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    The cytochrome P450 superfamily: Key players in plant development and defense
    XU Jun, WANG Xin-yu, GUO Wang-zhen
    2015, 14(9): 1673-1686.  DOI: 10.1016/S2095-3119(14)60980-1
    Abstract ( )   PDF in ScienceDirect  
    The cytochrome P450 (CYP) superfamily is the largest enzymatic protein family in plants, and it also widely exists in mammals, fungi, bacteria, insects and so on. Members of this superfamily are involved in multiple metabolic pathways with distinct and complex functions, playing important roles in a vast array of reactions. As a result, numerous secondary metabolites are synthesized that function as growth and developmental signals or protect plants from various biotic and abiotic stresses. Here, we summarize the characterization of CYPs, as well as their phylogenetic classification. We also focus on recent advances in elucidating the roles of CYPs in mediating plant growth and development as well as biotic and abiotic stresses responses, providing insights into their potential utilization in plant breeding.
    Crop Genetics · Breeding · Germplasm Resources
    Characterization and mapping of a novel light-dependent lesion mimic mutant lmm6 in rice (Oryza sativa L.)
    XIAO Gui-qing, ZHANG Hai-wen, LU Xiang-yang, HUANG Rong-feng
    2015, 14(9): 1687-1696.  DOI: 10.1016/S2095-3119(14)60975-8
    Abstract ( )   PDF in ScienceDirect  
    A novel rice lesion mimic mutant (LMM) was isolated from an ethane methyl sulfonate (EMS)-induced 02428 mutant bank. The mutant, tentatively designated as lmm6, develops necrotic lesions in the whole growth period along with changes in several important agronomic traits. We found that the initiation of the lesions was induced by light and cell death occurred in lmm6 accompanied with accumulation of reactive oxygen species (ROS). The lower chlorophyll content, soluble protein content and superoxide dismutase (SOD) activity, the higher malondialdehyde (MDA) content were detected in lmm6 than in the wild type (WT). Moreover, the observation by transmission electronic microscope (TEM) demonstrated that some organelles were damaged and the stroma lamella of chloroplast was irregular and loose in mesophyll cell of lmm6. In addition, lmm6 was more resistant than WT to rice blast fungus Magnaporthe grisea infection, which was consistent with increased expression of four genes involved in the defense-related reaction. Genetic analysis showed that mutant trait of lmm6 is inherited as a monogenic recessive nuclear gene located on the long arm of chromosome 6. Using simple sequence repeat (SSR) markers, the target gene was finally delimited to an interval of 80.8 kb between markers MM2359 and MM2370, containing 7 annotated genes. Taken together, our results provide the information to identify a new gene involved in rice lesion mimic, which will be helpful in clarifying the mechanism of cell death and disease resistance in rice.
    A genetic linkage map with 178 SSR and 1 901 SNP markers constructed using a RIL population in wheat (Triticum aestivum L.)
    ZHAI Hui-jie, FENG Zhi-yu, LIU Xin-ye, CHENG Xue-jiao, PENG Hui-ru, YAO Ying-yin, SUN Qi-xin, NI Zhong-fu
    2015, 14(9): 1697-1705.  DOI: 10.1016/S2095-3119(14)60902-3
    Abstract ( )   PDF in ScienceDirect  
    The construction of high density genetic linkage map provides a powerful tool to detect and map quantitative trait loci (QTLs) controlling agronomically important traits. In this study, simple sequence repeat (SSR) markers and Illumina 9K iSelect single nucleotide polymorphism (SNP) genechip were employed to construct one genetic linkage map of common wheat (Triticum aestivum L.) using 191 recombinant inbred lines (RILs) derived from cross Yu 8679×Jing 411. This map included 1 901 SNP loci and 178 SSR loci, covering 1 659.9 cM and 1 000 marker bins, with an average interval distance of 1.66 cM. A, B and D genomes covered 719.1, 703.5 and 237.3 cM, with an average interval distance of 1.66, 1.45 and 2.9 cM, respectively. Notably, the genetic linkage map covered 20 chromosomes, with the exception of chromosome 5D. Bioinformatics analysis revealed that 1 754 (92.27%) of 1 901 mapped SNP loci could be aligned to 1 215 distinct wheat unigenes, among which 1 184 (97.4%) were located on one single chromosome, and the rest 31 (2.6%) were located on 2 to 3 chromosomes. By performing in silico comparison, 214 chromosome deletion bin-mapped expressed sequence tags (ESTs), 1 043 Brachypodium genes and 1 033 rice genes were further added onto the genetic linkage map. This map not only integrated genetic and physical maps, SSR and SNP loci, respectively, but also provided the information of Brachypodium and rice genes corresponding to 1 754 SNP loci. Therefore, it will be a useful tool for comparative genomics analysis, fine mapping of QTL/gene controlling agronomically important traits and marker-assisted selection breeding in wheat.
