Cell-Wall-Degrading Enzymes-Related Genes Originating from Rhizoctonia solani Increase Sugar Beet Root Damage in the Presence of Leuconostoc mesenteroides

Sugar beet crown and root rot caused by Rhizoctonia solani is a major yield constraint. Root rot is highly increased when R. solani and Leuconostoc mesenteroides co-infect roots. We hypothesized that the absence of plant cell-wall-degrading enzymes in L. mesenteroides and their supply by R. solani during close contact, causes increased damage. In planta root inoculation with or without cell-wall-degrading enzymes showed greater rot when L. mesenteroides was combined with cellulase (22 mm rot), polygalacturonase (47 mm), and pectin lyase (57 mm) versus these enzymes (0–26 mm), R. solani (20 mm), and L. mesenteroides (13 mm) individually. Carbohydrate analysis revealed increased simpler carbohydrates (namely glucose + galactose, and fructose) in the infected roots versus mock control, possibly due to the degradation of complex cell wall carbohydrates. Expression of R. solani cellulase, polygalacturonase, and pectin lyase genes during root infection corroborated well with the enzyme data. Global mRNAseq analysis identified candidate genes and highly co-expressed gene modules in all three organisms that might be critical in host plant defense and pathogenesis. Targeting R. solani cell-wall-degrading enzymes in the future could be an effective strategy to mitigate root damage during its interaction with L. mesenteroides.     

Leaf Bacteriome in Sugar Beet Shows Differential Response against Beet curly top virus during Resistant and Susceptible Interactions

Beet curly top virus (BCTV) significantly reduces sugar beet yield in semi-arid production areas. Genetic resistance to BCTV is limited; therefore, identification of additional resistance-associated factors is highly desired. Using 16S rRNA sequencing and BCTV resistant (R) genotypes (KDH13, KDH4-9) along with a susceptible (S) genotype (KDH19-17), we investigated leaf bacteriome changes during BCTV post inoculation (pi). At day 6 (~6-week-old plants), Cyanobacteria were predominant (~90%); whereas, at week 4 (~10-week-old plants) Firmicutes (11–66%), Bacteroidetes (17–26%), and Verrucomicrobia (12–29%) were predominant phyla and genotype dependent. Both Bacteroidetes and Verrucomicrobia, increased post infection only in the R lines. The bacterial genera Brevibacillus increased at 6 dpi, and Akkermansia and Bacteroides at 4 wkpi in the R lines. Linear discriminant analysis effect size (LEfSe) identified potential biomarkers in the R vs. S lines. Functional profiling revealed bacterial enrichment associated with the TCA cycle, polyisoprenoid, and L-methionine biosynthesis pathways only in KDH4-9 at 6 dpi. At 4 wkpi, bacteria associated with tryptophan and palmitate biosynthesis in the R lines, and uridine monophosphate, phosphatidyl glycerol, and phospholipid biosynthesis in the S line, were enriched. Future characterization of bacterial genera with antiviral properties will help establish their use as biocontrol agents/biomarkers against BCTV.     

Fatigue Crack Growth Behavior of Silicon Nitride: Roles of Grain Aspect Ratio and Intergranular Film Composition

The role of microstructure in affecting the fatigue crack growth resistance of grain bridging silicon nitride ceramics doped with rare earth (RE = Y, La, Lu) oxide sintering additives was investigated. Three silicon nitride ceramics were prepared using MgO‐RE₂O₃ and results were compared with a commercial Al₂O₃‐Y₂O₃‐doped material. Decreasing stress intensity range (ΔK) fatigue tests were conducted using compact‐tension specimens to measure steady‐state fatigue crack growth rates. Specimens doped with MgO‐RE₂O₃ additives showed a significantly higher resistance to crack growth than those with Al₂O₃‐Y₂O₃ additives and this difference was attributed to the much higher grain aspect ratio for the MgO‐RE₂O₃‐doped ceramics. When the crack growth data were normalized with respect to the total contribution of toughening by bridging determined from the monotonically loaded R‐curves, the differences in fatigue resistance were greatly reduced with the data overlapping considerably. Finally, all of the MgO‐RE₂O₃‐doped silicon nitrides displayed similar steady‐state fatigue crack growth behavior suggesting that they are relatively insensitive to the intergranular film.     

