Salinity is an ever increasing menace that affects agriculture worldwide. Crops such as rice are salt sensitive, but its degree of susceptibility varies widely between cultivars pointing to extensive ...genetic diversity that can be exploited to identify genes and proteins that are relevant in the response of rice to salt stress. We used a diversity panel of 306 rice accessions and collected phenotypic data after short (6 h), medium (7 d) and long (30 d) salinity treatment (50 mm NaCl). A genome‐wide association study (GWAS) was subsequently performed, which identified around 1200 candidate genes from many functional categories, but this was treatment period dependent. Further analysis showed the presence of cation transporters and transcription factors with a known role in salinity tolerance and those that hitherto were not known to be involved in salt stress. Localization analysis of single nucleotide polymorphisms (SNPs) showed the presence of several hundred non‐synonymous SNPs (nsSNPs) in coding regions and earmarked specific genomic regions with increased numbers of nsSNPs. It points to components of the ubiquitination pathway as important sources of genetic diversity that could underpin phenotypic variation in stress tolerance.
Salinity is an ever increasing menace that affects agriculture worldwide. Crops such as rice are salt sensitive, but its degree of susceptibility varies widely between cultivars. We used a diversity panel of 306 rice accessions to perform genome‐wide association study (GWAS), identifying known and new transporters and transcription factors and components of the ubiquitination pathway as important sources of genetic diversity.
Increasing the potassium use efficiency (KUE) of crops is important for agricultural sustainability. However, a greater understanding of this complex trait is required to develop new, high-KUE ...cultivars. To this end, a genome-wide association study (GWAS) was applied to diverse rice (Oryza sativa L.) genotypes grown under potassium-stressed and -replete conditions. Using high-stringency criteria, the genetic architecture of KUE was uncovered, together with the breadth of physiological responses to low-potassium stress. Specifically, three quantitative trait loci (QTLs) were identified, which contained >90 candidate genes. Of these, the sodium transporter gene OsHKT2;1 emerged as a key factor that impacts on KUE based on (i) the correlation between shoot Na+ and KUE, and (ii) higher levels of HKT2;1 expression in high-KUE lines.
Archived samples from the Park Grass Experiment, established in 1856, were analysed to determine the impacts of long-term phosphate fertiliser applications on arsenic concentrations in soil and ...herbage. In plots receiving 35 kg P ha−1 annually (+P), topsoil As concentrations almost doubled from an initial value of ∼10 mg kg−1 during 1888–1947 and remained stable thereafter. The phosphate fertilisers used before 1948 contained 401–1575 mg As kg−1, compared to 1.6–20.3 mg As kg−1 in the later samples. Herbage samples from the +P plots collected during 1888–1947 contained significantly more As than those from the −P plots, but later samples did not differ significantly. Mass-balance calculations show that the increase in soil As can be explained by the As input from P fertiliser applications before 1948. The results demonstrate that the P fertilisers used on the Park Grass Experiment before 1948 caused substantial As contamination of the soil.
•Archived samples from the Park Grass Experiment (>150 years) were analysed.•Soil As concentration almost doubled during 1888–1947 in the +phosphate plots.•Phosphate fertilisers used before 1948 contained high concentrations of As.•Historically phosphate fertilisers could be an important source of As contamination.
Long-term phosphate applications before 1948 caused arsenic contamination in the soil of the Park Grass Experiment.
Natural variation can be exploited to identify allelic variants of proteins. In this study, patch clamp was used to determine transport properties of two AtTPK1 alleles from Landsberg and Kas‐2 ...ecotypes. No difference in conductance or ion selectivity was observed but the Kas version of TPK1 showed different Ca2+ dependence in its open probability compared to Ler. Leaves from Kas showed lower rates of water loss than those of Ler, in either the absence or presence of ABA, an observation that is consistent with higher TPK1 channel activity at comparable cytoplasmic Ca2+ concentrations. A model that explains the results is presented.
Natural variation can be exploited to identify allelic variants of proteins. In this study, patch clamp was used to determine transport properties of two At TPK 1 alleles from Landsberg and Kas‐2 ...ecotypes. No difference in conductance or ion selectivity was observed but the Kas version of TPK 1 showed different Ca 2+ dependence in its open probability compared to Ler. Leaves from Kas showed lower rates of water loss than those of Ler, in either the absence or presence of ABA , an observation that is consistent with higher TPK 1 channel activity at comparable cytoplasmic Ca 2+ concentrations. A model that explains the results is presented.
Impaired hepatic glucose and lipid metabolism are hallmarks of type 2 diabetes. Increased sulfide production or sulfide donor compounds may beneficially regulate hepatic metabolism. Disposal of ...sulfide through the sulfide oxidation pathway (SOP) is critical for maintaining sulfide within a safe physiological range. We show that mice lacking the liver- enriched mitochondrial SOP enzyme thiosulfate sulfurtransferase (Tst−/− mice) exhibit high circulating sulfide, increased gluconeogenesis, hypertriglyceridemia, and fatty liver. Unexpectedly, hepatic sulfide levels are normal in Tst−/− mice because of exaggerated induction of sulfide disposal, with associated suppression of global protein persulfidation and nuclear respiratory factor 2 target protein levels. Hepatic proteomic and persulfidomic profiles converge on gluconeogenesis and lipid metabolism, revealing a selective deficit in medium-chain fatty acid oxidation in Tst−/− mice. We reveal a critical role of TST in hepatic metabolism that has implications for sulfide donor strategies in the context of metabolic disease.
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•TST deficiency elevates sulfide, invoking exaggerated hepatic sulfide disposal•Exaggerated sulfide disposal triggers global hepatic protein underpersulfidation•Skewed persulfidation is associated with higher gluconeogenesis and impaired fat oxidation•Diabetogenic hepatic metabolism dominates over apparent peripheral insulin sensitization
Carter et al. show that mice lacking the mitochondrial sulfide oxidation pathway enzyme TST have high systemic sulfide levels that invoke an alternative hepatic sulfide disposal strategy. Consequently, hepatic metabolism is dominantly skewed toward a diabetogenic profile despite peripheral insulin sensitization. This has implications for sulfide donor therapeutic agents.
We review evidence for the boundary vector cell model of the environmental determinants of the firing of hippocampal place cells. Preliminary experimental results are presented concerning the effects ...of addition or removal of environmental boundaries on place cell firing and evidence that boundary vector cells may exist in the subiculum. We review and update computational simulations predicting the location of human search within a virtual environment of variable geometry, assuming that boundary vector cells provide one of the input representations of location used in mammalian spatial memory. Finally, we extend the model to include experience-dependent modification of connection strengths through a BCM-like learning rule - the size and sign of strength change is influenced by historic activity of the postsynaptic cell. Simulations are compared to experimental data on the firing of place cells under geometrical manipulations to their environment. The relationship between neurophysiological results in rats and spatial behaviour in humans is discussed.
Finding one's way in a large-scale environment may engage different cognitive processes than following a familiar route. The neural bases of these processes were investigated using functional MRI ...(fMRI). Subjects found their way in one virtual-reality town and followed a well-learned route in another. In a control condition, subjects followed a visible trail. Within subjects, accurate wayfinding activated the right posterior hippocampus. Between-subjects correlations with performance showed that good navigators (i.e., accurate wayfinders) activated the anterior hippocampus during wayfinding and head of caudate during route following. These results coincide with neurophysiological evidence for distinct response (caudate) and place (hippocampal) representations supporting navigation. We argue that the type of representation used influences both performance and concomitant fMRI activation patterns.
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