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    Crop Genetics · Breeding · Germplasm Resources
    Using the Phosphomannose Isomerase (PMI) Gene from Saccharomyces cerevisiae for Selection in Rice Transformation
    WANG Tao, LIU Liang-yu, TANG Yong-yan, ZHANG Xiao-bo, ZHANG Mei-dong, ZHENG Yong-lian, ZHANG Fang-dong
    2012, 12(9): 1391-1398.  DOI: 10.1016/S1671-2927(00)8670
    Abstract ( )   PDF in ScienceDirect  
    The phosphomannose isomerase (PMI) gene from Saccharomyces cerevisiae acted as selectable marker and mannose acted as selective agent for the production of transgenic plants of rice (Oryza sativa L.) via Agrobacterium-mediated transformation. The concentration of mannose during the selection was stepwise increased, 5 g L-1 mannose combined with 15 g L-1 sucrose and 500 mg L-1 cefotaxime was used in the initial selection stage, then the concentration of mannose was increased to 11 g L-1, the highest transformation rate was 20.0%. The integration of PMI gene was confirmed by PCR, and the result of RT-PCR assay proved that the intron of PMI gene can be excised correctly during RNA splicing. β- Glucuronidase (GUS) activity analysis confirmed the expression of GUS gene. All those means the PMI gene from yeast can be used as a selectable marker in rice transformation.
    Identification of QTLs Conferring Agronomic and Quality Traits in Hexaploid Wheat
    MAJun , ZHANGCai-ying , YANGui-jun , andLIUChun-ji
    2012, 12(9): 1399-1408.  DOI: 10.1016/S1671-2927(00)8671
    Abstract ( )   PDF in ScienceDirect  
    The availability of elite germplasm resources with high yield and quality potentials is very important for development of cultivars in wheat. Thus, seeking such resources has been the continuous effort of breeder community. In this study, genetic analysis of a novel resource, Triticum spelta line CSCR6, from Australia was made by use of a recombination inbred line (RIL) population of 82 individuals from the cross between CSCR6 and another Australian hexaploid wheat cultivar, Lang. Data of a multiple environmental test was employed to genetically dissect quantitative trait loci (QTL) for agronomic traits such as plant height (PH), spike length (SL), spikelet per spike (SPI), grain number per spike (GNS) and thousand grains weight (TGW) and for quality traits including grain protein content (GPC), gluten content (GC), grain hardness (GH), falling number (FN) and sedimentation value (SV). A 24 QTLs with additive effects were detected for all the investigated traits, and were located on chromosomes 1B, 1D, 2B, 3A, 3B, 3D, 4B, 5A, 5B, 7A, and 7B, respectively. Some QTLs located on 2B and 4B showed higher explanation of phenotypic variances and were not obviously interacted with environment. A QTL in the marker interval of wPT-5334-wPT-4918 (near the locus barc 0199) on 4B gave the highest contribution ratio of 30.76% on PH, while Qgpc-4B and Qgc-4B gave 13.07 and 14.70% contribution ratio on GPC and GC, respectively. Qph-2B, Qgns-2B, and Qgpc-2B showed 13.36, 10.00, and 10.79% contribution ratio on PH, GNS and GPC, respectively. Also, a QTL on 5A, Qsl- 5A, could explain 25.12% of phenotypic variance on SL. For most of agronomic and quality traits, CSCR6 alleles produced increase effects. The fact that a number of loci affecting the investigated traits were detected in T. spelta line CSCR6 revealed that it could offer a new opportunity for the manipulation of these traits in wheat breeding programs.
