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    Crop Genetics · Breeding · Germplasm Resources
    QTL Detection and Epistasis Analysis for Heading Date Using Single Segment Substitution Lines in Rice (Oryza sativa L.)
    LI Guang-xian, CHEN Ai-hua, LIU Xu, WANG Wen-ying, DING Han-feng, LI Jun, LIU Wei, LI Si-shen , YAO Fang-yin
    2014, 13(11): 2311-2321.  DOI: 10.1016/S2095-3119(13)60615-2
    Abstract ( )   PDF in ScienceDirect  
    Heading date of rice is a key agronomic trait determining cultivated areas and seasons and affecting yield. In the present study, five primary single segment substitution lines with the same genetic background were used to detect quantitative trait loci (QTLs) for heading date in rice. Two QTLs, qHD3 and qHD6 on the short arm of chromosome 3 and the short arm of chromosome 6, respectively, were identified under natural long-day (NLD). Nineteen secondary single segment substitution lines (SSSLs) and seven double segments pyramiding lines were designed to map the two QTLs and to evaluate their epistatic interaction between them. By overlapping mapping, qHD3 was mapped in a 791-kb interval between SSR markers RM3894 and RM569 and qHD6 in a 1 125-kb interval between RM587 and RM225. Results revealed the existence of epistatic interaction between qHD3 and qHD6 under natural long-day (NLD). It was also found that qHD3 and qHD6 had significant effects on plant height and yield traits, indicating that both of the QTLs have pleiotropic effects.
    Quantitative Trait Loci Associated with Micronutrient Concentrations in Two Recombinant Inbred Wheat Lines
    PU Zhi-en, YU Ma, HE Qiu-yi, CHEN Guo-yue, WANG Ji-rui, LIU Ya-xi, JIANG Qian-tao, LI Wei, DAI Shou-fen, WEI Yu-ming , ZHENG You-liang
    2014, 13(11): 2322-2329.  DOI: 10.1016/S2095-3119(13)60640-1
    Abstract ( )   PDF in ScienceDirect  
    Micronutrient malnutrition affects over three billion people worldwide, especially women and children in developing countries. Increasing the bioavailable concentrations of essential elements in the edible portions of crops is an effective resolution to address this issue. To determine the genetic factors controlling micronutrient concentration in wheat, the quantitative trait locus (QTL) analysis for iron, zinc, copper, manganese, and selenium concentrations in two recombinant inbred line populations was performed. In all, 39 QTLs for five micronutrient concentrations were identified in this study. Of these, 22 alleles from synthetic wheat SHW-L1 and seven alleles from the progeny line of the synthetic wheat Chuanmai 42 showed an increase in micronutrient concentrations. Five QTLs on chromosomes 2A, 3D, 4D, and 5B found in both the populations showed significant phenotypic variation for 2-3 micronutrient concentrations. Our results might help understand the genetic control of micronutrient concentration and allow the utilization of genetic resources of synthetic hexaploid wheat for improving micronutrient efficiency of cultivated wheat by using molecular marker-assisted selection.
    Characterization of the Promoter of a Homolog of Maize MADS-Box Gene m18
    QIN Hui-juan, PAN Hong, FAN Xian-wei, WU Qiao , LI You-zhi
    2014, 13(11): 2330-2345.  DOI: 10.1016/S2095-3119(13)60677-2
    Abstract ( )   PDF in ScienceDirect  
    Maize (Zea mays L.) is one of the world’s major food crops, and often suffers from tremendous yield loss caused by abiotic stresses. The MADS-box genes are known to play versatile roles in plants, controlling plant responses to multiple abiotic stresses. However, understanding of regulation of their expressions by the conventional loss-of-function approach is very difficult. So far, regulation of MADS-box gene expression is little known. The best approach to retrieve expression regulation of this category of genes is to characterize expression of their promoters. In this study, the promoter of a homolog (GenBank accession no. EC864166) of maize MADS-box gene m18 was cloned by way of genome-walking PCR, named Pro66. Predicative analysis indicated that Pro66 contains more than one TATA box and multiple cis-acting environmental conditions-responsive elements (ECREs). Pro66 could drive expression of the β-glucuronidase (GUS)-encoding gene in maize, and heterologous expression of GUS in red pepper stressed by water deficit, salt, copper, iron deficiency, heat, cold, and grown under short and long photoperiods, echoing predicative ECREs. Conclusively, maize MADS-box gene m18 likely plays versatile functions in maize response to multiple abiotic stresses due to the promoter with multiple cis-acting elements. The complex arrangement of multiple cis-acting elements in the promoter features meticulously regulated expression of m18. The results give informative clues for heterologous utilisation of the promoters in monocot and dicot species. The copy of the ECREs and heterologous expression of the promoter in dicot species are also discussed.
