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    Soil Organic Nitrogen and Its Contribution to Crop Production
    LI Sheng-xiu, WANG Zhao-hui, MIAO Yan-fang , LI Shi-qing
    2014, 13(10): 2061-2080.  DOI: 10.1016/S2095-3119(14)60847-9
    Abstract ( )   PDF in ScienceDirect  
    Plant growth and crop production depend to a large extent on soil N supplying capacity (SNSC): The higher the SNSC, the higher the dependence of crops on soil and the lower the N fertilizer recovery. Of the SNSC, soil organic N (ON) played a key role in supplying N nutrient to crop production and still does in many subsistence and low-input farming systems. In this paper, soil ON contents, types, chemical components and its contribution to plant production are reviewed up to date in details, the characteristics of ON in dryland soils discussed together with its chemical components, and the mineralization and availability to plants of some important chemical components are emphasized at the last part for practical considerations.
    Crop Genetics · Breeding · Germplasm Resources
    Development of Insect-Resistant Hybrid Rice by Introgressing the Bt Gene from Bt Rice Huahui 1 into II-32A/B, a Widely Used Cytogenic Male Sterile System
    LAI Yun-song, HUANG Hai-qing, XU Meng-yun, WANG Liang-chao, ZHANG Xiao-bo, ZHANG Ji-wen , TU Ju-min
    2014, 13(10): 2081-2090.  DOI: 10.1016/S2095-3119(13)60538-9
    Abstract ( )   PDF in ScienceDirect  
    Huahui 1 is an elite transgenic male sterile restorer line of wild rice abortive-type that expresses a Bacillus thuringiensis (Bt) δ-endotoxin and provides effective and economic control of lepidopteran insects. To exploit Huahui 1 to develop a new Bt rice, the insertion site of the Bt gene was determined by thermal asymmetric interlaced PCR (TAIL-PCR). Bt was located in the promoter region of LOC.Os10g10360, approximately 5.35 Mb from the telomere of the short arm of chromosome 10. For the first time, a Bt cytoplasmic male sterile (CMS) system was developed by introgressing Bt from Huahui 1. The recipient CMS system used consisted of Indonesia paddy rice-type II-32B (maintainer line) and II-32A (male sterile line). Marker-assisted selection was used to increase selection efficiency in the backcrossing program. In BC5F1, the Bt plant 85015-8 was selected for further analyses, as it had the highest SSR marker homozygosity. In addition, the linkage drag of the foreign Bt gene in 85015-8 was minimized to 8.01-11.46 Mb. The foreign Bt gene was then delivered from 85015-8 into II-32A. The resultant Bt II-32A and Bt II-32B lines were both resistant to lepidopteran in field trials, and agronomic traits were not disturbed. The maintainability of II-32B, and the male sterility and general combining ability of II-32A, were not affected by the Bt introgression. This study demonstrates a simple and fast approach to develop Bt hybrid rice.
    Expansin Genes Expressed Differentially in Peduncle Elongation of Near- Isogenic Wheat Rht Lines
    WANG Jia-li1, 3* , LIU Dong-cheng1*, GUO Xiao-li2, YANG Wen-long1 and ZHANG Ai-min1, 4
    2014, 13(10): 2091-2101.  DOI: 10.1016/S2095-3119(13)60725-X
    Abstract ( )   PDF in ScienceDirect  
    The introduction of reduced height (Rht) genes Rht-B1b and Rht-D1b led to impressive increases in wheat (Triticum aestivum L.) yields during the Green Revolution. In the present study, the dynamic elongation of peduncle in a set of near-isogenic lines (NILs) carrying different Rht alleles (Rht-B1b, Rht-D1b, Rht-B1c, Rht-D1b+Rht-B1b, and Rht-D1b+Rht-B1c) were investigated. The reduction of the final length of peduncle in NILs was dependent mainly on the elongation rate, which was reduced by Rht genes, during rapid elongation phase. Resin sections showed that Rht genes strongly reduced the cell extension in peduncle. The expression of expansin genes, which mediate cell wall loosening and leading to cell expansion, were analysed by using realtime quantitative PCR (qPCR). Among the 23 possible wheat expansin genes, 17 were expressed in the peduncle. The spatial distribution of expression was further analysed for five expansins that showed high expression levels in the peduncles of Rht lines. Compared to wild type plants, the incorporation of Rht-D1b allele decreased about 37 and 80% of the expression levels of ExpA7 and ExpA3 in elongation zone, respectively. The presence Rht-B1c dwarfing genes, however, produced 53% reduction in the expression level of ExpA7, and seriously decreased about 70% of ExpB9 expression. Although the expression levels of five genes exhibited variability among the lines, an expansin gene, ExpB2, showed its expression level highly associated with the cell elongation rate in peduncle of different Rht lines.
