Light affects salt stress-induced transcriptional memory of P5CS1 in Arabidopsis

Abstract

To cope with environmental stresses, plants often adopt a memory response upon primary stress exposure to facilitate a quicker and stronger reaction to recurring stresses. However, it remains unknown whether light is involved in the manifestation of stress memory. Proline accumulation is a striking metabolic adaptation of higher plants during various environmental stresses. Here we show that salinity-induced proline accumulation is memorable and HY5-dependent light signaling is required for such a memory response. Primary salt stress induced the expression of Δ 1 -pyrroline-5-carboxylate synthetase 1 (P5CS1), encoding a proline biosynthetic enzyme and proline accumulation, which were reduced to basal level during the recovery stage. Reoccurring salt stress-induced stronger P5CS1 expression and proline accumulation were dependent upon light exposure during the recovery stage. Further studies demonstrated that salt-induced transcriptional memory of P5CS1 is associated with the retention of increased H3K4me3 level at P5CS1 during the recovery stage. HY5 binds directly to light-responsive element, C/A-box, in the P5CS1 promoter. Deletion of the C/A-box or hy5 hyh mutations caused rapid reduction of H3K4me3 level at P5CS1 during the recovery stage, resulting in impairment of the stress memory response. These results unveil a previously unrecognized mechanism whereby light regulates salt-induced transcriptional memory via the function of HY5 in maintaining H3K4me3 level at the memory gene.transcriptional memory | light | H3K4me3 | HY5/HYH | P5CS1

Distinct heat shock factors and chromatin modifications mediate the organ‐autonomous transcriptional memory of heat stress

“…For APX2 , transcriptional memory was maintained for up to 1 week. This is very similar to what has been found for somatic stress memory in response to other stresses in A. thaliana ; after dehydration stress, transcriptional memory at RD29B was observed for at least 5 days but less than 7 days (Ding et al ., ) and similar results were observed for cross‐priming after repeated stress exposure (Singh et al ., ), while in response to salt stress the P5CS1 gene retained transcriptional memory for at least 5 days (Feng et al ., ). Interestingly, in all of these cases the transcriptional memory was associated with elevated histone H3K4me3 methylation, suggesting that there may be a common underlying mechanism.…”

“…In extreme cases, such a stress‐memory may extend into future generations (Pecinka et al ., ; Luna et al ., ; Rasmann et al ., ; Slaughter et al ., ; Wibowo et al ., ). Somatic transcriptional memory in the sense described above has been reported for drought stress (Ding et al ., ; Kim et al ., ), salt stress (Feng et al ., ) and for defense‐related genes after diverse priming stimuli (Jaskiewicz et al ., ; Singh et al ., ; Mozgova et al ., ). Chromatin modifications have been correlated with transcriptional memory in these cases (Jaskiewicz et al ., ; Ding et al ., ; Singh et al ., ; Feng et al ., ).…”

“…Somatic transcriptional memory in the sense described above has been reported for drought stress (Ding et al ., ; Kim et al ., ), salt stress (Feng et al ., ) and for defense‐related genes after diverse priming stimuli (Jaskiewicz et al ., ; Singh et al ., ; Mozgova et al ., ). Chromatin modifications have been correlated with transcriptional memory in these cases (Jaskiewicz et al ., ; Ding et al ., ; Singh et al ., ; Feng et al ., ). However, the mechanistic basis of stress‐induced transcriptional memory in all of these cases is still unknown, and it remains to be established whether the underlying mechanism is the same in all cases.…”

Epigenetic signatures of stress adaptation and flowering regulation in response to extended drought and recovery in Zea mays

“…Recently, H3K4me3 was linked to 'memory' both of drought and heat stress in plants (Ding, Fromm, & Avramova, 2012;Ding et al, 2013;Kim et al, 2012;Sani, Herzyk, Perrella, Colot, & Amtmann, 2013;Lamke, Brzezinka, Altmann & Bäurle 2016;Feng et al, 2016;Lamke & Bäurle, 2017). After a first moderate stress treatment, H3K4me3 levels at the promoters of 'memory genes' increased.…”

Lateral mechanical impedance rather than frontal, promotes cortical expansion of roots

“…Subsequently, quantitative real-time reverse transcription PCR (qRT-PCR) was performed using SsoFast™ EvaGreen® Supermix (Bio-Rad) in 96-well optical reaction plates in a Bio-Rad CFX96 Touch™ thermal cycler. Data were processed as described in our previous publication [13]. Quantification was performed using the 2−∆∆Ct method [14], where ∆∆Ct is the difference in threshold cycles between specific genes and the reference housekeeping gene eF1a.…”