    Inheritance and Availability of High Grain Number Per Spike in Two Wheat Germplasm Lines
    CHEN Dan, ZHANG Jin-peng, WANG Jian-sheng, YANG Xin-ming, LIU Wei-hua, GAO Ai-nong, LI
    2012, 12(9): 1409-1416.  DOI: 10.1016/S1671-2927(00)8673
    Abstract ( )   PDF in ScienceDirect  
    Grain number per spike (GNPS) is a major factor in wheat yield breeding. The development of high GNPS germplasm is widely emphasized in wheat-yield breeding. This paper reported two high GNPS wheat germplasm lines, Pubing 3228 and Pubing 3504, which had a stable and wide adaptability to different ecological regions. By exploring a nested cross design with reciprocals using Pubing 3228 or Pubing 3504 as a common parent and investigating the GNPS phenotypes of F1 hybrids in 2007-2008 and F2 populations in 2008-2009 of different cross combinations, the narrow-sense GNPS heritability was up to 49.58 and 52.23%, respectively. Genetic model analysis predictions suggested that GNPS in Pubing 3228 and Pubing 3504 was mainly controlled by additive genetic effects. Correlation analysis results between GNPS and 1 000- kernel weight (TKW) of F2 populations showed that TKW was not influenced with the increase of GNPS. The good coordination among three yield components of spike number per plant (SNPP), GNPS, and TKW in the F2 segregating population implied that selection of good candidate individuals in breeding programs would be relatively straightforward. Overall, our results indicated that Pubing 3228 and Pubing 3504 are two potential germplasm lines for yield improvement of GNPS in pedigree selection of wheat breeding.
    The Cloning and Fluorescence In situ Hybridization Analysis of Cotton Telomere Sequence
    LING Jian, CHENG Hua, LIU Fang, SONG Guo-li, WANG Chun-ying, LI Shao-hui, ZHANG Xiang-di, WANG Yu-hong, WANG Kun-bo
    2012, 12(9): 1417-1423.  DOI: 10.1016/S1671-2927(00)8672
    Abstract ( )   PDF in ScienceDirect  
    Telomeres form the ends of eukaryotic chromosomes and serve as protective caps that keep chromosomes structure independency and completeness. The first plant telomere DNA was isolated from Arabidopsis thaliana and was shown to have tandemly repeated sequence 5´-TTTAGGG-3´. The Arabidopsis-type telomere has been found in many plants, but several reports indicate that this sequence is absent in some plants. Up to now, no research has been conducted on the telomere of cotton. In this paper, the Arabidopsis-type telomere sequence was amplified and cloned using the primers designed based on the fragment containing telomere sequence in an Arabidopsis bacterial artificial chromosome (BAC). Fluorescence in situ hybridization (FISH) with cotton metaphase chromosomes using the Arabidopsis-type telomere sequence as probes indicated that the signals were located at all chromosome ends of seven diploid and two tetraploid cotton species with different signal intensities among chromosome complements of different cotton species, even between long and short arms of the same chromosome. To identify the signals of FISH, the genome DNA of Xinhai 7, a cultivar of Gossypium barbadense, digested by BAL-31 nuclease was introduced in this study. The result of BAL-31 digestion indicated that the hybridization signals of FISH represent the outermost DNA sequence of each cotton chromosomes. So we first proved that the telomeric repeats of cotton cross-hybridize with that of Arabidopsis. The results of terminal restriction fragment (TRF) showed significant variation in telomere length among cotton species. The telomere length of cultivated cotton was close to 20 kb and was larger than those of wild cotton species whose telomere length ranged from 6 to 20 kb.
    AFLP Fingerprinting and Genetic Diversity of Main Sweetpotato Varieties in China
    LIU De-gao, ZHAO Ning, ZHAI Hong, YU Xiao-xia, JIE Qin, WANG Lian-jun, HE Shao-zhen, LIU Qing-chang
    2012, 12(9): 1424-1433.  DOI: 10.1016/S1671-2927(00)8674
    Abstract ( )   PDF in ScienceDirect  
    AFLP fingerprinting of the 98 main sweetpotato varieties planted in China has been constructed. Using 17 AFLP primer combinations which were selected from 1 208 primer combinations and generated the most amounts of polymorphic bands, AFLP analysis of the 98 main sweetpotato varieties gave a total of 410 clear polymorphic bands with an average of 24.12 polymorphic bands per primer combination. Each one of the 98 sweetpotato varieties could be clearly distinguished by EcoR I-cta/Mse I-ggc primer combination which generated the most polymorphic bands. AFLP-based genetic distance ranged from 0.0546 to 0.5709 with an average of 0.3799. The dendrogram based on AFLP markers indicated that sweetpotato varieties coming from the same regions or having same parents were clustered in the same groups. Analysis of molecular variance (AMOVA) revealed greater variations within regions (94.08%) than among regions (5.92%). Thus, the genetic variations mainly existed within regions, while the variations among regions were very low in the tested sweetpotato varieties. Significant genetic variations existed between “Northern” and “Southern” sweetpotato varieties when Yangtze River was used as the dividing line.
