Histone modifications associated with drought tolerance in the desert plant Zygophyllum dumosum Boiss

Abstract

Zygophyllum dumosum Boiss. is a perennial Saharo-Arabian phytogeographical element and a dominant shrub on the rocky limestone southeast-facing slopes of the Negev desert. The plant is highly active during the winter, and semideciduous during the dry summer, i.e., it sheds its leaflets, while leaving the thick, fleshy petiole green and rather active during the dry season. Being resistant to extreme perennial drought, Z. dumosum appears to provide an intriguing model plant for studying epigenetic mechanisms associated with drought tolerance in natural habitats. The transition from the wet to the dry season was accompanied by a significant decrease in nuclear size and with posttranslational modifications of histone H3 N-terminal tail. Dimethylation of H3 at lysine 4 (H3K4)--a modification associated with active gene expression--was found to be high during the wet season but gradually diminished on progression to the dry season. Unexpectedly, H3K9 di- and trimethylation as well as H3K27 di- and trimethylation could not be detected in Z. dumosum; H3K9 monomethylation appears to be prominent in Z. dumosum during the wet but not during the dry season. Contrary to Z. dumosum, H3K9 dimethylation was detected in other desert plants, including Artemisia sieberi, Anabasis articulata and Haloxylon scoparium. Taken together, our results demonstrate dynamic genome organization and unique pattern of histone H3 methylation displayed by Z. dumosum, which could have an adaptive value in variable environments of the Negev desert.

Awaiting better times: A quiescence response and adventitious root primordia formation prolong survival under cadmium stress in Tetradenia riparia (Hochst.) Codd

“…Indeed, histone modifications, such as methylation and acetylation, in the chromatin surrounding genes are thought to regulate transcriptional activity and gene expression, with the methylation of H3-K4 generally associated with transcriptionally active chromatin (Pfluger and Wagner 2007;Granot et al, 2009). As plants are sessile organisms it has been shown that gene expression is dynamically controlled in response to the appearance or disappearance of an environmental stress through reversible and dynamic changes in histone modification (Tsuji et al, 2006), and declines in dimethylation of H3-K4 have been linked with the entry of the plants into a quiescent state during stressful periods (Granot et al, 2009).…”

“…The dynamics of histone modifications after 5 weeks of CdSO 4 treatments were analyzed, focusing on the demethylation of lysine 4, as this modification has previously been associated in plants with decondensed, transcriptionally active chromatin (Pfluger and Wagner 2007;Granot et al, 2009). Compared with the control plants, exposure for 5 weeks to 150 mM CdSO 4 led to the loss of the demethylation in lysine 4 (Fig.…”

“…Lawlor, 2013). This kind of survival has also been termed quiescence, and examples can be found in plants exposed to long periods of drought and salinity (Granot et al, 2009;Julkowska and Testerink, 2015) or in flooded plants (Bailey-Serres and Voesenek, 2008;Colmer et al, 2009;Luo et al, 2011;Bailey-Serres et al, 2012;Sasidharan and Voesenek, 2013). This inherent flexibility of plant in response to a changing environment has been related to the ability of the epigenetic status to alter rapidly and reversibly (Luo et al, 2012).…”

“…Chromatin status, which is governed by pattern and quantity of histone modifications that alter DNA-histone interaction and accessibility of transcription factors, has been implicated in the regulation of eukaryotic gene activity (Chinnusamy and Zhu, 2009;Kim et al, 2008). In particular the primary level controlling gene expression is the structure of chromatin, and modifications of the histone H3 at lysine 4 (H3-K4) have been associated with the transition from quiescent into active state as they dictate either gene silencing or gene activation (Tsuji et al, 2006;Granot et al, 2009).…”

Genetic and Molecular Aspects of Plant Response to Drought in Annual Crop Species

“…In particular, histone phosphorylation and ubiquitination showed a role in enhancing gene transcription , while biotinylation and sumoylation repress gene expression (Nathan et al, 2006;Camporeale et al, 2007). In the desert shrub Zygophyllum dumosum methylation level of histone H3 was higher in presence of water than under dry growth conditions indicating post-translational regulation of gene expression activity (Granot et al, 2009). …”