Ultraviolet radiation modulates both constitutive and inducible plant defenses against thrips but is dose and plant genotype dependent

Abstract

Ultraviolet (UV) radiation has emerged as an environmental cue with potential uses to enhance plant protection against arthropod pests in agriculture. UV can augment constitutive and inducible plant defenses against herbivorous arthropods. Here we investigated whether application of supplemental UV to chrysanthemum (Chrysanthemum × morifolium Ramat) cuttings during their rooting phase enhanced plant resistance to an important insect pest, Western flower thrips (Frankliniella occidentalis). For this, we analyzed how several daily UV exposure times affected plant damage by thrips on three different chrysanthemum cultivars. The most effective UV dose and responsive cultivar were further used to determine the UV effects on host plant preference by thrips, leaf metabolome and the induction of jasmonic acid (JA)-associated defenses. Our results showed that while short UV daily exposure times increased chrysanthemum resistance to thrips, longer exposure times had the opposite effect. Furthermore, we showed that UV-mediated induction of chrysanthemum resistance to thrips was genotype dependent and can persist after the end of the of the UV treatment. Yet, this induction was not transferred to the next generation from mother plants to cuttings. Nontargeted metabolomic, enzymatic and hormone analyses further revealed that UV slightly affected the leaf metabolome of chrysanthemum plants, and it enhanced the induction of JA-associated signaling after thrips infestation. Taken together, our results suggest that supplemental UV might modulate both constitutive and inducible chrysanthemum defenses against thrips.

Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020

“…UV-B radiation is also emerging as an environmental cue that can upregulate plant defences against herbivorous arthropods. For example, short daily exposures of UV radiation increased the resistance of chrysanthemum ( Chrysanthemum × morifolium ) to the insect pest, thrips ( Frankliniella occidentalis ) [ 210 ].…”

LED Lighting Strategies Affect Physiology and Resilience to Pathogens and Pests in Eggplant (Solanum melongena L.)

“…A strong reduction of thrips silver damage was reported by Escobar-Bravo et al (2019a) using the same UV-B intensity in tomato as in our trial. Doubling of this UV-B intensity was needed to increase resistance to thrips in chrysanthemum whereby effects were genotype dependent ( Escobar-Bravo et al, 2019b ). Although eggplant belongs to the plant family of the Solanaceae, as does tomato, it appears that UV-B treatments to increase host plant resistance may be species specific, especially seen in the relatively low window of effective UV-B ranges ( Escobar-Bravo et al, 2019a ).…”

Ecometabolomics of plant–herbivore and plant–fungi interactions: a synthesis study

“…Chen et al (2020) recently reported that the application of jasmonic acid to all leaves or only the apical leaves of chrysanthemums (Chrysanthemum × morifolium) increased the resistance to thrips, whereas the application to basal leaves was not v www.esajournals.org effective against the thrip pest (Chen et al 2020). Extra doses of ultraviolet radiation can induce defenses mediated by jasmonic acid, thereby increasing the resistance to thrips in Chrysanthemum × morifolium (Escobar- Bravo et al 2021). The dosage depended on time and genotype but demonstrated the possibility of some management strategies to efficiently stimulate natural plant defenses against arthropod herbivores.…”

“…Our synthesis of results from studies that have used metabolic platforms to investigate constitutive and inducible defenses against herbivorous attack at the level of metabolomic profiles clarifies the more widespread changes to metabolic pathways used across several plant species to minimize the negative effects of herbivore. Few studies, however, using metabolomics platforms have compared various constitutive and inducible defenses at once among plant genotypes in response to attacks by the same herbivore (Sato et al 2013, Cai et al 2017, Escobar-Bravo et al 2021, Perez-Fons et al 2019. Untargeted analyses that used ecometabolomics have demonstrated a large chemical diversity that can structure natural communities into metabolic subgroups to create high small-scale heterogeneity for specialized herbivores (Clancy et al 2017).…”