Detection of quantitative trait loci for kernel oil and protein concentration in a B73 and Zheng58 maize cross.

Maize (Zea mays L.) is one of the most important food crops throughout the world, and provides oil and proteins to humans and livestock. Kernel oil and protein content in maize are two complex quantitative traits. In order to identify quantitative trait loci (QTL) controlling oil and protein concentration in maize kernels, and to evaluate their genetic effects, QTL analysis was conducted on an F3:4 population derived from a cross between an inbred line with a low oil and protein concentration (Zheng58) and an inbred line with a higher oil and protein concentration (B73). A total of 189 polymorphic simple sequence repeat markers were used to construct a linkage map. Eleven QTLs for kernel oil concentration were detected on nine chromosomes, except for chromosome 9. A single QTL explained 4.6 to 11.1% of the phenotypic variance. Ten QTLs for kernel protein concentration were also detected on nine chromosomes, except for chromosome 9. A single QTL explained 4.2 to 11.4% of the phenotypic variance. Interestingly, novel QTLs for oil concentration (qOIL08-01 and qOIL10-01) and QTLs for protein concentration (qPRO01-01 and qPRO05-01) were specific to the population studied, which could explain 7.1 to 11.1% of the phenotypic variance. These results will provide better understanding of the genetic basis of oil and protein concentrations in maize. The markers closely linked with the QTLs will facilitate breeding of maize varieties with high oil and protein concentrations through molecular marker-assisted selection.

Influence of the DCC gene on proliferation and carcinoembryonic antigen expression in the human colorectal cancer cell line SW1116.

This study investigated the effects of stable transfection of the exogenous wild-type DCC gene on growth of the human colorectal carcinoma cell line SW1116 in vitro. The DCC gene was amplified from normal human colon tissue by reverse transcription-polymerase chain reaction and used to construct a recombinant expression plasmid, pcDNA3.1(+)-DCC. DCC-negative SW1116 cells were transfected with pcDNA3.1(+)-DCC. Cell viability was tested by the methyl thiazolyl tetrazolium (MTT) assay. Immunofluorescence staining was used to determine the effects of pcDNA3.1(+)-DCC on carcinoembryonic antigen (CEA) expression in transfected cells. The number of cells in the population transfected with pcDNA3.1(+)-DCC was lower than in that transfected with the control pcDNA3.1(+) plasmid or in normal cells (t1 = 3.645, P1 < 0.05, t2 = 3.132, P2 < 0.05) at 3-6 days after transfection, and the proliferation rate of pcDNA3.1(+)-DCC transfected cells was also lower (t1 = 2.134, P2 < 0.05; t2 = 2.736, P2 < 0.05). The total viability of pcDNA3.1(+)-DCC transfected cells was lower than that of normal cells (t1 = 3.053, P1 < 0.05) at 2-6 days after transfection, and of control-transfected cells (t2 = 2.816, P2 < 0.05) after 2, 4, 5, and 6 days. The population of pcDNA3.1(+)-DCC transfected colored of green fluorescent cells and their fluorescent intensities were lower than those of control-transfected and normal cells. Therefore, the transfected DCC gene can suppress cell proliferation and lead to downregulation of CEA expression in SW1116 cells, which might weaken its infiltration and metastasis abilities.

Genome-wide analysis of the GRAS gene family in physic nut (Jatropha curcas L.).

GRAS proteins play vital roles in plant growth and development. Physic nut (Jatropha curcas L.) was found to have a total of 48 GRAS family members (JcGRAS), 15 more than those found in Arabidopsis. The JcGRAS genes were divided into 12 subfamilies or 15 ancient monophyletic lineages based on the phylogenetic analysis of GRAS proteins from both flowering and lower plants. The functions of GRAS genes in 9 subfamilies have been reported previously for several plants, while the genes in the remaining 3 subfamilies were of unknown function; we named the latter families U1 to U3. No member of U3 subfamily is present in Arabidopsis and Poaceae species according to public genome sequence data. In comparison with the number of GRAS genes in Arabidopsis, more were detected in physic nut, resulting from the retention of many ancient GRAS subfamilies and the formation of tandem repeats during evolution. No evidence of recent duplication among JcGRAS genes was observed in physic nut. Based on digital gene expression data, 21 of the 48 genes exhibited differential expression in four tissues analyzed. Two members of subfamily U3 were expressed only in buds and flowers, implying that they may play specific roles. Our results provide valuable resources for future studies on the functions of GRAS proteins in physic nut.

Quantative trait loci of seed traits for soybean in multiple environments.

Seed length and seed width are an important factor to the soybean yield. So the quantitative trait loci (QTL) location for seed length and seed width could assistant the breeding of soybean. In this study, the QTL underlying seed length and seed width were studied. A recombinant inbred line population of soybeans derived from a cross between the American semi-draft cultivars Charleston and Dongnong 594 were used in 7 environments. The quantitative trait loci underlying seed length, seed width, and seed length/seed width were analyzed by the method of composite interval mapping. Then, the epistatic effects and the QTL-environment (QE) interaction effects were also analyzed. Some valuable QTL sites found had great effect to the seed trait. Results showed that 7 QTLs underlying seed length were identified mainly on linkage groups D1a, C2, B1, A1, G, and A2. For the seed width, 7 QTLs were identified on linkage groups D1a and O. Two QTLs of seed length/seed width were identified on linkage groups D1b and C2. No QE interaction was found for QTLs of seed length and seed width in 7 environments. QTLs of seed length/seed width on linkage groups A1 and I had a QE interaction in 7 environments. Seven pairs of QTLs were identified that affected additive x additive epistatic effect of seed length, seed width, and seed length/seed width, which occurred among 8 linkage groups. These results supply a good foundation for molecular assistant breeding for soybean seed trait.