IKBKE enhances TMZ-chemoresistance through upregulation of MGMT expression in glioblastoma.

PURPOSE: Glioblastoma multiforme (GBM) is the most common and aggressive malignant type of brain tumor. Despite advances in diagnosis and therapy, the prognosis of patients with GBM has remained dismal. Multidrug resistance and high recurrence are two of the major challenges in successfully treating brain tumors. IKBKE (inhibitor of nuclear factor kappa-B kinase subunit epsilon) is a major oncogenic protein in tumors and can inhibit glioblastoma cell proliferation, migration, and tumorigenesis. Our study aimed to investigate the mechanism of IKBKE enhancing the resistance of glioma cells to temozolomide. METHODS: For the in vitro experiments, LN18 and U118 glioblastoma cells were treated with a combination of sh/oe-IKBKE lentivirus and TMZ. Cell proliferation was determined by the EdU assay and colony formation assays. Apoptosis was analyzed by the TUNEL assay. In vivo, LN18 NC and LN18 sh-IKBKE cells were implanted into the cerebrums of nude mice to detect the effect of combination therapy. The protein and mRNA levels were assayed by western blot, immunohistochemistry, and qRT-PCR. RESULTS: In this study, we demonstrated that IKBKE enhances the resistance of glioblastoma cells to temozolomide (TMZ) by activating the AKT/NF-κB signaling pathway to upregulate the expression of the DNA repair enzyme o6-methylguanine-dna methyltransferase (MGMT). In glioblastoma cells, IKBKE knockdown enhances apoptosis and suppresses cell proliferation, clone formation, and tumor development in vivo induced by TMZ. However, overexpression of IKBKE reduces the effects of TMZ. CONCLUSION: Our studies suggest that inhibition of IKBKE can enhance the therapeutic effect of TMZ on GBM in vitro and in vivo, providing new research directions and therapeutic targets for the treatment of GBM.

Over-expression of both VEGF-C and Twist predicts poor prognosis in human breast cancer.

BACKGROUND: Angiogenesis is an indispensable step in the growth and invasiveness of breast cancers involving a series of exquisite molecular steps. Pro-angiogenic factors, including vascular endothelial growth factor (VEGF), have been recognized as pivotal therapeutic targets in the treatment of breast cancer. More recently, a highly conserved transcription factor Twist has been reported to be involved in tumor angiogenesis and metastasis. METHODS: The expression of VEGF-C and Twist was immunohistochemically determined in tissue samples of primary tumors from 408 patients undergoing curative surgical resection for breast cancer. The correlations of VEGF-C and Twist expressions with clinicopathologic parameters as well as survival outcomes were evaluated. RESULTS: Of the 408 patients evaluated, approximately 70% had high expression of VEGF-C which was significantly associated with advanced tumor stages (P = 0.019). Similarly, VEGF-C expression was associated with the proliferation index Ki67, N3 lymph node metastasis, and D2-40-positive lymphatic vessel invasion (LVI) in a univariate analysis. Furthermore, patients with high expressions of VEGF-C and Twist (V + T+) had significantly increased lymph node metastasis, higher clinical stage, and worse disease-free survival, DFS (P = 0.001) and overall survival, OS (P = 0.011). CONCLUSIONS: Our results suggested that co-expression of VEGF-C and Twist was associated with larger tumor size, higher numbers of lymph node involvement, D2-40-positive LVI, higher risk of distant metastasis, and worse DFS or OS in breast cancer patients.

Glucagon-like peptide 1 improves insulin resistance in vitro through anti-inflammation of macrophages.

