Mono- and sesquiterpene release from tomato ( Solanum lycopersicum ) leaves upon mild and severe heat stress and through recovery: From gene expression to emission responses

Abstract

Plants frequently experience heat ramps of various severities, but how and to what degree plant metabolic activity recovers from mild and severe heat stress is poorly understood. In this study, we exposed the constitutive terpene emitter, Solanum. lycopersicum leaves to mild (37 and 41 °C), moderate (46 °C) and severe (49 °C) heat ramps of 5 min. and monitored foliage photosynthetic activity, lipoxygenase pathway volatile (LOX), and mono-and sesquiterpene emissions and expression of two terpene synthase genes, β-phellandrene synthase and (E)-β-caryophyllene/α-humulene synthase, through a 24 h recovery period upon return to pre-stress conditions. Leaf monoterpene emissions were dominated by β-phellandrene and sesquiterpene emissions by (E)-β-caryophyllene, and thus, these two terpene synthase genes were representative for the two volatile terpene classes. Photosynthetic characteristics partly recovered under moderate heat stress, and very limited recovery was observed under severe stress. All stress treatments resulted in elicitation of LOX emissions that declined during recovery. Enhanced mono-and sesquiterpene emissions were observed immediately after the heat treatment, but the emissions decreased even to below the control treatment during recovery between 2-10 h, and raised again by 24 h. The expression of β-phellandrene and (E)-β-caryophyllene synthase genes decreased between 2-10 h after heat stress, and recovered to pre-stress level in mild heat stress treatment by 24 h. Overall, this study demonstrates a highly sensitive heat response of terpenoid synthesis that is mainly controlled by gene level responses under mild stress, while severe stress leads to non-recoverable declines in foliage physiological and gene expression activities.

Thecis-regulatory codes of response to combined heat and drought stress inArabidopsis thaliana

“…The regulatory codes underlying how plants respond to stressful environments involve many molecular players acting in interconnected ways. Stress responses are also dependent on countless other factors such as the duration (79), severity (80), and frequency (81) of the environmental stress and the cell/tissue type (82), developmental stage (83), and genetic background (83-85) of the plant. Thus, to more fully decipher these codes, it will be optimal to have multi-omics data with as many of the molecular players in place as possible, across multiple time points, in a myriad of environmental conditions, at different developmental stages, and from different tissue and cell types.…”

A New Modeling Approach for Estimating Abiotic and Biotic Stress-Induced de novo Emissions of Biogenic Volatile Organic Compounds From Plants

“…In parallel and without any further stress event, a slower response builds up within 5-15 h which needs ∼1-2 days to fade out. However, the pattern has not been observed in all investigations which might partly be related to methods that are too coarse to detect such fast responses (Behnke et al, 2009;Pazouki et al, 2016;Acton et al, 2018;Kanagendran et al, 2018a). In these cases, normally only the second peak is described in the publication.…”

“…In order to parameterize the emission pattern of the different compounds we have collected data from 11 studies that are providing response patterns for 9 of the 12 compounds (MeSA, monoterpenes, DMNT, sesquiterpenes, GLVs, acetaldehyde, acetone, and methanol) from all of the seven pathways. From these studies, five use ozone as the inducing abiotic stress (Beauchamp et al, 2005;Behnke et al, 2009;Pazouki et al, 2016;Li et al, 2017;Acton et al, 2018), six others apply biotic stressors and one both (Kanagendran et al, 2018b). From the abiotic stress experiments, two have exposed experimental plants to real insects (Mengistu et al, 2014;Yli-Pirilä et al, 2016), while four studies use mechanical wounding (Brilli et al, 2011;Erb et al, 2015;Portillo-Estrada et al, 2015;Kanagendran et al, 2018b) and two studies applied methyl-jasmonate (Faiola et al, 2015;Jiang et al, 2017) to mimic herbivory.…”

Ozone‐induced foliar damage and release of stress volatiles is highly dependent on stomatal openness and priming by low‐level ozone exposure in Phaseolus vulgaris

“…The release of plant stress volatiles such as methanol, LOX products and MeSA is highly enhanced by a variety of abiotic stresses including temperature, mechanical damage and O 3 exposure (Beauchamp et al 2005;Loreto & Schnitzler 2010;Niinemets 2010;Brilli et al 2011;Copolovici, Kännaste, Pazouki, & Niinemets 2012;Portillo-Estrada et al 2015;Pazouki et al 2016). As the emissions of stress volatiles are often quantitatively related to the severity of stress (Beauchamp et al 2005;Copolovici et al 2012;Portillo-Estrada et al 2015;Pazouki et al 2016), they can serve as an important tool to monitor development of stress response and recovery and gain insight into overall stress severity under given environmental conditions. increase (e and f) and decrease (g and h) for the two methanol bursts (a, c, e, g) and LOX products (b, d, f, h) with the total amount of O 3 taken up (Φ O3 ) in O 3 -exposed leaves of P. vulgaris.…”