Title : The volatilome of piper tenue in plant–coleopteran interactions
Abstract:
Piper species are rich in volatile metabolites (VMs), which comprise diverse classes of organic compounds whose composition and abundance vary according to environmental conditions and chemotypes. Monoterpenes, sesquiterpenes and phenylpropanoids are among the most important VM found in Piper species. Piper tenue grows between 80 and 180 m above sea level and is most frequently recorded in Colombia and Venezuela. The aim of this study was to determine the volatile chemical composition of fruits, pollen, and leaves from P. tenue collected in Arauca, Colombia. The volatile chemical composition of leaves from plants with and without coleopteran herbivory was also included. The VM constitute chemical signals (allelochemicals) that plants use in ecological interactions (communication, adaptation, and survival). Solid-Phase Microextraction (SPME) and Simultaneous Distillation–Extraction (SDE), coupled with Gas Chromatography and a Mass Selective Detector (GC-MSD), were used for the extraction and analysis of volatile compounds. P. tenue was characterized by a high proportion of sesquiterpenes (ST), monoterpenes (MT), and aromatic esters (AR-EST). Fruits were differentiated by a high content of MT and ST; pollen was dominated by ST and MT; leaves with herbivory were distinguished by a higher proportion of AR-EST; leaves without herbivory were differentiated by ST and AR-EST contents; and the volatile fraction of leaves obtained by SDE was characterized by a high content of aldehydes and MT. Volatile metabolites play key roles in attracting pollinators, repelling herbivorous insects, signalling neighbouring plants, and recruiting natural enemies of herbivores. The classification of VM as attractants or repellents is not standardized due to fluctuations in insect behavioural responses. This preliminary study contributes to supporting the ecological interactions of P. tenue related to herbivory by coleopteran insects.