Glucagon-like peptide 1 (GLP-1), a kind of gut hormone, is used in the treatment of type 2 diabetes (T2D). Emerging evidence indicates that GLP-1 has anti-inflammatory activity. Chronic inflammation in the adipose tissue of obese individuals is a cause of insulin resistance and T2D. We hypothesized that GLP-1 analogue therapy in patients with T2D could suppress the inflammatory response of macrophages, and therefore inhibit insulin resistance. Our results showed that GLP-1 agonist (exendin-4) not only attenuated macrophage infiltration, but also inhibited the macrophage secretion of inflammatory cytokines including TNF-ß, IL-6, and IL-1ß. Furthermore, we observed that lipopolysaccharide (LPS)-induced macrophage conditioned media could impair insulin-stimulated glucose uptake. This effect was compensated by treatment with the conditioned media from macrophages treated with the combination of LPS and exendin-4. It was also observed that exendin-4 directly inhibited the activation of NF-κB in macrophages. In conclusion, our results indicated that GLP-1 improved inflammatory macrophage-derived insulin resistance by inhibiting NF-κB pathway and secretion of inflammatory cytokines in macrophages. Furthermore, our observations suggested that the anti-inflammatory effect of GLP-1 on macrophages can contribute to GLP-1 analogue therapy of T2D.

Heterogeneous evolution of Ty3-gypsy retroelements among bamboo species.

Ty3-gypsy long-terminal repeat retroelements are ubiquitously found in many plant genomes. This study reports the occurrence of heterogeneous Ty3-gypsy retroelements in four representative bamboo species: Phyllostachys heterocycla (Carr.) Mitford cv. pubescens, P. heterocycla (Carr.) Mitford cv. heterocycla, Dendrocalamopsis oldhami, and Pleioblastus fortunei. Using degenerate oligonucleotide primers corresponding to the conserved domains of reverse transcriptase (rt) genes of Ty3-gypsy retroelements, 165 distinct sequences were amplified from genomic DNA. The length of the nucleotide sequences varied from 366 to 438 bp. The sequences demonstrated a high heterogeneity, with homology ranging from 52.2 to 99.8%. A phylogenetic tree was constructed, including Arabidopsis thaliana and Oryza sativa. Bamboo Ty3-gypsy sequences formed three distinct retroelement clusters (gypsy I-III). Further analysis indicated that there were not only nearly identical Ty3-gypsy retroelements found in distantly related species, but also highly diverse Ty3-gypsy retroelements observed in closely related species. The results of this study provide genetic and evolutionary information about the bamboo genome that could contribute to further studies of repetitive elements in bamboo as well as in other species.

Interleukin-6 -572G/C polymorphism and prostate cancer susceptibility.

Strong evidence suggests that cancer-associated inflammation promotes tumor growth and progression, and interleukin-6 (IL6) is an important modulator of inflammation. However, the roles of IL6 and mutations of its corresponding gene in prostate cancer have not been clearly documented. We retrieved data from the Oncomine database concerning IL6 expression in prostate cancer and its role in prostate-specific antigen (PSA) recurrence. We also performed a case-control study of the IL6 -572G/C polymorphism (rs1800796) in 236 sporadic prostate cancer patients and 256 healthy controls from a southern Han Chinese population. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association between rs1800796 and prostate cancer susceptibility. A dual-luciferase reporter assay was used to test the transcriptional activity of the IL6 promoter G and C alleles. IL6 was overexpressed in prostate cancer tissues compared to normal tissues, especially in those with higher Gleason scores. Moreover, elevated IL6 expression was associated with high PSA recurrence rate in Oncomine data. Our case-control study demonstrated that compared with the -572C allele, the -572G allele conferred a borderline increased risk of prostate cancer (OR = 1.31, 95%CI = 0.99-1.74, P = 0.061). This was more pronounced in the subgroup of individuals having never smoked (OR = 1.85, 95%CI = 1.07-3.22). Moreover, the G allele showed increased activity relative to the C allele in the dual-luciferase reporter assay. Our results suggest that the -572G/C polymorphism may be associated with IL6 expression, which in turn plays a role in prostate cancer development.

