Dec 2008, Volume 2 Issue 4

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  • LÜ Xiangling, LI Xinhai, XIE Chuanxiao, HAO Zhuanfang, JI Hailian, SHI Liyu, ZHANG Shihuang
    The development of genomics and bioinformatics offers new tools for comparative gene mapping. In this paper, an integrated QTL map for sugarcane mosaic virus (SCMV) resistance in maize was constructed by compiling a total of 81 QTL loci available, using the Genetic Map IBM2 2005 Neighbors as reference. These 81 QTL loci were scattered on 7 chromosomes of maize, and most of them were clustered on chromosomes 3 and 6. By using the method of meta-analysis, we identified one “consensus QTL” on chromosome 3 covering a genetic distance of 6.44 cM, and two on chromosome 6 covering genetic distances of 16 cM and 27.48 cM, respectively. Four positional candidate resistant genes were identified within the “consensus QTL” on chromosome 3 via the strategy of comparative genomics. These results suggest that application of a combination of meta-analysis within a species with sequence homology comparison in a related model plant is an efficient approach to identify the major QTL and its candidate gene(s) for the target traits. The results of this study provide useful information for identifying and cloning the major gene(s) conferring resistance to SCMV in maize.
  • PAN Zhifen, LONG Hai, YU Maoqun, DENG Guangbing, ZHAI Xuguang, TANG Yawei, QIANG Xiaolin
    Naked barley is widely planted in Qinghai-Tibet Plateau in China and is essential for the daily life of Tibetans in those regions. In this study, the genetic diversity of 64 cultivated naked barley accessions from Qinghai-Tibet Plateau in China was analyzed using 30 mapped SSRs linked with the important traits of barley improvement. A total of 132 alleles were identified at 22 polymorphic SSR loci, with the number of each locus ranging from 2 to 15, the polymorphism information content (PIC) values ranging from 0.16 to 0.91, and with an average of 0.65. Of the selected SSRs, 13 SSR markers with high PIC value were highly efficient for the genetic analysis of Chinese barley. The accessions were divided into five main groups by cluster analysis and could be differentiated from each other. The genetic diversity in the Tibet accessions was slightly higher than in the Sichuan accessions. It is found that there were specific genes linked with the collecting sites. These results indicate the cultivated naked barley from Qinghai-Tibet Plateau in China are highly polymorphic and could be considered as an important resource bank for cultivated naked barley breeding in the future.
  • WU Yuxiang, CHEN Chongqian, GAO Yanhui, ZHU Shuijin, JI Daofan
    A quadri-specific hybrid F1 (G.arboreum, G.herbaceum, G.hirsutum, and G.barbadense) was produced by crossing the doubled-chromosome (G.arboretum × G.herbaceum) F1 with (G.hirsutum × G.barbadense) F1. The hybrid plants were preserved for 15 years via the method of grafting. The hybrid flowers were self-crossed and back-crossed every year, and the pollen vigor was tested as well. The results showed that the percentage of fertile pollens and weak-vigor pollens increased with the time of plant preservation, especially for those of weak-vigor that occupied about 10% of the total pollens after 15 years of growth. Meanwhile, the percentage of the sterile pollens decreased with the plant preservation, and the fertility of the quadri-specific hybrid was recovered partially. After plant preservation for more than 10 years, some backcrossed seeds were obtained via backcrossing with upland cotton parents, and a few self-crossed seeds were produced finally. The characteristics of chromosome behavior and the chromosome configuration during the meiosis were studied and the results showed that the chromosome configuration of the quadri-specific hybrid plant grown for 15 years was 2n = 52 = 4.92I + 14.62II + 2.29III + 1.56IV + 0.71V + 0.19VI, while that from the plants of 15 years ago was 2n = 52 = 8.4I + 8.1II + 5.7III + 1.9IV + 0.6V. It was showed that the univalents decreased to 3.5 per cell, bivalents increased up to 6.5 per cell, and the number of multivalents decreased obviously as well. It was found from this experiment that extending the growth period by the method of grafting would be helpful to harmonize the relationship among the different chromosome groups which came from different species, and balance the chromosome configuration, which led to the partially recovering in plant fertility of the interspecific hybrids.
