Effects of multiple abiotic stresses on lipids and sterols profile in barley leaves (Hordeum vulgare L.)

open6siPlants are usually exposed to several types of abiotic stress in regular field conditions. The lipid profile of barley homozygous lines exposed to drought, heat, salinity, and their combinations, was investigated in the present study. Free fatty acids, free sterols, and diacylglycerols were the most abundant classes (∼8.0% of plant material). The genetic background significantly impacted the lipid composition rather than the treatments, and diacylglycerols were the only lipid class affected by salinity (1.84 mg/100 mg plant tissue; ∼33% reduction). However, the genotype × treatment interaction analysis revealed that the lipid and sterol compositions depended on both genotype and environment. Our results suggest that inborn stress tolerance in barley is manifested by enhanced accumulation of most lipids, mainly sterols, especially in heat/drought-stressed plants. In addition, expression of the LTP2 gene may be indirectly involved in the abiotic stress reaction of barley by mediating intracellular transport of some lipid classesopenA. Kuczyńska; V. Cardenia; P. Ogrodowicza; .M. Kempa; M. T. Rodriguez-Estrada; K. MikołajczakaA. Kuczyńska; V. Cardenia; P. Ogrodowicza; .M. Kempa; M. T. Rodriguez-Estrada; K. Mikołajczak

Mutations in two global regulators lower individual mortality in Escherichia coli

There has been considerable investigation into the survival of bacterial cells under stress conditions, but little is known about the causes of mortality in the absence of exogenous stress. That there is a basal frequency of cell death in such populations may reflect that it is either impossible to avoid all lethal events, or alternatively, that it is too costly. Here, through a genetic screen in the model organism Escherichia coli, we identify two mutants with lower frequencies of mortality: rssB and fliA. Intriguingly, these two genes both affect the levels of different sigma factors within the cell. The rssB mutant displays enhanced resistance to multiple external stresses, possibly indicating that the cell gains its increased vitality through elevated resistance to spontaneous, endogenous stresses. The loss of fliA does not result in elevated stress resistance; rather, its survival is apparently due to a decreased physical stress linked to the insertion of the flagellum through the membrane and energy saved through the loss of the motor proteins. The identification of these two mutants implies that reducing mortality is not impossible; rather, due to its cost, it is subject to trade-offs with other traits that contribute to the competitive success of the organism

Editing of the urease gene by CRISPR-Cas in the diatom Thalassiosira pseudonana

Background: CRISPR-Cas is a recent and powerful addition to the molecular toolbox which allows programmable genome editing. It has been used to modify genes in a wide variety of organisms, but only two alga to date. Here we present a methodology to edit the genome of Thalassiosira pseudonana, a model centric diatom with both ecological significance and high biotechnological potential, using CRISPR-Cas. Results: A single construct was assembled using Golden Gate cloning. Two sgRNAs were used to introduce a precise 37 nt deletion early in the coding region of the urease gene. A high percentage of bi-allelic mutations (≤61.5%) were observed in clones with the CRISPR-Cas construct. Growth of bi-allelic mutants in urea led to a significant reduction in growth rate and cell size compared to growth in nitrate. Conclusions: CRISPR-Cas can precisely and efficiently edit the genome of T. pseudonana. The use of Golden Gate cloning to assemble CRISPR-Cas constructs gives additional flexibility to the CRISPR-Cas method and facilitates modifications to target alternative genes or species

Testing the relationship between vertical crustal movement and geoid uplift for the Sudetes area

The aim of this study was to examine the relationship between vertical movements of the Earth’s crust and variation in geoid height. Data from the Gravity Recovery and Climate Experiment (GRACE), precise levelling, tidal gauge observations and Global Navigation Satellite Systems (GNSS) stations for the Sudetes area were used. The GRACE data provided the possibility of the analysis of geopotential changes. The geoid heights were calculated for the period from April 2002 to March 2016, using data from GeoForschungsZentrum (GFZ) GRACE Level-2 Product Release 05 in the form of spherical harmonic coefficients, truncated at degree and order (d/o) 60. Different filters were used. The calculated geoid change over time has the approximate value of 0.16 mm/y. This value was compared to the expected change in geoid height, determined on the basis of the Earth’s crustal movements