    ISSR-Based Molecular Characterization of an Elite Germplasm Collection of Sweet Potato (Ipomoea batatas L.) in China
    ZHANG Kai, WU Zheng-dan, LI Yan-hua, ZHANG Han, WANG Liang-ping, ZHOU Quan-lu, TANG Dao-bin, FU Yu-fan, HE Feng-fa, JIANG Yu-chun, YANG Hang , WANG Ji-chun
    2014, 13(11): 2346-2361.  DOI: 10.1016/S2095-3119(14)60779-6
    Abstract ( )   PDF in ScienceDirect  
    To determine the genetic diversity and population structure of sweet potato accessions cultivated in China, and to establish the genetic relationships among their germplasm types, a representative collection of 240 accessions was analyzed using inter-simple sequence repeat (ISSR) markers. The mean genetic similarity coefficient, Nei’s gene diversity, and shared allele distance of tested sweet potato accessions were 0.7302, 0.3167 and 0.2698, respectively. The 240 accessions could be divided into six subgroups and five subpopulations based on neighbor-joining (NJ) clustering and STRUCTURE results, and obvious genetic relationships among the tested sweet potato accessions were identified. The marker-based NJ clustering and population structure showed no distinct assignment pattern corresponding to flesh color or geographical ecotype of the tested sweet potato germplasm. Analysis of molecular variance (AMOVA) revealed small but significant difference between white and orange-fleshed sweet potato accessions. Small but significant difference were also observed among sweet potato accessions from the Southern summer-autumn sweet potato region, the Yellow River Basin spring and summer sweet potato region and the Yangtze River Basin summer sweet potato region. This study demonstrates that genetic diversity in the tested sweet potato germplasm collection in China is lower than that in some reported sweet potato germplasm collections from other regions. Pedigree investigations suggest that more diverse Chinese sweet potato varieties should be formed by broadening the selection scope of breeding parents and incorporating the introduced varieties into future breeding programs.
    Identification and Molecular Mapping of the RsDmR Locus Conferring Resistance to Downy Mildew at Seedling Stage in Radish (Raphanus sativus L.)
    XU Liang, JIANG Qiu-wei, WU Jian, WANG Yan, GONG Yi-qin, WANG Xian-li, Limera Cecilia , LIU Li-wang
    2014, 13(11): 2362-2369.  DOI: 10.1016/S2095-3119(14)60792-9
    Abstract ( )   PDF in ScienceDirect  
    Downy mildew (DM), caused by the fungus Peronospora parasitica, is a destructive disease of radish (Raphanus sativus L.) worldwide. Host resistance has been considered as an attractive and environmentally friendly approach to control the disease. However, the genetic mechanisms of resistance in radish to the pathogen remain unknown. To determine the inheritance of resistance to DM, F1, F2 and BC1F1 populations derived from reciprocal crosses between a resistant line NAU-dhp08 and a susceptible line NAU-qtbjq-06 were evaluated for their responses to DM at seedling stage. All F1 hybrid plants showed high resistance to DM and maternal effect was not detected. The segregation for resistant to susceptible individuals statistically fitted a 3:1 ratio in two F2 populations (F2(SR) and F2(RS)), and 1:1 ratio in two BC1F1 populations, indicating that resistance to DM at seedling stage in radish was controlled by a single dominant locus designated as RsDmR. A total of 1 972 primer pairs (1036 SRAP, 628 RAPD, 126 RGA, 110 EST-SSR and 72 ISSR) were screened, and 36 were polymorphic between the resistant and susceptible bulks, and consequently used for genotyping individuals in the F2 population. Three markers (Em9/ga24370, NAUISSR826700 and Me7/em10400) linked to the RsDmR locus within a 10.0 cM distance were identified using bulked segregant analysis (BSA). The SRAP marker Em9/ga24370 was the most tightly linked one with a distance of 2.3 cM to RsDmR. These markers tightly linked to the RsDmR locus would facilitate marker-assisted selection and resistance gene pyramiding in radish breeding programs.
    Production of Transgenic Anliucheng Sweet Orange (Citrus sinensis Osbeck) with Xa21 Gene for Potential Canker Resistance
    LI Ding-li, XIAO Xuan, GUO Wen-wu
    2014, 13(11): 2370-2377.  DOI: 10.1016/S2095-3119(13)60675-9
    Abstract ( )   PDF in ScienceDirect  
    Citrus canker, an epidemic quarantine disease caused by Xanthomonas axonopodis pv. citri, has brought a great damage in citrus production worldwide. Herein, a rice PRR (pattern recognition receptor) gene Xa21 together with GUS reporter gene and hygromycin phosphotransferase gene (HPT) was introduced into Anliucheng sweet orange (Citrus sinensis Osbeck) via Agrobacterium-mediated transformation of embryogenic callus. The transgenic calluses were screened on MT basal medium containing hygromycin (HYG) and detected by histochemical GUS staining. The transgenic plantlets were recovered through somatic embryogenesis pathway. The regenerated plantlets were accustomed to and maintained in the greenhouse. The transgene integration of recovered plantlets was identified by PCR and Southern blot hybridization. It showed that all the transgenic plantlets tested had undergone single copy integration, the expression of Xa21 in eight different transgenic lines detected by qRT-PCR can be divided into three grades, high for T5 and T6, middle for T4 and low for the rest. The tolerance to citrus canker disease of the three recovered transgenic lines T2, T4 and T6 was assessed by in vitro pin-puncture inoculation. The results showed that all the three transgenic lines conferred improved resistance to citrus canker bacterium infection and the T4 transgenic line displayed the highest resistance. The mechanism and feasibility of rice Xa21 in triggering innate immunity in citrus was briefly discussed.
