Efficient crop improvement depends on the application of accurate genetic information contained in diverse germplasm resources. Here we report a reference-grade genome of wild soybean accession W05, ...with a final assembled genome size of 1013.2 Mb and a contig N50 of 3.3 Mb. The analytical power of the W05 genome is demonstrated by several examples. First, we identify an inversion at the locus determining seed coat color during domestication. Second, a translocation event between chromosomes 11 and 13 of some genotypes is shown to interfere with the assignment of QTLs. Third, we find a region containing copy number variations of the Kunitz trypsin inhibitor (KTI) genes. Such findings illustrate the power of this assembly in the analysis of large structural variations in soybean germplasm collections. The wild soybean genome assembly has wide applications in comparative genomic and evolutionary studies, as well as in crop breeding and improvement programs.
The effects of RE and Ti microalloying during electroslag remelting (ESR) process on the microsegregation and morphology of eutectic M2C carbides in M2 high speed steel were investigated. The results ...show that the addition of 0.2 wt% RE can alleviate the segregation of C, W, Mo, V and Cr, while the morphology of eutectic M2C carbides hardly changes. The microalloying with the addition of 0.5 wt% Ti has the lowest degree of microsegregation due to the improvement of primary dendrites by the effective heterogeneous nucleating agent of (Ti,V) (C,N) particles. The addition of Ti makes the morphology of M2C carbides change from rod-like or maze-like shape into a coarse feathery shape, exhibiting anisotropic facet growth characteristics. For the microalloying of 0.2 wt% RE and 0.5 wt% Ti, the segregation of the main metal alloying elements is slightly more severe than that of the addition of only RE or Ti. Under the combined action of RE and Ti, the feathery eutectic M2C becomes thinner and shorter and tends to be isolated or distributed in a discontinuous network.
In-situ Ti microalloying during ESR significantly reduces dendritic segregation of M2 high speed steel, and changes the morphology of M2C carbides from rod-like or maze-like to coarse feathery shape. In-situ Ti and RE composite microalloying improves the feather-like M2C carbides, making them thinner and shorter, and tends to be isolated or distributed in a discontinuous network. Display omitted
Flavonoids are a class of polyphenolic compounds that naturally occur in plants. Sub-groups of flavonoids include flavone, flavonol, flavanone, flavanonol, anthocyanidin, flavanol and isoflavone. The ...various modifications on flavonoid molecules further increase the diversity of flavonoids. Certain crops are famous for being enriched in specific flavonoids. For example, anthocyanins, which give rise to a purplish color, are the characteristic compounds in berries; flavanols are enriched in teas; and isoflavones are uniquely found in several legumes. It is widely accepted that the antioxidative properties of flavonoids are beneficial for human health. In this review, we summarize the classification of the different sub-groups of flavonoids based on their molecular structures. The health benefits of flavonoids are addressed from the perspective of their molecular structures. The flavonoid biosynthesis pathways are compared among different crops to highlight the mechanisms that lead to the differential accumulation of different sub-groups of flavonoids. In addition, the mechanisms and genes involved in the transport and accumulation of flavonoids in crops are discussed. We hope the understanding of flavonoid accumulation in crops will guide the proper balance in their consumption to improve human health.
High chromium cast iron (HCCI) has been widely used as wear-resistant material in the industry. Alloying is an effective way to improve the microstructure and mechanical properties of HCCI. This ...paper added multi-component V-Fe-Ti-Nb-C-Zr-B alloy (VFC) to HCCI, showing a significant synergistic solution-strengthening effect. The results show that the added V-Ti-Nb-B are dissolved in M
C
carbide to form the (Cr, Fe, V, Ti, Nb)
(C, B)
alloy carbide, and a small amount of V and all Zr are dissolved in austenite and martensite. Adding VFC into HCCI improved the hardenability of HCCI, decreased the residual austenite content from 6.0 wt% to 0.9 wt%, increased the martensite content from 70.7 wt% to 82.5 wt%, and changed the structure and content of M
C
carbide. These changes increased the hardness of as-cast and heat-tread HCCI by 1.4% and 4.1%, increased the hardness of austenite and martensite by 7.9% and 7.0%, increased the impact toughness by 16.9%, and decreased the friction coefficient and wear loss by 2.3 % and 7.0 %, respectively. Thus, the hardness, toughness, wear resistance, and friction resistance of HCCI alloy are improved simultaneously.
Soybean is a major legume crop with high nutritional and environmental values suitable for sustainable agriculture. Noncoding RNAs (ncRNAs), including microRNAs (miRNAs) and long noncoding RNAs ...(lncRNAs), are important regulators of gene functions in eukaryotes. However, the interactions between these two types of ncRNAs in the context of plant physiology, especially in response to salinity stress, are poorly understood.
Here, we challenged a cultivated soybean accession (C08) and a wild one (W05) with salt treatment and obtained their small RNA transcriptomes at six time points from both root and leaf tissues. In addition to thoroughly analyzing the differentially expressed miRNAs, we also documented the first case of miRNA arm-switching (miR166m), the swapping of dominant miRNA arm expression, in soybean in different tissues. Two arms of miR166m target different genes related to salinity stress (chloroplastic beta-amylase 1 targeted by miR166m-5p and calcium-dependent protein kinase 1 targeted by miR166m-3p), suggesting arm-switching of miR166m play roles in soybean in response to salinity stress. Furthermore, two pairs of miRNA:lncRNA interacting partners (miR166i-5p and lncRNA Gmax_MSTRG.35921.1; and miR394a-3p and lncRNA Gmax_MSTRG.18616.1) were also discovered in reaction to salinity stress.