    Isolation and Expression Analysis of Two Genes Encoding Cinnamate 4-Hydroxylase from Cotton (Gossypium hirsutum)
    NI Zhi-yong, LI Bo, Neumann M Peter, Lü Meng , FAN Ling
    2014, 13(10): 2102-2112.  DOI: 10.1016/S2095-3119(13)60643-7
    Abstract ( )   PDF in ScienceDirect  
    Two genes (GhC4H1 and GhC4H2) that encode putative cotton cinnamate 4-hydroxylases that catalyze the second step in the phenylpropanoid pathway were isolated from developing cotton fibers. GhC4H1 and GhC4H2 each contain open reading frames of 1 518 base pairs (bp) in length and both encode proteins consisting of 505 amino acid residues. They are 90.89% identical to each other at the amino acid sequence level and belong to class I of plant C4Hs. GhC4H1 and GhC4H2 genomic DNA are 2 247 and 2 161 bp long, respectively, and contain two introns located at conserved positions relative to the coding sequence. GhC4H1 and GhC4H2 promoters were isolated and found to contain many cis-elements (boxes P, L and AC-I element) previously identified in the promoters of other phenylpropanoid pathway genes. Histochemical staining showed GUS expression driven by the GhC4H1 and GhC4H2 promoters in ovules and fibers tissues. GhC4H1 and GhC4H2 were also widely expressed in other cotton tissues. GhC4H2 expression reached its highest level during the elongation stage of fiber development, whereas GhC4H1 expression increased during the secondary wall development period in cotton fibers. Our results contribute to a better understanding of the biochemical role of GhC4H1 and GhC4H2 in cotton fiber development.
    Molecular Cloning and Characterization of an Allene Oxide Cyclase Gene Associated with Fiber Strength in Cotton
    WANG Li-man, ZHU You-min, TONG Xiang-chao, HU Wen-jing, CAI Cai-ping , GUO Wang-zhen
    2014, 13(10): 2113-2121.  DOI: 10.1016/S2095-3119(13)60666-8
    Abstract ( )   PDF in ScienceDirect  
    Allene oxide cyclase (AOC) is one of the most important enzymes in the biosynthetic pathway of the plant hormone jasmonic acid (JA). AOC catalyzes the conversion of allene oxide into 12-oxo-phytodienoic acid (OPDA), a precursor of JA. Using 28K cotton genome array hybridization, an expressed sequence tag (EST; GenBank accession no. ES792958) was investigated that exhibited significant expression differences between lintless-fuzzless XinWX and linted-fuzzless XinFLM isogenic lines during fiber initiation stages. The EST was used to search the Gossypium EST database (http://www.ncbi.nlm.nih.gov/) for corresponding cDNA sequences encoding full-length open reading frames (ORFs). Identified ORFs were confirmed using transcriptional and genomic data. As a result, a novel gene encoding AOC in cotton (Gossypium hirsutum AOC; GenBank accession no. KF383427) was cloned and characterized. The 741-bp GhAOC gene comprises three exons and two introns and encodes a polypeptide of 246 amino acids. Two homologous copies were identified in the tetraploid cotton species G. hirsutum acc. TM-1 and G. barbadense cv. Hai7124, and one copy in the diploid cotton species G. herbaceum and G. raimondii. qRT-PCR showed that the GhAOC transcript was abundant in cotton fiber tissues from 8 to 23 days post anthesis (DPA), and the expression profiles were similar in the two cultivated tetraploid cotton species G. hirsutum acc. TM-1 and G. barbadense cv. Hai7124, with a higher level of transcription in the former. One copy of GhAOC in tetraploid cotton was localized to chromosome 24 (Chr. D8) using the subgenome-specific single nucleotide polymorphism (SNP) marker analysis, which co-localized GhAOC to within 10 cM of a fiber strength quantitative trait locus (QTL) reported previously. GhAOC was highly correlated with fiber quality and strength (P=0.014) in an association analysis, suggesting a possible role in cotton fiber development, especially in secondary cell wall thickening.
    Haploid Induction via In vitro Gynogenesis in Tomato (Solanum lycopersicum L.)
    ZHAO He, WANG Xiao-xuan, DU Yong-chen, ZHU De-wei, GUO Yan-mei, GAO Jian-chang, LI Fei , John C Snyder
    2014, 13(10): 2122-2131.  DOI: 10.1016/S2095-3119(13)60672-3
    Abstract ( )   PDF in ScienceDirect  
    In order to determine the potential for haploid induction via in vitro gynogenesis in tomato, the ovules and protoplasts of embryo sacs from the hybrids Zhongza 101 and Zhongza 105 were cultured. An efficient method of ovule isolation was established in this study. Using this method, 100-150 ovules could be isolated from one ovary. Isolated ovules were cultured on three induction media to induce gynogenesis in vitro. During culture, ovules were enlarged markedly, with opaque white color. When observed microscopically, there were cell divisions and cell clumps in embryo sacs. Subsequently, the cell clumps in embryo sacs ceased growth, likely because the integument grew faster than embryo sacs did and hindered the further development of embryo sacs. Therefore, subsequent callus morphogenesis might be originated from the integument. Thousands of calli from the two tomato varieties were obtained. Five diploid plants were regenerated after 15 months of subculturing. To eliminate the hindering effect of integument on embryo sac cells, the protoplasts of embryo sacs were prepared and cultured. After 48 hours of culture, the protoplasts of embryo sacs doubled in size and gradually formed clusters of cells. These results suggested that gynogenesis might be a potential way for haploid induction in tomato.