    Effects of Tillage Practices on Water Consumption, Water Use Efficiency and Grain Yield in Wheat Field
    ZHENG Cheng-yan, YU Zhen-wen, SHI Yu, CUI Shi-ming, WANG Dong, ZHANG Yong-li, ZHAO Jun-ye
    2014, 13(11): 2378-2388.  DOI: 10.1016/S2095-3119(13)60733-9
    Abstract ( )   PDF in ScienceDirect  
    Water shortage is a serious issue threatening the sustainable development of agriculture in the North China Plain, with the winter wheat (Triticum aestivum L.) as its largest water-consuming crop. The effects of tillage practices on the water consumption and water use efficiency (WUE) of wheat under high-yield conditions using supplemental irrigation based on testing soil moisture dynamic change were examined in this study. This experiment was conducted from 2007 to 2010, with five tillage practice treatments, namely, strip rotary tillage (SR), strip rotary tillage after subsoiling (SRS), rotary tillage (R), rotary tillage after subsoiling (RS), and plowing tillage (P). The results showed that in the SRS and RS treatments the total water and soil water consumptions were 11.81, 25.18% and 12.16, 14.75% higher than those in SR and R treatments, respectively. The lowest ratio of irrigation consumption to total water consumption in the SRS treatment was 18.53 and 21.88% for the 2008-2009 and 2009- 2010 growing seasons, respectively. However, the highest percentage of water consumption was found in the SRS treatment from anthesis to maturity. No significant difference was found between the WUE of the flag leaf at the later filling stage in the SRS and RS treatments, but the flag leaf WUE at these stages were higher than those of other treatments. The SRS and RS treatments exhibited the highest grain yield (9 573.76 and 9 507.49 kg ha-1 for 3-yr average) with no significant difference between the two treatments, followed by P, R and SR treatments. But the SRS treatment had the highest WUE. Thus, the 1-yr subsoiling tillage, plus 2 yr of strip rotary planting operation may be an efficient measure to increase wheat yield and WUE.
    Response of Wheat to Tillage Plus Rice Residue and Nitrogen Management in Rice-Wheat System
    Khalid Usman, Ejaz Ahmad Khan, Niamatullah Khan, Abdur Rashid, Fazal Yazdan , Saleem Ud Din
    2014, 13(11): 2389-2398.  DOI: 10.1016/S2095-3119(13)60728-5
    Abstract ( )   PDF in ScienceDirect  
    Zero tillage with residues retention and optimizing nitrogen fertilization are important strategies to improve soil quality and wheat (Triticum aestivum L.) yield in rice (Oryza sativa L.)-wheat system. Field experiments were conducted on silty clay soil (Hyperthermic, and Typic Torrifluvents) in D. I. Khan, Pakistan, to explore the impact of six tillage methods (zero tillage straw retained (ZTsr), ZT straw burnt (ZTsb), reduced tillage straw incorporated (RTsi, including tiller and rotavator), RT straw burnt (RTsb), conventional tillage straw incorporated (CTsi, including disc plow, tiller, rotavator, and leveling operations), CT straw burnt (CTsb)) and five nitrogen rates, i.e., 0, 100, 150, 200, and 250 kg ha-1 on wheat yield. Mean values for N revealed that spikes m-2, grains/spike, 1 000-grain weight (g), and grain yield (kg ha-1) were significantly higher at 200 kg N ha-1 in both the years as well as mean over years than all other treatments. Mean values for tillage revealed that ZTsr produced highest number of spikes m-2 among tillage methods. However, grains/spike, 1 000-grain weight, and grain yield were higher in tillage methods with either straw retained/incorporated than tillage methods with straw burnt. Interaction effects were significant in year 1 and in mean over years regarding spikes m-2, 1 000-grain weight, total soil organic matter (SOM), and total soil N (TSN). ZTsr produced the most spikes m-2 and 1 000-grain weight at 200 kg N ha-1. ZTsr also produced higher SOM and TSN at 200-250 kg N ha-1 at the end of 2 yr cropping. Thus ZTsr with 200 kg N ha-1 may be an optimum and sustainable approach to enhance wheat yield and soil quality in rice-wheat system.
    Crop Genetics · Breeding · Germplasm Resources
    Effect of Drought Stress During Flowering Stage on Starch Accumulation and Starch Synthesis Enzymes in Sorghum Grains
    YI Bing, ZHOU Yu-fei, GAO Ming-yue, ZHANG Zhuang, HAN Yi, YANG Guang-dong, XU Wenjuan, HUANG Rui-dong
    2014, 13(11): 2399-2406.  DOI: 10.1016/S2095-3119(13)60694-2
    Abstract ( )   PDF in ScienceDirect  
    Starch content is a key factor affecting sorghum grain quality. The research of sorghum grain starch accumulation and the related synthesis enzyme activities has great significance for understanding the mechanisms of starch metabolisms. The differences between a high and a low starch content sorghum hybrids (Tieza 17 and Liaoza 11, respectively) in grain starch accumulation and the related synthesis enzyme activities were assessed following imposition of water stress during flowering stage. The total starch, amylase and amylopectin accumulation all decreased at the mid-late stage of grain filling under drought stress during flowering stage. The maximum and mean accumulation rates also decreased. During grain filling, soluble starch synthase (SSS), granule-bound starch synthase (GBSS), starch branching enzyme (SBE), and starch debranching enzymes (DBE) activities were all affected, though differently. Drought stress reduced starch accumulation in a larger extent for Tieza 17 than Liaoza 11. Drought stress during flowing stage reduced starch synthesis enzyme activities, thus reducing starch accumulation in grains, and the differences between starch components were also demonstrated under drought stress.