    Identification of a novel male sterile wheat mutant dms conferring dwarf status and multi-pistils
    DUANZong-biao , SHENChun-cai , LIQiao-yun , LüGui-zhen , NIYong-jing , YUDong-yan , NIUJi-shan
    2015, 14(9): 1706-1714.  DOI: 10.1016/S2095-3119(14)60936-9
    Abstract ( )   PDF in ScienceDirect  
    Plant height and fertility are two important traits of wheat (Triticum aestivum L.), whose mutants are ideal materials for studies on molecular mechanisms of stem and floral organ development. In this study, we identified a dwarf, multi-pistil and male sterile (dms hereafter) wheat mutant from Zhoumai 18. Simple sequence repeat (SSR) marker assay with 181 primer pairs showed that only one locus of GWM148-2B was divergent between Zhoumai 18 and dms. There were three typical phenotypes in the progeny of dms, tall (T; ca. 0.8 m), semi-dwarf (M; ca. 0.6 m) and dwarf (D; under 0.3 m) plants. Morphological investigation indicated that the internode length of M was shortened by about 20–50 mm each; the internode number of D was 2 less than that of T and Zhoumai 18, and its internode length was shorter also. The pollen vigor and hybridization test demonstrated that dms mutant was male sterility. Segregated phenotypes in progeny of M suggested that the multi-pistils and sterility were controlled by one recessive gene locus which was designated as dms temporarily, and the plant height was controlled by a semi-dominant gene locus Dms. Therefore, progeny individuals of the dms had three genotypes, DmsDms for tall plants, Dmsdms for semi-dwarf plants and dmsdms for dwarf plants. The mutant progenies were individually selected and propagated for more than 6 generations, thus a set of near isogenic lines of T, M and D for dms were developed. This study provides a set germplasms for studies on molecular mechanisms of wheat stem and spike development.
    Improvement on Mixograph test through water addition and parameter conversions
    SUN Jia-zhu, YANG Wen-long, LIU Dong-cheng, ZHAO Jun-tao, LUO Guang-bin, LI Xin, LIU Yanjun, GUO Jin-kao, ZHANG Ai-min
    2015, 14(9): 1715-1722.  DOI: 10.1016/S2095-3119(15)61078-4
    Abstract ( )   PDF in ScienceDirect  
    To improve Mixograph testing effect, Farinograph measurements were adopted as a quality standard and changes in water absorption and parameter conversion in Mixograph test were explored. Comparative study showed that increasing water absorption to about 73% and converting original parameters to compound parameters in Mixograph tests significantly increased their predictive power for flour quality. These efforts also enabled the adoption of fixed water addition level in Mixograph test and simplified the test procedure significantly. With the success in parameter conversions, Mixograph test results were successfully described by Farinograph parameters, which allow breeders to compare and exchange test results easily. All these changes optimized the official method of Mixograph test with simplified procedure and enhanced reliability and made the Mixograph being the superior tool for quality assessment in wheat-breeding programs.
    Comparison of transcriptomes undergoing waterlogging at the seedling stage between tolerant and sensitive varieties of Brassica napus L.
    ZOU Xi-ling, ZENG Liu, LU Guang-yuan, CHENG Yong, XU Jin-song, ZHANG Xue-kun
    2015, 14(9): 1723-1734.  DOI: 10.1016/S2095-3119(15)61138-8
    Abstract ( )   PDF in ScienceDirect  
    RNA sequencing of the sensitive GH01 variety of Brassica napus L. seedling roots under 12 h of waterlogging was compared with previously published data of the ZS9 tolerant variety to unravel genetic mechanisms of waterlogging tolerance beyond natural variation. A total of 2 977 genes with similar expression patterns and 17 genes with opposite expression patterns were identified in the transcription profiles of ZS9 and GH01. An additional 1 438 genes in ZS9 and 1 861 genes in GH01 showed strain specific regulation. Analysis of the overlapped genes between ZS9 and GH01 revealed that waterlogging tolerance is determined by ability to regulate genes with similar expression patterns. Moreover, differences in both gene expression profiles and abscisic acid (ABA) contents between the two varieties suggest that ABA may play some role in waterlogging tolerance. This study identifies a subset of candidate genes for further functional analysis.
    Increased grain yield with improved photosynthetic characters in modern maize parental lines
    LI Cong-feng, TAO Zhi-qiang, LIU Peng, ZHANG Ji-wang, ZHUANG Ke-zhang, DONG Shu-ting, ZHAO Ming
    2015, 14(9): 1735-1744.  DOI: 10.1016/S2095-3119(14)60959-X
    Abstract ( )   PDF in ScienceDirect  
    The grain yield of maize has increased continuously in past decades, largely through hybrid innovation, cultivation technology, and in particular, recent genetic improvements in photosynthesis. Elite inbred lines are crucial for innovating new germplasm. Here, we analyzed variations in grain yield and a series of eco-physiological photosynthetic traits after anthesis in sixteen parental lines of maize (Zea mays L.) released during three different eras (1960s, 1980s, 2000s). We found that grain yield and biomass significantly increased in the 2000s than those in the 1980s and 1960s. Leaf area, chlorophyll, and soluble protein content slowly decreased, and maintained a higher net photosynthesis rate (Pn) and improved stomatal conductance (Gs) after anthesis in the 2000s. In addition, the parental lines in the 2000s obtained higher actual photochemistry efficiency (ФPSII) and the maximum PSII photochemistry efficiency (Fv/Fm), which largely improved light partitioning and chlorophyll fluorescence characteristic, including higher photochemical and photosystem II (PSII) reaction center activity, lower thermal energy dissipation in antenna proteins. Meanwhile, more lamellae per granum within chloroplasts were observed in the parental lines of the 2000s, with a clear and complete chloroplast membrane, which will greatly help to improve photosynthetic capacity and energy efficiency of ear leaf in maize parental lines. It is concluded that grain yield increase in modern maize parental lines is mainly attributed to the improved chloroplast structure and more light energy catched for the photochemical reaction, thus having a better stay-green characteristic and stronger photosynthetic capacity after anthesis. Our direct physiological evaluation of these inbred lines provides important information for the further development of promising maize cultivars.