    Comparative Analysis of Gene Expression in Two Muskmelon Cultivars (Cucumis melo L.) Under Salt Stress
    WEI Shi-wei, ZHANG Fu-rong, ZHANG Yi-dong, WANG Li-min, CHEN Jia-bei , HUANG Danfeng
    2014, 13(10): 2132-2140.  DOI: 10.1016/S2095-3119(13)60673-5
    Abstract ( )   PDF in ScienceDirect  
    Salinity is one of the most important abiotic stresses that adversely affects crop growth and productivity. A subtractive suppression hybridization (SSH) library were constructed from the roots of salt-sensitive Yulu cultivar melon seedlings under salt stress; 557 high-quality expressed sequence tags (ESTs) were randomly sequenced, with an average size of 428 bp, which assembled into 68 contigs and 315 singletons. Compared with our previous SSH library generated from the salt-tolerant Bingxuecui cultivar, the proportion of transcripts involved in metabolism, protein fate, cellular communication/signal transduction mechanisms, and cell rescue/defense were 4, 1.46, 0.94, and 0.4% higher, respectively, in the salt-tolerant cultivar than the in salt-sensitive cultivar. Quantitative real-time PCR analysis of eleven transcripts revealed temporal variations in their expression in the two cultivars under salt stress. One NAC gene (JZ477011) was heterologously expressed in yeast for functional characterization, and enhanced the sensitivity of yeast cells to high-salinity to salt stress and inhibited their growth. Information regards to their functions would aid in the understanding of response mechanisms to saline stress and in the development of molecular markers for selecting salt-tolerant melon cultivars.
    Ethylene and Spermidine in Wheat Grains in Relation to Starch Content and Granule Size Distribution Under Water Deficit
    YANG Wei-bing, LI Yong, YIN Yan-ping, JIANG Wen-wen, PENG Dian-liang, CUI Zheng-yong, YANG Dong-qing , WANG Zhen-lin
    2014, 13(10): 2141-2153.  DOI: 10.1016/S2095-3119(13)60726-1
    Abstract ( )   PDF in ScienceDirect  
    Two wheat cultivars (Triticum aestivum L.) were used to evaluate the effects of post-anthesis severe water deficit (SD) on starch content and granule size distribution and their relations with ethylene and spermidine (Spd). Comparison to the well-watered (WW) treatment, SD led to lower Spd and higher 1-aminocylopropane-1-carboxylic acid (ACC) concentrations and ethylene evolution rate (EER) in grains at the critical stage of forming starch granules. Application of Spd or aminoethoxyvinylglycine (AVG) significantly reduced ACC concentration and EER and increased Spd concentration, while ethephon or methylglyoxal-bis (MGBG) had an opposite impact. The volume and surface area distribution of starch granules showed a bimodal curve, while the number distribution exhibited a unimodal curve. SD caused a marked drop in grain weight, grain number and starch content, also led to a significant reduction in the proportion (both by volume and by surface area) of B-type starch granules (<10 μm), with an increase in those of A-type starch granules (>10 μm). Application of Spd or AVG increased the proportion (both by volume and by surface area) of B-type starch granules under SD. Correlation analysis suggested that ethylene and Spd showed an antagonism relation in the formation of B-type granules. These results suggested that it would be good for the formation of B-type starch granules to have the physiological traits of higher Spd and lower ACC concentrations and ethylene emission under SD.
    Effects of Plant Density on Yield and Canopy Micro Environment in Hybrid Cotton
    YANG Guo-zheng, LUO Xue-jiao, NIE Yi-chun , ZHANG Xian-long
    2014, 13(10): 2154-2163.  DOI: 10.1016/S2095-3119(13)60727-3
    Abstract ( )   PDF in ScienceDirect  
    A rational plant population is an important attribute to high yield of cotton, because it can provide a beneficial micro environment within the canopy for plant growth and development as well as yield formation. A 2-yr field experiment was conducted to determine the optimal plant density based on cotton yield in relation to the canopy micro environment (canopy temperature, relative humidity and light transmittance). Six plant densities (1.2-5.7 plants m-2) were arranged with a completely randomized block design. The highest cotton yield (1 507 kg ha-1) was obtained at 3.0 plants m-2 due to more bolls per unit ground area (79 bolls m-2), while the lowest yield (1 091 kg ha-1) was obtained at 1.2 plants m-2. Under the moderate plant density (3.0 plants m-2), there was a lower mean daily temperature (MDT, 27.1°C) attributing to medium daily minimum temperature (Tmin, 21.9°C) and the lowest daily maximum temperature (Tmax, 35.8°C), a moderate mean canopy light transmittance of 0.51, and lower mean daily relative humidity (MRH) of 79.7% from June to October. The results suggest that 3.0 plants m-2 would be the optimal plant density because it provides a better canopy micro environment.
    Changes in the Vascular Cylinder of Wild Soybean Roots Under Alkaline Stress
    NIU Lu, LU Jing-mei, WU Dong-mei, LI Yan , GAO Ting-ting
    2014, 13(10): 2164-2169.  DOI: 10.1016/S2095-3119(13)60645-0
    Abstract ( )   PDF in ScienceDirect  
    Changes in the vascular cylinder of wild soybean (Glycine soja Sieb. et Zucc) roots under alkaline stress were investigated in an experiment that applied 90 mmol L-1 alkaline stress for 10 d at the five-trifoliate plant growth stage in Huinan County, Jilin Province, China. Root samples were collected and paraffin-cut sections were made, and the root structure was observed under an optical microscope. There were significant changes in the vascular cylinder of G. soja roots under alkaline stress. Root diameter was reduced and the vascular cylinder changed from tetrarch to triarch pattern. Alkaline stress resulted in reduced, diameters of root vessels, and a large amount of residual, alkaline solution was stained cyaneous in vessels. The paratracheal parenchymatous cells of the vessels were large and there was little secondary xylem. Thus, alkaline stress caused structural changes in the vascular cylinder of G. soja.
