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Meta‐analysis of the genetics of resistance to Fusarium head blight and deoxynivalenol accumulation in barley and considerations for breeding

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Abstract

Fusarium head blight (FHB) or scab is a devastating disease of barley that severely reduces the yield and quality of the grain. Additionally, mycotoxins produced by the causal Fusarium species can contaminate harvested grain, resulting in food safety concerns and further economic losses. In the Upper Midwest region of the United States, Fusarium graminearum is the primary causal agent, and deoxynivalenol (DON) is the main mycotoxin associated with Fusarium infection. Deployment of resistant cultivars is an important component of an integrated strategy to manage this disease. Unfortunately, few good sources of FHB resistance have been identified from the evaluation of large collections of Hordeum germplasm. Over the past 25 years, many barley mapping populations have been developed with selected resistance sources to identify the number, chromosomal position and allelic effect of quantitative trait loci (QTL) contributing to FHB resistance and DON accumulation. To consolidate the genetic data generated from 14 mapping studies that included 22 bi- or tri-parental mapping populations and three genome-wide association (GWAS) mapping panels, a consensus map was constructed that includes 4145 SNP, SSR, RFLP and AFLP markers. A meta-analysis based on this consensus map revealed 96 QTL for FHB resistance and 57 for DON accumulation scattered across the barley genome. Many of the QTL explained a low percentage (<10%) of variation for the traits and were often found significant in only one or a few environments in multi-year/multi-location field trials. Moreover, many of the FHB/DON QTL mapped to chromosomal positions coincided with various agro-morphological traits that could influence the level of disease (e.g. heading date, height, spike density, and spike angle), raising the important question of whether the former are true resistance factors or are simply the result of pleiotropy with the latter. Considering the magnitude of effect, consistency of detection across environments and independence from agro-morphological traits, only three of 96 QTL for FHB and five of 57 QTL for DON were considered priority targets for marker-assisted selection (MAS). In spite of the challenge for having a limited number of useful QTL for breeding, genomic selection holds promise for increasing the efficiency of developing FHB-resistant barley cultivars, an essential component of the overall management strategy for the disease.

Rat brown adipose tissue thermogenic markers are modulated by estrous cycle phases and short‐term fasting

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Rat brown adipose tissue thermogenic markers are modulated by estrous cycle phases and short-term fasting

This study confirmed that BAT exhibits morphological and functional changes in proestrus and diestrus. Moreover, BAT undergoes additional dynamic functional and morphological changes during short-term fasting.


Abstract

Brown adipose tissue (BAT) converts chemical energy into heat to maintain body temperature. Although fatty acids (FAs) represent a primary substrate for uncoupling protein 1 (UCP1)-dependent thermogenesis, BAT also utilizes glucose for the same purpose. Considering that estrous cycle effects on BAT are not greatly explored, we examined those of 6-h fasting on interscapular BAT (iBAT) thermogenic markers in proestrus and diestrus. We found that the percentage of multilocular adipocytes was lower in proestrus than in diestrus, although it was increased after fasting in both analyzed estrous cycle stages. Furthermore, the percentage of paucilocular adipocytes was increased by fasting, unlike the percentage of unilocular cells, which decreased in both analyzed stages of the estrous cycle. The UCP1 amount was lower in proestrus irrespectively of the examined dietary regimens. Regarding FA transporters, it was shown that iBAT CD36 content was increased in fasted rats in diestrus. In contrast to GLUT1, the level of GLUT4 was interactively modulated by selected estrous cycle phases and fasting. There was no change in insulin receptor and ERK1/2 activation, while AKT activation was interactively modulated by fasting and estrous cycle stages. Our study showed that iBAT exhibits morphological and functional changes in proestrus and diestrus. Moreover, iBAT undergoes additional dynamic functional and morphological changes during short-term fasting to modulate nutrient utilization and adjust energy expenditure.

Mineral nutrients in plants under changing environments: A road to future food and nutrition security

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Abstract

Plant nutrition is an important aspect that contributes significantly to sustainable agriculture, whereas minerals enrichment in edible source implies global human health; hence, both strategies need to be bridged to ensure “One Health” strategies. Abiotic stress-induced nutritional imbalance impairs plant growth. In this context, we discuss the molecular mechanisms related to the readjustment of nutrient pools for sustained plant growth under harsh conditions, and channeling the minerals to edible source (seeds) to address future nutritional security. This review particularly highlights interventions on (i) the physiological and molecular responses of mineral nutrients in crop plants under stressful environments; (ii) the deployment of breeding and biotechnological strategies for the optimization of nutrient acquisition, their transport, and distribution in plants under changing environments. Furthermore, the present review also infers the recent advancements in breeding and biotechnology-based biofortification approaches for nutrient enhancement in crop plants to optimize yield and grain mineral concentrations under control and stress-prone environments to address food and nutritional security.