    Seed priming improves early seedling vigor, growth and productivity of spring maize
    Hafeez ur Rehman, Hassan Iqbal, Shahzad M A Basra, Irfan Afzal, Muhammad Farooq, Abdul Wakeel, WANG Ning
    2015, 14(9): 1745-1754.  DOI: 10.1016/S2095-3119(14)61000-5
    Abstract ( )   PDF in ScienceDirect  
    Potential of seed priming treatments in improving the performance of early planted maize was evaluated against timely planting. Seeds of maize hybrid FH-810 were soaked in water (hydropriming), CaCl2 (2.2%, osmopriming), moringa leaf extracts (MLE 3.3%, osmopriming) and salicylic acid (SA, 50 mg L–1, hormonal priming) each for 18 h. Untreated and hydroprimed seeds were taken as control. Seeds primed with SA took less time in emergence and had high vigor in early planted maize. Amongst treatments, hormonal priming, reduced the electrical conductivity, increased the leaf relative and chlorophyll contents followed by osmopriming with CaCl2 at seedling stage. Likewise, plant height, grain rows and 1 000-grain weight, grain and biological yield and harvest index were also improved by seed priming; however hormonal priming and osmopriming with MLE were more effective in this regard. Improved yield performance by hormonal priming or osmopriming with MLE in early planting primarily owed to increased leaf area index, crop growth and net assimilation rates, and maintenance of green leaf area at maturity. In conclusion, osmopriming with MLE and hormonal priming with SA were the most economical treatments in improving productivity of early planted spring maize through stimulation of early seedling growth at low temperature.
    Effects of light intensity on photosynthesis and photoprotective mechanisms in apple under progressive drought
    MA Ping, BAI Tuan-hui, WANG Xiao-qian, MA Feng-wang
    2015, 14(9): 1755-1766.  DOI: 10.1016/S2095-3119(15)61148-0
    Abstract ( )   PDF in ScienceDirect  
    The effects of light intensity on photosynthesis and photoprotective mechanisms under progressive drought were studied on apple trees (Malus domestica Borkh.) Fuji. The potted trees were exposed to drought stress for 12 days and different light conditions (100, 60 and 25% sunlight). During the progressive drought, the relative water content (RWC) in leaf declined and was faster in full light than in 60 and 25% sunlight. However, the decrease in the net photosynthetic rate (Pn), stomatal conductance (Gs) and Rubisco activity were slower under 100% sunlight condition than other light conditions. After the 6 days of drought, the maximum PSII quantum yield (Fv/Fm), the capacity of electrons move beyond QA − (1–VJ) and electron move from intersystem to PSI acceptor side (1–VI)/(1–VJ) decreased, with greater decline extent in brighter light. While RWCs were >75%, the variations in different light intensities of Gs and Rubisco activity at identical RWC, suggested the direct effects of light. While the little difference in the state of photosynthetic electron transport chain among tested light intensities indicates the results of faster water loss rate of light. Our results also demonstrated that the enhancement the de-epoxidations of xanthophyll cycle, activities of ascorbate peroxidase (APX) and catalase (CAT) were directly regulated by light intensity. While the higher photorespiration rate (Pr) under stronger light condition was mainly caused by faster water loss rate of light.
    Plant Protection
    Expressing p20 hairpin RNA of Citrus tristeza virus confers Citrus aurantium with tolerance/resistance against stem pitting and seedling yellow CTV strains
    CHENG Chun-zhen, YANG Jia-wei, YAN Hu-bin, BEI Xue-jun, ZHANG Yong-yan, LU Zhi-ming, ZHONG Guang-yan
    2015, 14(9): 1767-1777.  DOI: 10.1016/S2095-3119(14)60937-0
    Abstract ( )   PDF in ScienceDirect  
    The Citrus tristeza virus (CTV) uses 3 silencing suppressor genes, p20, p23 and p25, to resist the attacks from its Citrus hosts. Inactivating these genes is therefore obviously a potential defensive option in addition to the current control strategies including aphid management and the use of mild strain cross protection. In this study, we cloned partial DNA fragments from the three genes, and used them to construct vectors for expressing hairpin RNAs (hpRNAs). To facilitate the formation of hpRNAs, the constructs were introduced in a loop structure. Following transformation of sour orange (Citrus aurantium) with these constructs, 8 p20 hpRNA (hp20) and 1 p25 hpRNA (hp25) expressing lines were obtained. The 7 hp20 transgenic lines were further characterized. Their reactions to CTV were tested following inoculation with CT14A and/ or TR-L514, both of which are severe strains. Results showed that 3 lines (hp20-5, hp20-6 and hp20-8) were completely resistant to TR-L514 under greenhouse conditions for no detectable viral load was found in their leaves by PCR. However, they exhibited only partial suppression of TR-L514 under screen house conditions since the virus was detected in their leaves, though 2 months later compared to non-transgenic controls. Further tests showed that hp20-5 was tolerant also to CT14A under screen house conditions. The growth of hp20-5 was much better than others including the controls that were concurrently challenged with CT14A. These results showed that expressing p20 hpRNA was sufficient to confer sour orange with CTV resistance/tolerance.