    Over-Expression of BnMAPK1 in Brassica napus Enhances Tolerance to Drought Stress
    WENG Chang-mei, LU Jun-xing, WAN Hua-fang, WANG Shu-wen, WANG Zhen, LU Kun, LIANG Ying
    2014, 13(11): 2407-2415.  DOI: 10.1016/S2095-3119(13)60696-6
    Abstract ( )   PDF in ScienceDirect  
    Mitogen-activated protein kinases (MAPKs) are a family of Ser/Thr protein kinases widely conserved in all eukaryotes and involved in responses to biotic and abiotic stresses. In this study, two over-expressing BnMAPK1 oilseed rape lines, ov3 and ov11, were used to study the drought-resistant mechanism of BnMAPK1 under natural drought and simulation drought through spraying 10% PEG 8000 in seedlings. Zhongyou 821 (WT) was used as control. Compared with wild type, transgenic seedlings had higher leaf water content, higher root activity, slightly higher peroxidase (POD) and superoxide dismutase (SOD) activity, higher proline content and lower malondialdehyde (MDA) content. The expression of drought-resistant related genes, including P5CSB, PLC, LEA4 and SCE1, have been up-regulated in some degree and the expressed time of transgenic lines were earlier than that of wild type. These results suggested that over-expression of BnMAPK1 can enhance the resistance to drought in oilseed rape (Brassica napus).
    Response of Nitrate Metabolism in Seedlings of Oilseed Rape (Brassica napus L.) to Low Oxygen Stress
    YU Chang-bing, XIE Yu-yun, HOU Jia-jia, FU You-qiang, SHEN Hong , LIAO Xing
    2014, 13(11): 2416-2423.  DOI: 10.1016/S2095-3119(13)60693-0
    Abstract ( )   PDF in ScienceDirect  
    In order to understand the response of nitrate metabolism in seedlings of oilseed rape (Brassica napus L.) to low oxygen stress (LOS), two cultivars were studied at different light, LOS time and exogenous nitrate concentrations under hydroponic stress. Results show that N-uptake and dry matter of rape seedlings were decreased after LOS stress while nitrate accumulation (NA) under LOS was induced by darkness. Nitrate accumulation peaked at 3 d while root activity (RA, defined as dehydrogenase activity) decreased with prolonged waterlogging exposure. Exogenous nitrate significantly elevated NA and RA. Tungstate (TS) and LOS inhibited nitrate reductase (NR) activity while NR transcription and activity were enhanced by exogenous nitrate. Low oxygen stress stimulated the activity of superoxide dismutase (SOD) and peroxidase (POD) slightly, but inhibited that of catalase (CAT). B. napus L. Zhongshuang 10 (ZS10), a LOS tolerant cultivar, displayed smaller decrease upon dry matter under LOS, higher NA in darkness and lower NA in light than B. napus L. Ganlan CC (GAC), a LOS sensitive variety. ZS10 had lower NA and higher RA after waterlogging and exogenous nitrate treatment, and higher NR activity under TS inhibition than GAC, but the activity of antioxidant enzymes did not change under LOS. The results indicate that nitrate metabolism involved tolerance of rape seedlings to LOS, with lower accumulation and higher reduction of nitrate being related to higher LOS tolerance of rape seedlings exposed to waterlogging.
    Plant Protection
    Virulence and Diversity of Blumeria graminis f. sp. tritici Populations in China
    ZENG Fan-song, YANG Li-jun, GONG Shuang-jun, SHI Wen-qi, ZHANG Xue-jiang, WANG Hua , XIANG Li-bo, XUE Min-Feng , YU Da-zhao
    2014, 13(11): 2424-2437.  DOI: 10.1016/S2095-3119(13)60669-3
    Abstract ( )   PDF in ScienceDirect  
    Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, is an important disease in China. To characterize the virulence and diversity of the pathogen, 1082 isolates were obtained from 8 major wheat-growing regions during the spring growing season in 2011. The virulence test was performed by inoculation on detached leaves of 22 differential lines with known Pm genes. Frequencies of virulence on these genotypes ranged from 0 to 97.4%. None of the 1 082 isolates was compatible to Pm21 and less than 20.0% were virulent to the genotype carrying Pm13. In contrast, the virulence frequencies of each population was more than 50.0% to differentials carrying Pm1a, Pm3b, Pm3c, Pm3f, Pm5a, Pm6 and Pm8. In total, 1028 pathotypes were detected, of which 984 were unique. Phenotypic diversity indices revealed a high level of diversity within populations. Genetic distance between different populations correlated significantly with geographical distance (R2=0.494, P 0.001). In addition, isolates from Xinjiang appear to form a separate group. Significant positive or negative associations between alleles at pairs of virulence loci were detected in 57 allele pairs to Pm genes. Virulence and diversity of the 8 populations suggested that varieties with effective resistance gene combinations should be developed at a regional level.
    A FIASCO-Based Approach for Detection and Diagnosis of Puccinia graminis f. sp. tritici in China
    LIU Tai-guo, WANG Xi, GAO Li, LIU Bo, CHEN Wan-quan , XIANG Wen-sheng
    2014, 13(11): 2438-2444.  DOI: 10.1016/S2095-3119(14)60895-9
    Abstract ( )   PDF in ScienceDirect  
    Stem or black rust of wheat, caused by the fungus Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn. (Pgt), has historically caused severe losses to wheat (Triticum aestivum L.) production worldwide. In the Fujian and Guangdong provinces of China, six moderate-to-severe epidemics of wheat stem rust have occurred, which caused destructive losses of wheat between 1949 and 1966, although these were brought under control by integrated management. A rapid and reliable detection of the pathogen will contribute to the accurate forecast and seasonal control of this disease. The objective of this study was to develop a diagnostic molecular marker generated from simple sequence repeats (SSR) for the early rapid identification of P. graminis. The genomic DNA of P. graminis, Puccinia striiformis, Puccinia triticina and seven other species was amplified by a pair of SSR primers generated by the FIASCO (fast isolation by AFLP sequences containing repeats) enrichment protocol. The primer set Pgtw (f)/ Pgtw (r) generated a polymorphic pattern displaying a 330-bp DNA fragment specific for P. graminis whereas no DNA fragment was obtained from other non-target wheat fungal pathogens. The detection limit of the primer was 1 ng DNA in a 25-mL PCR reaction. The SSR markers of P. graminis can also be used to detect the presence of latent hyphae in Pgt-infected wheat leaves as early as 30 h post-inoculation. A rapid approach to distinguish P. graminis from similar pathogenic fungi would be anticipated in further study.
