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    Crop Genetics · Breeding · Germplasm Resources
    Alterations of Alternative Splicing Patterns of Ser/Arg-Rich (SR) Genes in Response to Hormones and Stresses Treatments in Different Ecotypes of Rice (Oryza sativa)
    ZHANG Peng, DENG Heng, XIAO Fang-ming , LIU Yong-sheng
    2013, 12(5): 737-748.  DOI: 10.1016/S2095-3119(13)60260-9
    Abstract ( )   PDF in ScienceDirect  
    Ser/Arg-rich (SR) genes encode proteins that play pivotal roles in both constitutive and alternative splicing of pre-mRNA. However, not much effort has been made to investigate the alternative splicing of their own pre-mRNA. In this study, we conducted comprehensive analyses of pre-mRNA splicing for 22 SR genes in three rice (Oryza sativa L.) ecotypes indica, japonica and javanica. Using different ecotypes we characterized the variations in expression and splicing patterns of rice SR genes in different tissues and at different developmental stages. In addition, we compared the divergence in expression and splicing patterns of SR genes from seedlings of different rice ecotypes in response to hormones application and environmental stresses. Our results revealed the complexity of alternative splicing of SR genes in rice. The splicing varies in different tissues, in different ecotypes, in response to stresses and hormones. Thus, our study suggested that SR genes were subjected to sophisticated alternative splicing although their encoding proteins were involved in the splicing process.
    Identification of SSR Marker Linked to a Major Dwarfing Gene in Common Wheat
    MENG Ya-ning, KANG Su-hua, LAN Su-que, LI Xing-pu, ZHANG Ye-lun , BAI Feng
    2013, 12(5): 749-755.  DOI: 10.1016/S2095-3119(13)60266-X
    Abstract ( )   PDF in ScienceDirect  
    A segregating population with 410 F2 individuals from the cross MERCIA (Rht-B1a) × Dwarf 123 was made to identify a new major dwarfing gene carrying by novel wheat germplasm Dwarf 123. Combination of bulk segerant analysis method was used. A total of 145 SSR markers were tested for polymorphisms among parental lines and DNA bulks of F2 population. Out of 145 primer pairs only three markers revealed corresponding polymorphism among parental lines and F2 DNA bulks. The marker Barc20 was close to the dwarfing gene with a genetic distance of 1.8 cM, and markers Gwm513 and Gwm495 were linked to the gene with genetic distance of 6.7 and 13 cM, respectively. Linkage analysis mapped the dwarfing gene to the long arm of chromosome 4B with the order of Barc20-dwarfing gene-Gwm513-Gwm495. The Comparision between the new gene and the known Rht-B1 alleles showed that dwarfing gene Rht-Ai123 was different from the others. The identification of the new dwarfing gene and its linked markers will greatly facilitate its utilization in wheat high yield breeding for reducing plant height.
    QTL Mapping for Adult Plant Resistance to Powdery Mildew in Italian Wheat cv. Strampelli
    Asad Muhammad Azeem, BAI Bin, LAN Cai-xia, YAN Jun, XIA Xian-chun, ZHANG Yong , HE Zhong-hu
    2013, 12(5): 756-764.  DOI: 10.1016/S2095-3119(13)60297-X
    Abstract ( )   PDF in ScienceDirect  
    The Italian wheat cv. Strampelli displays high resistance to powdery mildew caused by Blumeria graminis f. sp. tritici. The objective of this study was to map quantitative trait loci (QTLs) for resistance to powdery mildew in a population of 249 F2:3 lines from Strampelli/Huixianhong. Adult plant powdery mildew tests were conducted over 2 yr in Beijing and 1 yr in Anyang and simple sequence repeat (SSR) markers were used for genotyping. QTLs Qpm.caas-3BS, Qpm.caas-5BL.1, and Qpm.caas-7DS were consistent across environments whereas, Qpm.caas-2BS.1 found in two environments, explained 0.4-1.6, 5.5-6.9, 27.1-34.5, and 1.0-3.5% of the phenotypic variation respectively. Qpm.caas-7DS corresponded to the genomic location of Pm38/Lr34/Yr18. Qpm.caas-4BL was identified in Anyang 2010 and Beijing 2011, accounting for 1.9-3.5% of phenotypic variation. Qpm.caas-2BS.1 and Qpm.caas-5BL.1 contributed by Strampelli and Qpm.caas-3BS by Huixianhong, seem to be new QTL for powdery mildew resistance. Qpm.caas-4BL, Qpm.caas-5BL.3, and Qpm.caas-7DS contributed by Strampelli appeared to be in the same genomic regions as those mapped previously for stripe rust resistance in the same population, indicating that these loci conferred resistance to both stripe rust and powdery mildew. Strampelli could be a valuable genetic resource for improving durable resistance to both powdery mildew and stripe rust in wheat.