  • NIU Na, ZHANG Gaisheng, CAO Yue, ZHANG Yu, WEI Fang
    A new method for producing a NIAN type wheat maintenance line with the male sterile gene rfv1 was described. That is the variety Xinong Fp1, a 1BL/1RS translocation line, as the acceptor and Triticum macha var. subletschchumicum, a non-1BL/1RS translocation line, as the donor, a directional substitution backcross was made and confirmed by chromosome of root tip preparations and SDS-PAGE analysis. The male sterile gene rfv1 of Triticum macha var. subletschchumicum was transferred to the genome of Xinong Fp1. A new NIAN type wheat maintenance line with the male sterile gene rfv1 was bred. The method described was successful in breeding a new male sterile type for hybrid wheat production.
  • GU Jian, LIU Kun, LI Shaoxiang, TIAN Yuxian, YANG Hexian, YANG Mujun
    The wheat × maize system is one of the most effective ways to produce haploids in wheat. Whether and how it could be successfully applied in practical breeding mostly depends upon the efficiency of haploid embryo production. To perfect the protocols of haploid embryo induction, the efficiency of haploid embryo production between in vitro culture of cut plant and intact plant growth for hybrid spikes with two F1 wheat hybrids and two maize varieties was compared. Effects of different cutting plant times and formulas of nutrient solutions for cut plant culture on haploid embryo formation were also studied. Results indicated that the embryo rate of in vitro culture was 3.29 times that of intact plant growth, with the figures of 31.6% vs 9.6%, respectively. The optimal time for cut plant culture was 24 h after pollination. Formulas of nutrient solutions significantly affected the efficiency of haploid embryo induction. With an embryo rate of 0–35.5%, adding calcium phosphate in the culture solution at 3 g·L-1 could raise the caryopsis and embryo rates. According to this study, the best medium for cut plant culture was: 100 mgL-1 2,4-D + 40 gL-1 sucrose + 10 mgL-1 silver nitrate + 8 mLL-1 sulfurous acid + 3 gL-1 calcium phosphate, with which a caryopsis rate of 95% and an embryo rate of about 30% could be obtained.
  • WANG Yijun, DENG Dexiang, BIAN Yunlong, XU Mingliang
    Transposable elements are widely distributed in eukaryotes. Due to its high copy numbers, high forward mutation rate and preferential insertion into low-copy DNA sequences, among others, the Mutator system has been widely used as a mutagen in genomic research. The discovery, classification, transposition specificity and epigenetic regulation of Mutator transposons were described. The application of Mutator tagging in plant genomic research was also presented. The role of Mu-like elements in genome evolution was briefly depicted. Moreover, the direction of Mutator transposon research in the future was discussed.
  • TIAN Yuqiang, SONG Minghua, HU Qiwu, OUYANG Hua, NIU Haishan
    The undisturbed regions along the Qinghai-Tibet Highway crossing the natural zones of montane desert, alpine meadow-steppe, and montane shrub-coniferous forest were chosen as the study areas. Soil samples were collected at 23 sites and the relations between the influencing factors and distribution of soil organic carbon (SOC) content were studied. The results indicated that the order of SOC content for the whole soil profile with different vegetations and in the horizontal direction was shown as below: forest > shrub > meadow > steppe > desert. All the SOC contents of the top 10 cm soil layers of forest, shrub and meadow vegetations, as well as that of the top 20 cm soil layers in steppe, in the vertical direction, were higher than those of corresponding lower soil layers. However, the SOC content in the desert soil was in accordance. The grey correlative analysis between the climatic factors and SOC content in the top soil show that precipitation was the dominant climatic factor affecting the distribution of SOC in the Tibetan Plateau transect. The influence of precipitation on the horizontal distribution of SOC decreased with the increase of precipitation in the horizontal direction. The vertical distribution of SOC along the soil profile was greatly affected by precipitation or the soil clay content in top soil layers, and was clearly influenced by soil silt content or sand content in lower soil layers, as well. The influences of both soil bulk density and soil pH on the vertical distribution of SOC along the soil profile gradually declined. The plant biomass was the most important biotic factors affecting the distribution of the SOC.