Interactive Effects of Silicon and Soil pH on Growth,Yield and Nutrient Uptake of Maize

Silicon - Priming crop seeds with silicon (Si) to withstand various abiotic stresses is a novel approach. As soil pH affects dissolution of Si pools and Si uptake by plant, evaluation of this...     

Immunological Roles of NLR in Allergic Diseases and Its Underlying Mechanisms

Our understanding on the immunological roles of pathogen recognition in innate immunity has vastly increased over the past 20 years. Nucleotide-binding oligomerization domain (NOD)-like receptors (NLR) are cytosolic pattern recognition receptors (PRR) that are responsible for sensing microbial motifs and endogenous damage signals in mammalian cytosol for immune surveillance and host defense. The accumulating discoveries on these NLR sensors in allergic diseases suggest that the pathogenesis of allergic diseases may not be confined to the adaptive immune response. Therapy targeting NLR in murine models also shields light on its potential in the treatment of allergies in man. In this review, we herein summarize the recent understanding of the role of NLR sensors and their molecular mechanisms involved in allergic inflammation, including atopic dermatitis and allergic asthma.     

除草剂甜菜安、甜菜宁与乙呋草黄的复配及其药效

采用盆栽喷雾法筛选了甜菜安、甜菜宁、乙呋草黄的复配配方,结果表明,组合70+90+110或90+90+90为优选配方。对21%甜菜安.甜菜宁.乙呋草黄乳油进行了2年3地的田间试验,结果表明,在有效成份1260～1680 g/hm2下,可以较好地防除阔叶杂草和部分禾本科杂草。本研究为甜菜田除草剂的研发提供了有益参考。     

Formation of Reaction-Bonded Silicon Nitride from Silane-Derived Silicon Powders: Nucleation and Growth Mechanisms

The nucleation and growth of Si₃N₄ on silane-derived Si powders was investigated with transmission electron microscopy and FTIR spectroscopy. Thermogravimetric analysis (TGA) was also used to monitor the process through different stages of the reaction. The FTIR and TEM results provide clear evidence that the nucleation of crystalline Si₃N₄ coincides with the onset of rapid nitridation. Electron diffraction indicates that Si₃N₄ forms heteroepitaxially on the Si powder surfaces, with Si (111) || Si₃N₄(0001) and Si     || Si₃N₄     . Also, flat interfaces between the Si and Si₃N₄ (compared to the initial spherical surface of the Si powders) indicate that a significant rearrangement of the particle surface occurs during the initial stages of nitridation. The results reported here demonstrate that the rapid, low-temperature nitridation observed with silane-derived powders is possible because the Si/vapor surfaces are not covered with a continuous Si₃N₄ product layer. The measured nitridation rates are comparable to Si evaporation rates, which suggests that Si vaporization is rate limiting. This is significantly different from conventional RBSN, where nitridation is limited by solid-state diffusion through a Si₃N₄ product layer.     

Cellular and Molecular Alterations Underlying Abnormal Bone Growth in X-Linked Hypophosphatemia

X-linked hypophosphatemia (XLH), the most common form of hereditary hypophosphatemic rickets, is caused by inactivating mutations of the phosphate-regulating endopeptidase gene (PHEX). XLH is mainly characterized by short stature, bone deformities and rickets, while in hypophosphatemia, normal or low vitamin D levels and low renal phosphate reabsorption are the principal biochemical aspects. The cause of growth impairment in patients with XLH is not completely understood yet, thus making the study of the growth plate (GP) alterations necessary. New treatment strategies targeting FGF23 have shown promising results in normalizing the growth velocity and improving the skeletal effects of XLH patients. However, further studies are necessary to evaluate how this treatment affects the GP as well as its long-term effects and the impact on adult height.     

Stress Alleviation and Crop Improvement Using Silicon Nanoparticles in Agriculture: a Review

Silicon - Silicon (Si) is not considered as essential element for plant growth and development but it provides benefits to the plants in several ways. Due to distinguishing physiological features,...     