    Identification of Quantitative Trait Loci for Phytic Acid Concentration in Maize Grain Under Two Nitrogen Conditions
    LIU Jian-chao, HUANG Ya-qun, MA Wen-qi, ZHOU Jin-feng, BIAN Fen-ru, CHEN Fan-jun , MI Guo-hua
    2013, 12(5): 765-772.  DOI: 10.1016/S2095-3119(13)60298-1
    Abstract ( )   PDF in ScienceDirect  
    Phytic acid (PA) is the main storage form of phosphorus (P) in seeds. It can form insoluble complexes with microelements, thereby reducing their bioavailability for animals. Identification of quantitative trait loci (QTLs) associated with grain PA concentration (PAC) is essential to improve this trait without affecting other aspects of grain nutrition such as protein content. Using a recombinant inbred line (RIL) population, we mapped QTL for grain PAC, as well as grain nitrogen concentration (NC) and P concentration (PC) in maize under two N conditions in 2 yr. We detected six QTLs for PAC. The QTL for PAC on chromosome 4 (phi072-umc1276) was identified under both low-N and high-N treatments, and explained 13.2 and 15.4% of the phenotypic variance, respectively. We identified three QTLs for grain NC, none of which were in the same region as the QTLs for PAC. We identified two QTLs for PC in the low-N treatment, one of which (umc1710-umc2197) was in the same interval as the QTL for PAC under high-N conditions. These results suggested that grain PAC can be improved without affecting grain NC and inorganic PC.
    Cloning and Functional Analysis of Lycopene ε-Cyclase (IbLCYe) Gene from Sweetpotato, Ipomoea batatas (L.) Lam.
    YU Ling, ZHAI Hong, CHEN Wei, HE Shao-zhen , LIU Qing-chang
    2013, 12(5): 773-780.  DOI: 10.1016/S2095-3119(13)60299-3
    Abstract ( )   PDF in ScienceDirect  
    This paper reported firstly successful cloning of lycopene ε-cyclase (IbLCYe) gene from sweetpotato, Ipomoea batatas (L.) Lam. Using rapid amplification of cDNA ends (RACE), IbLCYe gene was cloned from sweetpotato cv. Nongdafu 14 with high carotenoid content. The 1 805 bp cDNA sequence of IbLCYe gene contained a 1 236 bp open reading frame (ORF) encoding a 411 amino acids polypeptide with a molecular weight of 47 kDa and an isoelectric point (pI) of 6.95. IbLCYe protein contained one potential lycopene ε-cyclase domain and one potential FAD (flavinadenine dinucleotide)/NAD(P) (nicotinamide adenine dinucleotide phosphate)-binding domain, indicating that this protein shares the typical characteristics of LCYe proteins. The gDNA of IbLCYe gene was 4 029 bp and deduced to contain 5 introns and 6 exons. Real-time quantitative PCR analysis revealed that the expression level of IbLCYe gene was significantly higher in the storage roots of Nongdafu 14 than those in the leaves and stems. Transgenic tobacco (cv. Wisconsin 38) expressing IbLCYe gene accumulated significantly more β-carotene compared to the untransformed control plants. These results showed that IbLCYe gene has an important function for the accumulation of carotenoids of sweetpotato.