Gluten subfractions of wheat storage proteins are affected by high night temperature during grain formation

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Abstract

Gluten (gliadin + glutenin) protein in wheat flour is affected by high temperature (day and/or night) resulting in undesirable consequences on dough quality. A study was conducted with early and late-maturing wheat genotypes, to assess the spatial (superior- central and inferior- apical and basal spikelets) variation in the composition of gluten subfractions in the developing ear under high night temperature (HNT). We hypothesised that protein content in the superior and inferior grains may show a differential quantitative and qualitative response to HNT. HNT resulted in a significant increase in protein content which exhibited a strong (r = −0.44*) negative correlation with sedimentation volume (SV) that determines baking quality. The late-maturity genotypes were more responsive to HNT with changes in ω-5 and γ gliadin subfractions of both superior and inferior spikelets, though a consistent trend was not established. The proportion of high molecular weight (HMW) glutenins increased, whereas low molecular weight (LMW) glutenins reduced in most of the genotypes under HNT. Both HMW and LMW glutenins revealed significant positive (r = 0.43* and r = 0.81***, respectively) correlation with SV. The expression analysis of genes for gluten subfractions showed a significant decrease in transcript abundance of α, ω-5, γ, HMW, and LMW fractions under HNT.

Protein concentrations and activities of fatty acid desaturase and elongase enzymes in liver, brain, testicle, and kidney from mice: Substrate dependency

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Protein concentrations and activities of fatty acid desaturase and elongase enzymes in liver, brain, testicle, and kidney from mice: Substrate dependency

The liver had the highest capacity for PUFA biosynthesis, with limited activity in the brain, testicles, and kidney, while we failed to detect activity in the heart and lung. The protein content and activity of the enzymes were significantly correlated. The capacity for PUFA synthesis in mice mainly resides in the liver, with enzymes having preference for n-3 PUFAs.


Abstract

The synthesis rates of n-3 and n-6 polyunsaturated fatty acids (PUFAs) in rodents and humans are not agreed upon and depend on substrate availability independently of the capacity for synthesis. Therefore, we aimed to assess the activities of the enzymes for n-3 and n-6 PUFA synthesis pathways in liver, brain, testicle, kidney, heart, and lung, in relation to their protein concentration levels. Eight-week-old Balb/c mice (n = 8) were fed a standard chow diet (6.2% fat, 18.6% protein, and 44.2% carbohydrates) until 14 weeks of age, anesthetized with isoflurane and tissue samples were collected (previously perfused) and stored at −80°C. The protein concentration of the enzymes (Δ-6D, Δ-5D, Elovl2, and Elovl5) were assessed by ELISA kits; their activities were assayed using specific PUFA precursors and measuring the respective PUFA products as fatty acid methyl esters by gas chromatographic analysis. The liver had the highest capacity for PUFA biosynthesis, with limited activity in the brain, testicles, and kidney, while we failed to detect activity in the heart and lung. The protein concentration and activity of the enzymes were significantly correlated. Furthermore, Δ-6D, Δ-5D, and Elovl2 have a higher affinity for n-3 PUFA precursors compared to n-6 PUFA. The capacity for PUFA synthesis in mice mainly resides in the liver, with enzymes having preference for n-3 PUFAs.

Greater rate of nitrogen fertilizer application increases root rot caused by Phytophthora cinnamomi and P. plurivora in container‐grown rhododendron

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Greater rate of nitrogen fertilizer application increases root rot caused by Phytophthora cinnamomi and P. plurivora in container-grown rhododendron

Application of nitrogen accelerated Phytophthora root rot disease symptoms in rhododendron plants inoculated with Phytophthora cinnamomi and P. plurivora.


Abstract

Phytophthora root rot, caused by many Phytophthora species, decreases the health of rhododendrons produced in nurseries. Optimizing nitrogen (N) fertilizer is often used to improve nursery stock quality, but there is little information on how N fertilizers influence root rot caused by these pathogens. To understand the impact of N fertilizer and pathogen species on root rot development, rhododendrons were grown with no (0 g N/pot), low (1.04 g N/pot) or high (3.12 g N/pot) rates of N and inoculated with either P. cinnamomi or P. plurivora. Noninoculated plants at low and high N rates had greater biomass, leaf greenness and enhanced N, potassium, magnesium, phosphorus, sulphur and manganese uptake compared to plants grown with no N. When either Phytophthora species was present, N application increased aboveground disease symptoms (wilting, chlorosis, reduced stomatal conductance and biomass), but had no effect on root rot severity belowground. In addition, P. cinnamomi restricted uptake of several nutrients while P. plurivora had less influence on nutrient uptake. Nurseries frequently apply high amounts of N to promote fast growth. However, our results show that this can exacerbate root rot when P. cinnamomi or P. plurivora is present. Although decreasing N can reduce the number of overtly symptomatic plants, this may conversely increase the risk for selling apparently asymptomatic plants with low levels of infection. Additional studies are needed to determine how N fertilization influences Phytophthora root rot for a broader range of rhododendron cultivars and nursery crop species.

Genetic variants associated with leaf spot disease resistance in oil palm (Elaeis guineensis): A genome‐wide association study

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Genetic variants associated with leaf spot disease resistance in oil palm (Elaeis guineensis): A genome-wide association study

Genome-wide association study using a diverse genetic background of the oil palm population reveals associated genes contributing to leaf spot disease resistance.


