Guar gum is an effective depressant of talc, but it also has some depression effect on sulfide minerals. To find new selective depressants, the depression effects and mechanisms of tragacanth gum to ...talc were studied and its role in the flotation separation of chalcopyrite from talc was investigated by flotation test, adsorption and zeta potential tests as well as XPS analysis. The individual mineral flotation test results showed that the natural flotability of talc is good which make it easy to be reported into the concentrate. The guar gum and tragacanth gum can effectively depress the flotation of talc, and their depression effect is not affected by pH. The mixed minerals flotation tests indicated that the tragacanth gum can effectively separate chalcopyrite from talc, both the copper concentrate grade and recovery are high, besides, tragacanth gum exhibits less depression effects for chalcopyrite compared with guar gum. According to the Zeta potential and XPS measurements, it can be concluded that tragacanth gum adsorbed on talc surface mainly through physical interactions, and hydrophobic interaction was considered as the main driving force and hydrogen bond may also play a role.
MicroRNAs (miRNAs) are endogenous non-coding small RNAs that play vital regulatory roles in plant growth, development, and environmental stress responses. Cadmium (Cd) is a non-essential heavy metal ...that is highly toxic to living organisms. To date, a number of conserved and non-conserved miRNAs have been identified to be involved in response to Cd stress in some plant species. However, the miRNA-mediated gene regulatory networks responsive to Cd stress in radish (Raphanus sativus L.) remain largely unexplored. To dissect Cd-responsive miRNAs and their targets systematically at the global level, two small RNA libraries were constructed from Cd-treated and Cd-free roots of radish seedlings. Using Solexa sequencing technology, 93 conserved and 16 non-conserved miRNAs (representing 26 miRNA families) and 28 novel miRNAs (representing 22 miRNA families) were identified. In all, 15 known and eight novel miRNA families were significantly differently regulated under Cd stress. The expression patterns of a set of Cd-responsive miRNAs were validated by quantitative real-time PCR. Based on the radish mRNA transcriptome, 18 and 71 targets for novel and known miRNA families, respectively, were identified by the degradome sequencing approach. Furthermore, a few target transcripts including phytochelatin synthase 1 (PCS1), iron transporter protein, and ABC transporter protein were involved in plant response to Cd stress. This study represents the first transcriptome-based analysis of miRNAs and their targets responsive to Cd stress in radish roots. These findings could provide valuable information for functional characterization of miRNAs and their targets in regulatory networks responsive to Cd stress in radish.
Utilizing the digital economy’s contribution to green total factor productivity is a key strategy for accelerating China’s green growth, although more research is still needed to understand the ...mechanism of this influence. This study uses panel data from 282 Chinese prefecture-level cities from 2011 to 2019 to empirically assess the impact of the digital economy and city size on GTFP. First, GTFP overall exhibits an upward trend with excellent spatial correlation and minimal regional variation. Second, the findings demonstrate that, while surrounding locations’ GTFP is not affected by the digital economy, local productivity can be improved. Third, the heterogeneity study demonstrates that the digital economy contributes more to local GTFP in the eastern region compared to the central and western regions, with the central region making the largest contribution to GTFP in the surrounding regions; the first, second, and third tier cities have more contributions from the digital economy to local and neighboring GTFP than the fourth and fifth tier cities. Fourth, city size positively modifies the relationship between the green total factor productivity and the digital economy. The western region is where the positive moderating effect of city size expansion is greatest. Moreover, compared to first-, second-, and third-tier cities, the fourth- and fifth-tier cities have a stronger beneficial moderating effect of city size increase. In light of this, we should focus on the growth of the digital economy, optimize city scale, and fully exploit the scale effect produced by the concentration of the digital industries and the spillover effect produced by the spread of the digital technology.
Key message
We performed homoeologous recombination-based partitioning and physical mapping of wheat chromosome 3B and
Th. elongatum
chromosome 3E, providing a unique physical framework of this ...homoeologous pair for genome studies.