    Physiology & Biochentry · Tillage · Cultivation
    Numerical Simulation of Root Growth Dynamics of CO2-Enriched Hybrid Rice Cultivar Shanyou 63 Under Fully Open-Air Field Conditions
    SUN Cheng-ming, LIU Tao, GUO Dou-dou, ZHUANG Heng-yang, WANG Yu-long , ZHU Jian-guo
    2013, 12(5): 781-787.  DOI: 10.1016/S2095-3119(13)60261-0
    Abstract ( )   PDF in ScienceDirect  
    Hybrid indica rice (Oryza sativa L.) cultivars play an important role in rice production system due to its heterosis, resistance to environmental stress, large panicle, and high yield potential. However, no attention has been given to its root growth dynamic responses to rising atmospheric CO2 concentration ([CO2]) in conjunction with nitrogen (N) availability. Free air CO2 enrichment (FACE) and N have significant effects on rice root growth. In this experiment, a hybrid cultivar Shanyou 63 (Oryza sativa L.) was used to study the effects of FACE and N levels on roots growth of rice. The results showed a significant increase in both adventitious root volume (ARV) and adventitious root dry weight (ARD) under the FACE treatment. The application of nitrogen also increased ARV and ARD, but the increase was smaller than that under FACE treatment. On the basis of the FACE experiment, numerical models for rice adventitious root volume and dry weight were built with the time as the driving factor. The models illustrated the dynamic development of rice adventitious root volume and dry weight after transplanting, regulated either by the influence factor of atmospheric [CO2] or by N application. The models were successfully used to predict ARV and ARD under FACE treatment in a different year with the predicted data being closely related to the actual experimental data. The model had guiding significance to growth regulation of rice root under the condition of atmospheric [CO2] rising in the future.
    A New Method to Determine Central Wavelength and Optimal Bandwidth for Predicting Plant Nitrogen Uptake in Winter Wheat
    YAO Xin-feng, YAO Xia, TIAN Yong-chao, NI Jun, LIU Xiao-jun, CAO Wei-xing , ZHU Yan
    2013, 12(5): 788-802.  DOI: 10.1016/S2095-3119(13)60300-7
    Abstract ( )   PDF in ScienceDirect  
    Plant nitrogen (N) uptake is a good indicator of crop N status. In this study, a new method was designed to determine the central wavelength, optimal bandwidth and vegetation indices for predicting plant N uptake (g N m-2) in winter wheat (Triticum aestivum L.). The data were collected from the ground-based hyperspectral reflectance measurements in eight field experiments on winter wheat of different years, eco-sites, varieties, N rates, sowing dates, and densities. The plant N uptake index (PNUI) based on NDVI of 807 nm combined with 736 nm was selected as the optimal vegetation index, and a linear model was developed with R2 of 0.870 and RMSE of 1.546 g N m-2 for calibration, and R2 of 0.834, RMSE of 1.316 g N m-2, slope of 0.934, and intercept of 0.001 for validation. Then, the effect of the bandwidth of central wavelengths on model performance was determined based on the interaction between central wavelength and bandwidth expansion. The results indicated that the optimal bandwidth varies with the changes of the central wavelength and with the interaction between the two bands in one vegetation index. These findings are important for prediction and diagnosis of plant N uptake more precise and accurate in crop management.
    Detection of Tocopherol in Oilseed Rape (Brassica napus L.) Using Gas Chromatography with Flame Ionization Detector
    Nazim Hussain, Zahra Jabeen, LI Yuan-long, CHEN Ming-xun, LI Zhi-lan, GUO Wan-li, Imran Haider Shamsi, CHEN Xiao-yang , JIANG Li-xi
    2013, 12(5): 803-814.  DOI: 10.1016/S2095-3119(13)60301-9
    Abstract ( )   PDF in ScienceDirect  
    The variation among Chinese genotypes of Brassica napus L. for seed tocopherols content and their analysis using gas chromatography has not been comprehensively reported till to date. In the present study, the tocopherol contents of four Chinese genotypes of Brassica napus L., namely, Gaoyou 605, Zhejiang 619, Zheshuang 758, and Zheshuang 72, were evaluated using three modified sample preparation protocols (P1, P2, and P3) for tocopherol extraction. These methods were distinguished as follows. Protocol one (P1) included the evaporation of solvent after extraction without silylation. Protocol two (P2) followed the direct supernatant collection after overnight extraction without drying and silylation. Protocol three (P3) included trimethylsilylation with N,O-bis(trimethylsilyl) trifluoroacetamide. Genotypic comparison of tocopherol and its isoforms revealed that Gaoyou 605 was dominant over the other genotypes with (140.5±10.5), (316.2± 9.2), and (559.1± 24.3) μg g-1 of seed meal α-, γ-, and total (T-) tocopherol, respectively, and a 0.44±0.04 α- to γ-tocopherol ratio. The comparison of the sample preparation protocols, on the other hand, suggests that P3 is the most suitable method for the tocopherol extraction from Brassica oilseeds and for the analysis of tocopherols using gas chromatography flame ionization detector (GC-FID). Trimethylsilylation is the key step differentiating P3 from P1 and P2. Variations detected in tocopherol contents among the Chinese rapeseed (B. napus) genotypes signify the need to quantify a wide range of rapeseed germplasm for seed tocopherol dynamics in short and crop improvement in long.