    Functional Characterization of an Aldehyde Dehydrogenase Homologue in Rice
    YANG Sheng-hui, NIU Xiang-li, LUO Di, CHEN Chang-dong, YU Xu, TANG Wei, LU Bao-rong, LIU Yong-sheng
    2012, 12(9): 1434-1444.  DOI: 10.1016/S1671-2927(00)8675
    Abstract ( )   PDF in ScienceDirect  
    The aldehyde dehydrogenase (ALDH) superfamily of NAD(P)+-dependent enzymes, in general, oxidize a wide range of endogenous and exogenous aliphatic and aromatic aldehydes to their corresponding carboxylic acids and play an essential role in detoxification of reactive oxygen species (ROS) accumulated under the stressed conditions. In order to identify genes required for the stresses responses in the grass crop Oryza sativa, a homologue of ALDH gene (OsALDH22) was isolated and characterized. OsALDH22 is conserved in eukaryotes, shares high homology with the orthologs from aldehyde dehydrogenase subfamily ALDH22. The OsALDH22 encodes a protein of 597 amino acids that in plants exhibit high identity with the orthologs from Zea mays, Sorghum bicolor, Hordeum vulgare and Arabidopsis thaliana, respectively, and the conserved amino acid characteristics for ALDHs are present, including the possible NAD+ binding site (F-V-G-SP- G-V-G), the catalytic site (V-T-L-E-L-G-G-K) and the Cys active site. Semi-quantitative PCR and real-time PCR analysis indicates that OsALDH22 is expressed differentially in different tissues. Various elevated levels of OsALDH22 expression have been detected when the seedlings exposed to abiotic stresses including dehydration, high salinity and abscisic acid (ABA). Transgenic rice plants overexpressing OsALDH22 show elevated stresses tolerance. On the contrary, downregulation of OsALDH22 in the RNA interference (RNAi) repression transgenic lines manifests declined stresses tolerance.
    Estimating Wheat Grain Protein Content Using Multi-Temporal Remote Sensing Data Based on Partial Least Squares Regression
    LI Cun-jun, WANG Ji-hua, WANG Qian, WANG Da-cheng, SONG Xiao-yu, WANG Yan, HUANG Wen-jiang
    2012, 12(9): 1445-1452.  DOI: 10.1016/S1671-2927(00)8676
    Abstract ( )   PDF in ScienceDirect  
    Estimating wheat grain protein content by remote sensing is important for assessing wheat quality at maturity and making grains harvest and purchase policies. However, spatial variability of soil condition, temperature, and precipitation will affect grain protein contents and these factors usually cannot be monitored accurately by remote sensing data from single image. In this research, the relationships between wheat protein content at maturity and wheat agronomic parameters at different growing stages were analyzed and multi-temporal images of Landsat TM were used to estimate grain protein content by partial least squares regression. Experiment data were acquired in the suburb of Beijing during a 2-yr experiment in the period from 2003 to 2004. Determination coefficient, average deviation of self-modeling, and deviation of crossvalidation were employed to assess the estimation accuracy of wheat grain protein content. Their values were 0.88, 1.30%, 3.81% and 0.72, 5.22%, 12.36% for 2003 and 2004, respectively. The research laid an agronomic foundation for GPC (grain protein content) estimation by multi-temporal remote sensing. The results showed that it is feasible to estimate GPC of wheat from multi-temporal remote sensing data in large area.
