Stress Memory and the Inevitable Effects of Drought: A Physiological Perspective

Abstract

Plants grow and develop by adjusting their physiology to changes in their environment. Changes in the abiotic environment occur over years, seasons, and days, but also over minutes and even seconds. In this ever-changing environment, plants may adjust their structure and function rapidly to optimize growth and reproduction. Plant responses to reiterated drought (i.e., repeated cycles of drought) differ from those to single incidences of drought; in fact, in nature, plants are usually exposed to repeated cycles of drought that differ in duration and intensity. Nowadays, there is increased interest in better understanding mechanisms of plant response to reiterated drought due, at least in part, to the discovery of epigenomic changes that trigger drought stress memory in plants. Beyond epigenomic changes, there are, however, other aspects that should be considered in the study of plant responses to reiterated drought: from changes in other “omics” approaches (transcriptomics, proteomics, and metabolomics), to changes in plant structure; all of which may help us to better understand plant stress memory and its underlying mechanisms. Here, we present an example in which reiterated drought affects the pigment composition of leaves in the ornamental plant Silene dioica and discuss the importance of structural changes (in this case in the photosynthetic apparatus) for the plant response to reiterated drought; they represent a stress imprint that can affect plant response to subsequent stress episodes. Emphasis is placed on the importance of considering structural changes, in addition to physiological adjustments at the “omics” level, to understand stress memory in plants better.

Stress-Related Gene Expression Reflects Morphophysiological Responses to Water Deficit

“…We propose that the abundance of a specific transcript before the plant encounters WD may shape the plasticity of the morphophysiological responses. A similar observation was reported in studies on plant stress memory, which showed the central role for ABA signaling in this process (for review, see FletaSoriano andMunné-Bosch, 2016 andViirlouvet andFromm, 2005). In this regard, it is worth noting that MYB44 was characterized previously as a WD memory gene (Ding et al, 2013).…”

Irrigation affects characteristics of narrow-leaved lupin (Lupinus angustifolius L.) seeds

“…We have to take into consideration the fact that although mild drought reduces crop productivity, it may increase plant resistance to stress with naturally occurring mechanisms (Backhaus et al 2014). Stress memory would help to deal with unfavorable conditions in the next plant generation (Walter et al 2011;Crisp et al 2016;Fleta-Soriano and Munné-Bosch 2016;Li and Liu 2016).…”

Melatonin enhances cold tolerance in drought‐primed wild‐type and abscisic acid‐deficient mutant barley

“…The underlying mechanisms of the positive effects of priming on promoting subsequent stress tolerance include more effective subcellular antioxidant systems, sustained photosynthetic electron transport, and carbon assimilation rate in the primed plants . It has been documented that abscisic acid (ABA) plays a key role in the responses of plants to abiotic stress and in stress memory . For instance, ABA can act as an important player in regulating plant water status and modulating oxygen scavenging systems under drought and temperature stress …”

“…1,3 It has been documented that abscisic acid (ABA) plays a key role in the responses of plants to abiotic stress and in stress memory. 3,6,7 For instance, ABA can act as an important player in regulating plant water status and modulating oxygen scavenging systems under drought and temperature stress. 8 Melatonin (N-acetyl-5-methoxytryptamine) is a pleiotropic molecule with various functions in animals and plants [9][10][11] and proved to be an abiotic antistresser in plants.…”