    Grafting Raises the Cu Tolerance of Cucumber Through Protecting Roots Against Oxidative Stress Induced by Cu Stress
    ZHANG Zi-kun, LI Hua, HE Hong-jun , LIU Shi-qi
    2013, 12(5): 815-824.  DOI: 10.1016/S2095-3119(13)60268-3
    Abstract ( )   PDF in ScienceDirect  
    A greenhouse experiment was carried out to determine plant growth, reactive oxygen species (ROS) metabolism in roots and functions of plasma membrane (PM) and tonoplast in cucumber seedlings (Cucumis sativus L. cv. Xintaimici) treated with 40 μmol L-1 CuSO4·5H2O, which were either ungrafted or grafted onto the rootstock (Cucurbita ficifolia). Cu treatment inhibited growth, induced significant accumulation of H2O2 and led to serious lipid peroxidation in cucumber roots, and the ROS-scavenging enzymes activities in grafted seedlings roots were significantly higher than that of ungrafted plants, thus less accumulation in grafted cucumber roots induced by Cu. As a result, lipid peroxidation in roots decreased. Furthermore, the activities of H+-ATPase, H+-PPase and Ca2+-ATPase in PM and/or tonoplast in grafted cucumber seedlings under Cu stress were obviously higher than that in ungrafted plants, resulting into higher ability in grafted plants to expulse the excess H+, promote the cytoplasm alkalinization, regulate the intracellular Ca2+ concentration and brought the cytoplasma concentration of free Ca2+ to extremely low level under Cu stress.
    Arabidopsis LOS5 Gene Enhances Chilling and Salt Stress Tolerance in Cucumber
    LIU Li-ying, DUAN Liu-sheng, ZHANG Jia-chang, MI Guo-quan, ZHANG Xiao-lan, ZHANG Zhen-xian, REN Hua-zhong
    2013, 12(5): 825-834.  DOI: 10.1016/S2095-3119(13)60270-1
    Abstract ( )   PDF in ScienceDirect  
    Low temperature and high salinity are the major abiotic stresses that restrict cucumber growth and production, breeding materials with multiple abiotic resistance are in greatly need. Here we investigated the effect of introducing the LOS5 gene, a key regulator of ABA biosynthesis in Arabidopsis thaliana, under the stress-responsive RD29A promoter into cucumber (Cucumis sativus L. cv. S516). We found that T1 RD29A-LOS5 transgenic lines have enhanced tolerance to cold and salt stresses. Specifically, transgenic lines exhibited dwarf phenotypes with reduced leaf number, shorter internode, decreased length of the biggest leaf, fewer female flowers, shorter fruit neck and lower vitamin C (Vc). The increased cold tolerance can be reflected from the significantly decreased cold index, the reduced electrolyte leakage index and the MDA content upon cold treatment as compared to those in the control. This may result from the accumulation of internal ABA, soluble sugars and proline, and the enhanced activities of protective enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in the transgenic lines. Under salt treatment, the transgenic lines exhibited increased germination index, vigor index, more lateral roots and increased root fresh weight. Moreover, RD29A-LOS5 transgenic plants displayed quicker responses in salt stress than that in low-temperature stress.
    Plant Protection
    Biotic Homogenization Caused by the Invasion of Solidago canadensis in China
    CHEN Guo-qi, ZHANG Chao-bin, MA Ling, QIANG Sheng, John A Silander , Li Li Qi
    2013, 12(5): 835-845.  DOI: 10.1016/S2095-3119(13)60302-0
    Abstract ( )   PDF in ScienceDirect  
    Although studies argue that invasive species can cause biotic differentiation, some cases show that biological invasions actually decrease biodiversity through biotic homogenization. The concept of biotic homogenization through the invasion of a certain serious invasive plant species merit more studies. Hence, we used field surveys to quantitatively compare invasive populations of Solidago canadensis (SC) in China with the control sites (adjacent sites to SC present sites yet without the species) and SC native populations in the USA. We found that plant communities in SC invaded habitats shared similarities with those in SC native ranges. Bray-Curtis similarity clearly showed that the composition of plant communities in SC invaded habitats were similar to those in SC native ranges. Both in the native and introduced range, plant communities with SC present were characterized by SC being dominant, significantly lower species richness, α-diversity and β-diversity, as well as a decrease in the correlation coefficient between geographic distance and floristic similarities. SC favors fertile and moist loam habitat, while it dominated in various habitats in China, where more than 20 different dominants should have occurred. In conclusion, serious invasive species can quickly remodel and homogenize diverse communities by dominating them.