    Global Analysis of Cytosine Methylation and Proteome Under Cold Treatment in Brassica napus
    WEI Fang, HU Jie, CUI Ming-zhu, ZHANG Yan-hui, LI Yun-ling , TIAN Bao-ming
    2014, 13(10): 2170-2176.  DOI: 10.1016/S2095-3119(14)60838-8
    Abstract ( )   PDF in ScienceDirect  
    Cytosine methylation/demethylation plays pivotal roles in regulating gene expression at a genome-wide level. However, limited reports are available to reveal correlating changes of cytosine methylation and proteomic expression in Brassica napus so far. Therefore, in the present study, global cytosine methylation and proteome were analysed in B. napus after cold treatment by methylation-sensitive amplified polymorphism (MSAP) and two-dimensional protein electrophoresis technology (2-DE). The results showed that the lowered genome-wide DNA methylation status was revealed after cold treatment, and about 0.88% of discrepancy in DNA methylation was detected between the non-flowering and flowering plants after cold treatment. Moreover, the 52 significantly up-regulated proteins emerged in comparison with the 36 down-regulated proteins, as well as the 14 proteins exclusively detected in the flowering plants. Intriguingly the 8 specifically expressed proteins in the non-flowering plants disappeared in the flowering plants with cold treatment. Therefore, these present data proved that the correlating changes of cytosine methylation and proteomic expression were evidenced under cold treatment in B. napus.
    Plant Protection
    Jellyfish Green Fluorescent Protein (GFP) as a Reporter for Fusarium gramminearum Development on Wheat
    QI Jun-xian, LIU Tai-guo, XU Ying, CHEN Huai-gu, GAO Li, LIU Bo , CHEN Wan-quan
    2014, 13(10): 2177-2183.  DOI: 10.1016/S2095-3119(14)60875-3
    Abstract ( )   PDF in ScienceDirect  
    The plasmid pGPDGFP under the control of pgpdA promotor was used together with vector pAN7-1 containing the hygromycin resistance cassette to co-transform protoplasts of HG1, Fusarium graminearum from Hubei Province, China. Twelve out of 14 hygromycin-resistant transformants showed green signal under the UV light and contained one or several copies of gfp, as indicated by Southern analysis of genomic DNA digested with different restriction enzymes and hybridized to the gfp probe. A single gfp copy transformant (HG1C5) was selected for further evaluation of 80 Chinese wheat cultivars or advanced lines. The results showed different resistance type to F. graminearum were observed. GFP signals observed in the rachis and adjacent spikes of 70 Chinese wheat lines such as Chuanchongzu 104 indicated both type I (host resistance to the initial infection by the fungus) and type II (resistance to the spread of FHB symptoms within an infected spike) were not observed. While other 10 lines showed type II resistance to F. graminearum with GFP signals only in inoculated spikelets. Development of the mycelium can be intuitively observed and the resistance of wheat to F. graminearum can be identified at 7 days post inoculation (dpi) in this way. The results showed no differences were evaluated between the transformed HG1C5 and the non-transgene artificial inoculation by SAS paired chi-square test and McNemar’s test (P=0.0625).
    Genetic Diversity of Chinese Soybean mosaic virus Strains and Their Relationships with Other Plant Potyviruses Based on P3 Gene Sequences
    YANG Qing-hua, LI Kai, ZHI Hai-jian , GAI Jun-yi
    2014, 13(10): 2184-2195.  DOI: 10.1016/S2095-3119(13)60653-X
    Abstract ( )   PDF in ScienceDirect  
    Soybean mosaic virus (SMV), a member of the genus Potyvirus, is a major pathogen of soybean plants in China, and 16 SMV strains have been identified nationwide based on a former detailed SMV classification system. As the P3 gene is thought to be involved in viral replication, systemic infection, pathogenicity, and overcoming resistance, knowledge of the P3 gene sequences of SMV and other potyviruses would be useful in efforts to know the genetic relationships among them and control the disease. P3 gene sequences were obtained from representative isolates of the above-mentioned 16 SMV strains and were compared with other SMV strains and 16 Potyvirus species from the National Center for Biotechnology GenBank database. The P3 genes from the 16 SMV isolates are composed of 1 041 nucleotides, encoding 347 amino acids, and share 90.7-100% nucleotide (NT) sequence identities and 95.1-100% amino acid (AA) sequence identities. The P3 coding regions of the 16 SMV isolates share high identities (92.4-98.9% NT and 96.0-100% AA) with the reported Korean isolates, followed by the USA isolates (88.5-97.9% NT and 91.4-98.6% AA), and share low identities (80.5-85.2% NT and 82.1-84.7% AA) with the reported HZ1 and P isolates from Pinellia ternata. The sequence identities of the P3 genes between SMV and the 16 potyviruses varied from 44.4 to 81.9% in the NT sequences and from 21.4 to 85.3% in the AA sequences, respectively. Among them, SMV was closely related to Watermelon mosaic virus (WMV), with 76.0-81.9% NT and 77.5-85.3% AA identities. In addition, the SMV isolates and potyvirus species were clustered into six distinct groups. All the SMV strains isolated from soybean were clustered in Group I, and the remaining species were clustered in other groups. A multiple sequence alignment analysis of the C-terminal regions indicated that the P3 genes within a species were highly conserved, whereas those among species were relatively variable.
