BackgroundSugar beet is a highly salt-tolerant crop. However, its ability to withstand high salinity is reduced compared to sea beet, a wild ancestor of all beet crops. The aim of this study was to investigate transcriptional patterns associated with physiological, cytological and biochemical mechanisms involved in salt response in these closely related subspecies. Salt acclimation strategies were assessed in plants subjected to either gradually increasing salt levels (salt-stress) or in excised leaves, exposed instantly to salinity (salt-shock).ResultThe majority of DEGs was down-regulated under stress, which may lead to certain aspects of metabolism being reduced in this treatment, as exemplified by lowered transpiration and photosynthesis. This effect was more pronounced in sugar beet. Additionally, sugar beet, but not sea beet, growth was restricted. Silencing of genes encoding numerous transcription factors and signaling proteins was observed, concomitantly with the up-regulation of lipid transfer protein-encoding genes and those coding for NRTs. Bark storage protein genes were up-regulated in sugar beet to the level observed in unstressed sea beet. Osmotic adjustment, manifested by increased water and proline content, occurred in salt-shocked leaves of both genotypes, due to the concerted activation of genes encoding aquaporins, ion channels and osmoprotectants synthesizing enzymes. bHLH137 was the only TF-encoding gene induced by salt in a dose-dependent manner irrespective of the mode of salt treatment. Moreover, the incidence of bHLH-binding motives in promoter regions of salinity-regulated genes was significantly greater than in non-regulated ones.ConclusionsMaintaining homeostasis under salt stress requires deeper transcriptomic changes in the sugar beet than in the sea beet. In both genotypes salt shock elicits greater transcriptomic changes than stress and it results in greater number of up-regulated genes compared to the latter. NRTs and bark storage protein may play a yet undefined role in salt stress-acclimation in beet. bHLH is a putative regulator of salt response in beet leaves and a promising candidate for further studies.Electronic supplementary materialThe online version of this article (10.1186/s12870-019-1661-x) contains supplementary material, which is available to authorized users.

The metastable zone width of pure ammonium oxalate aqueous solutions, as represented by maximum supercooling ΔT max , is investigated as functions of cooling rate R and saturation temperature T 0 by the polythermal method. The experimental results are discussed by using two recently advanced approaches: (1) self-consistent Nývlt-like approach based on a power-law relationship between nucleation rate J and maximum supersaturation lnS max , and (2) a novel approach based on the relationship between J and lnS max described by the classical three-dimensional nucleation theory. Analysis of the experimental data revealed that both approaches describe the experimental data on metastable zone width by the polythermal method reliably and provide useful information about the physical processes and parameters involved in nucleation kinetics. The values of various physical quantities predicted by both of these approaches are reasonable for a fairly-soluble compound. A careful examination of the data on ΔT max as a function of T 0 obtained by polythermal method and from density measurements showed that ΔT max has a slight tendency to decrease with increasing saturation temperature T 0 . The values of lnS max at saturation temperature 303 K suggest that the metastable zone width of ammonium oxalate aqueous solutions is determined by primary nucleation in the polythermal method and by secondary nucleation during density measurements.

Eosinophils are core components of the immune system, yet tools are lacking to directly observe eosinophils in action in vivo. To better understand the role of tissue resident eosinophils, we used eosinophil-specific CRE (eoCRE) mice to create GFP and tdTomato reporters. We then employed intravital microscopy to examine the dynamic behaviour of eosinophils in the healthy GI tract, mesentery, liver, lymph node, skin and lung. Given the role of eosinophils in allergic airway diseases, we also examined eosinophils in the lung following ovalbumin sensitization and challenge. We were able to monitor and quantify eosinophilic behaviours including patrolling, crawling, clustering, tissue distribution and interactions with other leukocytes. Thus, these reporter mice allow eosinophils to be examined in real-time in living animals, paving the way to further understanding the roles eosinophils play in both health and disease.

Polyploidization is an important source of variability for plant breeding. Polyploids are often characterised by increased resistance to biotic and abiotic stresses. Since drought and pathogen attack are the main threats to apple cultivation, obtaining new sources of resistance is an important issue for apple breeding. The newly obtained autotetraploid clones of apple cv. ‘Redchief’ showed superior resistance to fire blight. The aim of the presented research was the in-depth phenotypic characterisation of ‘Redchief’ tetraploids and assessment of their response to drought at the physiological and genetic level. The growth of own-rooted five-year-old trees of ‘Redchief’ tetraploids was poor compared with diploids; all growth parameters—the number and length of current season shoots, the total length of current season shoots per tree and the cross-section area of the trunk—were reduced in tetraploid clones. Grafting on M9 rootstock improved the growth characteristics of ‘Redchief’ tetraploids. Compared with diploid plants, the leaves of tetraploids were thicker, with altered shape, higher chlorophyll content, and larger stomata, but the stomatal density decreased. The leaf anatomical structure of tetraploids was changed, the adaxial and abaxial epidermis and both types of mesophyll were significantly thicker than in diploids. Moreover, the pollen grains of tetraploids were larger, but their viability and germination were reduced. Under conditions of limited water supply, the reduction in growth parameters was smaller and the physiological parameters were higher in the ‘Redchief’ tetraploid clone 4x-25 than in diploid plants. The expression of APX gene was higher in tetraploids than in diploids 15 days after drought stress induction. The results suggest the enhanced drought tolerance of the studied ‘Redchief’ autotetraploid clone compared with its diploid counterpart.

To study possibility of protection of sweet cherry fruit against cracking several rows of ‘Lapins’ sweet cherry (Prunus avium L.) trees grafted on ‘Colt’ rootstock, spaced 5 × 2.5 m and trained to a central leader were covered with a plastic foil to a height of 5 m. Several rows were left uncovered as a control. In the years 2016 and 2018, sun irradiation, air temperature and fruit quality were evaluated. The plastic cover reduced solar irradiation under the tunnel roof by around 40%. Light distribution within tree canopies was depleted by roughly 50%, but in the lower parts of the tree canopies, it was reduced to 6%, which is below the critical level (20%) estimated for apple trees. These results indicate the necessity to remove the covers as soon as possible after harvesting. Mean daily temperature near the ground was lower under the covers than outside, but at the height of 4.0 m, daily mean temperature was 0.4 °C higher and mean temperature during midday hours was 1.5 °C higher. The plastic covering reduced the fruit cracking from about 20% to 2% in both seasons but did not affect the fruit yield. The plastic covering did not affect the firmness and antioxidant activity and total anthocyanin content, but in the year 2018, it reduced the mean fruit weight, soluble solid, titratable acidity, dry matter and total polyphenols content.