    Goosegrass (Eleusine indica) density effects on cotton (Gossypium hirsutum)
    MA Xiao-yan, WU Han-wen, JIANG Wei-li, MA Ya-jie, MA Yan
    2015, 14(9): 1778-1785.  DOI: 10.1016/S2095-3119(15)61058-9
    Abstract ( )   PDF in ScienceDirect  
    Goosegrass is one of the worst agricultural weeds on a worldwide basis. Understanding of its interference impact in crop field will provide useful information for weed control programs. Field experiments were conducted during 2010–2012 to determine the influence of goosegrass density on cotton growth at the weed densities of 0, 0.125, 0.25, 0.5, 1, 2, and 4 plants m–1 of row. Seed cotton yield tended to decrease with the increase in weed density, and goosegrass at a density of 4 plants m–1 of row significantly reduced cotton yields by 20 to 27%. A density of 11.6–19.2 goosegrass plant m–1 of row would result in a 50% cotton yield loss from the maximum yield according to the hyperbolic decay regression model. Boll production was not affected in the early growing season. But boll numbers per plant were reduced about 25% at the density of 4 plants m–1 of row in the late growing season. Both cotton boll weight and seed numbers per boll were significantly reduced (8%) at 4 goosegrass plants m–1 of row. Cotton plant height, stem diameter and sympodial branch number were not affected as much as cotton yields by goosegrass competition. Seed index, lint percentage and lint fiber properties were unaffected by weed competition. Intraspecific competition resulted in density-dependent effects on weed biomass per plant, 142–387 g dry weight by harvest. Goosegrass biomass m–2 tended to increase with increasing weed density as indicated by a quadratic response. The adverse impact of goosegrass on cotton yield identified in this study has indicated the need of effective goosegrass management.
    Cryptic species composition and genetic diversity within Bemisia tabaci complex in soybean in India revealed by mtCOI DNA sequence
    Prasanna H C, Kanakala S, Archana K, Jyothsna P, Varma R K, Malathi V G
    2015, 14(9): 1786-1795.  DOI: 10.1016/S2095-3119(14)60931-X
    Abstract ( )   PDF in ScienceDirect  
    Bemisia tabaci is a cryptic species complex, causing significant loss on many agriculturally important crops worldwide. Knowledge on species composition and diversity within B. tabaci complex is critical for evolving sustainable pest management strategies. Here we investigate the whitefly species complex in soybean in major soybean growing states of India. The mitochondrial cytochrome oxidase gene subunit-1 (mtCOI) based phylogenetic relationships established using Bayesian methods indicated the existence of three cryptic species namely Asia I, Asia II 1, and Asia II 7. All the haplotypes detected in the study could be assigned to these three cryptic species following the species demarcation criteria of 3.5% divergence threshold. Of these, Asia II 1 was found to be predominant with wide spread distribution across the surveyed regions from cool temperate zones to hot and humid tropical plains. On the contrary, cryptic species Asia II 7 showed localized distribution. The Asia II 1 exhibited the highest haplotype diversity and Asia I showed high level of nucleotide diversity. There was a significantly high genetic differentiation among these three cryptic species. The MEAM 1, a dreadful invasive species was not detected in the specimens tested in the current study. The diversity and distribution of three cryptic species is discussed in the light of current knowledge on distribution of whitefly species in India and yellow mosaic disease observed during sampling survey.
    Wing patterning genes of Nilaparvata lugens identification by transcriptome analysis, and their differential expression profile in wing pads between brachypterous and macropterous morphs
    LI Kai-yin, HU Ding-bang, LIU Fang-zhou, LONG Man, LIU Si-yi, ZHAO Jing, HE Yue-ping
    2015, 14(9): 1796-1807.  DOI: 10.1016/S2095-3119(14)60948-5
    Abstract ( )   PDF in ScienceDirect  
    The brown planthopper, Nilaparvata lugens is an economically important pest on rice plants. This species produces macropterous and brachypterous morphs in response to environmental cues, which makes it very difficult to control. The molecular basis of wing patterning in N. lugens is still unknown. It is necessary to identify wing patterning genes of N. lugens, and also to clarify the expression differences of wing patterning genes between macropterous and brachypterous morphs. High-throughput deep sequencing of transcriptome of N. lugens wing pad yielded 116 744 580 raw reads and 113 042 700 clean reads. All the reads were assembled into 55 963 unigenes with an average length of 804 bp. With the E-value cut-off of 1.0E–5,18 359 and 2 883 unigens had hits in NCBI-NR (NCBI non-redundant protein sequences) and NCBI-NT (NCBI nucleotide sequences) databases, respectively. A total of 16 502 unigenes were assigned to GO (gene ontology) classification, 9 709 ungenes were grouped into 26 COG (cluster of orthologous groups of proteins) classifications, and 6 724 unigenes were assigned to different KEGG (Kyoto encyclopedia of genes and genomes) pathways. In total, 56 unigenes which are homologous to wing patterning genes of Drosophila melanogaster or Tribolium castaneum were identified. Out of the 56 unigenes, 24 unigenes were selected, and their expression levels across the five nymphal stages between macropterous strain and brachypterous strain were examined by qRT-PCR. Two-way ANOVA analysis showed that development stage had significant effects on the expression level of all the 24 genes (P<0.05). The expression levels of 8 genes (Nlen, Nlhh, Nlsal, NlAbd-A, Nlwg, Nlvg, Nlexd and NlUbx) were significantly affected by wing morph. This is the first transcriptome analysis of wing pads of hemimetabolous insect, N. lugens. The identified wing patterning genes would be useful resource for future exploration of molecular basis of wing development. The 8 differentially expressed wing patterning genes between macropterous strain and brachypterous strain would contribute to explain molecular mechanism of wing-morph differentiation in N. lugens.