  • NIU Ling‘an, HAO Jinmin, ZHANG Baozhong, NIU Xinsheng, LU Zhenyu
    We carried out a long-term study and a systematic analysis on the spatial and temporal variations of the soil organic carbon contents in the counties of Handan Prefecture in Hebei Province, on the North China Plains. The analysis was based on the data collected in soil surveys conducted in 1980, 1993 and 2003, as well as the data from specific investigations using GIS and GPS receivers.The soil organic carbon content was higher in the western mountainous region than in the eastern plain region in 1980, and the difference in the average values was 17.745 t·hm-2. The soil organic carbon content was influenced by natural factors, such as climate and rainfall. In 1993, the soil organic carbon content showed an upward trend in the eastern plain region and a downward trend in the western mountainous region. The difference in the average values was 16.641 t·hm-2. The changing trend reflected the changes in farming practices where traditional farming was changed into modern farming gradually by increasing farming investment and output of grains. In 2003, the soil organic carbon content was high on the whole, and the difference in the average values was 16.984 t·hm-2, where the influence of human factors played an important role. In Cixian, Linzhang, Wuan and Handan counties, the increased value of soil organic carbon in the cultivated land exceeded 3.915 t·hm-2 due to the advocated application of straw and farmyard manure in these counties, but in Weixian, Jize and Quzhou counties, the soil organic carbon content was maintained or showed a slight decrease (-0.008–-1.727 t·hm-2). To increase carbon sequestration in soil, adoption of conservation tillage to increase soil organic carbon storage in the soil is recommended.
  • XU Huaqin, XIAO Runlin, SONG Tongqing
    The present study examined the influence of the different fertilization on the dynamic of soil microbial biomass carbon (SMBC) of red soil in tea gardens. The results showed that straw mulching, intercropping, chemical fertilizer could all improve the amount of the soil microbial biomass C. The annual variation of microbial biomass C showed the tendency of “low–high–low–high”, and the influences were variable with the time. For the annual average of soil microbial biomass C, Treatment 1(T1) (straw mulching + 100% organic manure), Treatment 2 (T2) (straw mulching + 75% organic manure + 25% fertilizer), Treatment 3 (T3) (straw mulching + 50% organic manure + 50% fertilizer), Treatment 4 (T4) (straw mulching + 25% organic manure + 75% fertilizer), Treatment 5 (T5) (100% fertilizer),Treatment 6 (T6) (intercropping white clover) were 17.05%, 32.38%, 32.05%, 24.30%, 26.23%, 24.63% higher, respectively, than CK, and the differences among all the treatments were significant (P < 0.05). The correlation of the SMBC with the active organic matter, the total nitrogen, the microbial biomass N, the microbial biomass P were remarkable, but no significant correlation was found with available nitrogen, total phosphorus, total potassium and moisture. Compared with other treatments, those mixed with organic matter and chemical fertilizer were more advantageous to enhance the soil fertility.
  • XIANG Jun, WANG Pei, YU Longjiang, LI Maoteng, CHEN Zhaobo
    Some experiments revealed that the Ca2+ has a relationship with drought resistance. In this paper, some physiological and biochemical indices were studied in order to analyze the effect of Ca2+ treatment on the drought resistance of Brassica napus. The physiological and biochemical experiments revealed that the proline content and the soluble sugar contents in the Ca2+-treated B. napus were much higher than those of water-treated B. napus. However, the content of malonaldehyde in the Ca2+ treated B. napus was lower than that of control. The transpiration and stomatal conductance analysis show that the transpiration and stomatal conductance in the Ca2+-treated materials were lower than those of water-treated materials. Further research revealed that the stomata hatch of Ca2+-treated materials was markedly less than that of water-treated materials, which indicated that the closure of the stomata was the main reason for the decrease of transpiration and stomatal conductance.
  • ZHANG Weixing, ZHAO Zhi, BAI Guangxiao, FU Fangjing
    Using cultivating experiments in fields under drought stress, yields and characteristics in morphology, growth and development of different genotype maize inbred lines were studied systematically. We evaluated and classified the drought resistance of these materials based on the needed indexes, including subordinate function values of drought resistance (SV), drought coefficient (DC) and drought index (DI) of yield by fuzzy function method and cluster analysis. We also analyzed the correlations between parameters and tested values of traits. The effective parameters and indexes of comprehensive evaluation for drought resistance were selected with principal component analysis. The results showed that under drought stress, the yield of maize inbred lines obviously decreased. The anthesis and silking interval (ASI) was prolonged compared with the control, with a smaller leaf area, thinner stalk, shorter and smaller ears, lengthened barren ear tip, a decline in plant height and ear position, reduced grain number per ear and grain weight, which led to a yield decline. Effects of drought treatment on different maize inbred lines were significantly different. 79-1E, Jiao51, Su1-1 and 18599 were found to be highly resistant to drought, while 1125 and 5311 performed the worst. DI and SV were significantly correlated with drought resistance. Our results indicated that DI, SV, yield and leaf area could be used as parameters and indexes to effectively evaluate the drought resistance of maize. Meanwhile, DC, plant height, ASI, grain number per ear or row, ear length and diameter could be taken as auxiliary parameters and indexes. An applied scientific method for the comprehensive evaluation of drought resistance was offered in this paper.
