Seasonal Growth of Zygophyllum dumosum Boiss.: Summer Dormancy Is Associated with Loss of the Permissive Epigenetic Marker Dimethyl H3K4 and Extensive Reduction in Proteins Involved in Basic Cell Functions

Abstract

Plants thriving in desert environments are suitable for studying mechanisms for plant survival under extreme seasonal climate variation. We studied epigenetic mechanisms underlying seasonal growth cycles in the desert plant Zygophyllum dumosum Boiss., which was previously shown to be deficient in repressive markers of di-methyl and tri-methyl H3K9 and their association with factors regulating basic cell functions. We showed a contingent association between rainfall and seasonal growth and the epigenetic marker of dimethyl H3K4, which disappears upon entry into the dry season and the acquisition of a dormant state. DNA methylation is not affected by a lack of H3K9 di-methyl and tri-methyl. Changes in methylation can occur between the wet and dry season. Proteome analysis of acid soluble fractions revealed an extensive reduction in ribosomal proteins and in proteins involved in chloroplasts and mitochondrial activities during the dry seasons concomitantly with up-regulation of molecular chaperone HSPs. Our results highlight mechanisms underlying Z. dumosum adaptation to seasonal climate variation. Particularly, summer dormancy is associated with a loss of the permissive epigenetic marker dimethyl H3K4, which might facilitate genome compaction concomitantly with a significant reduction in proteins involved in basic cell functions. HSP chaperones might safeguard the integrity of cell components.

Differential Response to Single and Combined Salt and Heat Stresses: Impact on Accumulation of Proteins and Metabolites in Dead Pericarps of Brassica juncea

“…The expression of small HSPs is commonly induced under various stress conditions but particularly following exposure to high temperature [49]. These proteins are accumulated in petioles of Zygophyllum dumosum during the dry season [50] or in husks of Avena sterilis growing in natural habitats experiencing drought [22] and implicated in stress tolerance, at least partly by serving as molecular chaperones that stabilize and maintain proper protein folding [51,52].…”

Continuum Modeling of Discrete Plant Communities: Why Does It Work and Why Is It Advantageous?

“…Plants thriving in variable desert environments show many additional mechanisms to cope with seasonal climate variations that involve changes in above-ground biomass. A good example of such mechanisms is found in Zygophyllum dumosum Boiss (bushy bean caper), which is well adapted to a variable, desert environment [17,18]. Its root system is composed mostly of lateral, rapidly growing roots in the upper soil layer that constitute the major active elements in absorbing water [19], but also a few roots that can extend several meters in depth [20].…”

Endophytic Bacteria Colonizing the Petiole of the Desert Plant Zygophyllum dumosum Boiss: Possible Role in Mitigating Stress

“…For preparation of petiole extracts (PEs), we used petioles that were collected during the summer (PE-S) and winter (PE-W) of 2010 and kept frozen at −80 °C until used [ 4 ]. Defrosted petioles (1 g) were first washed with sterile water to remove dust and ground with 10 mL of 20 mM of MES (2-(N-morpholino)-ethanesulfonic acid) buffer (pH 6) by using a mortar and pestle.…”

“…The leaf is compound and consist of a pair of fleshy leaflets, which are carried on a thick, fleshy, and wax-covered petiole ( Figure 1 B). It is semi-deciduous during the dry summer ( Figure 1 C); that is, it sheds its leaflets, while leaving the thick, fleshy petiole alive but dormant during the dry season ( Figure 1 D) [ 4 ]. At the beginning of the winter, metabolic processes reactivate in petioles and growth resumes, culminating in production of new stems carrying new compound leaves from buds located at petiole axils [ 1 , 5 ].…”

“…At the beginning of the winter, metabolic processes reactivate in petioles and growth resumes, culminating in production of new stems carrying new compound leaves from buds located at petiole axils [ 1 , 5 ]. Entry into a dormant state probably represents the major mechanism underlying petiole survival and the maintenance of cell components’ integrity during the dry season, which is accompanied by genome compaction and protein synthesis arrest [ 4 , 5 ]. How these petioles survive the long, hot summer while keeping the integrity of cellular components is still an open question.…”