    Relations Between Photosynthetic Parameters and Seed Yields of Adzuki Bean Cultivars (Vigna angularis)
    SONG Hui, GAO Jin-feng, GAO Xiao-li, DAI Hui-ping, ZHANG Pan-an, FENG Bai-li, WANG Peng-ke
    2012, 12(9): 1453-1461.  DOI: 10.1016/S1671-2927(00)8677
    Abstract ( )   PDF in ScienceDirect  
    The study comparatively examined the leaf photosynthetic capacities of different adzuki bean cultivars, high-yield 2000-75 and Jihong 9218, and low-yield Hongbao 1 and Wanxuan 1 from flowering to ripening. It showed that after flowering, the leaves of the cultivars gradually aged, the leaf chlorophyll (Chl.), soluble protein (SP) contents, net photosynthetic rates (Pn), transpiration rates (Tr) and stomatal conductance (Gs) of the cultivars tended to decline, but the leaf intercellular CO2 concentration (Ci) of the cultivars tended to rise. The leaf photosynthetic capacities of the cultivars decreased gradually from the lower to the upper nodes. The dry seed yields of the cultivars were positively correlated with their leaf Chl., SP, Pn, and Tr and Gs, and negatively associated with their leaf Ci. At the late growth stages, the high-yield cultivars maintained higher leaf Chl. contents, SP contents, Pn, Tr, and Gs than the low-yield cultivars, indicating that leaf photosynthetic capacity was one of important yield-affecting factors of adzuki bean. Therefore, it was important for a crop at the crucial stage of yield formation to maintain a high leaf chlorophyll content and a high leaf photosynthetic capacity and delay leaf aging.
    Influencing Factors on Rice Sheath Blight Epidemics in Integrated Rice-Duck System
    SU Pin, LIAO Xiao-lan, ZHANG Ya, HUANG Huang
    2012, 12(9): 1462-1473.  DOI: 10.1016/S1671-2927(00)8678
    Abstract ( )   PDF in ScienceDirect  
    Sheath blight, a disease caused by the fungus Rhizoctonia solani Kuhn (anamorph), has been the most economically significant disease of rice. It was frequently reported that the disease was well-controlled in integrated rice-duck system without the employment of fungicides. However, the effecting factors behind this phenomenon were rarely reported. In this research, experiment was carried out between two treatments, rice combined with ducks (RD) and conventional rice field without ducks rearing (CK) in early season rice paddy, to investigate the variations of sclerotia in floodwater and on rice plant, microclimate 10 cm above the waterline in rice paddy and activity of protective enzymes in rice plants. The results showed that the floating sclerotia in floodwater in RD was 86-91% lower than that in CK, and adhering sclerotia in rice plant in RD was 67-78% lower than that in CK. The relative humidity tested significantly lower and light intensity tested significantly higher in RD. The temperature in the early rice growth stages in RD was slightly lower than that in CK, but it was significantly higher (32.3-36.5°C) in the middle stage rice growth stages. The polyphenoloxidase (PPO) activity in RD were lower than that in CK, but the enhanced activity of phenylalanine ammonia-lyase (PAL), peroxidase (POD) and Chitinase was observed in different stages of rice growth in RD, especially the Chitinase which showed higher activity in all investigating days.
