Genetic architecture and marker-assisted breeding for salt tolerance in soybean

Salinity is one of the major abiotic stresses that inhibits plant growth and causes seed yield loss in soybean. Although a major gene for salt tolerance on chromosome (Chr.) 3 was mapped, cloned and characterized, it does not fully explain genetic variability for tolerance in soybean. Two mapping approaches, quantitative trait loci (QTL) mapping and genome-wide association study (GWAS), can complement each other to identify genomic regions and molecular markers associated with traits of interest. QTL mapping is more suitable to map traits governed by rare alleles in a designed population while GWAS is better in mapping traits underlined by few genes of large effect in the natural population. This study was performed to identify additional loci and new sources for salt tolerance by using both approaches. For bi-parental QTL mapping, salt tolerance of 132 F2 families was evaluated by accessing leaf scorch score (LSS), chlorophyll content ratio (CCR), leaf sodium content (LSC), and leaf chloride content (LCC). Their genotypes were obtained using the Illumina Infinium SoySNP6K BeadChip assay to map salt tolerant gene(s). A major locus significantly associated with LSS, CCR, LSC, and LCC was mapped to Chr. 3 with LOD scores of 19.1, 11.0, 7.7, and 25.6, respectively. In addition, a second locus associated with salt tolerance for LSC was also detected and mapped on Chr. 13 with a LOD score of 4.6 and an R2 of 0.115. The evaluation of salt tolerance of an F5 population derived from the same cross showed that combining salt tolerant alleles of major and minor loci significantly increased salt tolerance. On the other hand, GWAS for salt tolerance was conducted using SNPs of two datasets, SoySNP50K iSelect BeadChip and 3.7M SNP dataset (from whole-genome sequencing data), across 305 soybean accessions of a diverse panel. The known gene on Chr. 3 was confirmed by three gene-based markers (GBMs) that integrated into both datasets. Other genomic regions significantly associated with salt tolerance were identified on Chrs. 1, 2, 5, 6, 8, 14, 18, and 19 by analyzing 3.7M SNP dataset, in which the position on Chr. 8 strongly predicted a new minor locus for salt tolerance. The genotype-phenotype correlation using three GBMs discovered six new salt tolerant sources that may carry novel gene(s) for salt tolerance. By complementation tests and segregation analysis of salt tolerance among F2 plants developed from a cross of Fiskeby III and a salt tolerance accession, PI 468908, it was speculated that salt tolerance from PI 468908 was possibly controlled by a new gene instead of the known gene on Chr. 3. These significant loci in new salt tolerant sources coupled with significant SNP markers could be useful for marker-assisted selection in molecular breeding programs to improve salt tolerance in soybean.Includes bibliographical reference

PCB CONCENTRATIONS IN SQUID, BLOOD COCKLE, SNAIL, MUSSEL AND PORK IN SOUTH-EASTERN PROVINCES OF SOUTH VIETNAM

Joint Research on Environmental Science and Technology for the Eart

PRELIMINARY SURVEY OF ARSENIC CONCENTRATIONS IN WATERS OF DIFFERENT SOURCES IN HOCHIMINH CITY AND OTHER PROVINCES

Joint Research on Environmental Science and Technology for the Eart

Stability investigations of isotropic and anisotropic exponential inflation in the Starobinsky-Bel-Robinson gravity

In this paper, we would like to examine whether a novel Starobinsky-Bel-Robinson gravity model admits stable exponential inflationary solutions with or without spatial anisotropies. As a result, we are able to derive an exact de Sitter inflationary to this Starobinsky-Bel-Robinson model. Furthermore, we observe that an exact Bianchi type I inflationary solution does not exist in the Starobinsky-Bel-Robinson model. However, we find that a modified Starobinsky-Bel-Robinson model, in which the sign of coefficient of $R^2$ term is flipped from positive to negative, can admit the corresponding Bianchi type I inflationary solution. Unfortunately, stability analysis using the dynamical system approach indicates that both of these inflationary solutions turn out to be unstable. Interestingly, we show that a stable de Sitter inflationary solution can be obtained in the modified Starobinsky-Bel-Robinson gravity.Comment: 26 pages, 2 figures. V2 with the abstract revised to improve its clarity, some relevant references added, and some typos fixed. All main calculations and conclusions remain unchanged. Comments are welcom

