Plant memory: a tentative model

Abstract

All memory functions have molecular bases, namely in signal reception and transduction, and in storage and recall of information. Thus, at all levels of organisation living organisms have some kind of memory. In plants one may distinguish two types. There are linear pathways from reception of signals and propagation of effectors to a type of memory that may be described by terms such as learning, habituation or priming. There is a storage and recall memory based on a complex network of elements with a high degree of integration and feedback. The most important elements envisaged are calcium waves, epigenetic modifications of DNA and histones, and regulation of timing via a biological clock. Experiments are described that document the occurrence of the two sorts of memory and which show how they can be distinguished. A schematic model of plant memory is derived as emergent from integration of the various modules. Possessing the two forms of memory supports the fitness of plants in response to environmental stimuli and stress.

DNA Methylation Changes Induced in Rice by Exposure to High Concentrations of the Nitric Oxide Modulator, Sodium Nitroprusside

“…This later scenario however cannot explain the results observed in the S1 generation, in which epigenetic status of treated plants was faithfully inherited to the next generation even in the absence of SNP. Nevertheless, it is compatible with the function of DNA methylation in mediating plant stress memory, which plays an important role both in immediate as well as long-term response of an organism to stress (Boyko and Kovalchuk 2011;Kou et al 2011;Ou et al 2012;Paszkowski and Grossniklaus 2011;Hauser et al 2011;Sahu et al 2013;Thellier and Lüttge 2013). Therefore, a meaningful follow-up study is to test whether progenies of the SNPtreated plants will show enhanced tolerance to various abiotic stresses.…”

Action potentials in abscisic acid-deficient tomato mutant generated spontaneously and evoked by electrical stimulation

“…In the growth room the light was turned on at 6 a.m., thus the highest number of SAPs, at this time, could mean a photoperiodic ''remembered'' response (Goodrich and Tweedie 2002;Bruce et al 2007;Thellier and Lüttge 2013). In the case of mutant plants, another important factor to be considered is the humidity.…”

Systems-Wide Analysis of Acclimation Responses to Long-Term Heat Stress and Recovery in the Photosynthetic Model OrganismChlamydomonas reinhardtii

“…Perhaps in support for the latter idea, average cell diameter and average contents of DNA, protein, and chlorophyll were higher after 24 h of recovery compared with pre-HS conditions, although cells had divided already ;1.6 times (Figure 2). Experiments monitoring cellular states for days after recovery from prolonged HS will be required to test whether such a "stress memory," potentially realized by epigenetic marks (Thellier and Lüttge, 2013), might exist in Chlamydomonas.…”