Background: Cinnamomum longepaniculatum is an important commercial crop and the main source of volatile terpenoids. The biosynthesis of key bioactive metabolites of C. longepaniculatum is not well understood due to the lack of available genomic and transcriptomic information. To address this issue, we performed transcriptome sequencing of C. longepaniculatum leaves to identify factors involved in terpenoid metabolite biosynthesis.

Results: Transcriptome sequencing of C. longepaniculatum leaves generated over 56 million raw reads. The transcriptome was assembled using Trinity and yielded 82,061 unigenes with an average length of 879.43bp and N50 value of 1,387 bp. Furthermore, Benchmarking Universal Single-Copy Orthologs (BUSCO) analysis indicated that our assembly is 91% complete. The unigenes were used to query the non-redundant database based on sequence similarity; 42,809 unigenes were homologous to known genes indifferent species, with an annotation rate of 42.87%. The transcript abundance and Gene Ontology analyses revealed that numerous unigenes were associated with metabolism, while others were annotated in functional categories including transcription, signal transduction, and secondary metabolism. The Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that 19,260 unigenes were involved in 385 metabolic pathways, with 233 unigenes found to be involved in terpenoid metabolism. Additionally, 23,463 simple sequence repeats were identified using the microsatellite identification tool.

Conclusion: This is the first detailed transcriptome analysis of C. longepaniculatum. The findings provide insights into the molecular basis of terpenoid biosynthesis and a reference for future studies on the genetics and breeding of C. longepaniculatum.