    Spectroscopic Leaf Level Detection of Powdery Mildew for Winter Wheat Using Continuous Wavelet Analysis
    ZHANG Jing-cheng, YUAN Lin, WANG Ji-hua, HUANG Wen-jiang, CHEN Li-ping, ZHANG Dong-yan
    2012, 12(9): 1474-1484.  DOI: 10.1016/S1671-2927(00)8679
    Abstract ( )   PDF in ScienceDirect  
    Powdery mildew (Blumeria graminis) is one of the most destructive crop diseases infecting winter wheat plants, and has devastated millions of hectares of farmlands in China. The objective of this study is to detect the disease damage of powdery mildew on leaf level by means of the hyperspectral measurements, particularly using the continuous wavelet analysis. In May 2010, the reflectance spectra and the biochemical properties were measured for 114 leaf samples with various disease severity degrees. A hyperspectral imaging system was also employed for obtaining detailed hyperspectral information of the normal and the pustule areas within one diseased leaf. Based on these spectra data, a continuous wavelet analysis (CWA) was carried out in conjunction with a correlation analysis, which generated a so-called correlation scalogram that summarizes the correlations between disease severity and the wavelet power at different wavelengths and decomposition scales. By using a thresholding approach, seven wavelet features were isolated for developing models in determining disease severity. In addition, 22 conventional spectral features (SFs) were also tested and compared with wavelet features for their efficiency in estimating disease severity. The multivariate linear regression (MLR) analysis and the partial least square regression (PLSR) analysis were adopted as training methods in model development. The spectral characteristics of the powdery mildew on leaf level were found to be closely related with the spectral characteristics of the pustule area and the content of chlorophyll. The wavelet features performed better than the conventional SFs in capturing this spectral change. Moreover, the regression model composed by seven wavelet features outperformed (R2=0.77, relative root mean square error RRMSE=0.28) the model composed by 14 optimal conventional SFs (R2=0.69, RRMSE=0.32) in estimating the disease severity. The PLSR method yielded a higher accuracy than the MLR method. A combination of CWA and PLSR was found to be promising in providing relatively accurate estimates of disease severity of powdery mildew on leaf level.
    Optimization and Characterization of Nicosulfuron-Degrading Enzyme from Bacillus subtilis Strain YB1
    KANG Zhan-hai, Dong Jin-gao, ZHANG Jin-lin
    2012, 12(9): 1485-1492.  DOI: 10.1016/S1671-2927(00)8680
    Abstract ( )   PDF in ScienceDirect  
    A strain of Bacillus subtilis strain YB1, isolated and preserved in our lab., showed a high nicosulfuron-degrading activity. Optimization of culture conditions on production of nicosulfuron-degrading enzyme from Bacillus subtilis strain YB1 was carried out through mono-factor experiments. The characterization of degrading enzyme(s) was studied in this paper. The results showed that B. subtilis YB1 can use nicosulfuron as sole carbon source under aerobic condition. The key enzyme(s) involved in the initial biodegradation of nicosulfuron was localized to extracellular proteins and showed to be induced expressed. Enzyme-specific activity was up to 89.34 U mg-1 at pH 8.0 and 30°C, incubation for 96 h, inoculum 4.5×108 CFU mL-1 in Luria-Bertani liquid medium with nicosulfuron of 40 mg L-1. The maximum degradation rate of extracellular crude enzymes on nicosulfuron was 66% at pH 9.0, 35°C in the enzymatic reaction system with nicosulfuron of 5 mg L-1. This degrading enzyme(s) was sensitive to high temperature, but kept high activity under alkaline conditions.
    Effects of Transgenic Bt+CpTI Cotton on Field Abundance of Non-Target Pests and Predators in Xinjiang, China
    XU Yao, WU Kong-ming, LI Hao-bing, LIU Jian, DING Rui-feng, WANG Fei, Ahtam Uwayis, LI Haiqiang, WANG Dong-mei, CHEN Xue-xin
    2012, 12(9): 1493-1499.  DOI: 10.1016/S1671-2927(00)8681
    Abstract ( )   PDF in ScienceDirect  
    Transgenic insect-resistant cotton is being increasingly planted in Xinjiang cotton-planting regions, where geographical climate conditions and species composition of pests and natural enemies are greatly unique in China. Limited studies have been conducted on the ecological impacts of transgenic insect-resistant cotton, especially for transgenic double genes (Bt+CpTI) cotton, in this region. In this study, the potential effects of transgenic Bt+CpTI cotton on the seasonal abundance of non-target pests and predators were assessed from 2009 to 2011 in Korla, Xinjiang. The results showed that species composition and seasonal abundance of 5 groups of pests and 5 groups of predators were not significantly different between transgenic Bt+CpTI cotton and non-transgenic cotton every year. It suggests that transgenic Bt+CpTI cotton per se does not affect the population dynamics of non-target pests and predators on this crop in Xinjiang.
