Abstract
Monoterpenes, which are among the major components of plant essential oils, are known for their ecological roles as well for pharmaceutical properties. Geraniol, an acyclic monoterpene induces cell cycle arrest and apoptosis/senescence in various cancer cells and plants; however, the genes involved in the process and the underlying molecular mechanisms are not well understood. In this study, we demonstrate that treatment of tomato plants with geraniol results in induction of senescence due to a substantial alteration in transcriptome. We have identified several geraniol-responsive protein encoding genes in tomato using suppression subtractive hybridization (SSH) approach. These genes comprise of various components of signal transduction, cellular metabolism, reactive oxygen species (ROS), ethylene signalling, apoptosis and DNA damage response. Upregulation of NADPH oxidase and antioxidant genes, and increase in ROS level after geraniol treatment point towards the involvement of ROS in geraniol-mediated senescence. The delayed onset of seedling death and induced expression of geraniol-responsive genes in geraniol-treated ethylene receptor mutant (Nr) suggest that geraniol-mediated senescence involves both ethylene dependent and independent pathways. Moreover, expression analysis during tomato ripening revealed that geraniol-responsive genes are also associated with the natural organ senescence process.
Highlights
Plants produce a large variety of phytochemicals with specialized/secondary functions
To know how plants respond to monoterpene, tomato plants were treated with geraniol and its derivatives geranyl acetate, citral and bcitronellol (Figure 1) [26]
To maintain an atmosphere rich in monoterpene vapour, 45-days old potted plants were entirely covered with polypropylene bag (12 inches616 inches) and a cotton ball (1.5 cm in diameter) containing 5–20 ml of monoterpene compound was placed inside the bag
Summary
Plants produce a large variety of phytochemicals with specialized/secondary functions. The involvement of volatile terpenes in mediating plantplant interactions has been proposed [7,8,9,10] Besides their ecological roles, plant-derived terpenes have a multitude of pharmaceutical and industrial applications as flavours, fragrances, antioxidants, anti-malarial and anti-cancer drugs etc [1]. Plant-derived terpenes have a multitude of pharmaceutical and industrial applications as flavours, fragrances, antioxidants, anti-malarial and anti-cancer drugs etc [1] Their availability, in most cases, is limited to the natural source, where they are synthesised and accumulated in specialized tissue types like glandular trichomes, possibly for the autotoxicity avoidance [11]. As many of them are phytotoxic, successful metabolic engineering of the terpenes requires an in-depth understanding of the biosynthetic pathway, and how these compounds affect the physiology of the plants [12]
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.
