2018 Vol. 17 No. 12 Previous Issue    Next Issue

    Crop Science
    Plant Protection
    Animal Science · Veterinary Medicine
    Agricultural Economics and Management
    Agro-ecosystem & Environment
    Short Communication

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    Crop Science
    Analysis of three types of resistance gene analogs in PmU region from Triticum urartu
    ZHANG Lei, ZHENG Xing-wei, QIAO Lin-yi, QIAO Ling, ZHAO Jia-jia, WANG Jian-ming, ZHENG Jun
    2018, 17(12): 2601-2611.  DOI: 10.1016/S2095-3119(18)61995-1
    Abstract ( )   PDF in ScienceDirect  
    Resistance gene analog (RGA) screening of mapped disease-resistant genes not only helps to clone these genes but also helps to develop efficient molecular markers for resistance breeding. The present study focused on the PmU region located on chromosome 7AuL of Triticum urartu, and recently, a nucleotide binding site (NBS)-encoding gene, Pm60, was cloned from the same chromosome arm. In this research, NBS, protein kinase (PK), and ATP-binding cassette (ABC), the three disease resistance-related gene families, were analyzed within PmU region by using informatics tools, and an expression experiment was conducted to verify their functions in vivo. Comparative genomic analysis revealed that 126 RGAs were included on chromosome 7AuL, and 30 of the RGAs as well as Pm60 were found in the PmU region. Transcriptome database analysis of T. urartu revealed 14 PmU-RGAs with expression data, and three PmU-NBSs exhibited significant changes in expression after inoculation with Blumeria graminis f. sp. tritici (Bgt); TRIUR3_14879 was up-regulated, while TRIUR3_00450 and TRIUR3_06270 were down-regulated. Cluster analysis showed that these three PmU-NBSs were clustered far from the cloned wheat resistance genes. Then, qRT-PCR was performed to investigate the expression of 14 PmU-RGAs and Pm60 after inoculation with Bgt race E09; the results showed that Pm60 was specifically expressed in UR206 which carrying PmU, but not in susceptible UR203; while TRIUR3_14879 was significantly up-regulated and TRIUR3_00450 was downregulated in UR206 after inoculation. These results indicated that PmU is Pm60, and TRIUR3_14879 and TRIUR3_00450 may also be involved in the defense against Bgt.
    Overexpression of the Suaeda salsa SsNHX1 gene confers enhanced salt and drought tolerance to transgenic Zea mays
    HUANG Ying, ZHANG Xiao-xia, LI Yi-hong, DING Jian-zhou, DU Han-mei, ZHAO Zhuo, ZHOU Li-na, LIU Chan, GAO Shi-bin, CAO Mo-ju, LU Yan-li, ZHANG Su-zhi
    2018, 17(12): 2612-2623.  DOI: 10.1016/S2095-3119(18)61998-7
    Abstract ( )   PDF in ScienceDirect  
    Maize is one of the most important crops worldwide, but it suffers from salt stress when grown in saline-alkaline soil. There is therefore an urgent need to improve maize salt tolerance and crop yield. In this study, the SsNHX1 gene of Suaeda salsa, which encodes a vacuolar membrane Na+/H+ antiporter, was transformed into the maize inbred line 18-599 by Agrobacterium-mediated transformation. Transgenic maize plants overexpressing the SsNHX1 gene showed less growth retardation when treated with an increasing NaCl gradient of up to 1%, indicating enhanced salt tolerance. The improved salt tolerance of transgenic plants was also demonstrated by a significantly elevated seed germination rate (79%) and a reduction in seminal root length inhibition. Moreover, transgenic plants under salt stress exhibited less physiological damage. SsNHX1-overexpressing transgenic maize accumulated more Na+ and K+ than wild-type (WT) plants particularly in the leaves, resulting in a higher ratio of K+/Na+ in the leaves under salt stress. This result revealed that the improved salt tolerance of SsNHX1-overexpressing transgenic maize plants was likely attributed to SsNHX1-mediated localization of Na+ to vacuoles and subsequent maintenance of the cytosolic ionic balance. In addition, SsNHX1 overexpression also improved the drought tolerance of the transgenic maize plants, as rehydrated transgenic plants were restored to normal growth while WT plants did not grow normally after dehydration treatment. Therefore, based on our engineering approach, SsNHX1 represents a promising candidate gene for improving the salt and drought tolerance of maize and other crops.
    Effects of planting methods on yield and quality of different types of japonica rice in northern Jiangsu plain, China
    BIAN Jin-long, XU Fang-fu, HAN Chao, QIU Shi, GE Jia-lin, XU Jing, ZHANG Hong-cheng, WEI Hai-yan
    2018, 17(12): 2624-2635.  DOI: 10.1016/S2095-3119(18)62141-0
    Abstract ( )   PDF in ScienceDirect  
    Mechanical transplanting with carpet seedlings (MC) and mechanical direct seeding (MD) are newly developed planting methods, which increase in popularity and planted area each year. Knowing the difference for yield and rice quality under different planting methods is of great importance for the development of high quality and yield cultivation techniques under mechanical conditions. Therefore, three kinds of japonica rice including hybrid japonica rice, inbreed japonica rice, and soft rice were adopted as materials. And the differences in the quality of processing, appearance, cooking and eating quality, nutrition, and the rapid viscosity analyzer (RVA) profile were studied to reveal the effects of planting methods on yield and quality of different types of japonica rice. Results showed that the milled rice and head rice rates under MC was significantly higher than those under MD, and the processing quality of inbreed japonica rice was the most stable. Compared with MC, length/width ratio of rice under MD was significantly increased, and chalkiness rate, size, and degree were significantly decreased. The protein content under MD was lower than that under MC. MC showed higher peak viscosity and breakdown value than MD. The taste value was the greatest for soft rice, followed by inbreed japonica rice, and then by japonica hybrid rice, with no significant differences resulting from planting methods. Compared with MC, MD significantly improved the appearance quality, though processing quality and nutritional quality were decreased. And there was no significant difference in cooking and eating quality between MC and MD. Under different planting methods, the appearance quality of inbreed japonica rice changed the most and the processing quality was the most stable. The nutritional, cooking and eating quality of soft rice changed the least. Therefore, according to the different planting methods and market needs, selecting the appropriate rice varieties can reduce the risks in rice production and achieve good rice quality.
    The role of rhizobacteria in rice plants: Growth and mitigation of toxicity
    Marcela C F Rêgo, Aline F Cardoso, Thayná da C Ferreira, Marta C C de Filippi, Telma F V Batista, Rafael G Viana, Gisele B da Silva
    2018, 17(12): 2636-2647.  DOI: 10.1016/S2095-3119(18)62039-8
    Abstract ( )   PDF (4500KB) ( )  

