Multiple exposures to drought 'train' transcriptional responses in Arabidopsis

Abstract

Pre-exposure to stress may alter plants' subsequent responses by producing faster and/or stronger reactions implying that plants exercise a form of 'stress memory'. The mechanisms of plants' stress memory responses are poorly understood leaving this fundamental biological question unanswered. Here we show that during recurring dehydration stresses Arabidopsis plants display transcriptional stress memory demonstrated by an increase in the rate of transcription and elevated transcript levels of a subset of the stress-response genes (trainable genes). During recovery (watered) states, trainable genes produce transcripts at basal (preinduced) levels, but remain associated with atypically high H3K4me3 and ser5P polymerase II levels, indicating that RnA polymerase II is stalled. This is the first example of a stalled RnA polymerase II and its involvement in transcriptional memory in plants. These newly discovered phenomena might be a general feature of plant stress-response systems and could lead to novel approaches for increasing the flexibility of a plant's ability to respond to the environment.

Rapid hyperosmotic-induced Ca 2+ responses in Arabidopsis thaliana exhibit sensory potentiation and involvement of plastidial KEA transporters

“…However, the expression, activity, or sensitivity of the sensory components is increased after a previous experience of hyperosmotic stress, thereby exhibiting sensory potentiation. Important and interesting examples in the literature describe the enhancement of responses after experiencing stress, sometimes referred to as "priming" or "memory" (43)(44)(45)(46). The present study, however, reports that the earliest sensory components of the rapid osmotic stress response can be up-regulated in such a manner.…”

Interplay between Heat Shock Proteins HSP101 and HSA32 Prolongs Heat Acclimation Memory Posttranscriptionally in Arabidopsis

“…D, The LAT phenotypes of wild-type and pEi32 seedlings with or without late induction with 10 mM estradiol as in C. yet understood. Recently, transcriptional memory to drought acclimation mediated by chromatin modification has been shown in Arabidopsis (Ding et al, 2012). Here, we demonstrated another example in which acclimation memory can be modulated by the interplay of stress proteins at the posttranscriptional level.…”

Osmotic stress induces phosphorylation of histone H3 at threonine 3 in pericentromeric regions of Arabidopsis thaliana

“…Changes in DNA methylation, several posttranslational histone modifications, as well as a linker histone H1 variant have been implicated in plant responses to osmotic/salt stress (2,3,6,10,20,21,(42)(43)(44)(45), but in most cases the relationship among chromatin status, transcriptional responsiveness, and physiological outcomes is not clearly understood. Interestingly, in both metazoans and plants, histone phosphorylation appears to be involved in responses to osmotic/salt stress (3,17,(19)(20)(21).…”