This study demonstrates how ncRNA involves in salinity stress responses in soybean by miRNA arm switching and miRNA:lncRNA interactions. The behaviors of ncRNAs revealed in this study will shed new light on molecular regulatory mechanisms of stress responses in plants, and hence provide potential new strategies for crop improvement.
Salinity is a major environmental factor that constrains soybean yield and grain quality. Given our past observations using the salt-sensitive soybean (
L. Merr.) accession C08 on its early responses ...to salinity and salt-induced transcriptomic modifications, the aim of this study was to assess the lipid profile changes in this cultivar before and after short-term salt stress, and to explore the adaptive mechanisms underpinning lipid homeostasis. To this end, lipid profiling and proteomic analyses were performed on the leaves of soybean seedlings subjected to salt treatment for 0, 0.5, 1, and 2 h. Our results revealed that short-term salt stress caused dynamic lipid alterations resulting in recycling for both galactolipids and phospholipids. A comprehensive understanding of membrane lipid adaption following salt treatment was achieved by combining time-dependent lipidomic and proteomic data. Proteins involved in phosphoinositide synthesis and turnover were upregulated at the onset of salt treatment. Salinity-induced lipid recycling was shown to enhance jasmonic acid and phosphatidylinositol biosyntheses. Our study demonstrated that salt stress resulted in a remodeling of membrane lipid composition and an alteration in membrane lipids associated with lipid signaling and metabolism in C08 leaves.
Oxide particles with suitable size can refine the microstructure and improve the strength and toughness of steel. In this study, the particles containing Al2O3 were successfully introduced into H13 ...steel by vacuum casting. The micro-sized Al2O3-containg particles were randomly distributed in the dendritic structure and their number was increased by almost a factor of one. The secondary dendritic arm spacing of the ingot was decreased, which might be attributed to the heterogeneous nucleation of these oxides during solidification. Meanwhile, the alloying element segregation of the ingot was also alleviated. The micro-sized primary carbides were refined as the oxide particles were introduced to H13 steel, especially for V-rich carbides. After hot rolling and heat treatment, the size of austenitic grain was reduced by up to 75% (7.2 ± 1.8 μm), which was due to the particle stimulated nucleation and Zener pinning of micro- and nanoscale oxides in the oxide-added steel. The mechanical properties were obviously modified with the ultimate tensile strength of 1835 MPa, yield strength of 1479 MPa, tensile elongation of 13.4% and impact toughness of 24 J/cm2 after the introduction of oxide particles. It is expected that the introduction of oxide particles by vacuum casting can be applied widely in other die steel for superior performance.
Lamellar orientations and growth directions of β dendrites are investigated in Ti–47Al–2Cr–2Nb alloy with different temperature gradients (
G) and growth rates (
v) by directional solidification ...technique. It shows that β phase is the primary solidification phase when
G/v ratio is equal to or less than 4.8×10
8
K
s
m
−2, while the lamellar orientations vary with
G and
v. At
G of 40
K/cm and
v of 1
mm/min, lamellar orientation inclined at the angle of 74° to growth direction is preferred. As
G is increased to 125
K/cm, or
v is increased to 10
mm/min, lamellar orientation aligned at about 45° to growth direction is favored. At intermediate
G and
v, the orientations are aligned in the range of 45–78° to growth direction. Calculation of β-dendrite growth direction shows that growth direction is 〈2
2
1〉
β at low
G or
v, while the direction tends to be 〈1
0
0〉
β at high
G or
v.
► Lamellar orientations in Ti–47Al–2Cr–2Nb alloy vary with
G and
v. ► Growth direction is 〈2
2
1〉
β at low
G or
v, while the direction tends to be 〈1
0
0〉
β at high
G or
v. ► β phase is the primary solidification phase when
G/
v ratio is equal to or less than 4.8×10
8
K
s
m
−2.
Thermogravimetry-differential scanning calorimetry-mass spectrometry-Fourier transform infrared spectrometry（TG-DSC-MS-FTIR） simultaneous analysis was used to study the effects of 10.7 μm and 40 nm ...Al on the thermal decomposition of the Hexogen/ammonium perchlorate（RDX/AP,1/2,mass ratio） mixture.TG-DSC results show that there are two mass loss processes for the thermal decomposition of RDX/AP/Al.The first one is mainly ascribed to the thermal decomposition of RDX.The reaction rate of RDX/AP/10.7 μm Al is so fast that the apparent activation energy,calculated by model-free Friedman method,is negative,which is the same as that of RDX/AP.30％（mass fraction） 40 nm Al added in RDX/AP change the activation energy from negative to positive value.The second mass loss process of the RDX/AP/A1 mixture is ascribed to the thermal decomposition of AP.This process can be divided into three stages for RDX/AP with and without Al.The kinetics model is not changed in the presence of micro-sized Al,while it is changed from CnB/D1/D1 to CnB/D1/D4 after the addition of 40 nm Al to RDX/AP.The reaction rate constant of the first stage and the end temperature of the second stage decrease,while the end temperatures of the third stage increase in the presence of 40 nm Al.The MS-FTIR results show there is a competition between the formation reactions of HNCO,N2O and NO2 during the second mass loss process.
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