One Hundred Candidate Genes and Their Roles in Drought and Salt Tolerance in Wheat

Drought and salinity are major constraints to agriculture. In this review, we present an overview of the global situation and the consequences of drought and salt stress connected to climatic changes. We provide a list of possible genetic resources as sources of resistance or tolerant traits, together with the previous studies that focused on transferring genes from the germplasm to cultivated varieties. We explained the morphological and physiological aspects connected to hydric stresses, described the mechanisms that induce tolerance, and discussed the results of the main studies. Finally, we described more than 100 genes associated with tolerance to hydric stresses in the Triticeae. These were divided in agreement with their main function into osmotic adjustment and ionic and redox homeostasis. The understanding of a given gene function and expression pattern according to hydric stress is particularly important for the efficient selection of new tolerant genotypes in classical breeding. For this reason, the current review provides a crucial reference for future studies on the mechanism involved in hydric stress tolerance and the use of these genes in mark assistance selection (MAS) to select the wheat germplasm to face the climatic changes.     

The Preference of Silicon Carbide for Growth in the Metastable Cubic Form

A paradox is discussed concerning the growth of SiC polytypes from the vapor or the melt, based on recent ab initio quantum calculations of the relative energies of several polytypes in bulk. Why does the cubic (3C) structure grow in preference to all others, although the calculations indicate it is not the stable phase at any temperature? This can be explained from the calculations, with some further approximations, as due to the constrained equilibrium when adding one atomic double layer at a time to the growing crystal in the hexagonal direction without allowing rearrangement of the lower layers. The differing roles of donor and acceptor impurities are also discussed, with donors being found to favor the cubic structure.     

Integrating the Roles for Cytokinin and Auxin in De Novo Shoot Organogenesis: From Hormone Uptake to Signaling Outputs

De novo shoot organogenesis (DNSO) is a procedure commonly used for the in vitro regeneration of shoots from a variety of plant tissues. Shoot regeneration occurs on nutrient media supplemented with the plant hormones cytokinin (CK) and auxin, which play essential roles in this process, and genes involved in their signaling cascades act as master regulators of the different phases of shoot regeneration. In the last 20 years, the genetic regulation of DNSO has been characterized in detail. However, as of today, the CK and auxin signaling events associated with shoot regeneration are often interpreted as a consequence of these hormones simply being present in the regeneration media, whereas the roles for their prior uptake and transport into the cultivated plant tissues are generally overlooked. Additionally, sucrose, commonly added to the regeneration media as a carbon source, plays a signaling role and has been recently shown to interact with CK and auxin and to affect the efficiency of shoot regeneration. In this review, we provide an integrative interpretation of the roles for CK and auxin in the process of DNSO, adding emphasis on their uptake from the regeneration media and their interaction with sucrose present in the media to their complex signaling outputs that mediate shoot regeneration.     

The Manipulation and Alignment of Silicon Carbide Whiskers for Gallium Nitride Epitaxial Growth

As a substrate candidate for low‐cost III‐nitride thin film growth, 3C–SiC whiskers are employed and manipulated in this work. The alignment of the whiskers is achieved on a patterned 3M Vikuiti^? Brightness Enhancement Film surface. The degree of whisker alignment using this approach is higher than the whiskers lined up by extrusion methods according to X‐ray diffraction (XRD) analysis. The aligned whiskers are transferred from the 3M film and embedded into an alumina matrix by tape casting. A self‐regulating sintering technique for SiC whiskers is used to protect the whiskers from being oxidized in air during sintering at 1600°C. The aligned whiskers are rigidly embedded in the alumina matrix as shown in scanning electron microscopy (SEM) images and energy‐dispersive X‐ray spectrometry energy mapping images. GaN thin films grown by a low‐cost sputtering process on Alumina/SiC as well as Si and SiC as reference materials are characterized by XRD and SEM.     

A New Design of Side Heater for 3D Solid-liquid Interface Improvement in G8 Directional Solidification Silicon Ingot Growth

Silicon - G8 ingots have a significant advantage in production capacity and yield improvement for directional solidification silicon. To improve the uniformity of the 3D solid/liquid (S/L)...     