    The mRNA Expression Profiles of Five Heat Shock Protein Genes from Frankliniella occidentalis at Different Stages and Their Responses to Temperatures and Insecticides
    WANG Hai-hong, Stuart R Reitz, WANG Li-xia, WANG Shuai-yu, LI Xue , LEI Zhong-ren
    2014, 13(10): 2196-2210.  DOI: 10.1016/S2095-3119(13)60680-2
    Abstract ( )   PDF in ScienceDirect  
    The western flower thrips, Frankliniella occidentalis (Pergande) is a highly invasive pest that is able to exploit many crops across a wide range of environmental conditions. Five full-length cDNAs of heat shock protein (HSP) genes (Fo-HSP90, Fo-HSP70, Fo-HSP60, Fo-HSP40 and Fo-HSP28.9) were cloned from F. occidentalis, and their expression profiles were investigated under conditions of thermal stress and insecticide exposure, and at different stages during development, using real-time quantitative PCR. All five gene sequences showed high similarity to homologs in other species, indicating the conserved function of this gene family. HSP60 represents an informative phylogenetic marker at the ordinal taxonomic level within Insecta, but HSP90, which has two homologous copies in Hymenoptera, was not informative. The expression of Fo-HSPs under thermal stress suggests that Fo-HSP90, Fo-HSP70, and Fo-HSP28.9 are inducible by both cold and heat stress, Fo-HSP40 is only heat-inducible, and Fo-HSP60 is thermally insensitive. There were two patterns of cold induction of Fo-HSPs: one is from 0 to 4°C and the other is around -8°C. All five Fo-HSPs genes were induced by exposure to sublethal concentrations of the insecticide avermectin. The expression of the five Fo-HSPs during different developmental stages suggests that they all play a role in development of F. occidentalis.
    Density and Seasonal Dynamics of Bemisia tabaci (Gennadius) Mediterranean on Common Crops and Weeds Around Cotton Fields in Northern China
    ZHANG Xiao-ming, YANG Nian-wan, WAN Fang-hao , Gabor L L?vei
    2014, 13(10): 2211-2220.  DOI: 10.1016/S2095-3119(13)60613-9
    Abstract ( )   PDF in ScienceDirect  
    The density seasonal dynamics of Bemisia tabaci MED were evaluated over two years in a cotton-growing area in Langfang, Hebei Province, northern China on cotton (Gossypium hirsutum L.) and six other co-occurring common plants, common ragweed (Ambrosia artemisiifolia L.), piemarker (Abutilon theophrasti Medicus), sunflower (Helianthus annuus L.), sweet potato (Ipomoea batatas L.), soybean (Glycine max L.), and maize (Zea mays L.). The whitefly species identity was repeatedly tested and confirmed; seasonal dynamics on the various host plants were standardized by the quartile method. B. tabaci MED appeared on weeds (the common ragweed and piemarker) about 10 days earlier than on cotton, or the other cultivated plants. The peak population densities were observed over a span of 2 to 3 weeks on cotton, starting in early (2010) or mid-August (2011). The common ragweed growing adjacent to cotton supported the highest B. tabaci densities (no. on 100 cm2 leaf surface), 12-22 fold higher than on cotton itself. Sunflower supported more B. tabaci than the other plants, and about 1.5-2 fold higher than cotton did. Our results indicate that weeds (esp. the common ragweed) around cotton fields could increase the population density of B. tabaci MED on cotton, while sunflower could act as a trap crop for decreasing pest pressure on cotton.
    Assessment of Rice Cultivars in China for Field Resistance to Aphelenchoides besseyi
    FENG Hui, WEI Li-hui, LIN Mao-song , ZHOU Yi-jun
    2014, 13(10): 2221-2228.  DOI: 10.1016/S2095-3119(13)60608-5
    Abstract ( )   PDF in ScienceDirect  
    The effect of Aphelenchoides besseyi on 27 cultivars of rice (23 japonica and 4 indica) was assessed in the field for two seasons during 2010 and 2011. The vigorous pathogenic nematodes culturing on Botrytis cinerea were used for this experiment. Inoculation was carried out at the tilling stage; the growth parameters and nematode population were recorded at the end of growth of rice plants. The results showed that the cultivars differed in their response to infection. Most of cultivars were lack of the characteristic symptom of white tip, which was seen less frequently than the other two symptoms, namely small grains and erect panicles; moreover, the expression of symptoms was probably hereditary. The infection lowered the values of all the measured biological parameters, namely length of the stem and of the panicle, the number of filled grains per panicle, and 100-grain weight, in all the cultivars. The final nematode population indicated that the threshold of economic damage had also been exceeded in 10 cultivars, and none of them was immune. Three japonica cultivars proved most vulnerable whereas Tetep, an indica type, showed a level of resistance potentially useful in controlling A. besseyi.
    Detection of Thrips Defect on Green-Peel Citrus Using Hyperspectral Imaging Technology Combining PCA and B-Spline Lighting Correction Method
    DONG Chun-wang, YE Yang, ZHANG Jian-qiang, ZHU Hong-kai , LIU Fei
    2014, 13(10): 2229-2235.  DOI: 10.1016/S2095-3119(13)60671-1
    Abstract ( )   PDF in ScienceDirect  
    In order to find an effective method of detecting thrips defect on green-peel citrus, a defect segmentation method was developed using a single threshold value based on combination of characteristic wavelengths principal component analysis (PCA) and B-spline lighting correction method in this study. At first, four characteristic wavelengths (523, 587, 700 and 768 nm) were obtained using PCA of Vis-NIR (visible and near-infrared) bands and analysis of weighting coefficients; secondarily, PCA was performed using characteristic wavelengths and the second principal component (PC2) was selected to classify images; then, B-spline lighting correction method was proposed to overcome the influence of lighting non-uniform on citrus when thrips defect was segmented; finally, thrips defect on citrus was extracted by global threshold segmentation and morphological image processing. The experimental results show that thrips defect in citrus can be detected with an accuracy of 96.5% by characteristic wavelengths PCA and B-spline lighting correction method. This study shows that thrips defect on green-peel citrus can be effectively identified using hyperspectral imaging technology.