  • WU Yuxiang, ZHU Shuijin, JIN Kuiying, JI Daofan, FANG Weiping
    The effects of upland cotton root exudates on the growth and development of Verticillium dahliae were studied, through the compared analysis of the root exudates components between the resistant and susceptive cotton materials, using a pair of resistant and susceptive isogenic lines to Verticillium wilt, Z5629 and Z421, as well as 4 other upland cotton cultivars with different resistant levels of Verticillium wilt. The results showed that the amino acids in the root exudates of the resistant cultivars were much less than that of the susceptible ones. Compared with the susceptible ones, there were a lack of aspartic acid, threonine, glutamic acid, alanine, isoleucine, leucine, phenylalanine, lysine and proline in the root exudates from the resistant cultivars. On the contrary, arginine was lacking in the susceptive cultivars. The saccharide types in the root exudates were no different between the two kinds of cultivars, but the contents of glucose, fructose and sucrose in the root exudates of the susceptible varieties were much higher than those in the resistant ones. The experiment of Verticillium dahliae culture showed that the cotton root exudates from resistant cultivars can effectively restrain the spore germination and mycelium growth of Verticillium dahliae, and the arginine was the leading amino acid in this inhibitory action, besides the nutrition of the root exudates. However, the cotton root exudates from the susceptive cotton cultivars can improve the growth and development of Verticillium dahliae effectively; among the amino acid in the exudates, alanine was the most active one in this stimulating function.
  • LIU Qiongguang, ZHANG Jingyi, WANG Yutao, WANG Zhenzhong, HE Landi
    Activities of reactive oxygen species (ROS) were investigated in the interaction between rice and Erwinia chrysanthemi pv. zeae. Results showed that O2·-, H2O2 and malondialdehyde (MDA) in resistant variety (128) had higher increases in activity compared to those in the susceptible variety (Texian 13) 24 hours after bacteria inoculation. The activities of superoxide dismutase (SOD) increased in 128 and Texian 13 twenty-four hours after inoculation and then decreased, but the SOD activity in 128 was found to be usually lower than that in Texian 13. The CAT activity in Texian 13 had two peaks at 24 h and 96 h after inoculation, while little change was seen in 128. In conclusion, ROS and its related enzymes could be correlated to rice resistance against E. chrysanthemi pv. zeae.
  • XU Jiao, XU Wenchao, YANG Yajun, TAO Bu, ZHANG Jinlin
    To identify the allelopathic effect of Flaveria bidentis (L.) Kuntze (F. bidenti) on other plants, the effects of different extracts from F. bidentis on the growth of several plants were studied by bioassay. Results showed that the water extracts inhibited the growth of corn (Zea mays L.), wheat (Triticum aestivum L.), cotton (Gassypium Hirsutum L.), soybean (Glycine hispida L.), peanut (Arachi shypogaea L.), rice (Oryza sativa L.), crabgrass (Digitaria sanguinalis L.) and rigweed (Amaranthus retroflexus L.), with the most reactive indexes found in root and stem of cotton at -0.85 and -0.88, respectively, at a concentration of 0.2 g·mL-1. However, the water extracts accelerated the growth of rice. In addition, the reactive indexes of the extracts of petroleum ether chloroform, ethyl acetate, acet and alcohol were higher than that of the water extracts, and that of the acet extracts was the highest. The melting point of the refined acetone extract ranged from 192.5°C to 193.5°C, and its maximum absorbing wavelength was 220 nm. This extract was found to be herbicide-active and played an inhibitory role in the growth of crabgrass and rigweed at concentrations of 1000, 500, 100 and 50 mg·L-1.