    Comparative Morphology and Morphometry of Six Biotypes of Bemisia tabaci (Hemiptera: Aleyrodidae) from China
    LI Jing-jing, TANG Qing-bo, BAI Run-e, LI Xiao-min, JIANG Jin-wei, ZHAI Qing , YAN Feng-ming
    2013, 12(5): 846-852.  DOI: 10.1016/S2095-3119(13)60303-2
    Abstract ( )   PDF in ScienceDirect  
    Morphology and morphometry of six biotypes (B, Q, Cv, ZHJ-1, ZHJ-2 and ZHJ-3) of Bemisia tabaci (Gennadius) from China on cotton plants were studied by using microscopes. Nymphal body sizes and characters were measured and observed, especially on the 4th instar (pupal case), including the vasiform orifice, operculum, lingula, length and thickness of anterior and posterior wax margins, width of thoracic tracheal combs. Adult characters of both sexes were investigated including the body size, compound eyes, antennal segments, vasiform orifice, hind tarsi and genitals. The results indicated that differences of some morphological characters or morphometrics were significant among the six biotypes of B. tabaci in China: (1) Pupal sizes of the exotic biotypes (B and Q) were significantly larger than the indigenous biotypes with the following order as B>Q>ZHJ-1>Cv>ZHJ-3>ZHJ-2; (2) for both male and female adults, sizes of all characters investigated in the invading biotypes (B and Q), especially B, were much larger than those of the indigenous ones.
    Functional Characteristics of a Novel Chemosensory Protein in the Cotton Bollworm Helicoverpa armigera (Hübner)
    ZHANG Tian-tao, WANG Wei-xuan, ZHANG Zi-ding, ZHANG Yong-jun , GUO Yu-yuan
    2013, 12(5): 853-861.  DOI: 10.1016/S2095-3119(13)60304-4
    Abstract ( )   PDF in ScienceDirect  
    A chemosensory protein named HarmCSP5 in cotton bollworm Helicoverpa armigera (Hübner) was obtained from antennal cDNA libraries and expressed in Escherichia coli. The real time quantitative PCR (RT-qPCR) results indicated that HarmCSP5 gene was mainly expressed in male and female antennae but also expressed in female legs and wings. Competitive binding assays were performed to test the binding affinity of recombinant HarmCSP5 to 60 odor molecules including some cotton volatiles. The resules showed that HarmCSP5 showed strong binding abilities to 4-ehtylbenzaldehyde and 3,4-dimethlbenz aldehyde, whereas methyl phenylacetate, 2-decanone, 1-pentanol, carvenol, isoborneol, nerolidol, 2- nonanone and ethyl heptanoate have relatively weak binding affinity. Moreover, the predicted 3D model of HarmCSP5 consists of six α-helices located among residues 33-38 (α1), 40-48 (α2), 62-72 (α3), 80-96 (α4), 98-108 (α5), and 116-119 (α6), two pairs of disulfide bridges Cys49-Cys55, Cys75-Cys78. The two amino acid residues, Ile94 and Trp101, may play crucial roles in HarmCSP5 binding with ligands and need further study for confirmation.