    Animal Science · Veterinary Science
    Effect of the C.–1 388 A>G polymorphism in chicken heat shock transcription factor 3 gene on heat tolerance
    ZHANG Wen-wu, KONG Li-na, ZHANG De-xiang, JI Cong-liang, ZHANG Xi-quan, LUO Qing-bin
    2015, 14(9): 1808-1815.  DOI: 10.1016/S2095-3119(14)60943-6
    Abstract ( )   PDF in ScienceDirect  
    Heat stress is one of the main factors that influence poultry production. Heat shock proteins (HSPs) are known to affect heat tolerance. The formation of HSPs is regulated by heat shock transcription factor 3 (HSF3) in chicken. A DNA pool was established for identifying single nucleotide polymorphisms (SNPs) of the chicken HSF3, and 13 SNPs were detected. The bioinformatic analysis showed that 8 SNPs had the capacity to alter the transcription activity of HSF3. The dual luciferase report gene assay showed that there was a significant difference (P<0.01) in the Firefly luciferase/Renilla luciferase ratio (F/R) of C.–1 703 A>G (S1) and C.–1 388 A>G (S4) sites at the 5´-untranslated region (UTR) of chicken HSF3. The electrophoretic mobility shift assay showed that the S4 site was a transcription binding factor. The analysis of the association of the S1 and S4 sites with heat tolerance index revealed that the S4 site was significantly correlated with the CD3+ T cell, corticosterone, and T3 levels in Lingshan chickens and with the heterophil/lymphocyte value in White Recessive Rock. These results showed that the S4 site at the 5´ UTR of chicken HSF3 might have an impact on heat tolerance in summer and could be used as a potential marker for the selection of chicken with heat tolerance in the future.
    Cloning of a novel phytase from an anaerobic rumen bacterium, Mitsuokella jalaludinii, and its expression in Escherichia coli
    TAN Wan-qin, Phang Chiun Yee, Sieo Chin Chin, Yiap Beow Chin, Clemente Michael Wong Vui Ling, Norhani Abdullah, Son Radu, Ho Yin Wan
    2015, 14(9): 1816-1826.  DOI: 10.1016/S2095-3119(14)60960-6
    Abstract ( )   PDF in ScienceDirect  
    The full length phytase gene of Mitsuokella jalaludinii was successfully cloned and was found to be 1 047 bp in length, with 348 amino acids, and was designated as PHY7 phytase gene. A comparison of the sequence of PHY7 phytase gene of M. jalaludinii with various microbial phytase gene sequences showed that it was not similar to those from other bacteria except Selenomonas ruminatium, thus suggesting that they may both express a new class of phytase. The PHY7 phytase gene was subsequently subcloned into bacterial expression vector, pET32a, for expression in Escherichia coli strain Rosetta- gami. Expression of the recombinant phytase gene was optimised and characterised. The recombinant phytase was estimated to be approximately 55 kDa by SDS-PAGE analysis. The recombinant phytase exhibited optimum activity at 55°C, pH 4.5 and showed good pH stability from pH 3.5 to 5.5 (>78% relative activity). Metal ions such as Ca2+, Mg2+, and K+ were found to exert significant stimulatory effect on the recombinant phytase activity while Cu2+, Fe3+, and Zn2+ greatly inhibited the enzyme activity. The recombinant phytase showed moderate resistance to trypsin proteolysis, but susceptible to pepsin proteolysis. The results of the study showed that several characteristics of recombinant phytase were slightly different from the native enzyme. Unfavourable characteristics such as reduced pH stability and metal ion effects should be taken into consideration during feed enzyme formulation.
