prevalent. Expression profile analysis indicated tissue-specific expression patterns, with most CcAP2/ERF genes highly expressed in the roots. Correlation analysis revealed that 44 CcAP2/ERF genes were strongly correlated with 6 terpene synthase (TPS) genes involved in monoterpene biosynthesis, suggesting regulatory functions. Strikingly, CcERF_104 was identified as a high-potential hub regulator, co-expressed two with borneol diphosphate synthase (BPPS) genes (CcTPS26 and CcTPS49). Moreover, a suite of regulators (including CcERF_27, CcERF_42, CcERF_83, CcERF_87, CcAP2_12, and CcAP2_13) showed strong positive correlation with CcTPS72, the most catalytically efficient BPPS synthase in C. camphora, highlighting sophisticated transcriptional control over monoterpene biosynthesis. Conclusion This study provides a comprehensive analysis of the AP2/ERF transcription factor family in C. camphora and elucidates their potential roles in regulating terpene biosynthesis. The findings lay the foundation for future functional characterization of key CcAP2/ERF genes using genetic and biochemical approaches, with the goal of enhancing terpenoid content in C. camphora leaves through genetic improvement technologies.

Genome-wide identification and characterization of the AP2/ERF gene family in Cinnamomum camphora

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2025年10月30日

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Zerui Yang,
Xinnan Yang,
Xiasheng Zheng

摘要

Background

The camphor tree (Cinnamomum camphora) is a valuable source of essential oils rich in monoterpenes and sesquiterpenes, which exhibit antibacterial, antioxidant, and insecticidal properties. The AP2/ERF transcription factor family is known for its roles in regulating secondary metabolite biosynthesis and stress responses in plants. However, the functions and regulatory mechanisms of AP2/ERF transcription factors in camphor tree remain largely unexplored.

Results

A total of 154 unique AP2/ERF genes were identified in the camphor tree genome and classified into four subfamilies (RAV, AP2, ERF, and DREB), among which the ERF subfamily comprises 75 members and represents the largest. The physicochemical properties of the proteins were diverse, with predicted nuclear localization. Phylogenetic analysis revealed distinct clustering patterns consistent with their subfamily classification. Gene structure analysis showed variation in exon-intron organization among subfamilies. A total of 5,910 cis-acting elements were identified in the promoters, with MeJA-responsive and stress responsiveness elements being most prevalent. Expression profile analysis indicated tissue-specific expression patterns, with most CcAP2/ERF genes highly expressed in the roots. Correlation analysis revealed that 44 CcAP2/ERF genes were strongly correlated with 6 terpene synthase (TPS) genes involved in monoterpene biosynthesis, suggesting regulatory functions. Strikingly, CcERF_104 was identified as a high-potential hub regulator, co-expressed two with borneol diphosphate synthase (BPPS) genes (CcTPS26 and CcTPS49). Moreover, a suite of regulators (including CcERF_27, CcERF_42, CcERF_83, CcERF_87, CcAP2_12, and CcAP2_13) showed strong positive correlation with CcTPS72, the most catalytically efficient BPPS synthase in C. camphora, highlighting sophisticated transcriptional control over monoterpene biosynthesis.

Conclusion

This study provides a comprehensive analysis of the AP2/ERF transcription factor family in C. camphora and elucidates their potential roles in regulating terpene biosynthesis. The findings lay the foundation for future functional characterization of key CcAP2/ERF genes using genetic and biochemical approaches, with the goal of enhancing terpenoid content in C. camphora leaves through genetic improvement technologies.