  • WANG Jianshe, YAO Jianchun, LI Wei
    A molecular map of melon (Cucumis melo L.) was constructed with SRAP (Sequence-Related Amplified Polymorphism) markers using a population consisting of 114 F2 individuals derived from the cross of 4G21 (C. melo var. chinensis) and 3A832 (C. melo var. saccherinus). Twenty-nine primer pairs were used and 187 polymorphic loci were produced. The map consists of 12 linkage groups that include 152 genetic markers and cover 2077.1 cM with an average genetic distance of 13.67 cM. Every linkage group has 6–32 genetic markers with average genetic distance of 9.72–19.19 cM. The length of linkage group is 85.3–496.1 cM.
  • CHEN Anhe, LI Jiana, CHAI Yourong, WANG Rui, LU Jun
    A 2431-bp full-length cinnamate 4-hydroxylase gene, BoC4H, was cloned from Brassica oleracea L. var. acephala DC.. It contains 2 introns. Its mRNA is 1715 bp, encoding a deduced 481-amino-acid polypeptide with wide homologies to C4Hs from other plants. It possesses cytochrome P450 conserved domains and motifs such as the haem-iron binding motif, the E-R-R triad, the T-containing binding pocket motif and the hinge motif necessary for optimal orientation of the enzyme. It also has most of the canonical C4H/CYP73A5-featured substrate-recognition sites (SRSs) and active site residues. However, owing to a single-base deletion at C2242 and subsequent frame shift within the 3′ coding region as compared with C4H genes from Arabidopsis thaliana and other plants, BoC4H shows a 36-aa deletion/variation at its C-terminus and the SRS6 motif together with active site residues therein are absent. Thus BoC4H may be of no function or low activity. BoC4H is a membrane protein and is probably associated with the endoplasmic reticulum. Its secondary structure is dominated by alpha helices and random coils. The Swiss-Model could not predict its tertiary structure. B. oleracea contains a C4H gene family with at least 5 members.
  • YAO Yuxin, ZHAI Heng, ZHAO Lingling, YI Kai, LIU Zhi, SONG Ye
    It is necessary to find out the genetic characteristics of malic acid in the course of apple genomic research and breeding. In this study, the SSR marker linked to the acid/low-acid trait in apple fruit was identified from 140 SSR primer pairs, using 91 F1 population hybrids from the intra-specific cross between apple cultivar ‘Dongguang’ and ‘Fuji’ as the experimental materials. Of 140 SSR primer pairs, only primer SDY085 produced a polymorphic band linked to acid trait, and the linkage distance was 8.89 cM. Also, the titrated acid and malic acid in different developmental stages were determined. The SSR marker analysis, coupled with the change of the total acid and malic acid contents, revealed that the acid/low-acid trait was governed by a major gene and acid trait was completely dominant.
  • CAO Shangyin, GUO Junying, CHEN Yuling, XUE Huabai, ZHANG Qiuming, ZHU Zhiyong
    Apple is one of the most important fruit trees in the world. Nevertheless, mainly due to its long juvenile period, its breeding work constantly falls far behind other crops. So the aim of this study is to reveal the mechanism of apple flower bud differentiation, shorten the juvenile period and accelerate its breeding process. Proteomics technology (including two-dimensional gel electrophoresis (2-DE), biomass spectrometry and bioinformatics) was applied to work on the specific protein of flower bud and leaf bud after the brachyblasts of ‘Fuji’ stopped growth for 3–9 weeks. The results showed that the morphodifferentiation of flower bud did not begin until the seventh week after the brachyblast stopped growth. Furthermore, compared with the leaf bud, flower bud had significant changes in the expression of 283 protein spots in quality and quantity on 2-DE maps. Among the 283 protein spots, four protein spots (16.4, 30.2, 40.3 and 65.1 kD) were characteristic of the flower bud in the archae-stage (initial inflorescence appeared) at the beginning of flower-bud differentiation, three (39.3, 60.2 and 66.3 kD) in the post-stage (Lateral-flower appears) and one (77.1 kD) in the sepal stage on 2-DE maps. Analysis by peptide mass fingerprinting and matrix-assisted laser desorption ionization time of flight mass spectrometry also identified and forecasted functionally by blasting different databases. In the four specific proteins, it was found that spots No. 256 (16.4 kD) and 298 (30.2 kD) were unknown proteins, spot Nos. 327 (40.3 kD) was identified as the synthesis enzyme protein and spot No. 367 (40.3 kD) was identified as a RNA-binding protein involved in transcription. When flower bud started to differentiate morphologically, we detected four specific proteins which were 16.4, 30.2, 40.3 and 65.1 kD. Three specific proteins 39.3, 60.2 and 66.3 kD were observed at side flower-appearing stage. When calyx began to emerge, there was one specific protein: 77.1 kD. The proteins 16.4 kD and 30.2 kD were two unknown specific proteins. The 40.3 kD protein was related to methionine synthetase while 65.1 kD protein, a RNA-binding protein, was related to transcription.
