Abstract
BackgroundAmber-like compounds form in tobacco (Nicotiana tabacum) during leaf curing and impact aromatic quality. In particular, cis-abienol, a polycyclic labdane-related diterpenoid, is of research interest as a precursor of these compounds. Glandular trichome cells specifically express copalyl diphosphate synthase (NtCPS2) at high levels in tobacco, which, together with NtABS, are major regulators of cis-abienol biosynthesis in tobacco.ResultsTo identify the genes involved in the biosynthesis of cis-abienol in tobacco, we constructed transgenic tobacco lines based on an NtCPS2 gene-knockdown model using CRISPR/Cas9 genome-editing technology to inhibit NtCPS2 function in vitro. In mutant plants, cis-abienol and labdene diol contents decreased, whereas the gibberellin and abscisic acid (ABA) contents increased compared with those in wild-type tobacco plants. RNA sequencing analysis revealed the presence of 9514 differentially expressed genes (DEGs; 4279 upregulated, 5235 downregulated) when the leaves of wild-type and NtCPS2-knockdown tobacco plants were screened. Among these DEGs, the genes encoding cis-abienol synthase, ent-kaurene oxidase, auxin/ABA-related proteins, and transcription factors were found to be involved in various biological and physiochemical processes, including diterpenoid biosynthesis, plant hormone signal transduction, and plant-pathogen interactions.ConclusionsThe present study provides insight into the unique transcriptome profile of NtCPS2 knockdown tobacco, allowing for a better understanding of the biosynthesis of cis-abienol in tobacco.
Highlights
Amber-like compounds form in tobacco (Nicotiana tabacum) during leaf curing and impact aromatic quality
The results indicate that NtCPS2 is one of the key genes regulating the cis-abienol biosynthesis pathway, and NtCPS2 knockdown results in low levels of cis-abienol biosynthesis and accumulation
The results indicate that NtCPS2 plays a key role in cisabienol biosynthesis; downregulated gene expression leads to inactivation of the cis-abienol biosynthesis pathway
Summary
Amber-like compounds form in tobacco (Nicotiana tabacum) during leaf curing and impact aromatic quality. Glandular trichome cells express copalyl diphosphate synthase (NtCPS2) at high levels in tobacco, which, together with NtABS, are major regulators of cis-abienol biosynthesis in tobacco. An important aromatic substance in tobacco leaf surface secretions is cis-abienol, which belongs to the. He et al BMC Genomics (2021) 22:467. Sallaud et al [16] cloned NtCPS2 and NtABS from tobacco and showed that both genes are involved in the biosynthesis of cis-abienol, which involves two steps. The identification of NtCPS2 and NtABS is of great significance for breeding high-quality tobacco and future microbial metabolic engineering. From this knowledge base, other diterpenoid-synthesising genes can be cloned and identified
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
