Transcriptome Analysis of Light-Regulated Monoterpenes Biosynthesis in Leaves of Mentha canadensis L.

Abstract

Light is a key environmental aspect that regulates secondary metabolic synthesis. The essential oil produced in mint (Mentha canadensis L.) leaves is used widely in the aromatics industry and in medicine. Under low-light treatment, significant reductions in peltate glandular trichome densities were observed. GC-MS analysis showed dramatically reduced essential oil and menthol contents. Light affected the peltate glandular trichomes’ development and essential oil yield production. However, the underlying mechanisms of this regulation were elusive. To identify the critical genes during light-regulated changes in oil content, following a 24 h darkness treatment and a 24 h recovery light treatment, leaves were collected for transcriptome analysis. A total of 95,579 unigenes were obtained, with an average length of 754 bp. About 56.58% of the unigenes were annotated using four public protein databases: 10,977 differentially expressed genes (DEGs) were found to be involved in the light signaling pathway and monoterpene synthesis pathway. Most of the TPs showed a similar expression pattern: downregulation after darkness treatment and upregulation after the return of light. In addition, the genes involved in the light signal transduction pathway were analyzed. A series of responsive transcription factors (TFs) were identified and could be used in metabolic engineering as an effective strategy for increasing essential oil yields.

Molecular Mechanisms of Plant Trichome Development

“…Plant trichome development is influenced by genetic factors and environmental factors such as hormones, water and light (reviewed by Khan et al, 2021 ). The effects of hormones, water, and light on trichome development have been demonstrated in detail in previous publications ( Ning et al, 2016 ; Li et al, 2021b ; Yu et al, 2021b ). The trichome pattern formation process has been well studied, mainly because trichomes can easily be observed and used in experiments ( Han et al, 2016 ).…”

AmPIF4 negatively regulates the blue light-induced synthesis of volatile terpenoids in snapdragon

“…The content of linalool, citronellol, and geraniol increases signi cantly after overexpression of TPS59 and VvDXS4 in grape [51]. The expression of TPS and genes encoding enzymes involved in the MEP pathway can be regulated by light [52]. However, the effects of light on terpenoid biosynthesis may vary among plants, and the differences may be related to upstream regulation.…”