Genome-Wide Identification and Characterisation of Wheat MATE Genes Reveals Their Roles in Aluminium Tolerance

The Multidrug and toxin efflux (MATE) gene family plays crucial roles in plant growth and development and response to adverse stresses. This work investigated the structural and evolutionary characteristics, expression profiling and potential functions involved in aluminium (Al) tolerance from a genome-wide level. In total, 211 wheat MATE genes were identified, which were classified into four subfamilies and unevenly distributed on chromosomes. Duplication analysis showed that fragments and tandem repeats played the main roles in the amplification of TaMATEs, and Type II functional disproportionation had a leading role in the differentiation of TaMATEs. TaMATEs had abundant Al resistance and environmental stress-related elements, and generally had a high expression level in roots and leaves and in response to Al stress. The 3D structure prediction by AlphaFold and molecular docking showed that six TaMATE proteins localised in the plasmalemma could combine with citrate via amino acids in the citrate exuding motif and other sites, and then transport citrate to soil to form citrate aluminium. Meanwhile, citrate aluminium formed in root cells might be transported to leaves by TaMATEs to deposit in vacuoles, thereby alleviating Al toxicity.     

Expression Patterns of Sugar Transporter Genes in the Allocation of Assimilates and Abiotic Stress in Lily

During the growth cycle of lilies, assimilates undergo a process of accumulation, consumption and reaccumulation in bulbs and are transported and allocated between aboveground and underground organs and tissues. The sink–source relationship changes with the allocation of assimilates, affecting the vegetative growth and morphological establishment of lilies. In this study, the carbohydrate contents in different tissues of five critical stages during lily development were measured to observe the assimilates allocation. The results showed bulbs acted as the main source to provide energy before the budding stage (S3); after the flowering stage (S4), bulbs began to accumulate assimilates as a sink organ again. During the period when the plant height was 30cm with leaf-spread (S2), leaves mainly accumulated assimilates from bulbs through the symplastic pathway, while when leaves were fully expanded, it transformed to export carbohydrates. At the S4 stage, flowers became a new active sink with assimilates influx. To further understand the allocation of assimilates, 16 genes related to sugar transport and metabolism (ST genes) were identified and categorized into different subfamilies based on the phylogenetic analysis, and their protein physicochemical properties were also predicted. Tissue-specific analysis showed that most of the genes were highly expressed in stems and petals, and it was mainly the MST (monosaccharide transporter) genes that were obviously expressed in petals during the S4 stage, suggesting that they may be associated with the accumulation of carbohydrates in flowers and thus affect flower development process. LoSWEET14 (the Sugar will eventually be exported transporters) was significantly correlated with starch in scales and with soluble sugar in leaves. Sugar transporters LoHXT6 and LoSUT1 were significantly correlated with soluble sugar and sucrose in leaves, suggesting that these genes may play key roles in the accumulation and transportation of assimilates in lilies. In addition, we analyzed the expression patterns of ST genes under different abiotic stresses, and the results showed that all genes were significantly upregulated. This study lays a solid foundation for further research on molecular mechanism of sink–source change and response to abiotic stresses in lilies.     

Dynamics of Consolidation and Crack Growth in Nanocluster-Assembled Amorphous Silicon Nitride

Consolidation and fracture dynamics in nanophase amorphous Si3N4 are investigated using 106-atom molecular-dynamics simulations. At a pressure of 15 GPa and 2000 K, the nanophase system is almost fully consolidated within a fraction of a nanosecond. The consolidation process is well-described by the classical theory of sintering. Under an applied strain the consolidated system develops several cracks which propagate parallel to each other, causing failure at multiple sites. The critical strain at which the nanophase system fractures is much larger than that for crystalline Si3N4.     

Subcritical Crack Growth in CVI Silicon Carbide Reinforced with Nicalon Fibers: Experiment and Model

Subcritical crack growth measurements of ceramic-matrix composites have been conducted on materials consisting of CVI SiC matrix reinforced with Nicalon fibers (SiC/SiC_f) having C and BN fiber–matrix interfaces. Velocities of effective elastic cracks were determined as a function of applied stress intensity in pure Ar and in Ar plus 2000 ppm O₂ at 1100°C. A stage-II regime, where the crack velocity depends only weakly on the applied stress intensity, was observed in the V–K diagrams over a range of applied stress intensities that correspond to the R -curve of the materials. This stage-II behavior was followed by a stage-III, or power-law, regime at higher stress intensity values. Oxygen was observed to increase the crack velocity in the stage-II regime and to shift the stage-II-to-stage-III transition to lower stress intensity values. A 2D micromechanics approach was developed to model the time dependence of observed crack-bridging events and is able to rationalize the measured effective crack velocities, the time dependence of the crack velocity, and the stage-II-to-stage-III transition in terms of the stress relaxation of crack-bridging fibers.