Association between miR-137 polymorphism and risk of schizophrenia: a meta-analysis.

miR-137, a brain-enriched microRNA, is involved in the control of neuronal proliferation, differentiation, and dendritic arborization, all of which are important for proper neurogenesis and relevant to schizophrenia. miR-137 is also known to regulate many genes implicated in schizophrenia risk. Although reports have associated the miR-137 polymorphism rs1625579 with this disease, their results have been inconsistent. The aim of this meta-analysis was to evaluate the relationship between rs1625579 and schizophrenia. Data were obtained from an electronic database, and pooled odds ratios (ORs) with 95% confidence intervals (95%CI) were used to test the association using the RevMan 5.3 software. Twelve case-control studies comprising 11,583 cases and 14,315 controls were included. An estimated lambda value of 0.46 was recorded, suggesting that a codominant model of inheritance was most likely. A statistically significant association was established under allelic (T vs G: OR = 1.15, 95%CI = 1.10-1.21, P < 0.001) and homogeneous codominant models (TT vs GG: OR = 1.32, 95%CI = 1.13-1.54, P < 0.001), but no such relationship was detected using the heterogeneous codominant model (GT vs GG: OR = 1.14, 95%CI = 0.97-1.34, P = 0.11). This meta-analysis demonstrates that the rs1625579 miR-137 genetic variant significantly increases schizophrenia risk.

Cloning and characterization of a novel betaine aldehyde dehydrogenase gene from Suaeda corniculata.

Glycine betaine is an important quaternary ammonium compound that is produced in response to several abiotic stresses in many organisms. The synthesis of glycine betaine requires the catalysis of betaine aldehyde dehydrogenase (BADH), which can convert betaine aldehyde into glycine betaine in plants, especially in halotolerant plants. In this study, we isolated the full-length cDNA of BADH from Suaeda corniculata (ScBADH) using reverse transcriptase-polymerase chain reaction and rapid amplification of cDNA ends. Next, we analyzed the expression profile of ScBADH using real-time PCR. The results showed that ScBADH expression was induced in the roots, stems, and leaves of S. corniculata seedlings under salt and drought stress. Next, ScBADH was overexpressed in Arabidopsis, resulting in the transgenic plants exhibiting enhanced tolerance over wild-type plants under salt and drought stress. We then analyzed the levels of glycine betaine and proline, as well as superoxide dismutase (SOD) activity, during salt stress in WT and transgenic Arabidopsis. The results indicated that overexpression of ScBADH produced more glycine betaine and proline, and increased SOD activity under NaCl treatment. Our results suggest that ScBADH might be a positive regulator in plants during the response to NaCl.

Prolonged activation of human islet cannabinoid receptors in vitro induces adaptation but not dysfunction.

BACKGROUND: Although in vivo studies have implicated endocannabinoids in metabolic dysfunction, little is known about direct, chronic activation of the endocannabinoid system (ECS) in human islets. Therefore, this study investigated the effects of prolonged exposure to cannabinoid agonists on human islet gene expression and function. METHODS: Human islets were maintained for 2 and 5 days in the absence or presence of CB1r (ACEA) or CB2r (JWH015) agonists. Gene expression was quantified by RT-PCR, hormone levels by radioimmunoassay and apoptosis by caspase activities. RESULTS: Human islets express an ECS, with mRNAs encoding the biosynthetic and degrading enzymes NAPE-PLD, FAAH and MAGL being considerably more abundant than DAGLα, an enzyme involved in 2-AG synthesis, or CB1 and CB2 receptor mRNAs. Prolonged activation of CB1r and CB2r altered expression of mRNAs encoding ECS components, but did not have major effects on islet hormone secretion. JWH015 enhanced insulin and glucagon content at 2 days, but had no effect after 5 days. Treatment with ACEA or JWH015 for up to 5 days did not have marked effects on islet viability, as assessed by morphology and caspase activities. CONCLUSIONS: Maintenance of human islets for up to 5 days in the presence of CB1 and CB2 receptor agonists causes modifications in ECS element gene expression, but does not have any major impact on islet function or viability. GENERAL SIGNIFICANCE: These data suggest that the metabolic dysfunction associated with over-activation of the ECS in obesity and diabetes in humans is unlikely to be secondary to impaired islet function.

