Abstract
Background:Nardostachys jatamansi (D. Don) DC. (N. jatamansi.) is an endangered medicinal plant native to the Himalayas that is widely used in traditional medicine due to its terpenoid compounds, especially sesquiterpenes, which are abundant in N. jatamansi. However, the mechanism of sesquiterpene metabolism remains unclear. Methods: Transcriptome sequencing analyses of different parts (roots and rhizomes, leaves, anthocaulus and flowers) and developmental stages (rejuvenation, budding, flowering, fruiting and withering) of cultivated N. jatamansi were conducted using the Illumina platform. Key genes involved in regulating the sesquiterpene metabolism pathway in N. jatamansi were identified by combining component analyses of various tissues and developmental stages. Furthermore, these key genes were validated through MeJA treatment and a chemical composition analysis. Results: A transcriptome sequencing analysis was performed on 24 samples from four tissues and in five developmental stages, yielding 183.18 Gb of clean data with a Q30 base percentage of 92% or above. A total of 269,136 UniGenes were obtained and annotated. Genes related to sesquiterpene synthesis were screened and validated by RT-qPCR using annotation results from various databases. Twelve candidate genes involved in sesquiterpene synthase were identified. Following MeJA treatment, an RT-qPCR analysis revealed that the expression of the NjTPS-49, NjTPS-54, NjTPS-56, NjTPS-57 and NjTPS-59 genes was positively regulated. Additionally, an HPLC analysis indicated an increase in the nardosinone content after MeJA treatment. This study demonstrates that NjTPS-49, NjTPS-54, NjTPS-56, NjTPS-57 and NjTPS-59 are potential candidate genes for sesquiterpene synthesis. Conclusion: The obtained findings establish the groundwork for elucidating the mechanism of sesquiterpene synthesis in N. jatamansi and contribute to the conservation of N. jatamansi resources.