  • YE Manhong, CAO Honghe, LI Hongbin, CHEN Jilan, ZHAO Guiping, ZHENG Maiqing
    PCR-SSCP analysis was used to detect polymorphic sites in chicken adipocyte fatty acid binding protein (A-FABP) gene. Six Chinese local breeds, Beijing-You chicken, Dwarf chicken, Taihe silky chicken, Chongrenma chicken, Xiayan chicken, Luyuan chicken and an introduced foreign breed, Arbor Acre broiler, were used as test populations. Three PCR-SSCP loci were detected. Statistical results showed that frequencies of genotypes and alleles were significantly different in the test populations. Sequence analysis revealed that C → T, G → A, and C → T transitions were responsible for the polymorphisms. Some fat-related traits such as body weight, content of intramuscular fat (IMF) and percentage of abdominal fat (AFP) were measured in Dwarf chickens and male Beijing-You chickens. We found out that chicken quality was significantly related to different genotypes in these two populations.
  • ZUO Jianjun, DONG Zemin, YAN Xiling, YE Hui, CAO Qingyun, FENG Dingyuan
    In order to develop a new method for determining the phosphorus (P) digestibility in vitro in feedstuffs by dialysis tube, a L32(49) orthogonal experiment with eight factors (4 levels for each factor) and a single factor experiment on the enzymatic reactivity were carried out. The sequence of significance of the eight factors on sample-P dialyzability was as follows: trypsin digestion for 6 h, dialyzing solution at 100 mL, pH of pepsin solution at 2.5, pepsin concentration at 2000 UmL-1 pepsin digestion for 100 min, at temperature of 35°C, trypsin concentration at 1625 UmL-1, and pH of trypsin solution at 6.5, respectively. And in vitro dialyzabilities of P in soybean meal, barley, sorghum, peanut meal, and rapeseed meal were (36.91 ± 0.58)%, (27.28 ± 0.94)%, (26.95 ± 0.58)%, (30.51 ± 0.83)%, and (20.82 ± 1.09)%, respectively.
  • HOU Ning, LI Yong, LI Dayu, LIU Fujun, MAO Ruixin, SUN Xiaowen, HOU Xiaoshu
    Using 30 microsatellite markers and combining quantifiable characteristics such as body weight, body length and body width, we evaluated the genetic potential of 3 German mirror carp (Cyprinus carpio L.) populations. Number of effective alleles (Ae), observed (Ho) and expected (He) heterozygosity values and polymorphic information contents (PIC) were all calculated. Two hundred and eighty-seven alleles and 559 genotypes were detected. The DNA fragment length was 109–400 bp. The Hardy-Weinberg Equilibrium was checked and the phenomenon of some disequilibrium was studied according to the ?2 test. The results showed that the level of genetic variability was moderate, but genetic potential of Shuanglai population was much lower than that of Huanxin and Songpu breeding populations. PIC of the three populations of German mirror carp were between 0.08787 and 0.5377, both highly and moderately polymorphic markers were 13. The number of the Ae was between 1.1014 and 6.4665. The Ho and He heterozygosity values were 0.0968–0.9892 and 0.0926–0.8554, respectively. The linkage correlation was analyzed using the data of body weight, body length and body width, and 30 loci. The result showed that there existed 2 loci, HLJ319 and HLJ693, associated with body length. The HLJ693 locus was significantly correlated with body weight trait. The HLJ677 locus was linked with body width. And then the result was verified in Recombinant Inbred Lines (RIL) of common carp. It showed that the HLJ319 locus was significantly linked with body length, the same as the result of quantitative trait loci (QTL) location for common carp.
