Abstract
BackgroundAsarum heterotropides Fr. Schmidt var. mandshuricum (Maxim.) Kitag. is an important medicinal and industrial plant, which is used in the treatment of various diseases. The main bioactive ingredient is the volatile oil having more than 82 identified components of which methyleugenol, safrole, myristicin, and toluene account for about 70% of the total volume. As a sciophyte plant, the amount of light it absorbs through leaves is an important factor for growth and metabolism.ResultsWe grew Asarum plants under full, 50, 28, and 12% sunlight conditions to investigate the effect of different light irradiances on the four major volatile oil components. We employed de novo transcriptome sequencing to understand the transcriptional behavior of Asarum leaves regarding the biosynthetic pathways of the four volatile oil components, photosynthesis and biomass accumulation, and hormone signaling. Our results demonstrated that the increasing light conditions promoted higher percent of the four components. Under full sunlight conditions, cinnamyl alcohol dehydrogenase and cytochrome p450719As were upregulated and led the increased methyleugenol, safrole, and myristicin. The transcriptomic data also showed that Asarum leaves, under full sunlight conditions, adjust their photosynthesis-antenna proteins as a photoprotective response with the help of carotenoids. Plant hormone-signaling related genes were also differentially expressed between full sunlight and low light conditions.ConclusionsHigh light induces accumulation of major bioactive ingredients A. heterotropides volatile oil and this is ascribed to upregulation of key genes such as cinnamyl alcohol dehydrogenase and cytochrome p450719As. The transcriptome data presented here lays the foundation of further understanding of light responses in sciophytes and provides guidance for increasing bioactive molecules in Asarum.
Highlights
The study by Wang et al, [7] used Gas chromatography-mass spectrometery (GC-MS) to determine the composition of the oil and reported variation in oil composition under different light treatments suggesting that light treatments somehow affect the regulation of the pathways involved in volatile oil biosynthesis
Effect of shade treatments on important volatile oil constituents Asarum plants were grown under four light irradiances including, full sunlight (L1), 50% sunlight (L2), 28% sunlight (L3), and 12% sunlight (L4)
Because leaf is the plant organ, where light is directly absorbed and the main photosynthate is produced and processed, we focused on the essential oil changes and transcriptional responses as adopted in a previous studies [6]
Summary
Mandshuricum (Maxim.) Kitag., a perennial herb endemic to China, has been exploited as a traditional medicinal herb due to its anti-inflammatory, anti-bacterial, anti-pyretic, anticancer, fungistatic and analgesic properties [1, 2] This species has a wide geographical distribution and grows in shady habitats and mountainous wetlands. Solar irradiance levels altered volatile oil contents in basil (Ocimum basilicum L.), Myrtus communis L., Ocimum gratissimum, damask rose (Rosa damascena Mill.), and other aromatic plants [10,11,12,13] These contradicting reports suggest that a deeper understanding is a prerequisite for establishing an optimal irradiation protocol for Asarum growth, which can provide high yield of volatile oil and its major bioactive components for industrial scale volatile oils
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
