Transcriptome analysis provides insights into key gene(s) involved in steroidal alkaloid biosynthesis in the medicinally important herb Fritillaria taipaiensis

Abstract

Background Fritillariae Cirrhosae Bulbus, which is a traditional antitussive and expectorant medicine in China, is derived from six original plants. Among these six species, all except for Fritillaria taipaiensis and Fritillaria unibracteata var. wabuensis have been recorded in the National Protected Plants III. Their major bioactive compounds, including imperialine and peimisine, are steroidal alkaloids, derived from the steroid synthesis pathway. However, research on the F. taipaiensis genome, transcriptomes and steroid-synthesis-related genes has been lacking for a long time. In this study, the first transcriptome sequencing of F. taipaiensis was performed. Results A total of 94,396,694 (~11.4 Gb) high-quality reads obtained using paired-end Illumina sequencing were de novo assembled into 190,350 transcripts. Functional annotation with multiple public databases identified an array of genes involved in steroidal alkaloid biosynthesis and other secondary metabolite pathways, including steroid and terpenoid backbone biosynthesis, and important oxidoreductases. The large number of differentially expressed transcripts together with CYPs suggests the involvement of these candidates in tissue-specific expression. The expression analysis revealed that bulbs may be the main site of the upstream steroidal alkaloid biosynthesis pathway, and we speculated that the downstream reactions, including the oxidation-reduction reaction catalyzed by CYPs, might also occur primarily in bulbs. Conclusion In conclusion, the comprehensive transcriptome dataset created in this study will serve as a resource for the identification of potential candidates for the genetic manipulation of targeted bioactive metabolites and will also contribute to the development of functionally relevant molecular marker resources to expedite molecular breeding and conservation efforts for F. taipaiensis.

Transcriptomic and metabolomic analyses provide new insights into the appropriate harvest period in regenerated bulbs of Fritillaria hupehensis

“…In the current study, one FPS1 gene was expressed maximally in IM02 compared with IM01 and IM03. Squalene epoxidase (SQE) is an essential enzyme to convert squalene to 2,3-oxidosqualene ( Kumar et al., 2021 ), and 2, 3-oxidosqualene is cyclized by cycloartenol synthase (CAS) to produce cycloartenol, which serves as an important precursor of steroidal alkaloids ( Wang et al, 2019 ; Lu et al., 2022 ). Subsequently, steroidal alkaloids are produced by modification reactions ( Duan et al., 2022 ).…”

Full-Length Transcriptome Sequencing Provides Insights into Flavonoid Biosynthesis in Fritillaria hupehensis

“…The abundant pharmacological and phytochemical profiles in Fritillaria species have made them the objects of diverse studies, and a broad variety of new steroid alkaloids have been recently isolated [ 7 , 10 ]. Understanding biosynthetic pathways is necessary for the efficient utilization of key phytochemicals present in F. hupehensis [ 5 , 9 , 11 ].…”