Herbivore-Induced Volatiles as Rapid Signals in Systemic Plant Responses

Abstract

Plants respond to local herbivory or pathogen infection with phenotypic changes, which reduce the danger of future attack. This so-called induced resistance is usually not restricted to the attacked plant organ but is also expressed in distant, so far undamaged parts of the plant. Signaling compounds such as jasmonic acid and salicylic acid have been discovered that move within the plant via the xylem or the phloem and elicit the resistance, thus acting as plant hormones. We now found that volatiles released in response to herbivore damage are required to elicit extrafloral nectar secretion in other parts of the same plant. Extrafloral nectar attracts ants and other carnivorous arthropods and serves as an effective indirect defense against herbivores. So called green leaf volatiles are released within minutes in response to tissue damage and were among the compounds that induced nectar secretion in yet undamaged parts of the damaged plant, but also in neighboring plants. Being gaseous and transported via the air, green leaf volatiles can serve a rapid within-plant communication, which moves much faster from one plant organ to the other than any plant-internal compound.

Similar local, but different systemic, metabolomic responses of closely related pine subspecies to folivory by caterpillars of the processionary moth

“…These results support the premise that local PPM attack is able to trigger significant responses in Scots pine systemically by shifting a large proportion of the overall pine metabolome (Sticher et al . ; Heil & Bueno ; Heil ).…”

“…Herbivore attack induces the synthesis of defence compounds at both local and systemic levels (Karban & Baldwin ; Sticher et al . ; Heil & Bueno ; Heil ) through induced internal plant signalling (Howe & Jander ; Wu & Baldwin ) and production of reactive oxygen species (ROS) (Orozco‐Cardenas & Ryan ; Wu & Baldwin ).…”

Crop Root Behavior Coordinates Phosphorus Status and Neighbors: From Field Studies to Three-Dimensional in Situ Reconstruction of Root System Architecture

“…Some reports stated that emission of a chemical signal from one plant could determine the growth performance. For example, maize released (Z)-3-hexen-1-ol (Z-3-ol) in response to leaf damage so as to help the neighbor plants to avoid an herbivore attack (Heil and Bueno, 2007;Heil and Karban, 2010). Therefore, we speculated that the genotypic-dependent maize/soybean recognition might also involve in chemical communication in above-ground parts and need to be further studied.…”

Plant Volatile Signalling: Multitrophic Interactions in the Headspace

“…There is increasing evidence that plants can use VOC signals to elicit defences in neighbouring leaves and branches -even when they are not physically connected. 85,86 Unlike vascular signals, all leaves within air contact of a damaged leaf can detect volatile signals, and volatiles travel rapidly -providing the opportunity for advanced warning in distal undamaged plant parts. For instance, volatiles from herbivore-damaged lima bean leaves elicit extrafloral nectar secretion in neighbouring undamaged leaves.…”

“…For example, when one lima bean branch is damaged by herbivores, VOCs are perceived by undamaged lima bean plants that then induce extrafloral nectar production. 85 Similarly, sagebrush (Artemisia tridentata) becomes more resistant to herbivory after exposure to VOCs from damaged neighbours. 148 Plants within 60 cm of a damaged sagebrush experienced this benefit.…”