    The Effects of Different Sex-Linked Dwarf Variations on Chinese Native Chickens
    OUYANG Jian-hua, XIE Liang, NIE Qing-hua, ZENG Hua, PENG Zhi-jun, ZHANG De-xiang, ZHANG Xi-quan
    2012, 12(9): 1500-1508.  DOI: 10.1016/S1671-2927(00)8682
    Abstract ( )   PDF in ScienceDirect  
    Variants in chicken growth hormone receptor (GHR) gene lead to sex-linked dwarf (SLD) chickens, but effects of different variants are distinct. In this study, 11 SLD chicken breeds or strains including 3 Chinese native breeds and 8 breeding strains were studied in order to investigate the effects of different sex-linked dwarf variations on growth performance. The results showed that there were three reasons which could lead to dwarfism in the 11 breeds or strains. Firstly, an about 1.7 kb deletion of growth hormone receptor (GHR) gene leads to dwarfism in Jiangxi dwarf chicken, strains GF24, GF26, N308, N309, and N310. Secondly, a T354C mutation in exon 5 of the GHR gene leads to dwarfism in strains N301 and N305. Thirdly, an unknown variant leads to dwarfism in Guizhou Yellow Dwarf chicken and Yixing Bantam chicken. In addition, all individuals of N303 had the 1.7 kb deletion of the GHR gene, and additionally, some of them also carried the T354C mutation. As far as the performance of individuals were compared among T354C homozygote, deletion homozygote, and heterozygote carrying both T354C and deletion, it was found that the T354C’s impacts on body weight of Chinese chickens were maximum, the body weight of chickens with homozygote T354C was 92.12% of those with heterozygote, and the difference of the body weight between deletion homozygote and heterozygote was not significant. There was no significant difference of shank length among three genotypes.
    Effects of Reduced Nocturnal Temperature on Performance and Behavior of Nursery Pigs
    WANG Li-hua, LI Yu-zhi, Lee J Johnston
    2012, 12(9): 1509-1516.  DOI: 10.1016/S1671-2927(00)8683
    Abstract ( )   PDF in ScienceDirect  
    Previous studies suggested that pigs prefer lower environmental temperatures during nighttime compared to daytime. So reducing nocturnal temperature in nursery barns may not jeopardize performance or welfare of pigs, but can save energy for heating the barn. A study was conducted to investigate growth performance and behavioral response of nursery pigs to reduced nocturnal temperature. This study was conducted in four replicates, each utilizing 270 newly weaned pigs and lasting for 5 wk. Temperature setpoint in the control room (CON) was started at 30°C and decreased by 2°C per week. In the treatment room (RNT), temperature setpoint was maintained same as in CON between 7:00 h and 19:00 h, and reduced by 8°C between 19:00 h and 7:00 h starting from d 5. Growth performance (15 pens/room, 9 pigs/pen, BW=(6.3±0.61) kg) was monitored for 5 wk, and behaviors in 6 pens in each room were video-recorded for 24 h 3 d after being exposed to the experimental temperature. Instantaneous scan sampling was performed to determine time budgets for standing, sitting, eating, drinking, belly nosing, three postures of lying, and huddling. Two focal pigs were continuously viewed to record duration and occurrence of eating and drinking. Reduced nocturnal temperature did not affect the growth performance of the pigs, time spent standing, sitting, total lying and eating or duration and frequencies of eating and drinking (all P>0.10). However, RNT increased time spent lying sternal (83 vs. 72%, P<0.001) and number of pigs that were huddling (70 vs. 50% of lying pigs, P<0.001), and decreased time spent lying laterally (0.8 vs. 4.6%, P<0.001), lying half laterally (5.3 vs. 11.0%, P<0.001), and belly nosing (0.9 vs. 1.7%, P=0.01) during nighttime. These results indicate that nursery pigs adopted the posture of lying sternal and huddled together to reduce heat loss from their body surface to maintain thermal balance and growth performance in RNT. Such mild reduction in nocturnal temperature in the nursery barn can save energy for heating the barn without negative effects on performance and behavior of nursery pigs.
