Far-red light increases maize volatile emissions in response to volatile cues from neighboring plants

Abstract

Plants perceive the presence and defense status of their neighbors through light and volatile cues. How plants integrate these stimuli into adaptive responses is not well understood. We investigated whether perception of vegetation through the reduction in Red to Far Red light (R:FR) ratios affects maize (Zea mays) responses to the herbivore-induced plant volatile (Z)-3-hexenyl acetate. By supplementing FR light and using a phyB1phyB2 maize mutant, we modulated plant light signaling and perception and determined defense responses, including stress hormone deployment and volatile release. Exposure to (Z)-3-hexenyl acetate induced maize volatile release. FR supplementation increased this response. FR also boosted (Z)-3-hexenyl acetate induced JA-Ile levels and promoted stomatal opening and photosynthesis. FR effects were most pronounced after 2 days of light treatment, becoming weaker with longer exposures. In contrast to FR supplementation, the phyB1phyB2 mutant displayed reduced volatile responsiveness. Comparative analyses with wheat and tomato revealed that the integration of light and volatile cues into enhanced volatile-release is species-specific. In conclusion, FR light enhances maize volatile emissions in response to stress volatiles, likely via stronger hormonal signaling and enhanced photosynthesis. Species-specific integration of light and volatile cues into distinct defense responses may have important consequences for plant-plant and plant-herbivore dynamics.

Dynamic environmental interactions shaped by vegetative plant volatiles

“…130 These effects may be in part explained by the positive impact of supplemental FR on stomatal conductance and photosynthetic rate. 130 Similar effects have also been found in goldenrod (Solidago altissima), where FR enhanced plant volatile emissions in response to volatile cues from nondamaged neighbors. 131 3.2.4 Ozone and other stresses.…”

“…129 FR supplementation can enhance the emission of maize (Z. mays) volatiles in response to herbivory or volatile cues emitted by neighboring plants. 130 These effects may be in part explained by the positive impact of supplemental FR on stomatal conductance and photosynthetic rate. 130 ) is a major phytotoxic air pollutant.…”

“…130 These effects may be in part explained by the positive impact of supplemental FR on stomatal conductance and photosynthetic rate. 130 ) is a major phytotoxic air pollutant. 132 Ozone exposure alone has been shown to induce the synthesis and release of vegetative plant volatiles in some cases, 133 including herbivore-induced plant volatile emissions 134 (Fig.…”

“… 129 FR supplementation can enhance the emission of maize ( Z. mays ) volatiles in response to herbivory or volatile cues emitted by neighboring plants. 130 These effects may be in part explained by the positive impact of supplemental FR on stomatal conductance and photosynthetic rate. 130 Similar effects have also been found in goldenrod ( Solidago altissima ), where FR enhanced plant volatile emissions in response to volatile cues from non-damaged neighbors.…”

“…Recently, technological advancements have allowed for real-time measurements of volatiles across multiple plants, however this has yet to be implemented in a field setting. 130 By consequence, we lack a detailed understanding of spatial and temporal volatile dynamics at the plant and interplant scale within plant canopies. 256 Developing our understanding of how vegetation creates a “volatile landscape” in terrestrial ecosystems is important to understand how ecosystem-scale volatile dynamics mediate ecosystem functioning.…”