    Animal Science · Veterinary Science
    Muscle Biological Characteristics of Differentially Expressed Genes in Wujin and Landrace Pigs
    XU Hong, HUANG Ying, LI Wei-zhen, YANG Ming-hua, GE Chang-rong, ZHANG Xi, LI Liu-an , GAO Shi-zheng , ZHAO Su-mei
    2014, 13(10): 2236-2242.  DOI: 10.1016/S2095-3119(13)60605-X
    Abstract ( )   PDF in ScienceDirect  
    The biological chemistry would be responsible for the meat quality. This study tried to investigate the transcript expression profile and explain the characteristics of differentially expressed genes between the Wujin and Landrace pigs. The results showed that 526 differentially expressed genes were found by comparing the transcript expression profile of muscle tissue between Wujin and Landrace pigs. Among them, 335 genes showed up-regulations and 191 genes showed down-regulations in Wujin pigs compared with the Landrace pigs. Gene ontology (GO) analysis indicated that the differentially expressed genes were clustered into three groups involving in protein synthesis, energy metabolism and immune response. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis found that these differentially expressed genes participated in protein synthesis metabolism, energy metabolism and immune response pathway. The Database for Annotation, Visualization and Integrated Discovery (DAVID) analysis of protein function and protein domains function also confirmed that differentially expressed genes belonged to protein synthesis, energy metabolism and immune response. Genes related protein synthesis metabolism pathway in Landrace was higher than in Wujin pigs. However, differentially expressed genes related energy metabolism and immune response was up-regulated in Wujin pigs compared with Landrace pigs. Quantitative real-time RT-PCR on selected genes was used to confirm the results from the microarray. These suggested that the genes related to protein synthesis, energy metabolism and immune response would contribute to the growth performance, meat quality as well as anti-disease capacity.
    Genome Array on Differentially Expressed Genes of Skin Tissue in Cashmere Goat at Early Anagen of Cashmere Growth Cycle Using DNA Microarray
    DI Jiang, XU Xin-ming, Lazate Ainiwaer, ZHANG Yan-hua, TIAN Ke-chuan, YU Li-juan, WU Weiwei, Hanikezi Tulafu, FU Xue-feng , Marzeya Yasen
    2014, 13(10): 2243-2252.  DOI: 10.1016/S2095-3119(13)60606-1
    Abstract ( )   PDF in ScienceDirect  
    In order to study the molecular mechanism involved in cashmere regeneration, this study investigated the gene expression profile of skin tissue at various stages of the cashmere growth cycle and screen differentially expressed genes at proangen in 10 cashmere goats at 2 years of age using agilent sheep oligo microarray. Significance analysis of microarray (SAM) methods was used to identify the differentially expressed genes, Hierarchical clustering was performed to clarify these genes in association with different cashmere growth stages, and GO (Gene ontology) and the pathway analyses were con-ducted by a free web-based Molecular Annotation System3.0 (MAS 3.0). Approximately 10200 probe sets were detected in skin tissue of 2-yr-old cashmere goat. After SAM analysis of the microarray data, totally 417 genes were shown to be differentially expressed at different cashmere growth stages, and 24 genes are significantly up-regulated (21) or down-regulated (3) at proangen concurrently compared to angen and telogen. Hierarchical clustering analysis clearly distinguished the differentially expressed genes of each stage. GO analysis indicated that these altered genes at proangen were predominantly involved in collagen fibril organization, integrin-mediated signaling pathway, cell-matrix adhesion, cell adhesion, transforming growth factor-β (TGF-β) receptor signaling pathway, regulation of cell growth. Kyoto encyclopedia of genes and genomes (KEGG) analysis showed that the significant pathways involved mainly included focal adhesion and extracellular matrixc (ECM)-receptor interaction. Some important genes involved in these biological processes, such as COL1A1, COL1A2, COL3A1, SPARC, CYR61 and CTGF, were related to tissue remolding and repairing and detected by more than one probe with similar expression trends at different stages of cashmere growth cycle. The different expression of these genes may contribute to understanding the molecular mechanism of cashmere regeneration.