The wheat (
Triticum aestivum
, 2
n
= 6
x
= 42, AABBDD) and
Thinopyrum elongatum
(2
n
= 2
x
= 14, EE) genomes can be differentiated from each other by fluorescent genomic in situ hybridization (FGISH) as well as molecular markers. This has facilitated homoeologous recombination-based partitioning and engineering of their genomes for physical mapping and alien introgression. Here, we constructed a special wheat genotype, which was double monosomic for wheat chromosome 3B and
Th. elongatum
chromosome 3E and homozygous for the
ph1b
mutant, to induce 3B–3E homoeologous recombination. Totally, 81 3B–3E recombinants were recovered and detected in the primary, secondary, and tertiary homoeologous recombination cycles by FGISH. Comparing to the primary recombination, the secondary and tertiary recombination shifted toward the proximal regions due to the increase in homology between the pairing partners. The 3B–3E recombinants were genotyped by high-throughput wheat 90-K single nucleotide polymorphism (SNP) arrays and their recombination breakpoints physically mapped based on the FGISH patterns and SNP results. The 3B–3E recombination physically partitioned chromosome 3B into 38 bins, and 429 SNPs were assigned to the distinct bins. Integrative analysis of FGISH and SNP results led to the construction of a composite bin map for chromosome 3B. Additionally, we developed 22 SNP-derived semi-thermal asymmetric reverse PCR markers specific for chromosome 3E and constructed a comparative map of homoeologous chromosomes 3E, 3B, 3A, and 3D. In summary, this work provides a unique physical framework for further studies of the 3B–3E homoeologous pair and diversifies the wheat genome for wheat improvement.
Alternative splicing (AS) plays important roles in gene expression and proteome diversity. Single nucleotide polymorphism (SNP) and insertion/deletion (InDel) are abundant polymorphisms and ...co-dominant inheritance markers, which have been widely used in germplasm identification, genetic mapping and marker-assisted selection in plants. So far, however, little information is available on utilization of AS events and development of SNP and InDel markers from transcriptome in radish.
In this study, three radish transcriptome datasets were collected and aligned to the reference radish genome. A total of 56,530 AS events were identified from three radish genotypes with intron retention (IR) being the most frequent AS type, which accounted for 59.4% of the total expressed genes in radish. In all, 22,412 SNPs and 9436 InDels were identified with an average frequency of 1 SNP/17.9 kb and 1 InDel/42.5 kb, respectively. A total of 43,680 potential SSRs were identified in 31,604 assembled unigenes with a density of 1 SSR/2.5 kb. The ratio of SNPs with nonsynonymous/synonymous mutations was 1.05:1. Moreover, 35 SNPs and 200 InDels were randomly selected and validated by Sanger sequencing, 83.9% of the SNPs and 70% of the InDels exhibited polymorphism among these three genotypes. In addition, the 15 SNPs and 125 InDels were found to be unevenly distributed on 9 linkage groups. Furthermore, 40 informative InDel markers were successfully used for the genetic diversity analysis on 32 radish accessions.
These results would not only provide new insights into transcriptome complexity and AS regulation, but also furnish large amount of molecular marker resources for germplasm identification, genetic mapping and further genetic improvement of radish in breeding programs.
MicroRNAs (miRNAs) are a type of endogenous non-coding small RNAs that play critical roles in plant growth and developmental processes. Cytoplasmic male sterility (CMS) is typically a maternally ...inherited trait and widely used in plant heterosis utilization. However, the miRNA-mediated regulatory network of CMS occurrence during anther development remains largely unknown in radish. In this study, a comparative small RNAome sequencing was conducted in floral buds of CMS line 'WA' and its maintainer line 'WB' by high-throughput sequencing. A total of 162 known miRNAs belonging to 25 conserved and 24 non-conserved miRNA families were isolated and 27 potential novel miRNA families were identified for the first time in floral buds of radish. Of these miRNAs, 28 known and 14 potential novel miRNAs were differentially expressed during anther development. Several target genes for CMS occurrence-related miRNAs encode important transcription factors and functional proteins, which might be involved in multiple biological processes including auxin signaling pathways, signal transduction, miRNA target silencing, floral organ development, and organellar gene expression. Moreover, the expression patterns of several CMS occurrence-related miRNAs and their targets during three stages of anther development were validated by qRT-PCR. In addition, a potential miRNA-mediated regulatory network of CMS occurrence during anther development was firstly proposed in radish. These findings could contribute new insights into complex miRNA-mediated genetic regulatory network of CMS occurrence and advance our understanding of the roles of miRNAs during CMS occurrence and microspore formation in radish and other crops.
