The Systems Architecture of Molecular Memory in Poplar after Abiotic Stress

Abstract

Throughout the temperate zones, plants face combined drought and heat spells in increasing frequency and intensity. Here, we compared periodic (intermittent, i.e., high-frequency) versus chronic (continuous, i.e., high-intensity) drought-heat stress scenarios in gray poplar (Populus3 canescens) plants for phenotypic and transcriptomic effects during stress and after recovery. Photosynthetic productivity after stress recovery exceeded the performance of poplar trees without stress experience. We analyzed the molecular basis of this stress-related memory phenotype and investigated gene expression responses across five major tree compartments including organs and wood tissues. For each of these tissue samples, transcriptomic changes induced by the two stress scenarios were highly similar during the stress phase but strikingly divergent after recovery. Characteristic molecular response patterns were found across tissues but involved different genes in each tissue. Only a small fraction of genes showed similar stress and recovery expression profiles across all tissues, including type 2C protein phosphatases, the LATE EMBRYOGENESIS ABUNDANT PROTEIN4-5 genes, and homologs of the Arabidopsis (Arabidopsis thaliana) transcription factor HOMEOBOX7. Analysis of the predicted transcription factor regulatory networks for these genes suggested that a complex interplay of common and tissue-specific components contributes to the coordination of post-recovery responses to stress in woody plants.

Distinctive Gene Expression Patterns Define Endodormancy to Ecodormancy Transition in Apricot and Peach

“…Among these 18 genes, two Myb-containing domain genes Myb108 (Prupe.1G111700) and Myb102 (Prupe.4G192000) and one homeobox 7 (HB7, Prupe.3G316600) were differentially expressed in both species. Past studies reported that HB7 is a stress response protein positively regulated by the ABA pathway (Söderman et al, 1996;Georgii et al, 2019). The high expression level of HB7 transcripts during ecodormancy in apricot and peach suggests high concentrations of ABA, which may be acting to repress bud break during ecodormancy.…”

Transcriptional Regulation of Drought Response in Arabidopsis and Woody Plants

“…Using periodically combined drought and heat treatments, several stress-related memory genes were identified through tissue-specific transcriptomic profiling studies in poplar. Among them, the homologs of Arabidopsis HOMEOBOX7 ( HB7 ) were proposed as the most prominent candidates enhancing plant photosynthesis during stress recovery ( Georgii et al, 2019 ). In conclusion, epigenetic regulation and stress memory play important roles in drought response and tolerance, but their regulatory roles have not been well defined and deserve further investigations.…”

Integrative Analysis ofSorghum BicolorGreen Prop Roots Under Elevated CO2and Water Deficit Conditions

“…A survey for related studies in the literature (E[CO 2 ] and water stress) was performed in order to compare the sorghum GPR expression pattern to Populus trichocarpa (Georgii et al, 2019), Glycine max (Bencke-Malato et al, 2019), Oryza sativa (Shen et al, 2011), and Zea mays (Opitz et al, 2014). After the selection of the studies, we performed the best hits identification between S. bicolor and each other species via Blastp analysis based on the following thresholds: percentage of identity ≥ 70% and e-value < 1e-10.…”