Gideon Grafi

Plants thriving in harsh desert environments provide a suitable bio-system for unraveling novel mechanisms for survival under seasonal climate change and combination of temperature extremes, low water and nutrient availability and high salinity and radiation levels. The study of the desert plant Zygophyllum dumosum Boiss in its the natural habitat of the Negev desert revealed that stress tolerance is achieved by a plethora of mechanisms (e.g. morphological, molecular and developmental mechanisms), which are probably regulated by multiple genes that act together to bring about tolerance. Of particular interest is the finding that Z. dumosum like other Zygophyllaceae species, most of which inhabit dry and semidry regions of the world, do not possess the repressive epigenetic markers of histone H3 di- and tri-methylated at lysine 9; yet they possess mono methyl H3K9. We discuss the adaptive value of lessening epigenetic constraints with regard to the opportunistic behavior that makes plants most adaptable to change.

Simcha Lev-Yadun, Gideon Grafi and Dalia Grafi

Harvester ants are common and very efficient granivores in many regions of the world. The ants may collect dispersed seeds from the ground or climb on plants to harvest seeds. While collecting or harvesting wild cereal seeds they first trim the long and bulky awns to allow better seed transportation to their nests and through the narrow passages inside their nests. In domesticated free-threshing cereals, flower parts including awns are not adhered to the seeds as in wild-type cereals and cutting open the loose glumes is sufficient to free the seeds. However, when various harvester ant (Messor spp.) species climb on domesticated free-threshing bread wheat in agricultural fields to harvest seeds they keep their ancient habit of beginning harvest by awn trimming of wild-types in spite of the fact that it is not necessary in the domesticated ones. We show and discuss their conservative harvest behavior.

Noga Sikron-Persi, Gila Granot, Gideon Grafi and Aaron Fait

The biochemical composition of Zygophyllum dumosum Boiss (Zygophyllaceae) was analyzed in petioles collected in the summer and winter from plants growing in a natural ecosystem on a southeast-facing slope of the Negev desert. UPLC-QTOF MS based analysis identified season specific sulfur containing phenylpropanoids unreported in plants. Sulfuric-caffeic and -ferulic acid derivatives and isorhamnetin 3-O-(4-sulfate-rutinoside) were measured to accumulate specifically in the summer. The reported identification and accumulation of sulfate containing metabolites during the hot and dry summer can be related to the putative protective role reported for these compounds.