    Animal Science · Veterinary Science
    Effect of Dietary Folic Acid Supplementation on Growth Performance and Hepatic Protein Metabolism in Early-Weaned Intrauterine Growth Retardation Piglets
    YAO Ying, YU Bing, CHEN Dai-wen, TIAN Gang, MAO Xiang-bing, ZHENG Ping, , LIUJing-bo
    2013, 12(5): 862-868.  DOI: 10.1016/S2095-3119(13)60262-2
    Abstract ( )   PDF in ScienceDirect  
    To investigate the effects of dietary supplementation with folic acid on growth performance, hepatic protein metabolism and serum biochemical indices of early-weaned intrauterine growth retardation (IUGR) piglets, 24 male (Duroc× (Landrace×Yorkshire)) weaned (14-d-old) IUGR piglets were randomly divided into 3 treatments with 8 replicates of 1 piglet per replicate. The piglets in each treatment were fed basal diet supplementation with either 0 (control), 5 and 10 mg kg-1 folic acid. The trial lasted for 21 d. Dietary folic acid supplementation reduced average daily feed intake (ADFI) (P<0.05). In addition, the average daily gain (ADG) in 10 mg kg-1 folic acid group was significantly decreased (P<0.01) and the ratio of feed:gain (F/G) increased slightly (P>0.05). Serum folic acid concentration increased (P<0.01) with increasing folic acid inclusion, however, serum homocysteine concentration decreased significantly (P<0.01). Enhanced serum urine nitrogen (SUN) and diminished serum total protein (TP) as well as liver TP content were observed in 10 mg kg-1 folic acid group (P<0.05). Furthermore, the relative mRNA expressions of insulin-like growth factor 1 (IGF-1) and mammalian target of rapamycin (m-TOR) in liver were respectively tended to reduce (P=0.06) and significantly downregulated (P<0.05) in 10 mg kg-1 group, in compared with 5 mg kg-1 group. However, when compared with control group, folic acid supplementation had no significant effect on the mRNA abundance of IGF-1 and m-TOR. The results indicated that supplementation with 10 mg kg-1 folic acid impaired growth performance and hepatic protein metabolism of early-weaned IUGR piglets while 5 mg kg-1 folic acid enriched diet exerted limited positive effects.
    Optimization of Solid-State Fermentation with Lactobacillus brevis and Aspergillus oryzae for Trypsin Inhibitor Degradation in Soybean Meal
    GAO You-ling, WANG Cai-sheng, ZHU Qiu-hua , QIAN Guo-ying
    2013, 12(5): 869-876.  DOI: 10.1016/S2095-3119(13)60305-6
    Abstract ( )   PDF in ScienceDirect  
    The aim of the present study was to optimize trypsin inhibitor degradation in soybean meal by solid-state fermentation (SSF) with Lactobacillus brevis and Aspergillus oryzae, and to determine the effect of SSF on phytic acid, crude protein, crude fat, and amino acid profile. Response surface methodology (RSM) with Box-Behnken design was used to optimize SSF. The optimal conditions derived from RSM for L. brevis fermentation were: pH=5.1; inoculum size=10%; duration=72 h; substrate to water ratio=1.5. The minimum content of trypsin inhibitors was 6.4 mg g-1 dry matter. The optimal conditions derived from RSM for A. oryzae fermentation were: substrate to water ratio= 0.81; inoculum size=4%; duration=120 h. The minimum content of trypsin inhibitors was 1.6 mg g-1 dry matter. Both L. brevis and A. oryzae decreased trypsin inhibitors dramatically (57.1 and 89.2% respectively). L. brevis fermentation did not affect phytic acid (0.4%) and crude fat (5.2%) considerably, whereas A. oryzae fermentation degraded phytic acid (34.8%) and crude fat (22.0%) contents to a certain extent. Crude protein content was increased after both fermentation (6.4 and 12.9% for L. brevis and A. oryzae respectively). Urease activity was reduced greatly (83.3 and 58.3% for L. brevis and A. oryzae respectively). In conclusion, SSF with A. oryzae and L. brevis reduced trypsin inhibitor content and modified major macronutrients in soybean meal.
    Rapid Recovery of Classical Swine Fever Virus Directly from Cloned cDNA
    HUANG Jun-hua, LI Yong-feng, HE Fan, LI Dan, SUN Yuan, HAN Wen , QIU Hua-ji
    2013, 12(5): 877-883.  DOI: 10.1016/S2095-3119(13)60258-0
    Abstract ( )   PDF in ScienceDirect  
    The reverse genetics for classical swine fever virus (CSFV) is currently based on the transfection of in vitro transcribed RNA from a viral genomic cDNA clone, which is inefficient and time-consuming. This study was aimed to develop an improved method for rapid recovery of CSFV directly from cloned cDNA. Full-length genomic cDNA from the CSFV Shimen strain, which was flanked by a T7 promoter, the hepatitis delta virus ribozyme and T7 terminator sequences, was cloned into the lowcopy vector pOK12, producing pOKShimen-RzT . Direct transfection of pOKShimen-RzT into PK/T7 cells, a PK-15- derived cell line stably expressing bacteriophage T7 RNA polymerase, allowed CSFV to be rescued rapidly and efficiently, i.e., at least 12 h faster and 31.6-fold greater viral titer when compared with the in vitro transcription-based rescue system. Furthermore, the progeny virus rescued from PK/T7 cells was indistinguishable, both in vitro and in vivo, from its parent virus and the virus rescued from classical reverse genetics. The reverse genetics based on intracellular transcription is efficient, convenient and cost-effective. The PK/T7 cell line can be used to rescue CSFV directly from cloned cDNA and it can also be used as an intracellular transcription and expression system for studying the structure and function of viral genes.