    Endocrine and ovarian responses in water buffalo cows immunized against inhibin and subjected to the Ovsynch protocol
    Abdalla Bahareldin-Ali, QIN Guang-sheng, GUO Ri-hong, Anastasia Tsigkou, TAN Zheng-zhun, HUANG Jian, LI Hui, LI Hui, SHI Zhen-dan
    2015, 14(9): 1827-1837.  DOI: 10.1016/S2095-3119(15)61034-6
    Abstract ( )   PDF in ScienceDirect  
    The aim of this study was to investigate the feasibility of stimulating ovarian follicle development in order to improve fertility in water buffalo cows by immunization against inhibin. The experiment was carried out in early summer (May) and included 24 multi-parity crossbred Murrah-Swamp buffaloes that were divided into immunized (n=11) and control (n=13) groups. Each immunized cow was administered with a 2-mL immunogen of mineral oil adjuvant containing 2 mg of recombinant inhibin α-subunit fusion protein. The controls were treated with the adjuvant only. All animals received Ovsynch protocol treatment, starting on the day of the antigen administration, and they were artificially inseminated upon behavioral estrus. As a result, all of the immunized buffaloes generated antibodies against inhibin during the experimental period and had higher plasma concentrations of follicle-stimulating hormone (FSH), activin, and estradiol (E2) related to estrous expression. A higher proportion of immunized animals expressed estrus behavior than did the controls (72% vs. 30%, P<0.05). On average, inhibin-immunized buffaloes had significantly more large follicles (≥9 mm in diameter) than the controls (mean±SEM; 1.2±0.1 vs. 0.84±0.1, respectively; P<0.05) and a slightly higher mean total number of follicles (≥2 mm; 11.4±0.7 vs. 9.0±1.1, respectively; P=0.09) and small (2–4 mm) follicles (8.81±0.6 vs. 6.84±1.0, respectively; P=0.12). A higher percentage of cows ovulated in the immunized group than in the control group (91% (10/11) vs. 54% (7/13), respectively; P<0.05). Moreover, inhibin-immunized cows had slightly larger corpus luteum (CL) than the controls 9 days after ovulation and significantly higher (P<0.01) post-ovulation peak plasma progesterone (P4) concentrations. Immunization against inhibin also marginally increased the conception rate 42 days after insemination (45.8% vs. 15.4%; P>0.05). These results demonstrate that immunization against inhibin, coupled with the treatment with the Ovsynch protocol, can constitute a new technique to increase fertility in water buffalo cows.
    Investigation on the co-infections of Toxoplasma gondii with PRRSV, CSFV or PCV-2 in swine in part of China
    Wang Shuai, ZHang Meng, LIU Xin-chao, LIn Tao, Yang Han-chun, YUan Shi-shan, ZHao guang-wei, Ia Hassan, Yan Ruo-feng, Song Xiao-kai, XU Li-xin, LI Xiang-rui
    2015, 14(9): 1838-1844.  DOI: 10.1016/S2095-3119(15)61044-9
    Abstract ( )   PDF in ScienceDirect  
    The objective of the present investigation was to estimate the prevalence of Toxoplasma gondii infection and co-infection with porcine reproductive and respiratory syndrome virus (PRRSV), classical swine fever virus (CSFV) and porcine circovirus type 2 (PCV-2) in pigs in China. A total of 372 tissues or serum samples collected from pigs distributed in 9 provinces/ municipalities of China during the period from February 2011 to November 2012 were assayed for T. gondii antigens and antibodies using enzyme linked immunosorbent assay (ELISA) technique, while the PCR was designed for the detection of the PRRSV, CSFV and PCV-2, respectively. The total positive rate of T. gondii, PRSSV, CSFV and PCV-2 was 9.14% (34/372), 50.00% (186/372), 37.10% (138/372) and 3.23% (12/372), respectively. Among the 34 T. gondii positive samples, 26 samples were simultaneously infected with T. gondii and viruses, while the remaining eight samples were infected with T. gondii alone. In addition, the co-infection rate of T. gondii with PRSSV, T. gondii with PRSSV and CSFV, T. gondii with PRSSV and PCV-2, T. gondii with CSFV and PCV-2, T. gondii with PRSSV, CSFV and PCV-2 was 1.61% (6/372), 4.03% (15/372), 0.27% (1/372), 0.27% (1/372) and 0.81% (3/372), respectively. The results of the present survey revealed that PRRSV and CSFV were the common pathogens co-existing with porcine toxoplasmosis in China, and both of them could increase the chances of T. gondii infection in pig. This is the first report of T. gondii co-infections with viruses in pigs. It is very important to understand the interactions of parasite and virus, and can be used as reference data for the control and prevention of co-infections of T. gondii and viruses in pigs.
    Soil & Fertilization﹒Irrigation﹒Plant Nutrition﹒ Agro-Ecology & Environment
    Variation of Cd concentration in various rice cultivars and derivation of cadmium toxicity thresholds for paddy soil by species-sensitivity distribution
    SONG Wen-en, CHEN Shi-bao, LIU Ji-fang, CHEN Li, SONG Ning-ning, LI Ning, LIU Bin
    2015, 14(9): 1845-1854.  DOI: 10.1016/S2095-3119(14)60926-6
    Abstract ( )   PDF in ScienceDirect  
    It is imperative to derive an appropriate cadmium (Cd) health risk toxicity threshold for paddy soils to ensure the Cd concentration of rice grains meet the food safety standard. In this study, 20 rice cultivars from the main rice producing areas in China were selected, and a pot-experiment was conducted to investigate transformation of Cd in paddy soil-rice system with 0 (CK), 0.3 mg kg–1 (T1) and 0.6 mg kg–1 (T2) Cd treatments in greenhouse. The results showed that Cd concentrations of rice grains existed significant difference (P<0.05) in 20 rice cultivars under the same Cd level in soil. The Cd concentrations of rice grains of the CK, T1 and T2 treatments were in the range of 0.143–0.202, 0.128–0.458 and 0.332–0.806 mg kg–1, respectively. Marked differences of the ratios of Cd concentration for soil to rice grain (BCFs) and transfer factors (TFs, root to grain and straw to grain) among the tested cultivars were observed in this study. The bioconcentration factors (BCFgrain) and TFs of the 20 rice cultivars were 0.300–1.112 and 0.342–0.817, respectively. The TFs of Cd from straw to grain ranged from 0.366 to 1.71, with significant differences among these 20 rice cultivars. The bioconcentration factors (BCFgrain) and TFs among the 20 rice cultivars ranged from 0.300–1.112 and 0.342–0.817, respectively. The species-sensitivity distribution (SSD) of Cd sensitivity of the rice species could be fitted well with Burr-III (R2=0.987) based on the data of BCFs. The toxicity threshold of Cd derived from SSD for the paddy soil was 0.507 mg kg–1 in the present study.