  • ZHANG Xiaohui, XU Shangzhong, GAO Xue, REN Hongyan, CHEN Jinbao
    The cDNA of cattle Smad4 gene was cloned by RT-PCR, 3′ RACE and 5′ RACE and got a 3503-bp full-long cDNA sequence. The cloned cattle Smad4 cDNA sequence had been send to GenBank and got an accession number: DQ494856. Cattle Smad4 gene consists of 12 exons and codes 553 amino acids. Cattle Smad4 cDNA shares 99%, 96%, 95%, 91% and 91% similarity in nucleic acid sequences, and 99%, 98%, 98%, 99% and 98% similarity in amino acid sequences with sheep, pig, human, rat and mouse, respectively. Smad4 cDNA was found in the testes, pancreas, liver, small intestine, ovary, lymph, cardiac muscle, skeleton muscle and thymus gland, which indicated that Smad4 was broadly expressed in cattle.
  • JIANG Tao, ZHANG Donglin, NIE Hao, ZHAO Junlong, YAO Baoan
    The sequence encoding MIC3 was obtained by amplification from genomic DNA of Toxoplasma gondii RH strain and cloned into the vector pMD18-T. The target gene was subcloned into the eukaryotic vector pcDNA3.1 after the identification of pMD18-T-MIC3 by enzyme digesting, PCR amplification and sequencing. Then the target recombinant plasmids pcMIC3 were transfected into IBRS-2 cells, and the positive cells containing pcMIC3 plasmids were obtained under the selection of G418. The expressed proteins from the positive cells were detected by SDS-PAGE, Western blot and ELISA. The results showed that the DNA sequence identity was 99.9% between amplified MIC3 and that from GenBank. The molecular weight of the recombinant MIC3 protein with good immuno-activity was about 39.2 ku. These available data would lay the foundation for further studies on DNA vaccine against Toxoplasma gondii.
  • YIN Jun, ZHANG Yanjun, LI Changqing, LI Jinquan
    The keratin family includes the epithelial (soft) keratins and the hair (hard) keratins, which can be divided into two subfamilies-the acidic type I and the basic or neutral type II. A cDNA is isolated and sequenced from a cDNA library constructed with poly (A) + RNA derived from the goat skin. Because the gene sequence of the known type I hair keratins 8C1 is in accordance with that of the hHa1, this keratin can be identified as the goat hair keratin gHa1 cDNA (GenBank Accession No. AY510110.1). The 413 amino acid sequence derived is compared with the Sheep 8C1 type I mRNA and they exhibit the highest homology (97.8%). In in situ hybridization, it has revealed a strong expression in the cortex of both primary and secondary hair follicles.
  • LIU Ji, FENG Shutang, PAN Dengke, ZHANG Li, MU Yulian, GONG Liguo, WANG Zirong
    Epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) were added into the culture medium in different culturing stages. The effects of EGF or bFGF on the development of porcine parthenogenetic embryos were studied in vitro. The results were as follows: The addition of EGF significantly enhanced the cleavage rate of porcine parthenogenetic embryos (P < 0.05). The addition of EGF or bFGF also significantly enhanced the rate of blastocysts formation of 2–4-cell porcine parthenogenetic embryos (P < 0.05). Additionally, the group of bFGF had more numbers of blastocysts and higher rates of blastocysts formation than the groups of EGF and the control. In conclusion, EGF and bFGF were found propitious to the development of porcine parthenogenetic embryos in vitro, and bFGF increased the quality of blastocysts by increasing the total cell number in porcine parthenogenetic embryos.
  • WANG Qiong, YANG Chaowu, LIU Yiping, QIU Mohan, ZHU Qing, JIANG Xiaosong, DU Huarui
    In this study, PCR-SSCP technique was designed to investigate the effect of the myogenin (MyoG) gene on quality of chicken meat (developed by Sichuan Dahen Poultry Breeding Company using local breeds). Four mutations at base position in the promoter region were detected among individuals in each line, i.e. T/C in locus A, and T/A, T/C and A/G in locus B. Least squares analysis showed that there was a significant difference between genotype and breast muscle percentage and some carcass traits (P < 0.05) for locus A. There were significant differences (P < 0.05) in breast muscle weight between AC, AA and AB genotypes; a significant difference (P < 0.05) in leg muscle percentage between CC and AC for locus B, and an extremely significant difference (P < 0.01) in the frequency of genotype muscle fiber density for both locus A and locus B. Nonsignificant difference (P > 0.05) was detected in the other traits. It was concluded that the MyoG gene is the major gene affecting the muscle fiber traits of chicken or it links with the candidate gene, and the mutation can be used as the molecular genetic marker to select the chickens for meat quality traits.