    Identification of Sheep Endogenous Beta-Retroviruses with Uterus-Specific Expression in the Pregnant Mongolian Ewe
    QI Jing-wei, XU Meng-jie, LIU Shu-ying, ZHANG Yu-fei, LIU Yue, ZHANG Ya-kun , CAO Gui-fang
    2013, 12(5): 884-891.  DOI: 10.1016/S2095-3119(13)60306-8
    Abstract ( )   PDF in ScienceDirect  
    The sheep genome harbours approximately 20 copies of endogenous beta-retroviruses (enJSRVs), and circumstantial evidence suggests that enJSRVs might play a role in mammalian reproduction, particularly placental morphogenesis. This study was aimed to assess the expression of mRNAs of an enJSRV and its receptor, HYAL2, in the uterus and conceptuses of Mongolian ewes throughout gestation, using real-time reverse transcription polymerase chain reaction and in situ hybridization analysis. The results showed that enJSRV and HYAL2 mRNAs were found to be expressed throughout gestation in the endometrium, chorion, placenta, and conceptus. The enJSRV mRNA was most abundant in the placenta on day 90 of pregnancy, in the endometrium on day 30 and 50, and in the chorion on day 70 and 110. However, HYAL2 mRNA was most abundant in the endometrium on day 30. These differences were all significantly different from each other (P<0.01). In situ hybridization showed that enJSRV and HYAL2 mRNAs were specifically expressed in endometrial luminal epithelium and glandular epithelium, trophoblastic giant binucleated cells (BNCs), endometrial caruncles, placental cotyledons, stroma, trophectoderm, as well as multinucleated syncytia of the placenta and blood vessel endothelial cells. Collectively, little is known about the molecular mechanisms by which trophoblastic differentiation and multinucleated syncytia formation are regulated by enJSRVs. However, the temporal and spatial distributions of enJSRV expression in the uterus and conceptus indicate that differentiation of BNCs and the formation of a multinucleated syncytiotrophoblast involve enJSRV and possibly its cellular receptor, HYAL2. Therefore, enJSRV and HYAL2 appear to play important roles in the female reproductive physiology in this breed of sheep.
    Climate Change Modelling and Its Roles to Chinese Crops Yield
    JU Hui, LIN Er-da, Tim Wheeler, rew Challinor , JIANG Shuai
    2013, 12(5): 892-902.  DOI: 10.1016/S2095-3119(13)60307-X
    Abstract ( )   PDF in ScienceDirect  
    Climate has been changing in the last fifty years in China and will continue to change regardless any efforts for mitigation. Agriculture is a climate-dependent activity and highly sensitive to climate changes and climate variability. Understanding the interactions between climate change and agricultural production is essential for society stable development of China. The first mission is to fully understand how to predict future climate and link it with agriculture production system. In this paper, recent studies both domestic and international are reviewed in order to provide an overall image of the progress in climate change researches. The methods for climate change scenarios construction are introduced. The pivotal techniques linking crop model and climate models are systematically assessed and climate change impacts on Chinese crops yield among model results are summarized. The study found that simulated productions of grain crop inherit uncertainty from using different climate models, emission scenarios and the crops simulation models. Moreover, studies have different spatial resolutions, and methods for general circulation model (GCM) downscaling which increase the uncertainty for regional impacts assessment. However, the magnitude of change in crop production due to climate change (at 700 ppm CO2 eq correct) appears within ±10% for China in these assessments. In most literatures, the three cereal crop yields showed decline under climate change scenarios and only wheat in some region showed increase. Finally, the paper points out several gaps in current researches which need more studies to shorten the distance for objective recognizing the impacts of climate change on crops. The uncertainty for crop yield projection is associated with climate change scenarios, CO2 fertilization effects and adaptation options. Therefore, more studies on the fields such as free air CO2 enrichment experiment and practical adaptations implemented need to be carried out.
