Plant neighbor detection and allelochemical response are driven by root-secreted signaling chemicals

Chui-Hua Kong,Song-Zhu Zhang,Peng Wang,Scott J Meiners,Yong-Hua Li,Zhi-Chao Xia,Xue-Fang Yang

doi:10.1038/s41467-018-06429-1

Abstract

Plant neighbor detection and response strategies are important mediators of interactions among species. Despite increasing knowledge of neighbor detection and response involving plant volatiles, less is known about how soil-borne signaling chemicals may act belowground in plant–plant interactions. Here, we experimentally demonstrate neighbor detection and allelopathic responses between wheat and 100 other plant species via belowground signaling. Wheat can detect both conspecific and heterospecific neighbors and responds by increasing allelochemical production. Furthermore, we show that (-)-loliolide and jasmonic acid are present in root exudates from a diverse range of species and are able to trigger allelochemical production in wheat. These findings suggest that root-secreted (-)-loliolide and jasmonic acid are involved in plant neighbor detection and allelochemical response and may be widespread mediators of belowground plant-plant interactions.

Highlights

Plant neighbor detection and response strategies are important mediators of interactions among species
When wheat was paired with itself and eight common weeds (Eleusine indica, Digitaria sanguinalis, Abutilon theophrasti, Bidens frondosa, Lolium perenne, Avena fatua, Alopecurus japonicus, and Aegilops tauschii) that often come into contact with wheat, allelochemical DIMBOA concentration varied with the density of the neighbors
It appeared that the presence of either conspecific or heterospecifc neighbors could induce the allelochemical response in a density-dependent manner

Summary

Introduction

Plant neighbor detection and response strategies are important mediators of interactions among species. We show that (-)-loliolide and jasmonic acid are present in root exudates from a diverse range of species and are able to trigger allelochemical production in wheat These findings suggest that root-secreted (-)-loliolide and jasmonic acid are involved in plant neighbor detection and allelochemical response and may be widespread mediators of belowground plant-plant interactions. Plant neighbor detection involves both physical and chemical signals, including far-red light reflection, alteration of nutrient availability and plant-released secondary metabolites These signals trigger complex plant response strategies such as shade avoidance, root foraging, and chemical defense[4,5,6]. Neighbor detection and allelochemical response are two inseparable processes when one or more plants occur together and interact[30] This pattern may arise through the production and release of signaling chemicals that induce the production of defensive allelochemicals. Allelochemical production may be constitutive, produced whether or not neighbors are present, potentially wasting valuable plant resources[26]

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