    Multiphasic characterization of a plant growth promoting bacterial strain, Burkholderia sp. 7016 and its effect on tomato growth in the field
    GAO Miao, ZHOU Jian-jiao, WANG En-tao, CHEN Qian, XU Jing, SUN Jian-guang
    2015, 14(9): 1855-1863.  DOI: 10.1016/S2095-3119(14)60932-1
    Abstract ( )   PDF in ScienceDirect  
    Aiming at searching for plant growth promoting rhizobacteria (PGPR), a bacterium strain coded as 7016 was isolated from soybean rhizosphere and was characterized in the present study. It was identified as Burkholderia sp. based on 16S rDNA sequence analysis, as well as phenotypic and biochemical characterizations. This bacterium presented nitrogenase activity, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity and phosphate solubilizing ability; inhibited the growth of Sclerotinia sclerotiorum, Gibberella zeae and Verticillium dahliae; and produced small quantities of indole acetic acid (IAA). In green house experiments, significant increases in shoot height and weight, root length and weight, and stem diameter were observed on tomato plants in 30 d after inoculation with strain 7016. Result of 16S rDNA PCR-DGGE showed that 7016 survived in the rhizosphere of tomato seedlings. In the field experiments, Burkholderia sp. 7016 enhanced the tomato yield and significantly promoted activities of soil urease, phosphatase, sucrase, and catalase. All these results demonstrated Burkholderia sp. 7016 as a valuable PGPR and a candidate of biofertilizer.
    Effect of nitrogen fertilization on yield, N content, and nitrogen fixation of alfalfa and smooth bromegrass grown alone or in mixture in greenhouse pots
    XIE Kai-yun, LI Xiang-lin, HE Feng, ZHANG Ying-jun, WAN Li-qiang, David B Hannaway, WANG Dong, QIN Yan, Gamal M A Fadul
    2015, 14(9): 1864-1876.  DOI: 10.1016/S2095-3119(15)61150-9
    Abstract ( )   PDF in ScienceDirect  
    Planting grass and legume mixtures on improved grasslands has the potential advantage of realizing both higher yields and lower environmental pollution by optimizing the balance between applied N fertilizer and the natural process of legume biological nitrogen fixation. However, the optimal level of N fertilization for grass-legume mixtures, to obtain the highest yield, quality, and contribution of N2 fixation, varies with species. A greenhouse pot experiment was conducted to study the temporal dynamics of N2 fixation of alfalfa (Medicago sativa L.) grown alone and in mixture with smooth bromegrass (Bromus inermis Leyss.) in response to the addition of fertilizer N. Three levels of N (0, 75, and 150 kg ha–1) were examined using 15N-labeled urea to evaluate N2 fixation via the 15N isotope dilution method. Treatments were designated N0 (0.001 g per pot), N75 (1.07 g per pot) and N150 (2.14 g per pot). Alfalfa grown alone did not benefit from the addition of fertilizer N; dry matter was not significantly increased. In contrast, dry weight and N content of smooth bromegrass grown alone was increased significantly by N application. When grown as a mixture, smooth bromegrass biomass was increased significantly by N application, resulted in a decrease in alfalfa biomass. In addition, individual alfalfa plant dry weight (shoots+roots) was significantly lower in the mixture than when grown alone at all N levels. Smooth bromegrass shoot and root dry weight were significantly higher when grown with alfalfa than when grown alone, regardless of N application level. When grown alone, alfalfa’s N2 fixation was reduced with N fertilization (R2=0.9376, P=0.0057). When grown in a mixture with smooth bromegrass, with 75 kg ha–1 of N fertilizer, the percentage of atmospheric N2 fixation contribution to total N in alfalfa (%Ndfa) had a maximum of 84.07 and 83.05% in the 2nd and 3rd harvests, respectively. Total 3-harvest %Ndfa was higher when alfalfa was grown in a mixture than when grown alone (shoots: |t|=3.39, P=0.0096; root: |t|=3.57, P=0.0073). We believe this was due to smooth bromegrass being better able to absorb available soil N (due to its fibrous root system), resulting in lower soil N availability and allowing alfalfa to develop an effective N2 fixing symbiosis prior to the 1st harvest. Once soil N levels were depleted, alfalfa was able to fix N2, resulting in the majority of its tissue N being derived from biological nitrogen fixation (BNF) in the 2nd and 3rd harvests. When grown in a mixture, with added N, alfalfa established an effective symbiosis earlier than when grown alone; in monoculture BNF did not contribute a significant portion of plant N in the N75 and N150 treatments, whereas in the mixture, BNF contributed 17.90 and 16.28% for these treatments respectively. Alfalfa has a higher BNF efficiency when grown in a mixture, initiating BNF earlier, and having higher N2 fixation due to less inhibition by soil-available N. For the greatest N-use-efficiency and sustainable production, grass-legume mixtures are recommended for improving grasslands, using a moderate amount of N fertilizer (75 kg N ha–1) to provide optimum benefits.