Glucagon-like peptide 1 improves insulin resistance in vitro through anti-inflammation of macrophages

Glucagon-like peptide 1 (GLP-1), a kind of gut hormone, is used in the treatment of type 2 diabetes (T2D). Emerging evidence indicates that GLP-1 has anti-inflammatory activity. Chronic inflammation in the adipose tissue of obese individuals is a cause of insulin resistance and T2D. We hypothesized that GLP-1 analogue therapy in patients with T2D could suppress the inflammatory response of macrophages, and therefore inhibit insulin resistance. Our results showed that GLP-1 agonist (exendin-4) not only attenuated macrophage infiltration, but also inhibited the macrophage secretion of inflammatory cytokines including TNF-β, IL-6, and IL-1β. Furthermore, we observed that lipopolysaccharide (LPS)-induced macrophage conditioned media could impair insulin-stimulated glucose uptake. This effect was compensated by treatment with the conditioned media from macrophages treated with the combination of LPS and exendin-4. It was also observed that exendin-4 directly inhibited the activation of NF-κB in macrophages. In conclusion, our results indicated that GLP-1 improved inflammatory macrophage-derived insulin resistance by inhibiting NF-κB pathway and secretion of inflammatory cytokines in macrophages. Furthermore, our observations suggested that the anti-inflammatory effect of GLP-1 on macrophages can contribute to GLP-1 analogue therapy of T2D.

Association between IL2/IL21 and SH2B3 polymorphisms and risk of celiac disease: a meta-analysis.

Celiac disease (CD) is a common autoimmune disorder characterized by heightened immunological response to ingested gluten. Certain gene polymorphisms of IL2/IL21 (rs6822844 and rs6840978) and SH2B3 (rs3184504) may influence susceptibility to CD, although the effects remain unclear. We performed a meta-analysis of the associations between rs6822844, rs6840978, and rs3184504 polymorphisms and CD risk. PubMed, EMBASE, and the China National Knowledge Infrastructure were searched. ORs and 95%CIs of each single nucleotide polymorphism (SNP) were estimated using the fixed-effect model if I(2) < 50% in the test of heterogeneity; otherwise, the random-effect model was used. Our meta-analysis included 12,986 CD cases and 28,733 controls from 16 independent samples, and the analysis of each SNP contained a subset of the total. We found that the minor allele T of both rs6822844 (T vs G, OR = 0.72, 95%CI = 0.67-0.78, P < 0.001) and rs6840978 (T vs C, OR = 0.76, 95%CI = 0.71-0.83, P < 0.001) in IL2/IL21 significantly decreased the risk of CD. However, the minor allele A of rs3184504 (A vs G, OR = 1.18, 95%CI = 1.12-1.24, P < 0.001) in SH2B3 significantly increased CD susceptibility. The estimated lambda values were 0.49, 0.50, and 0.53 for rs6822844, rs6840978, and rs3184504, respectively, suggesting that a co-dominant model of genotype effect was most appropriate for the three SNPs. Our results support associations between the three SNPs and CD and provide a strong argument for further research.

Expression of aquaporin 1 and 4 in rats with acute hypoxic lung injury and its significance.

Aquaporin (AQP)-1 and AQP-4 expression in lung tissues of SD rats during high altitude hypoxic lung injury, and the relationship between AQP-1 and AQP-4 expression, and acute hypoxic lung injury was analyzed. Thirty six healthy SD rats were divided into hypoxia 1d, 2d, 3d, 5d, and 7d groups and control group (N = 6). Pathological changes in lung tissue were observed by hematoxylin and eosin staining; lung injury was scored, and ultrastructural changes in lung tissue were observed by transmission electron microscopy. Changes in moisture content in lung tissues were determined by analyzing the wet/dry weight ratio (W/D). Localization of AQP-1 and AQP-4 was determined by immunohistochemistry. AQP-1 and AQP-4 expression were detected by western blot. Lung W/D was lower in hypoxia groups than in control group, and the highest in 3d group (P < 0.05). Light microscopy revealed a thickening alveolar wall and outstretched and congestive alveolar wall in hypoxia group; electron microscopy revealed the presence of abnormal alveolar type II epithelial cells, cavitation in cytoplasm, microvillus-like protrusions, and a reduced lamellar body. AQP- 1 and AQP-4 were mainly distributed in the capillaries and lymphatic and alveolar epithelial cells and airway epithelial cells, respectively. AQP-1 protein expression was decreased (western blot) in hypoxia 1d group (the lowest in 3d group; P < 0.05); there were no significant changes about AQP- 4 expression. Therefore, AQP-1 may be involved in abnormal transport of liquid ALI and pathogenesis of lung edema. AQP-4 may not be involved in the formation of ALI lung edema.