Government Support and Firm Profitability in Vietnam

Existing studies on the linkage between government subsidies and firm financial performance often use a mean regression approach and focus mainly on developed countries. To fill the gap, this study, for the first time, considers the impact of government support activities on the profitability of manufacturing SMEs in a developing country, Vietnam. Using an unbalanced panel dataset covering the period 2009–2015, government financial supports show an insignificant linkage with firm profitability when using OLS. However, a fixed-effect quantile approach reveals that government financial support is negatively related for firms with low profit but is positively related for firms in the high profitability percentile. Our findings also suggest that policymakers should focus on helping start-ups instead of ineffective, informal firms

Optimization of L-asparaginase production from Escherichia coli using response surface methodology

Among the antitumor drugs, bacterial enzyme L-asparaginase has been employed as the most effective chemotherapeutic agent in pediatric oncotherapy especially for acute lymphoblastic leukemia. In previous study, the L-asparaginase from Erwinia chrysanthermy was expressed in Escherichia coli BL21(DE3). The recombinant L-asparaginase was produced from recombinant E.coli BL21(DE3) under different cultivation conditions (inducer concentration, inoculum concentration and KH2PO4 concentration). The optimized conditions by response surface methodology using face centered central composite design. The analysis of variance coupled with larger value of R2 (0.9) showed that the quadratic model used for the prediction was highly significant (p 0.05). Under the optimized conditions, the model produced L-asparaginase activity of 123.74 U/ml at 1.03 mM IPTG, 3% (v/v) inoculum and 0.5% (w/v) KH2PO4. Recombinant protein was purified by two step using gel filtration and DEAE chromatography. The purified L-asparaginase had a molecular mass of 37 kDa with specific activity of 462 U/mg and identified by MALDI-TOF mass spectrometry. Results of MALDI-TOF analysis confirmed that recombinant protein was L-asparaginase II. Recombinant L-asparaginase has antiproliferative activity with K562 cell line. In conclusion, this study has innovatively developed cultivation conditions for better production of recombinant L-asparaginase in shake flask culture

Cloning and expression of pigC gene in Escherichia coli

Prodigiosin (Pg), which is particularly of interest because of anticancer and antimicrobial activities, can be produced through the PigC-catalyzed condensation reaction of 4-methoxy-2, 2’-bipyrrole-5-carboxyaldehyde (MBC) and 2-methyl-3-amylpyrrole (MAP). Therefore, the PigC protein plays an important role in prodigiosin biosynthetic pathway. However, studies related to PigC protein have not been carried out in Vietnam yet. In this work, the pigC gene was cloned and expressed in Escherichia coli DH10B and BL21 (DE3), respectively. Using PCR and universal primers, we amplified a fragment of 3 kb covering entire coding region of the pigC gene from Serratia sp. strain M5. The pigC gene was inserted into pJET1.2 vector, and then transformed into E. coli DH10B. The sequence of a recombinant vector pJET1.2/pigC was evaluated by using whole colony PCR amplification. Sequence alignment results revealed that the obtained pigC gene possesses 71.5% and 75.4% of nucleotide identity in comparison with two strains, Serratia 39006 and Serratia sp. AS9 published in GenBank with their respective accession numbers of AJ833001 and CP002773. The recombinant vector pJET1.2/pigC was used to reamplify pigC, and the acquired amplicon was inserted into pET22b vector at the site of HindIII and XhoI. The clone E. coli BL21 (DE3) containing recombinant vector pET22b/pigC was expressed in the auto-induced medium. The presence of PigC protein in the lysate was identified as a 100 kDa band through Western Blot analysis using anti his-tag antibody. Afterward, the PigC protein was purified by Ni-NTA column, and its expression level was quantified through SDS-PAGE analysis. The results of our study provide a potential material for producing prodigiosin from recombinant protein in Vietnam