    Soil & Fertilization · Irrigation · Agro-Ecology & Environment
    Spatial Exploration of Multiple Cropping Efficiency in China Based on Time Series Remote Sensing Data and Econometric Model
    ZUO Li-jun, WANG Xiao, LIU Fang , YI Ling
    2013, 12(5): 903-913.  DOI: 10.1016/S2095-3119(13)60308-1
    Abstract ( )   PDF in ScienceDirect  
    This study explored spatial explicit multiple cropping efficiency (MCE) of China in 2005 by coupling time series remote sensing data with an econometric model - stochastic frontier analysis (SFA). We firstly extracted multiple cropping index (MCI) on the basis of the close relationship between crop phenologies and moderate-resolution imaging spectroradiometer (MODIS) enhanced vegetation index (EVI) value. Then, SFA model was employed to calculate MCE, by considering several indicators of meteorological conditions as inputs of multiple cropping systems and the extracted MCI was the output. The result showed that 46% of the cultivated land in China in 2005 was multiple cropped, including 39% doublecropped land and 7% triple-cropped land. Most of the multiple cropped land was distributed in the south of Great Wall. The total efficiency of multiple cropping in China was 87.61% in 2005. Southwestern China, Ganxin Region, the middle and lower reaches of Yangtze River and Huanghuaihai Plain were the four agricultural zones with the largest rooms for increasing MCI and improving MCE. Fragmental terrain, soil salinization, deficiency of water resources, and loss of labor force were the obstacles for MCE promotion in different zones. The method proposed in this paper is theoretically reliable for MCE extraction, whereas further studies are need to be done to investigate the most proper indicators of meteorological conditions as the inputs of multiple cropping systems.
    CFD Based Study of Heterogeneous Microclimate in a Typical Chinese Greenhouse in Central China
    WANG Xiao-wei, LUO Jin-yao , LI Xiao-ping
    2013, 12(5): 914-923.  DOI: 10.1016/S2095-3119(13)60309-3
    Abstract ( )   PDF in ScienceDirect  
    Indoor microclimate is important for crop production and quality in greenhouse cultivation. This paper focuses on microclimate study based on a computational fluid dynamics (CFD) model of a typical plastic greenhouse (with a sector shape vertical cross-section) popularly used in central China. A radiation model is added into the CFD model so as to simulate coupling of convective transfers and radiative exchanges at the cover and the roof, instead of using the usual coupling approach based on energy balance. In addition, a fractal permeability model is innovatively adopted in the modeling of the crop canopy. Compared the numerical results with measured experimental data, the model simulation is proved with success. This model then is used to explore the microclimate variable distributions in the greenhouse. It shows that the airflow pattern, temperature and humidity profiles are different from those in a sawtooth Mediterraneantype greenhouse. The study suggests that this deliberately developed CFD model can be served as a useful tool in macroclimate research and greenhouse design investigating.
    Effects of Drip System Uniformity and Irrigation Amount on Water and Salt Distributions in Soil Under Arid Conditions
    GUAN Hong-jie, LI Jiu-sheng, , LI Yan-feng
    2013, 12(5): 924-939.  DOI: 10.1016/S2095-3119(13)60310-X
    Abstract ( )   PDF in ScienceDirect  
    The dynamics of water and salt in soil were monitored in the 2010 and 2011 growing seasons of cotton to evaluate the salinity risk of soil under drip irrigation in arid environments for different management practices of drip system uniformity and irrigation amount. In the experiments, three Christiansen uniformity coefficients (CU) of approximately 65, 80, and 95% (referred to as low, medium, and high uniformity, respectively) and three irrigation amounts of 50, 75, and 100% of full irrigation were used. The distribution of the soil water content and bulk electrical conductivity (ECb) was monitored continuously with approximately equally spaced frequency domain reflectometry (FDR) sensors located along a dripline. Gravimetric samples of soil were collected regularly to determine the distribution of soil salinity. A great fluctuation in CU of water content and ECb at 60 cm depth was observed for the low uniformity treatment during the irrigation season, while a relatively stable variation pattern was observed for the high uniformity treatment. The ECb CU was substantially lower than the water content CU and its value was greatly related to the water content CU and the initial ECb CU. The spatial variation of seasonal mean soil water content and seasonal mean soil bulk electrical conductivity showed a high dependence on the variation pattern of emitter discharge rate along a dripline for the low and medium uniformity treatments. A greater irrigation amount produced a significantly lower soil salinity at the end of the irrigation season, while the influence of the system uniformity on the soil salinity was insignificant at a probability level of 0.1. In arid regions, the determination of the target drip irrigation system uniformity should consider the potential salinity risk of soil caused by nonuniform water application as the influence of the system uniformity on the distribution of the soil salinity was progressively strengthened during the growing season of crop.