Genome-wide identification and characterization of the Dof gene family in Medicago truncatula.

The DNA-binding one zinc finger (Dof) family is a classic plant-specific zinc-finger transcription factor family, which is involved in many important processes, including seed maturation and germination, plant growth and development, and light responses. Investigation of the Medicago truncatula genome revealed 42 putative Dof genes, each of which holds one Dof domain. These genes were classified into four groups based on phylogenetic analysis, which are similar to the groups reported for Arabidopsis and rice. Based on genome duplication analysis, it was found that the MtDof genes were distributed on all chromosomes and had expanded through tandem gene duplication and segmental duplication events. Two main duplication regions were identified, one from tandem duplication and another from segmental duplication. By analyzing high-throughput sequencing data from M. truncatula, we found that most of the MtDof genes showed specific expression patterns in different tissues. According to cis-regulatory element analysis, these MtDof genes are regulated by different cis-acting motifs, which are important for the functional divergence of the MtDof genes in different processes. Thus, using genome-wide identification, evolution, and expression pattern analysis of the Dof genes in M. truncatula, our study provides valuable information for understanding the potential function of the Dof genes in regulating the growth and development of M. truncatula.

Effects of acupotomylysis on basic fibroblast growth factor and CD34 levels in rabbits with third lumbar vertebral transverse foramen syndrome.

This study observed the local tissue homogenates in rabbits with third lumbar vertebral transverse foramen syndrome and explored the mechanism of acupotomylysis in local tissue revascularization. Thirty Japanese white rabbits were randomly divided into the following 5 groups of 6 rabbits each: normal, model, acupotomy, electroacupuncture (EA), and acupotomy-EA groups. All except the normal group were comprised of animal models of third lumbar vertebral transverse foramen syndrome prepared by embedding sponge in the left third lumbar transverse process. The rabbits in the acupotomy and EA groups underwent bilateral acupotomylysis intervention; those in the acupotomy-EA group underwent acupotomylysis and EA interventions. On the 28th day after modeling, the double-antibody ELISA was used to detect b-FGF and CD34 levels in the serum and homogenates of a muscle tissue sample from the left side of the third lumbar transverse process. The b-FGF levels in local muscle homogenates were significantly higher in the modeled rabbits than in the normal rabbits (P < 0.01), and the CD34 levels in the modeled group were significantly lower than in the normal group (P < 0.01). The b-FGF and CD34 levels in the EA, acutopomy, and acutopomy-EA groups were significantly lower than those in the modeled group (P < 0.01); the CD34 levels were significantly higher in the acupotomy-EA group than in the model group (P < 0.05); and the differences among the EA, acupotomy, and acupotomy-EA groups were not significant (P > 0.05). In conclusion, acupotomylysis regulates the levels of b-FGF and CD34 levels in serum and muscle tissue as well as local tissue revascularization.

Immunomodulatory effect of bone marrow mesenchymal stem cells on T lymphocytes in patients with decompensated liver cirrhosis.