    Antagonizing Aspergillus parasiticus and Promoting Peanut Growth of Bacillus Isolated from Peanut Geocarposphere Soil
    XIAO Wei, YAN Pei-sheng, WU Han-qi and LIN Feng
    2014, 13(11): 2445-2451.  DOI: 10.1016/S2095-3119(13)60609-7
    Abstract ( )   PDF in ScienceDirect  
    A set of 38 Bacillus strains isolated from peanut geocarposphere soil were screened as potential biological control agent anti- Aspergillus parasiticus. Tip-culture method with rapid and quantitative characteristics was used to determine anti-A. parasiticus activity and the process of isolation could be accelerated with this method. 12 out of 38 Bacillus strains showed high anti-aflatoxin production activity. These 12 Bacillus strains were selected to identify the characteristics of promoting peanuts germination rate. Pot experiment in greenhouse was carried out by using these strains which can promote peanuts germination. Phytohormones in the fermentation broth were also detected as another important reference factor to select the isolates as biological control agent with PGPR features. These Bacillus strains isolated from peanut geocarposphere soil not only had high ability anti-Aspergillus parasiticus, but also promoted peanut growth. Therefore, these Bacillus strains were well adapted to peanut production in the field as biological control agent with plant growth promoting rhizobacteria (PGPR) features.
    Biochemical Mechanism of Chlorantraniliprole Resistance in the Diamondback Moth, Plutella xylostella Linnaeus
    HU Zhen-di, FENG Xia, LIN Qing-sheng, CHEN Huan-yu, LI Zhen-yu, YIN Fei, LIANG Pei , GAO Xi-wu
    2014, 13(11): 2452-2459.  DOI: 10.1016/S2095-3119(14)60748-6
    Abstract ( )   PDF in ScienceDirect  
    The insecticide chlorantraniliprole exhibits good efficacy and plays an important role in controlling the diamondback moth, Plutella xylostella Linnaeus. However, resistance to chlorantraniliprole has been observed recently in some field populations. At present study, diamondback moths with resistance to chlorantraniliprole (resistant ratio (RR) was 82.18) for biochemical assays were selected. The assays were performed to determine potential resistance mechanisms. The results showed that the selected resistant moths (GDLZ-R) and susceptible moth could be synergized by known metabolic inhibitors such as piperonyl butoxide (PBO), triphenyl phosphate (TPP) and diethyl-maleate (DEM) at different levels (1.68-5.50-fold and 2.20-2.89-fold, respectively), and DEM showed the maximum synergism in both strains. In enzymes assays, a high level of glutathione-S-transferase (GST) was observed in the resistant moth, in contrast, moths that are susceptible to the insecticide had only 1/3 the GST activity of the resistant moths. The analysis of short-term exposure of chlorantraniliprole on biochemical response in the resistant strain also showed that GST activity was significantly elevated after exposure to a sub-lethal concentration of chlorantraniliprole (about 1/3 LC50, 12 mg L-1) 12 and 24 h, respectively. The results show that there is a strong correlation between the enzyme activity and resistance, and GST is likely the main detoxification mechanism responsible for resistance to chlorantraniliprole in P. xylostella L., cytochrome P450 monooxygenase (P450) and carboxy-lesterase (CarE) are involved in to some extent.
    Rice Grain Damage by Combination and Sequence Infestations by the Rice Leaffolder, Cnaphalocrocis medinalis Guenee (Lepidoptera: Pyralidae), and the White-Backed Rice Planthopper, Sogatella furcifera Horváth (Hemiptera: Delphacidae)
    JIANG Li-ben, ZHU Zhan-fei, GE Lin-quan, YANG Guo-qing, WU Jin-cai
    2014, 13(11): 2460-2470.  DOI: 10.1016/S2095-3119(14)60745-0
    Abstract ( )   PDF in ScienceDirect  
    The rice leaffolder (RLF), Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae), and the white-backed rice planthopper (WBPH), Sogatella furcifera Horváth (Hemiptera: Delphacidae), are major insect pests in China and several other Asian countries. These two pests commonly occur simultaneously or in a temporal sequence. Thus, the investigation of the effect of complex infestations or temporal sequence infestations by these pests on rice yield has a practical significance for the control of these pests. The present study comprised experiments with the following four different variables in potted rice at the tillering stage: single pest species infestation, complex infestation, complete combination infestation and temporal sequence infestation (C. medinalis infestation prior to S. furcifera and S. furcifera infestation prior to C. medinalis). The results showed that the four infestations resulted in a significant decrease in 1 000-grain weight (1 000GW) and rate of yield loss (RYL) but an increase in blighted grain rate (BGR), with a significant positive correlation with the infestation density. However, the influences of the complex infestation, complete combination infestation or sequence infestation on the 1 000GW, BGR and RYL were greater than those of the single pest species infestations but did not have addition effects, i.e., the effects of the complex infestation and combination infestation or sequence infestation on the 1 000GW, BGR and RYL were less than the additive effects of the two single pest species infestations at the same densities. In the condition of the same total infestation pressure, no significant differences in the 1 000GW, BGR and RYL were found between C. medinalis infestation prior to S. furcifera and S. furcifera infestation prior to C. medinalis as well as between the sequence infestation and the complex infestation.