    Identification of Antigens Common to Streptococcus suis Serotypes 2 and 9 by ImmunoproteomicAnalysis
    WU Zong-fu, ZHANGWei , WANGYang , LUYan , LUCheng-ping
    2012, 12(9): 1517-1527.  DOI: 10.1016/S1671-2927(00)8684
    Abstract ( )   PDF in ScienceDirect  
    Streptococcus suis is a Gram-positive pathogen that causes serious diseases in pigs. In addition to S. suis serotype 2 (SS2), S. suis serotype 9 (SS9) is another prevalent serotype, which is frequently isolated from the organs of diseased pigs in China. An immunoproteomic-based approach was developed to identify antigens common to SS2 and SS9 for vaccine development. Cell wall proteins extracted from SS2 strain HA9801 were screened by two-dimensional Western blot using anti-SS2 sera, anti-SS9 sera, or pre-immune sera pooled from specific pathogen free (SPF) mice. Protein spots on preparative gels were excised and identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry, which led to the identification of four shared immunogenic proteins (arginine deiminase, translation elongation factor-Ts, o-acetylserine lyase, and 1-phosphofructokinase). The genes encoding these four proteins from SS9 strain GZ0565 were cloned and their proteins were overexpressed in Escherichia coli BL21. Western blot analysis of these recombinant proteins using the convalescent serum of an SPF mini-pig inoculated with the SS2 strain, anti-SS2 sera, and anti-SS9 sera pooled from SPF mice further confirmed the immunogenicity of these proteins. These immunogenic proteins, which are encoded by genes that are reasonably conserved among SS2 and SS9 strains, could be developed as vaccine candidates.
    Identification of Differentially Expressed Genes in the Salivary Gand of Rhipicephalus haemaphysaloides by the Suppression Subtractive Hybridization Approach
    XIANG Fei-yu, ZHOU Yong-zhi, ZHOU Jin-lin
    2012, 12(9): 1528-1536.  DOI: 10.1016/S1671-2927(00)8685
    Abstract ( )   PDF in ScienceDirect  
    For the purpose of screening and analyzing the differentially expressed genes from the salivary gland of Rhipicephalus haemaphysaloides, two salivary gland-subtracted cDNA libraries of partially fed female ticks and fed male ticks were constructed using suppression subtractive hybridization (SSH). A total of 247 female expression sequence tags (ESTs) and 168 male ESTs were obtained from the two SSH cDNA libraries. It is predicted that 25 female ESTs and 44 female ESTs contain the 5´ and 3´ ends, respectively, and that 53 male ESTs and 74 male ESTs contain the 5´ and 3´ ends, respectively. To identify the subtraction rate of the two SSH cDNA libraries, the RT-PCR method was used to test 24 female ESTs and 21 male ESTs selected randomly but not repeatedly. The results showed that there were 13 upregulated or differentially expressed genes in the partially fed salivary gland of the female R. haemaphysaloides and that the differentially expressed rate was 54%. In addition, they indicated that there were 9 upregulated or differently expressed genes in the fed salivary gland of the male R. haemaphysaloides and that the differentially expressed rate was 43%. Putative translations of 141 (57%) female ESTs and 125 (74%) male ESTs had similarity to GenBank sequences, and 32 (23%) female ESTs and 29 (23%) male ESTs exhibited similarity to tick proteins, which showed that most of the proteins in the libraries were mainly related to the feeding blood physiology of the ticks.
