Metabolomics reveals ionones upregulation in MeJA elicited Cinnamomum camphora (camphor tree) cell culture

Abstract

Cell suspension culture offers an approach for elucidating secondary metabolites biosynthetic pathways and its regulatory mechanism. In this work, Cinnamomum camphora (camphor tree) a plant enriched in essential oil components and employed in traditional medicine for the treatment of several conditions was subjected to callus induction. Callus growth was optimized in terms of medium type and concentration of plant growth regulators, revealing that Murashige and Skoog (MS) medium containing 2.0 mg L−1 naphthalene acetic acid plus 1.0 mg L−1 6-benzylaminopurine yielded the best combination for callus growth. Moreover, an MS-based metabolomics approach was used to compare volatile profile of intact leaf versus callus. Few reports in planta have addressed differences in volatiles composition between cell cultures (callus) and its original explants using such large scale analytical approaches. Headspace solid phase microextraction coupled to gas chromatography mass spectrometry was utilized to profile C. camphora leaf volatiles with a total of 47 volatiles including monoterpenoids viz., cineole and β-phellandrene as major constituents. In contrast, callus volatile profile showed qualitative and quantitative differences from that of leaf tissue and with its aroma being mostly dominated by aldehydes viz., benzaldehyde. Methyl jasmonate (MeJA) phytohormone elicitation effect was further applied with the aim of enhancing flavours volatiles production. Multivariate data analyses revealed that MeJA led to the upregulation of ionones production first time to be reported in C. comphora. This study extends our knowledge regarding ionones formation and to extend MeJA as a potential inducer of such flavour volatile class in planta.