    Dissipation and Adsorption Behavior of the Insecticide Ethiprole on Various Cultivated Soils in China
    LIU Xin-gang, DONG Feng-shou, XU Jun, YUAN Shan-kui , ZHENG Yong-quan
    2014, 13(11): 2471-2478.  DOI: 10.1016/S2095-3119(13)60685-1
    Abstract ( )   PDF in ScienceDirect  
    In this study, the hydrolysis of the insecticide ethiprole in buffered solutions at pH 4.0, 7.0 and 9.0, respectively, and the degradation and adsorption-desorption behaviors of ethiprole in five agricultural soil samples from China were investigated. The half-lives under anaerobic conditions were faster than that in the aerobic experiment. Ethiprole was relatively stable under both acidic and neutral conditions while it was readily hydrolyzed under alkaling condition. The sorption of ethiprole on five soils was well described by the linear and Freundlich equation and mainly governed by soil organic matter. The exothermic process of ethiprole adsorption can also be well explained by physical adsorption. A weak adsorption capacity was observed in all soils, which could readily lead to leaching problems.
    Animal Science · Veterinary Science
    Heat Stress Upregulates the Expression of TLR4 and Its Alternative Splicing Variant in Bama Miniature Pigs
    JU Xiang-hong, XU Han-jin, YONG Yan-hong, AN Li-long, XU Ying-mei, JIAO Pei-rong , LIAO Ming
    2014, 13(11): 2479-2487.  DOI: 10.1016/S2095-3119(13)60574-2
    Abstract ( )   PDF in ScienceDirect  
    Alternative splicing is a cellular mechanism in eukaryotes that results in considerable diversity of gene products. It plays an important role in several diseases and cellular signal regulation. Heat stress is a major factor that induces immunosuppression in pigs. Little is known about the correlation between alternative splicing and heat stress in pigs. Therefore, this study aimed to clone, sequence and quantify the alternative splicing variant of toll-like receptor 4 (TLR4) in Bama miniature pigs (Sus scrofa domestica) following exposure to heat stress. The results showed that the second exon of TLR4 was spliced and 167 bp shorter in the alternative splicing variant, and the protein was putatively identified as a type of truncated membrane protein consisting of extramembrane, transmembrane and intramembrane regions lacking a signal peptide. Further, it was not a nonclassical secretory protein. Five potential reference genes were screened for their potential as reliable standards to quantify the expression of TLR4 alternative spliced variants by real-time quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR). The stability of these reference genes was ranked using the geNorm and NormFinder programs, and ribosomal protein L4 (RPL4) and TATA box-binding protein (TBP) were found to be the two genes showing the most stable expression in the in vitro cultured peripheral blood mononuclear cells (PBMCs) during heat shock. The mRNA level of the TLR4 gene (both classical and spliced) in stressed pigs increased significantly (P<0.05). Further, the expression levels of the alternative spliced variant of TLR4 (TLR4-ASV) showed a 2-3 folds increase in heat-stressed PBMCs as compared to control pigs. The results of the present study suggested that heat shock might modulate the host immune response by regulating the expressions of TLR4 and its alternative splicing variant.
    Myristic Acid (MA) Promotes Adipogenic Gene Expression and the Differentiation of Porcine Intramuscular Adipocyte Precursor Cells
    LU Nai-sheng, SHU Gang, XIE Qiu-ping, ZHU Xiao-tong, GAO Ping, ZHOU Gui-xuan, WANG Songbo, WANG Li-na, XI Qian-yun, ZHANG Yong-liang , JIANG Qing-yan
    2014, 13(11): 2488-2499.  DOI: 10.1016/S2095-3119(13)60664-4
    Abstract ( )   PDF in ScienceDirect  
    Intramuscular fat (IMF) content is considered to be a key factor that affects the marbling, tenderness, juiciness and flavor of pork. To investigate the effects of myristic acid (MA) on the differentiation of porcine intramuscular adipocytes, cells were isolated from longissimus dorsi muscle (LDM) and treated with 0, 10, 50 or 100 μmol L-1 MA. The results showed that MA significantly promotes the differentiation of intramuscular adipocytes in a dose-dependent manner. MA also led to a parallel increase in the expression of peroxisome proliferator activated receptor-γ (PPARγ) and adipose-related genes, such as glucose transporter 1 (GLUT1), lipoprotein lipase (LPL), adipocyte fatty acid binding protein 4 (FABP4/aP2), fatty acid translocase (FAT), acetyl-CoA carboxylase α (ACCα), adipose triglyceride lipase (ATGL) and fatty acid synthase (FASN). However, no significant effects of MA were observed on the expression of CAAT enhancer binding protein-α (C/EBPα) or hormone sensitive lipase (HSL). The expression of pyruvate dehydrogenase kinase 4 (PDK4) was increased by MA during the early stages of differentiation (day 1-3). In addition, MA also increased the absolute content of C14 (P<0.001) and saturated fatty acids (SFA) (P<0.05) to varying degrees, but no effects were observed on other fatty acids. These results suggest that MA might be able to enhance the IMF content of pork and increase the accumulation of myristic and myristoleic acid in muscle, which might have beneficial implications for human health.
