Root volatiles in plant–plant interactions I: High root sesquiterpene release is associated with increased germination and growth of plant neighbours

• DOI: 10.1111/pce.13532
• Publication Date: 2019-02-09T05:10:05Z
• Authors: Valentin Gfeller; Meret Huber; Christiane Förster; Wei Huang; Tobias G. Köllner; Matthias Erb
• Keywords: Polycyclic Sesquiterpenes; 0301 basic medicine; Volatile Organic Compounds; Terpenes; Plant Development; Centaurea; Germination; Original Articles; Plants; 15. Life on land; Plant Roots; Plant Leaves; 03 medical and health sciences; Transcriptome; Sequence Analysis; Sesquiterpenes; Plant Proteins

AbstractVolatile organic compounds (VOCs) emitted by plant leaves can influence the physiology of neighbouring plants. In contrast to leaf VOCs, little is known about the role of root VOCs in plant–plant interactions. Here, we characterize constitutive root VOC emissions of the spotted knapweed (Centaurea stoebe) and explore the impact of these VOCs on the germination and growth of different sympatric plant species. We show that C. stoebe roots emit high amounts of sesquiterpenes, with estimated release rates of (E)‐β‐caryophyllene above 3 μg g−1 dw hr−1. Sesquiterpene emissions show little variation between different C. stoebe populations but vary substantially between different Centaurea species. Through root transcriptome sequencing, we identify six root‐expressed sesquiterpene synthases (TPSs). Two root‐specific TPSs, CsTPS4 and CsTPS5, are sufficient to produce the full blend of emitted root sesquiterpenes. VOC‐exposure experiments demonstrate that C. stoebe root VOCs have neutral to positive effects on the germination and growth of different sympatric neighbours. Thus, constitutive root sesquiterpenes produced by two C. stoebe TPSs are associated with facilitation of sympatric neighbouring plants. The release of root VOCs may thus influence plant community structure in nature.