    Effects of Fermentation Product Containing Phytase on Productive Performance, Egg Quality, and Phosphorous Apparent Metabolism of Laying Hens Fed Different Levels of Phosphorus
    WANG Zhi-hong, DONG Xiao-fang, TONG Jian-ming , XU Shang-zhong
    2014, 13(10): 2253-2259.  DOI: 10.1016/S2095-3119(13)60663-2
    Abstract ( )   PDF in ScienceDirect  
    This study investigated the effects of fermentation product containing phytase (FPP) that was fermented using waste vinegar residue (WVR) as substrate from Aspergillus ficuum NTG-23 on productive performance, egg quality, and phosphorus apparent metabolism of laying hens. First, 375 22-wk-old Jinghong hens were allocated into 5 treatments (5 replicates of 15 hens each) in an 8-wk experiment for evaluating the parameters of productive performance, egg quality, serum, and tibia. Experimental diets contained 4% FPP and 96% corn-soybean diet. The levels of dicalcium phosphate (DCP) were 1.34, 1.01, 0.67, 0.34 and 0%. Next, thirty 31-wk-old Jinghong hens were fed 5 types of diets for evaluating phosphorous apparent metabolism rate. Egg productive rate, egg weight, feed conversion ratio, Haugh unit, egg albumen height, serum calcium, tibia ash, tibia ash calcium and tibia breaking strength were not different significantly among 5 treatments. The significant difference of average daily feed intake was not appeared when the DCP content of corn-soybean-FPP diet was reduced to 0.67%; the eggshell hardness, eggshell thickness and serum phosphorus were not reduced significantly until the DCP content of corn-soybean-FPP diet was reduced to 0.34%. The yolk color was improved when the laying hens fed deficient DCP corn-soybean-FPP diet. A 22.14% reduction in excreta phosphorus was observed when the laying hens fed low phosphorus (0.67% DCP) corn-soybean-FPP diet. A 30% elevation of phosphorus apparent metabolism rate was obtained when the DCP content of corn-soybean-FPP diet was decreased from 1.34 to 1.01%. The reducing cost of layer diet was totalized about 120 CNY 1 000 kg-1 diet when the content of DCP was 0.67% in corn-soybean-FPP diet. These results indicated that FPP could be applied in laying hen as a potential, cost-effective and rational application of WVR.
    Yield Evaluation of Twenty-Eight Alfalfa Cultivars in Hebei Province of China
    ZHANG Tie-jun, KANG Jun-mei, GUO Wen-shan, ZHAO Zhong-xiang, XU Yu-peng, YAN Xudong , YANG Qing-chuan
    2014, 13(10): 2260-2267.  DOI: 10.1016/S2095-3119(13)60576-6
    Abstract ( )   PDF in ScienceDirect  
    Cultivar selection is important for alfalfa (Medicago sativa L.) hay production. From 2009 to 2012, a field study was conducted to evaluate the dry matter yield (DMY) of 28 cultivars in Cangzhou District of Hebei province, China, and to determine the most suitable cultivars for this province and other zones with similar climate conditions. 28 alfalfa cultivars were sown in late March of 2009 and were harvested for hay four times in each subsequent year. The results showed that the climatic conditions resulted in significant differences in annual DMY among years, with the second year being the highest and the first year the lowest. The top five cultivars with the highest total DMY were L2750 (62.75 t ha-1), Horn (62.72 t ha-1), 86-266 (61.55 t ha-1), German (61.44 t ha-1) and Zhongmu 1 (61.18 t ha-1), respectively. Across all four years, first harvest had the highest ratios to annual DMY except the cultivar of Rambler, while the fourth harvest had the lowest ratio. There were positive correlation relationships between DMY of each harvest and annual DMY, and the correlation coefficients were all significant in four years. And the path coefficients of first harvest were always the highest in four years. The qualities showed small variations among these cultivars and the cultivar L3750 presented the highest crude protein in both years. Crude protein had significant positive correlation with relative feed value (RFV) in both years while crude fiber had significant negative correlation with RFV and crude fiber.
    Construction and Virulence of Filamentous Hemagglutinin Protein B1 Mutant of Pasteurella multocida in Chickens
    GUO Dong-chun, SUN Yan, ZHANG Ai-qin, LIU Jia-sen, LU Yan, LIU Pei-xin, YUAN Dongwei, JIANG Qian, SI Chang-de , QU Lian-dong
    2014, 13(10): 2268-2275.  DOI: 10.1016/S2095-3119(14)60844-3
    Abstract ( )   PDF in ScienceDirect  
    Pasteurella multocida, a Gram-negative nonmotile coccobacillus, is the causative agent of fowl cholera, bovine hemorrhagic septicemia, enzoonotic pneumonia and swine atropic rhinitis. Two filamentous hemagglutinin genes, fhaB1 and fhaB2, are the potential virulence factors. In this study, an inactivation fhaB1 mutant of P. multocida in avian strain C48-102 was constructed by a kanamycin-resistance cassette. The virulence of the fhaB1 mutant and the wild type strain was assessed in chickens by intranasal and intramuscular challenge. The inactivation of fhaB1 resulted in a high degree of attenuation when the chickens were challenged intranasally and a lesser degree when challenged intramuscularly. The fhaB1 mutant and the wild type strain were investigated their sensitivity to the antibody-dependent classical complement-mediated killing pathway in 90% convalescent chicken serum. The fhaB1 mutant was serum sensitive as the viability has reduced between untreated serum and heat inactivated chicken serum (P<0.007). These results confirmed that FhaB1 played the critical roles in the bacterial pathogenesis and further studies were needed to investigate the mechanism which caused reduced virulence of the fhaB1 mutant.