We explored the immunomodulatory effects of bone marrow mesenchymal stem cells (BMSCs) on peripheral blood T lym-phocytes in patients with decompensation stage, hepatitis B-associated cirrhosis. MSCs from nine patients were analyzed by flow cytometry. Peripheral blood lymphocytes were isolated for fluorescent staining. Following stimulation by phytohemagglutinin (PHA), peripheral blood lymphocytes were co-cultured with BMSCs in serum and divided into four groups: (1) BMSC + lymphocyte + PHA contact culture group; (2) BMSC + lymphocyte + PHA non-contact culture group; (3) lym-phocyte + PHA positive control group; and (4) lymphocyte-only negative control group. Lymphocyte proliferation and frequencies of CD4(+)CD25(+)CD127(-) Tregs and CD4(+)CD8(-)IL-17(+) (Th17) cells were de-tected. Cell proliferation in groups 1 and 2 declined compared with group 3 (P < 0.01), and was notably higher than in group 4 (P < 0.01). CD4(+)CD25(+)CD127(-) Tregs frequencies in groups 1 and 2 were higher than in groups 3 and 4. In an intra-group comparison before and after culture, Th17 cell frequencies in groups 1 and 2 were higher than in group 4 (P < 0.01), but lower than in group 3 (P < 0.01). The Treg/Th17 ratio in groups 1 and 2 increased (P < 0.01), but did not change signifi-cantly in groups 3 and 4 (P > 0.05). In a comparison between groups after culture, the Treg/Th17 ratio in groups 1 and 2 increased more than in groups 3 and 4 (P < 0.01). BMSCs from cirrhotic patients can inhibit the proliferation of peripheral blood T lymphocytes, upregulate the ex-pression of CD4(+)CD25(+)CD127(-) Tregs, and improve Treg/Th17 imbal-ance. The mechanism by which this takes place may be associated with immunomodulatory effects induced by the secretion of soluble factors.

Nested polymerase chain reaction amplification and sequencing analysis of the light-chain and heavy-chain variable regions in the influenza A H1N1 virus hemagglutinin monoclonal antibody gene.

The nested polymerase chain reaction (PCR) method was used for the amplification of the influenza A H1N1 virus hemagglutinin monoclonal antibody light-chain and heavy-chain genes. Sequence analysis of the obtained genes was then used to identify common cloning methods of the mouse immunoglobulin-kappa (Igκ) light-chain and heavy-chain variable gene regions. Twenty-two pairs of amplification primers for the mouse Igκ light-chain and heavy-chain variable gene regions were designed, and 6 mouse anti-human H1N1 influenza virus hemagglutinin monoclonal antibody light-chain and heavy-chain variable gene regions were cloned and sequenced. Comparative analysis was conducted between our results and the mouse Ig sequences published in the National Center of Biotechnology Information (NCBI). The nested PCR method effectively avoided cloning the pseudogenes of the monoclonal antibody, and the amino acid sequence obtained was consistent with the characteristics of the mouse Ig variable region. A general method of cloning the mouse Ig light-chain and heavy-chain variable gene regions was established, which provides a basis for further cloning of mouse monoclonal antibody variable gene regions. This study also provides data for further studies of H1N1 influenza virus hemagglutinin antibody binding sites.

Identification and assessment of differentially expressed genes involved in growth regulation in Apostichopus japonicus.

Rapid and efficient growth is a major consideration and challenge for global mariculture. The differential growth rate of the sea cucumber, Apostichopus japonicus, has significantly hampered the total production of the industry. In the present study, forward and reverse suppression subtractive hybridization libraries were constructed and sequenced from a fast-growth group and a slow-growth group of the sea cucumber. A total of 142 differentially expressed sequence tags (ESTs) with insertions longer than 150 bp were identified and further analyzed. Fifty-seven of these ESTs (approximately 40%) were functionally annotated for cell structure, energy metabolism, immunity response, and growth factor categories. Six candidate genes, arginine kinase, cytochrome c oxidase subunit I, HSP70, ß-actin, ferritin, and the ADP-ribosylation factor, were further validated by quantitative PCR. Significant differences were found between the fast- and slow-growth groups (P < 0.05) for the expression levels of arginine kinase, cytochrome c oxidase, HSP70, the ADP-ribosylation factor, and ß-actin. However, no significant difference was observed for ferritin. Our results provide promising candidate gene markers for practical size screening, and also further promote marker-assisted selective breeding of this species.

Polymorphisms of the angiotensin II type 1 receptor gene affect antihypertensive response to angiotensin receptor blockers in hypertensive Chinese.