Hexaploid‐derived resistance genes exhibit complex inheritance and expression patterns in tetraploid backgrounds. This study aimed to characterize the inheritance patterns and genomic compatibilities ...of hexaploid‐derived Fusarium head blight (FHB) resistance genes in tetraploid durum wheat (Triticum durum Desf.). Evaluation of FHB resistance for F1 hybrids of hexaploid ‘Sumai 3’ crossed with tetraploid and hexaploid wheats indicated that Sumai 3‐derived FHB resistance genes exhibit a dominant phenotypic effect seen only in hexaploid hybrids. Alternately, the hexaploid‐derived FHB resistance genes from PI 277012 exhibited complete dominance in the crosses with both tetraploid and hexaploid wheat. FHB evaluation of the F1 hybrids of Sumai 3 and PI 277012 crossed with ‘Langdon’ (LDN)–‘Chinese Spring’ D‐genome substitution lines suggested that chromosomes 2B, 3B, 4B, 5B, 6B, 3A, 4A, 6A, and 7A contain genes that suppress expression of the Sumai 3‐derived FHB resistance, whereas chromosomes 4A, 6A, and 6B contain genes required for expression of PI 277012‐derived FHB resistance. A wide range of segregation for FHB severity (10–90%) was observed in the F2 generation of Sumai 3 crossed with durum cultivars LDN and ‘Divide’, but the distribution of F3 families derived from the most resistant F2 segregants was skewed towards susceptibility. Similar segregation trends were observed in the crosses of PI 277012 with other durum wheats, whereby FHB resistance became slightly diluted over successive generations. These results suggest tetraploid durum wheat contains the unique alleles at multiple gene loci on different chromosomes that positively and/or negatively regulate the expression of hexaploid‐derived FHB resistance genes, which complicate efforts to deploy these genes in durum breeding programs.
Core Ideas
Durum contains genes that enhance or suppress hexaploid‐derived FHB resistance.
The hexaploid‐derived FHB resistance genes were inherited differently in durum.
Genomic compatibility for FHB resistance was assessed by D genome substitutions.
Sumai 3‐derived FHB resistance was suppressed by loci on nine durum chromosomes.
Three durum chromosomes contain loci needed for PI 277012‐derived FHB resistance.
At this stage, the rapid development of computer technology and information technology in China has provided favorable conditions for the development of the game. In order to pursue the game ...experience, how to use artificial intelligence in the game has become a new research hotspot. Therefore, the current situation of artificial intelligence used in games was investigated, and the principles of Unity3D game engine were studied; then the intelligent behavior model for NPC was established by using the behavior tree as the basic algorithm, and the AI architecture of the agent in the game was designed; moreover, combined with the above analysis, the behavior tree model based on Q learning algorithm was calculated, and the application of Unity3D in the game was completed; finally, a game model was developed in combination with Unity3D game engine. The results show that the behavior tree based on Unity3D game engine can realize NPC’s intelligent behavior simply and efficiently, and the system can run at a good speed, which has theoretical guidance for the follow-up research of game artificial intelligence and simulation training.
Ascorbate is a primary antioxidant and an essential enzyme cofactor in plants, which has an important effect on the development of plant root system. To investigate the molecular mechanisms of ...ascorbate accumulation during root development and reveal the key genes of the ascorbate biosynthesis and recycling pathways, the expression of 16 related genes together with ascorbate abundance were analyzed in the flesh and skin of radish (Raphanus sativus L.) fleshy root. The content of ascorbate decreased with root growth in both the flesh and skin. Expression of GDP-d-mannose pyrophosphorylase, GDP-d-mannose-3′,5′-epimerase and d-galacturonate reductase were also decreased and correlated with ascorbate levels in the flesh. In the skin, the expression of GDP-d-mannose pyrophosphorylase and l-galactose dehydrogenase was correlated with ascorbate levels. These results suggested that ascorbate accumulation is affected mainly by biosynthesis rather than recycling in radish root, and the l-galactose pathway may be the major biosynthetic route of ascorbate, and moreover, the salvage pathway may also contribute to ascorbate accumulation. The data suggested that GDP-d-mannose pyrophosphorylase could play an important role in the regulation of ascorbate accumulation during radish fleshy taproot development.
•Expression profiling of 16 AsA related genes were firstly conducted in radish root.•AsA content variations were analyzed in flesh and skin during root development.•l-galactose pathway was found to be the major AsA biosynthetic route in radish root.•GMP was proposed to play a regulatory role in AsA accumulation of radish root.
The settling behavior of quartz using chitosan as flocculant has been studied and the mechanism has been discussed. The sedimentation results show that pH has an influence on the settling behavior of ...quartz particles and the sedimentation velocity is more quickly at acidic pH range. Chitosan is a useful flocculant for the settling of quartz but its flocculation effect is influenced greatly by pH. The sedimentation velocity of quartz is quickly and the volume of sediment is large when chitosan was added at pH 9. The reason is that chitosan is only sparingly soluble in water at pH 9, thus the adsorption amount is large and produce strongly flocculation effect. However, when the pH was changed from 9 to 3, the adsorbed chitosan desorption from quartz surface and the flocculation effect disappeared. The flocs were disorganized to the particles and the sediment can be consolidated to significantly higher densities.
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