    Estimation of USLE crop and management factor values for crop rotation systems in China
    GUO Qian-kun, LIU Bao-yuan, XIE Yun, LIU Ying-na, YIN Shui-qing
    2015, 14(9): 1877-1888.  DOI: 10.1016/S2095-3119(15)61097-8
    Abstract ( )   PDF in ScienceDirect  
    Soil erosion on cropland is a major source of environmental problems in China ranging from the losses of a non-renewable resource and of nutrients at the source to contamination of downstream areas. Regional soil loss assessments using the Universal Soil Loss Equation (USLE) would supply a scientific basis for soil conservation planning. However, a lack of information on the cover and management (C) factor for cropland, one of the most important factors in the USLE, has limited accurate regional assessments in China due to the large number of crops grown and their complicated rotation systems. In this study, single crop soil loss ratios (SLRs) were collected and quantified for 10 primary crops from past studies or reports. The mean annual C values for 88 crop rotation systems in 12 cropping system regions were estimated based on the combined effects of single crop SLRs and the percentage of annual rainfall erosivity (R) during the corresponding periods for each system. The C values in different cropping system regions were compared and discussed. The results indicated that the SLRs of the 10 primary crops ranged from 0.15 to 0.74. The mean annual C value for all 88 crop rotation systems was 0.34, with a standard deviation of 0.12. The mean C values in the single, double and triple cropping zones were 0.37, 0.36 and 0.28, respectively, and the C value in the triple zone was significantly different from those in single and double zones. The C values of dryland crop systems exhibited significant differences in the single and triple cropping system regions but the differences in the double regions were not significant. This study is the first report of the C values of crop rotation systems in China at the national scale. It will provide necessary and practical parameters for accurately assessing regional soil losses from cropland to guide soil conservation plans and to optimize crop rotation systems.
    Agricultural Economics And Management
    China agricultural outlook for 2015–2024 based on China Agricultural Monitoring and Early-warning System (CAMES)
    XU Shi-wei, LI Gan-qiong, LI Zhe-min
    2015, 14(9): 1889-1902.  DOI: 10.1016/S2095-3119(15)61149-2
    Abstract ( )   PDF in ScienceDirect  
    The primary goal of Chinese agricultural development is to guarantee national food security and supply of major agricultural products. Hence, the scientific work on agricultural monitoring and early warning as well as agricultural outlook must be strengthened. In this study, we develop the China Agricultural Monitoring and Early-warning System (CAMES) on the basis of a comparative study of domestic and international agricultural outlook models. The system is a dynamic and multi-market partial equilibrium model that integrates biological mechanisms with economic mechanisms. This system, which includes 11 categories of 953 kinds of agricultural products, could dynamically project agricultural market supply and demand, assess food security, and conduct scenario analysis at different spatial levels, time scale levels, and macro-micro levels. Based on the CAMES, the production, consumption, and trade of the major agricultural products in China over the next decade are projected. The following conclusions are drawn: i) The production of major agricultural products will continue to grow steadily, mainly because of the increase in yield. ii) The growth of agricultural consumption will be slightly higher than that of agricultural production. Meanwhile, a high self-sufficiency rate is expected for cereals such as rice, wheat, and maize, with the rate being stable at around 97%. iii) Agricultural trade will continue to thrive. The growth of soybean and milk imports will slow down, but the growth of traditional agricultural exports such as vegetables and fruits is expected to continue.
    Productivity effect and overuse of pesticide in crop production in China
    ZHANG Chao, Guanming Shi , SHEN Jian, HU Rui-fa
    2015, 14(9): 1903-1910.  DOI: 10.1016/S2095-3119(15)61056-5
    Abstract ( )   PDF in ScienceDirect  
    Chinese farmers are often accused of overusing pesticides that play a crucial role in enhancing crop yield by reducing losses to crop pests. Pesticide overuse has caused a series of negative health and environmental externalities. This paper quantifies the productivity effect and the optimal amount of pesticides in rice, cotton and maize production in China from the economic perspective. Using survey data collected in 2012 and 2013, both Cobb-Douglas and Weibull damage control specifications are used to estimate the production function. Results show that pesticides have statistically significant productivity effect on crop yield. On the condition of Weibull damage control specifications, the marginal products of 1 kg of the active ingredients of pesticides for rice, cotton and maize are 71.06, 22.73 and 98.45 kg, respectively. However, 57, 64 and 17% of the actual amount of pesticides are overused for rice, cotton and maize, respectively. Moreover, the productivity effect of pesticides would be overestimated using Cobb-Douglas specification without incorporating a damage control agent.