The renin-angiotensin-aldosterone system plays a key role in regulating blood pressure by maintaining vascular tone and the water/sodium balance. Many antihypertensive drugs target the renin-angiotensin-aldosterone system, but the effect differs considerably among hypertensive patients. We investigated whether genetic variants of the angiotensin II type 1 receptor are associated with blood pressure response to angiotensin II receptor blockers in hypertensive Chinese patients. After a 2-week single-blind placebo run-in period, 148 patients with mild-to-moderate primary hypertension received monotherapy with 80 mg/day telmisartan and then were followed up for 8 weeks. The 1166A/C, 573T/C, -810A/T, and -521C/T polymorphisms of the AT1R gene were determined through PCR and RFLP analysis. The relationship between these polymorphisms and changes in blood pressure was observed and evaluated after 8 weeks of treatment. Patients with the AT1R -521CC genotype had a significant reduction in diastolic blood pressure compared to those carrying the T allele. No significant reduction in blood pressure was found in individuals with the 1166A/C, 573T/C, or -810A/T polymorphisms of the AT1R gene. We conclude that only the AT1R -521CC genotype is associated with a significant decrease in blood pressure in response to telmisartan treatment in Chinese hypertensive patients.

Genomic selection of seed weight based on low-density SCAR markers in soybean.

With the development of molecular marker technology, crop breeding has been accelerated by marker-assisted selection for the improvement of quantitative traits. However, due to the traits' polygenic nature, traditional marker-assisted selection methods are ill-suited for identification of quantitative trait loci. Genomic selection (GS) was introduced into crop breeding to achieve more accurate predictions by considering all genes or markers simultaneously. We used dozens of sequence-characterized amplified region (SCAR) markers for genotyping soybean varieties, and we identified markers associated with hundred-seed weight. The best linear unbiased predictor and Bayesian liner regression methods were used to construct GS models to predict the hundred-seed weight trait based upon genotype information for trait selection. Both GS models showed good prediction performance in soybean, as the correlation coefficient between genomic estimated breeding values and true breeding values was as high as 0.904. This indicated that GS was performed effectively based on dozens of SCAR markers in soybean; these markers were of low density but easily detectable. Therefore, the combination of GS modeling and highly effective molecular marker technology involving SCAR markers can facilitate genetic breeding in soybean. This approach may also be suitable for genetic selection in other crops, such as wheat, maize, and rice.

Gametocidal chromosomes enhancing chromosome aberration in common wheat induced by 5-azacytidine.

The gametocidal (Gc) chromosome from Aegilops spp induces chromosome mutation, which is introduced into common wheat as a tool of chromosome manipulation for genetic improvement. The Gc chromosome functions similar to a restriction-modification system in bacteria, in which DNA methylation is an important regulator. We treated root tips of wheat carrying Gc chromosomes with the hypomethylation agent 5-azacytidine; chromosome breakage and micronuclei were observed in these root tips. The frequency of aberrations differed in wheat containing different Gc chromosomes, suggesting different functions inducing chromosome breakage. Gc chromosome 3C caused the greatest degree of chromosome aberration, while Gc chromosome 3C(SAT) and 2C caused only slight chromosome aberration. Gc chromosome 3C induced different degrees of chromosome aberration in wheat varieties Triticum aestivum var. Chinese Spring and Norin 26, demonstrating an inhibition function in common wheat.

RAPD and ISSR-assisted identification and development of three new SCAR markers specific for the Thinopyrum elongatum E (Poaceae) genome.

Diploid Thinopyrum elongatum, a wild relative of wheat, contains many agronomically desirable traits and has potential for increasing genetic variability and introducing desirable characters in this crop. Few molecular markers are available for rapid screening of T. elongatum genome segments in the wheat genetic background. We used 36 RAPD primers and 33 ISSR primers to screen for polymorphisms in the common wheat variety Chinese Spring and in T. elongatum. Two RAPD markers and one ISSR marker, designated OPF03(1407), LW10(1487) and UBC841(701), were identified and were specific for the T. elongatum E genome. Three pairs of primers flanking these specific sequences were designed to produce SCAR markers. All three SCAR markers were T. elongatum E genome-specific. Two of these SCAR markers, SCAR(807) and SCAR(577), were present in all seven T. elongatum chromosomes, while SCAR(839) was specific for T. elongatum chromosomes 2E and 3E. These newly developed SCAR markers should be useful for detecting alien genome chromatin or chromosome segments in the genetic background of common wheat.