    Overexpression of a Cytosolic Ascorbate Peroxidase Gene, OsAPX2, Increases Salt Tolerance in Transgenic Alfalfa
    ZHANG Qian, MA Cui, XUE Xin, XU Ming, LI Jing , WU Jin-xia
    2014, 13(11): 2500-2507.  DOI: 10.1016/S2095-3119(13)60691-7
    Abstract ( )   PDF in ScienceDirect  
    Alfalfa (Medicago sativa L.) is an important forage crop in the world and it is of great significance for the improvement of its salt tolerance. To improve salt tolerance in alfalfa, a rice ascorbate peroxidase gene (OsAPX2) was introduced into alfalfa using Agrobacterium tumefaciens-mediated transformation with marker gene bar. The different T-DNA insertions in T1 transgenic alfalfa were identified by Southern hybridization. Three independent T2 transgenic lines were selected for stress analysis and the results showed that all of them were salt tolerant compared with wild-type plants. The transgenic plants had low levels of H2O2, malondialdehyde and relative electrical conductivity under salt and drought stresses. Moreover, the contents of chlorophyll and proline, and APX activity were high in transgenic plants under salt and drought stresses. Taken together, the overexpression of OsAPX2 enhances salt tolerance in alfalfa through scavenging reactive oxygen species.
    Soil & Fertilization · Irrigation · Agro-Ecology & Environment
    Cell Production and Expansion in the Primary Root of Maize in Response to Low-Nitrogen Stress
    GAO Kun, CHEN Fan-jun, YUAN Li-xing , MI Guo-hua
    2014, 13(11): 2508-2517.  DOI: 10.1016/S2095-3119(13)60523-7
    Abstract ( )   PDF in ScienceDirect  
    Maize plants respond to low-nitrogen stress by enhancing root elongation. The underlying physiological mechanism remains unknown. Seedlings of maize (Zea mays L., cv. Zhengdan 958) were grown in hydroponics with the control (4 mmol L-1) or low-nitrogen (40 μmol L-1) for 12 d, supplied as nitrate. Low nitrogen enhanced root elongation rate by 4.1-fold, accompanied by increases in cell production rate by 2.2-fold, maximal elemental elongation rate (by 2.5-fold), the length of elongation zone (by 1.5-fold), and final cell length by 1.8-fold. On low nitrogen, the higher cell production rate resulted from a higher cell division rate and in fact the number of dividing cells was reduced. Consequently, the residence time of a cell in the division zone tended to be shorter under low nitrogen. In addition, low nitrogen increased root diameter, an increase that occurred specifically in the cortex and was accompanied by an increase in cell number. It is concluded that roots elongates in response to low-nitrogen stress by accelerating cell production and expansion.
    Fruit Yield and Quality, and Irrigation Water Use Efficiency of Summer Squash Drip-Irrigated with Different Irrigation Quantities in a Semi-Arid Agricultural Area
    Yasemin Kuslu, Ustun Sahin, Fatih M Kiziloglu, Selcuk Memis
    2014, 13(11): 2518-2526.  DOI: 10.1016/S2095-3119(13)60611-5
    Abstract ( )   PDF in ScienceDirect  
    Fruit yield, yield components, fruit mineral content, total phenolic content, antioxidant activity and irrigation water use efficiency (IWUE) of summer squash responses to different irrigation quantities were evaluated with a field study. Irrigations were done when the total evaporated water from a Class A pan was about 30 mm. Different irrigation quantities were adjusted using three different plant-pan coefficients (Kcp, 100% (Kcp1), 85% (Kcp2) and 70% (Kcp3)). Results indicated that lower irrigation quantities provided statistically lower yield and yield components. The highest seasonal fruit yield (80.0 t ha-1) was determined in the Kcp1 treatment, which applied the highest volume of irrigation water (452.9 mm). The highest early fruit yield, average fruit weight and fruit diameter, length and number per plant were also determined in the Kcp1 treatment, with values of 7.25 t ha-1, 264.1 g, 5.49 cm, 19.95 cm and 10.92, respectively. Although the IWUE value was the highest in the Kcp1 treatment (176.6 kg ha-1 mm-1), it was statistically similar to the value for Kcp3 treatment (157.1 kg ha-1 mm-1). Total phenolic content and antioxidant activity of fruits was higher in the Kcp1 (44.27 μg gallic acid equivalents (GAE) mg-1 fresh sample) and in the Kcp2 (84.75%) treatments, respectively. Major (Na, N, P, K, Ca, Mg and S) and trace (Fe, Cu, Mn, Zn and B) mineral contents of squash fruits were the highest in the Kcp2 treatment, with the exception of P, Ca and Cu. Mineral contents and total phenolic content were significantly affected by irrigation quantities, but antioxidant activity was not affected. It can be concluded that the Kcp1 treatment was the most suitable for achieving higher yield and IWUE. However, the Kcp2 treatment will be the most suitable due to the high fruit quality and relatively high yield in water shortage conditions.