    Effects of Chinese Milk Vetch (Astragalus sinicus L.) Residue Incorporation on CH4 and N2O Emission from a Double-Rice Paddy Soil
    ZHU Bo, YI Li-xia, HU Yue-gao, ZENG Zhao-hai, TANG Hai-ming, YANG Guang-li, XIAO Xiao-ping
    2012, 12(9): 1537-1544.  DOI: 10.1016/S1671-2927(00)8686
    Abstract ( )   PDF in ScienceDirect  
    Methane (CH4) and nitrous oxide (N2O) emissions from paddy soils have seldom been estimated when leguminous green manure is applied as a nitrogen source. In this paper, gas fluxes were measured by using a pot sampling device combined with a static chamber method to estimate the effects of Chinese milk vetch (Astragalus sinicus L., CMV) on CH4 and N2O emissions and their integrated global warming potentials (GWP) in a double-rice cropping system. Four treatments (no nitrogen fertilizer, NF; urea as chemical fertilizer, CF; CMV incorporation, MV; 50% CMV incorporation and 50% urea, MVCF) were established. CH4 flux peaked on the 15th d after treatment application. Total season CH4 emission was increased by MV and MVCF by 370 and 209%, 152 and 66%, when compared with NF and CF, respectively. Most of the increased CH4 was emitted in the first two months after incorporation of CMV. N2O emission from CF was 17- and 5.6-fold higher than that from MV and MVCF, respectively. Application of CMV restricted N2O emission caused by the application of urea. Improved CMV residue management was needed to minify CH4 emission induced by the input of organic material. Despite the highest GWP being found in MV, we recommend CMV, when applied as an N source in paddy fields, as a potential mitigation tool for greenhouse gas emissions.
    On-Farm Assessment of Biosolids Effects on Nitrogen and Phosphorus Accumulation in Soils
    LI Qiong, LI Ju-mei, CUI Xi-long, WEI Dong-pu, MA Yi-bing
    2012, 12(9): 1545-1554.  DOI: 10.1016/S1671-2927(00)8687
    Abstract ( )   PDF in ScienceDirect  
    A field plot experiment in a calcareous soil with wheat and maize rotation was carried out for 2 yr. The study aimed to investigate the effects of biosolids (sewage sludge or chicken manure) application on nitrogen (N) and phosphorus (P) accumulation in soils and to develop a model for the effects of biosolids application on available P (Olsen-P) accumulation in soils, by which the quantities of biosolids that can be safely applied to agricultural soils were estimated. The results showed that heavy application of biosolids to agricultural soils based on the N requirement of a wheat-maize rotation cropping system will oversupply P. Soil total N was increased by 0.010 g kg-1 at application rate of 1 ton sewage sludge per hectare. The high ratio of N to P in grains of wheat and maize (from 4.0 to 7.6) and low ratio of N to P in biosolids (<2) led to more surplus P accumulated in soils. Although plant yields and P uptake by plants increased with increasing quantities of applied biosolids in soils, there was still an average 2.87 mg kg-1 increase in Olsen-P in the plough layer treated with biosolids for every 100 kg P ha-1 surplus. A predictive model was developed based upon the initial Olsen-P in soils, P input rates, crop yield, soil pH, and cultivation time. From the model, it is suggested that sewage sludge could be applied to calcareous soils for 12 yr using the recommended application rate (9 tons ha-1 yr-1). The field results will be helpful in achieving best management of biosolids application for agricultural production and environmental protection.
    Nitrate Leaching from Maize Intercropping Systems with N Fertilizer Over-Dose
    NIE Sheng-wei, A Egrinya Eneji, CHEN Yuan-quan, SUI Peng, HUANG Jian-xiong, HUANG Shao-min
    2012, 12(9): 1555-1565.  DOI: 10.1016/S1671-2927(00)8688
    Abstract ( )   PDF in ScienceDirect  
    A 2-yr field experiment was conducted on a calcareous alluvial soil with four summer maize intercropping systems at Shangzhuang Experiment Station (116.3°E, 39.9°N) in the North China Plain. The objective was to determine nitrate leaching from intercropping systems involving maize (Zea mays L.): sole maize (CK), maize + soybean (CST), maize + groundnut (CGT), maize+ ryegrass (CHM), and maize + alfalfa (CMX). Intercropping greatly reduced nitrate accumulation in the 100-200 cm soil layers compared with maize monoculture. Nitrate accumulation under intercropping systems decreased significantly at the 140-200 cm soil depth; the accumulation varied in the order CK>CST>CMX>CHM>CGT. However, compared to the CK treatment, nitrate leaching losses during the maize growing period were reduced by 20.9- 174.8 (CGT), 35.2-130.8 (CHM), 60.4-122.0 (CMX), and 30.6-82.4 kg ha-1 (CST). The results also suggested that intercropping is an effective way to reduce nitrogen leaching in fields with N fertilizer over-dose.