    Soil & Fertilization · Irrigation · Agro-Ecology & Environment
    Long-Term Manure Amendments Enhance Soil Aggregation and Carbon Saturation of Stable Pools in North China Plain
    DU Zhang-liu, WU Wen-liang, ZHANG Qing-zhong, GUO Yan-bin , MENG Fan-qiao
    2014, 13(10): 2276-2285.  DOI: 10.1016/S2095-3119(14)60823-6
    Abstract ( )   PDF in ScienceDirect  
    Organic amendment is considered as an effective way to increase soil organic carbon (SOC) stock in croplands. To better understand its potential for SOC sequestration, whether SOC saturation could be observed in an intensive agricultural ecosystem receiving long-term composted manure were examined. Different SOC pools were isolated by physical fractionation techniques of a Cambisol soil under a long-term manure experiment with wheat-maize cropping in North China Plain. A field experiment was initiated in 1993, with 6 treatments including control (i.e., without fertilization), chemical fertilizer only, low rate of traditional composted manure (7.5 t ha-1), high rate of traditional composted manure (15 t ha-1), low rate of bio-composted manure (7.5 t ha-1) and high rate of bio-composted manure (15 t ha-1). The results showed that consecutive (for up to 20 years) composted manure amendments significantly improved soil macro-aggregation, aggregate associated SOC concentration, and soil structure stability. In detail, SOC concentration in the sand-sized fraction (>53 μm) continued to increase with manure application rate, while the silt (2-53 μm) and clay (<2 μm) particles showed no further increase with greater C inputs, exhibiting the C saturation. Further physical separation of small macro-aggregates (250-2 000 μm) into subpools showed that the non-protected coarse particulate organic matter (cPOM, >250 μm) was the fraction in which SOC continued to increase with increasing manure application rate. In contrast, the chemical and physical protected C pools (i.e., micro-aggregates and silt-clay occluded in the small macroaggregates) exhibited no additional C sequestration when the manure application rate was increased. It can be concluded that repeated manure amendments can increase soil macro-aggregation and lead to the increase in relatively stable C pools, showing hierarchical saturation behavior in the intensive cropping system of North China Plain.
    Impact of Long-Term Fertilization on Community Structure of Ammonia Oxidizing and Denitrifying Bacteria Based on amoA and nirK Genes in a Rice Paddy from Tai Lake Region, China
    JIN Zhen-jiang, LI Lian-qing, LIU Xiao-yu, PAN Gen-xing, Qaiser Hussein , LIU Yong-zhuo
    2014, 13(10): 2286-2298.  DOI: 10.1016/S2095-3119(14)60784-X
    Abstract ( )   PDF in ScienceDirect  
    Ammonia oxidizing (AOB) and denitrifying bacteria (DNB) play an important role in soil nitrogen transformation in natural and agricultural ecosystems. Effects of long-term fertilization on abundance and community composition of AOB and DNB were studied with targeting ammonia monooxygenase (amoA) and nitrite reductase (nirK) genes using polymerase chain reactiondenaturing gradient gel electrophoresis (PCR-DGGE) and real-time PCR, respectively. A field trial with different fertilization treatments in a rice paddy from Tai Lake region, centre East China was used in this study, including no fertilizer application (NF), balanced chemical fertilizers (CF), combined organic/inorganic fertilizer of balanced chemical fertilizers plus pig manure (CFM), and plus rice straw return (CFS). The abundances and richnesses of amoA and nirK were increased in CF, CFM and CFS compared to NF. Principle component analysis of DGGE profiles showed significant difference in nirK and amoA genes composition between organic amended (CFS and CFM) and the non-organic amended (CF and NF) plots. Number of amoA copies was significantly positively correlated with normalized soil nutrient richness (NSNR) of soil organic carbon (SOC) and total nitrogen (T-N), and that of nirK copies was with NSNR of SOC, T-N plus total phosphorus. Moreover, nitrification potential showed a positive correlation with SOC content, while a significantly lower denitrification potential was found under CFM compared to under CFS. Therefore, SOC accumulation accompanied with soil nutrient richness under long-term balanced and organic/inorganic combined fertilization promoted abundance and diversity of AOB and DNB in the rice paddy.
    Analysis of Differences in Productivity, Profitability and Soil Fertility Between Organic and Conventional Cropping Systems in the Tropics and Sub-tropics
    Te Pas C M , Rees R M
    2014, 13(10): 2299-2310.  DOI: 10.1016/S2095-3119(14)60786-3
    Abstract ( )   PDF in ScienceDirect  
    Organic farming aims to stimulate soil fertility by avoiding the use of synthetic fertiliser inputs, relying instead on locally available natural resources. It is regarded by many as a sustainable alternative to conventional farming because it ensures higher biodiversity, restricts environmental pollution, prevents land degradation and is easy to apply for smallholder and subsistence farmers. Although widely practiced and studied in temperate regions, little is known about the potential overall benefits of organic farming in the tropics and subtropics. This paper addresses this gap by undertaking an analysis of the differences between organic and conventional agriculture in the tropics and sub-tropics based on an extensive literature review including 88 papers with 458 data pairs. The comparison is based on three main indicators: yield, gross margin and soil organic carbon (SOC). The differences between the organic and conventional systems for each of these main indicators is represented by the ratio of the value of the indicator in the organic system divided by the corresponding value in the conventional system. This was initially calculated for each data pair individually, and grouped by a variety of explanatory factors, such as precipitation, human development level, soil texture, crop type, organic input type, time after conversion and certification. The results demonstrate that under organic management, yields were on average 26% higher, gross margins 51% higher and soil organic carbon 53% higher than under conventional management. The highest yield increases in organic cropping systems were achieved in the least developed countries, in arid regions and on coarse soils. For gross margins, certification was the main reason for differences between organic and conventional systems. Certified farmers, mostly located in developed countries, receive significantly higher prices. Furthermore, organic farming in the driest regions results in higher profits than in other regions. Even though soil organic carbon was significantly higher overall under organic management, the results do not show significant differences when grouped by the explanatory factors. They do however suggest that the highest carbon sequestration potential occurs in systems that had a high level of inputs, in regions with 1 000-1 500 mm of rainfall and on clayey soils.