    Species Composition, Richness and Aboveground Biomass of Natural Grassland in Hilly-Gully Regions of the Loess Plateau, China
    DENG Lei , SHANGGUAN , Zhou-ping
    2014, 13(11): 2527-2536.  DOI: 10.1016/S2095-3119(13)60590-0
    Abstract ( )   PDF in ScienceDirect  
    In order to study the characteristics of species composition, richness and aboveground biomass of natural grasslands, and then find out the relations between species richness and aboveground productivity of the communities and possible mechanisms to form the relations, four typical grassland communities (Artemisia capillaries (AC), Thymus quinquecostatus (TQ), Stipa bungeana (SB) and Stipa grandis (SG)) along with a succession sequence in hilly-gully regions of the Loess Plateau, China, were investigated by field survey and laboratory analysis. The results were summarized as follows: Different succession stages had different species compositions as well as different proportions of plant life forms and photosynthetic types, and Asteraceae, Poaceae and Leguminosae were their dominant species as well as their dominant perennial herb species; and different succession stages had significantly different species richness and aboveground biomasses. There were many relation patterns (linear positive correlation, unrelated relations and unimodal relations) between the species richness and aboveground biomass in different succession stages and a significant unimodal relation between the species richness and aboveground biomass in all the grassland communities and the highest species diversity appeared at a moderate level of productivity. The results suggest the unimodal relations in all the grassland communities are accumulative results of the relations in each succession stage.
    Agricultural Economic
    Crop Insurance, Premium Subsidy and Agricultural Output
    XU Jing-feng , LIAO Pu
    2014, 13(11): 2537-2545.  DOI: 10.1016/S2095-3119(13)60674-7
    Abstract ( )   PDF in ScienceDirect  
    This paper studied the effects of crop insurance on agricultural output with an economic growth model. Based on Ramsey- Cass-Koopmans (RCK) model, a basic model of agriculture economic growth was developed. Extending the basic model to incorporate uncertainty and insurance mechanism, a risk model and a risk-insurance model were built to study the influences of risk and crop insurance on agricultural output. Compared with the steady states of the three models, the following results are achieved: (i) agricultural output decreases if we introduce uncertainty into the risk-free model; (ii) crop insurance promotes agriculture economic growth if insurance mechanism is introduced into the risk model; (iii) premium subsidy constantly improves agricultural output. Our contribution is that we studied the effects of crop insurance and premium subsidy from the perspective of economic growth in a dynamic framework, and proved the output promotion of crop insurance theoretically.
    Do Land Characteristics Affect Farmers’ Soil Fertility Management?
    Tan Shu-hao
    2014, 13(11): 2546-2557.  DOI: 10.1016/S2095-3119(14)60840-6
    Abstract ( )   PDF in ScienceDirect  
    Soil fertility management (SFM) has important implications for sustaining agricultural development and food self-sufficiency. Better understanding the determinants of farmers’ SFM can be a great help to the adoption of effective SFM practices. Based on a dataset of 315 plots collected from a typical rice growing area of South China, this study applied statistical method and econometric models to examine the impacts of land characteristics on farmers’ SFM practices at plot scale. Main results showed that in general land characteristics affected SFM behaviors. Securer land tenure arrangements facilitated effective practices of SFM through more diversified and more soil-friendly cropping pattern choices. Plot size significantly reduced the intensities of phosphorus and potassium fertilizer application. Given other factors, 1 ha increase in plot size might reduce 3.0 kg ha-1 P2O5 and 1.8 kg ha-1 K2O. Plots far from the homestead were paid less attention in terms of both chemical fertilizers and manure applications. Besides, plots with better quality were put more efforts on management by applying more nitrogen and manure, and by planting green manure crops. Significant differences existed in SFM practices between the surveyed villages with different socio-economic conditions. The findings are expected to provide important references to the policy-making incentive for improving soil quality and crop productivity.
    Short Communication
    Effects of Polysaccharides from Pulsatilla Decoction on the Microvascular Endothelial Glycocalyx
    ZHANG Tao, WU Shuang, SUN Xiong, DUAN Hui-qin , MU Xiang
    2014, 13(11): 2558-2561.  DOI: 10.1016/S2095-3119(14)60896-0
    Abstract ( )   PDF in ScienceDirect  
    Pulsatilla decoction is a famous traditional Chinese herbal formula for clearing heat and treating dysentery of animals or human. To elucidate its mechanism, many active components have been studied, however, the roles of its polysaccharides still remain unclear. This study aimed to explore effects of polysaccharides from Pulsatilla decoction (PPD) on the microvascular endothelial glycocalyx (eGC). The polysaccharides were extracted from PPD by water extraction and alcohol precipitation method. Mice were administered with PPD for 4 wk, and were then anesthetized with ether inhalation and were fixed by cardiac perfusion with gradient concentration alcian blue solution. The jejunum was sampled and jejunal mucosa was prepared for ultrathin sections by routine method and was analyzed by transmission electron microscope. The results indicated that the eGC was observed as a strong electron-dense smooth linear margin or nonuniform conglomerates coating cell membranes, and PPD significantly increased its thickness from (21.85±1.87) to (28.71±3.61) nm and improved its integrity. This study suggested that PPD may express their biological activities and protect against pathogenic factor damages by influencing the eGC.
    Complete Genome Sequence of Mycoplasma ovipneumoniae Strain NM2010, Which Was Isolated from a Sheep in China
    WANG Xiao-hui, HUANG Hai-bi, CHENG Chen, WANG Ren-chao, ZHENG Jia-qi, HAO Yongqing, ZHANG Wen-guang
    2014, 13(11): 2562-2563.  DOI: 10.1016/S2095-3119(14)60825-X
    Abstract ( )   PDF in ScienceDirect  
    Mycoplasma ovipneumoniae, a kind of mycoplasma bacteria, commonly infects the respiratory tract causing respiratory disease in sheep and goats worldwide. Here, the complete genome sequence of M. ovipneumoniae strain NM2010 isolated from a sheep in China was reported for the first time.