Mechanisms of far-red light-mediated dampening of defense against Botrytis cinerea in tomato leaves

Abstract

Plants detect neighboring competitors through a decrease in the ratio between red and far-red light (R:FR). This decreased R:FR is perceived by phytochrome photoreceptors and triggers shade avoidance responses such as shoot elongation and upward leaf movement (hyponasty). In addition to promoting elongation growth, low R:FR perception enhances plant susceptibility to pathogens: the growth-defense trade-off. Although increased susceptibility in low R:FR has been studied for over a decade, the associated timing of molecular events is still unknown. Here, we studied the chronology of FR-induced susceptibility events in tomato (Solanum lycopersicum) plants pre-exposed to either white light (WL) or WL supplemented with FR light (WL+FR) prior to inoculation with the necrotrophic fungus Botrytis cinerea (B.c.). We monitored the leaf transcriptional changes over a 30-hr time course upon infection and followed up with functional studies to identify mechanisms. We found that FR-induced susceptibility in tomato is linked to a general dampening of B.c.-responsive gene expression, and a delay in both pathogen recognition and jasmonic acid-mediated defense gene expression. In addition, we found that the supplemental FR-induced ethylene emissions affected plant immune responses under the WL+FR condition. This study improves our understanding of the growth–immunity trade-off, while simultaneously providing leads to improve tomato resistance against pathogens in dense cropping systems.

LED Lighting: A Grower’s Guide to Light Spectra

“…B FR illumination can also affect disease responses. Whereas red light improved disease resistance in tomato, cucumber, broad bean (Vicia faba), watermelon (Citrullus lanatus), and roses (Rosa ×hybrida) through the regulation of plant defense hormones such as salicylic acid (Nagendran and Lee 2015;Rahman et al 2003;Suthaparan et al 2010;Wang et al 2010;Yang et al 2015Yang et al , 2018, FR light reduced resistance to Botrytis cineria in tomato and powdery mildew in cucumber, indicating that the balance of red to FR is also important for optimizing resistance to plant disease (Courbier et al 2021;Ji et al 2019;Shibuya et al 2011;Wang et al 2010).…”

The THO/TREX Complex Active in Alternative Splicing Mediates Plant Responses to Salicylic Acid and Jasmonic Acid

“…Previous studies suggest that both SA and JA could induce plant resistance to multiple pathogens [16,[41][42][43][44], while little is known about the common factors used by these two hormones. In this study, we found that EDS8 mediated the plant response to both SA and JA.…”

Tuning the Wavelength: Manipulation of Light Signaling to Control Plant Defense

“…This suggests that RL perception is important to Botrytis . Intriguingly, recent work has shown that RL and FRL perception in plants regulates defense against Botrytis , specifically by reducing the expression of Botrytis -responsive defense genes and delaying recognition and JA signaling [ 171 ]. However, another study has shown that red LED light improved basal resistance to Botrytis isolates [ 172 ]; therefore, more research is needed to unravel the complexity involved.…”