Abstract

Leaf spot is considered as a common disease of oil palm, caused primarily by Curvularia spp. fungi. This disease mainly affects the early stages of oil palm and if not adequately controlled can cause plant death. Among the methods available to control the disease, breeding resistant varieties is the most economically effective and promising strategy. A genome-wide association study for leaf spot resistance was conducted on 210 individual tenera palms from seven different (origin) crosses. These palms were subsequently infected with Curvularia spp. pathogenic inoculum in a nursery trial located in an endemic area. The area under the disease progress curve was used as a phenotypic measure. In addition, a genotyping-by-sequencing (GBS) approach was used to obtain the genotyping data of each individual. We found two loci, at chromosome 2 and chromosome 13, that were significantly associated with leaf spot disease resistance. Six genetic variants at the two loci (five variants at chromosome 2 and one variant at chromosome 13) surpassed the threshold for genome-wide significance (p < 106). These loci are linked with three widely known disease-related genes, namely, resistance gene analogue 3 (RGA3), resistance gene analogue 4 (RGA4) and receptor-like protein 9a (RLP9a). The loci identified here can be used for marker-assisted selection when developing leaf spot disease-resistant oil palm varieties.

Sodium Danshensu ameliorates cerebral ischemia/reperfusion injury by inhibiting CLIC4/NLRP3 inflammasome‐mediated endothelial cell pyroptosis

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Sodium Danshensu ameliorates cerebral ischemia/reperfusion injury by inhibiting CLIC4/NLRP3 inflammasome-mediated endothelial cell pyroptosis

Mechanism of SDSS in inhibiting endothelial cell pyroptosis. In the priming step, NLRP3, pro-Caspase-1, GSDMD-full, pro-IL-1β, and pro-IL-18 were up-regulated. Furthermore, the translocation of CLIC4 from cytoplasm to the membrane induced chloride outflow, resulting in the assembly of NLRP3, ASC and Pro-Caspase-1 into a platform (activation step). By binding CLIC4 and blocking its membrane localization, SDSS inhibited chloride outflow, thus inhibiting the activation of NLRP3 inflammasome and then the cleavage of pro-Caspase-1 into Caspase-1. This inhibited pyroptosis along with the release of IL-1β and IL-18, resulting from Caspase-1-dependent GSDMD-N cleavage.


Abstract

Endothelial pyroptosis promotes cerebral ischemia/reperfusion injury (CIRI). Sodium Danshensu (SDSS) has been shown to attenuate CIRI and have anti-inflammatory properties in endothelial cells. However, the mechanism and effect of SDSS on alleviating endothelial pyroptosis after CIRI remains poorly understood. Thus, we aimed to investigate the efficacy and mechanism of SDSS in reducing endothelial pyroptosis. It has been shown that SDSS administration inhibited NLRP3 inflammasome-mediated pyroptosis. As demonstrated by protein microarrays, molecular docking, CETSA and ITDRFCETSA, SDSS bound strongly to CLIC4. Furthermore, SDSS can decrease its expression and inhibit its translocation. Its effectiveness was lowered by CLIC4 overexpression but not by knockdown. Overall The beneficial effect of SDSS against CIRI in this study can be ascribed to blocking endothelial pyroptosis by binding to CLIC4 and then inhibiting chloride efflux-dependent NLRP3 inflammasome activation.

Genetic characterization and prevalence of Pseudomonas syringae strains from sweet cherry orchards in New Zealand

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Genetic characterization and prevalence of Pseudomonas syringae strains from sweet cherry orchards in New Zealand

The study identified prevalent Pseudomonas syringae strains in New Zealand cherry orchards, with P. syringae pv. syringae as the predominant pathovar in Central Otago, providing valuable insights for future epidemiology research.


Abstract

Bacterial canker of cherry, caused by Pseudomonas syringae pathovars, is a major constraint to cherry growing in New Zealand. The prevalence of strains from cherry orchards in Central Otago, the main growing area for cherries in New Zealand, was studied, to better understand the epidemiology of the disease. Pseudomonas spp. isolates were collected from symptomatic and asymptomatic cherry tissue from 23 commercial cherry orchards in 2015. Isolates were classified into strains belonging to three different taxonomic groups by determining their phylogeny using the gltA gene sequence for all the strains and multilocus sequence analysis (MLSA) of four housekeeping genes for 35 strains. Pathogenicity of all Central Otago strains was tested on immature cherry fruit to support the phylogenetic classification. The two main taxonomic groups were P. syringae pv. syringae (Pss) and P. syringae pv. morsprunorum race 1 (Psm1), in Phylogroup 2 (PG2) and Phylogroup 3 (PG3), respectively. The third group comprised nonpathogenic strains classified as Pseudomonas spp. Strains of Psm1 formed a monophyletic group, representing an almost clonal population. There was more variation detected within strains of Pss, although they were restricted to group PG2d. Nonpathogenic Pseudomonas spp. and pathogenic Pss and Psm1 strains coexisted in the same orchard. It was concluded that Pss is the predominant pathovar in Central Otago. This is the first detailed study of the P. syringae species complex in cherry orchards in New Zealand and provides the basis for future epidemiology studies.