    Allelopathic compounds reduce the growth and productivity of upland rice plants, especially in consecutive plantations.
    The rhizobacteria Pseudomonas fluorescens BRM-32111 and Burkholderia pyrrocinia BRM-32113 have been recorded as
    growth promoters in rice. This study was developed to understand the effect of the application of rhizobacteria on upland
    rice plants in consecutive plantations. Experiments were conducted in a completely randomized design with four replications
    of four treatments: rice seed inoculated with P. fluorescens BRM-32111, rice seed inoculated with B. pyrrocinia BRM-32113
    (both sown on soil with rice residue), non-inoculated plants sown on soil with rice residue (control with residue (WR)), and
    non-inoculated plants on soil with no residue (NR). Roots and seedling growth were adversely affected by allelopathic
    compounds in control WR plants. Plants inoculated with rhizobacteria P. fluorescens BRM-32111 or B. pyrrocinia BRM-32113
    induced an increase of 88% in biomass, 3% in the leaf area, 40% in length, 67% in root biomass, 21% in chlorophyll a,
    53% in chlorophyll (a+b), 50% in rate of carbon assimilation (A), 227% in A/rubisco carboxylation efficiency (Ci) and 63%
    in water use efficiency (WUE) compared to control WR plants. These results indicate that rhizobacteria P. fluorescens
    BRM-32111 and B. pyrrocinia BRM-32113 increase the tolerance of rice plants to stress from allelochemicals. There are
    possible practical agricultural applications of these results for mitigating the effects of environmental allelochemistry on
    upland rice.

    Postponed and reduced basal nitrogen application improves nitrogen use efficiency and plant growth of winter wheat
    TIAN Zhong-wei, LIU Xiao-xue, GU Shi-lu, YU Jin-hong, ZHANG Lei, ZHANG Wei-wei, JIANG Dong, CAO Wei-xing, DAI Ting-bo
    2018, 17(12): 2648-2661.  DOI: 10.1016/S2095-3119(18)62086-6
    Abstract ( )   PDF (1285KB) ( )  
    Excessive nitrogen (N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency (NUE) and has led to environmental problems in the Yangtze River Basin, China.  However, wheat requires less N fertilizer at seedling growth stage, and its basal N fertilizer utilization efficiency is relatively low; therefore, reducing the N application rate at the seedling stage and postponing the N fertilization period may be effective for reducing N application and increasing wheat yield and NUE.  A 4-year field experiment was conducted with two cultivars under four N rates (240 kg N ha–1 (N240),
    180 kg N ha–1 (N180), 150 kg N ha–1 (N150), and 0 kg N ha–1 (N0)) and three basal N application stages (seeding (L0), four-leaf stage (L4), and six-leaf stage (L6)) to investigate the effects of reducing the basal N application rate and postponing the basal N fertilization period on grain yield, NUE, and N balance in a soil-wheat system.  There was no significant difference in grain yield between the N180L4 and N240L0 (control) treatments, and the maximum N recovery efficiency and N agronomy efficiency were observed in the N180L4 treatment.  Grain yield and NUE were the highest in the L4 treatment.  The leaf area index, flag leaf photosynthesis rate, flag leaf nitrate reductase and glutamine synthase activities, dry matter accumulation, and N uptake post-jointing under N180L4 did not differ significantly from those under N240L0.  Reduced N application decreased the inorganic N content in the 0–60-cm soil layer, and the inorganic N content of the L6 treatment was higher than those of the L0 and L4 treatments at the same N level.  Surplus N was low under the reduced N rates and delayed basal N application treatments.  Therefore, postponing and reducing basal N fertilization could maintain a high yield and improve NUE by improving the photosynthetic production capacity, promoting N uptake and assimilation, and reducing surplus N in soil-wheat systems.
    Effects of variety and chemical regulators on cold tolerance during maize germination
    WANG Li-jun, ZHANG Ping, WANG Ruo-nan, WANG Pu, HUANG Shou-bing
    2018, 17(12): 2662-2669.  DOI: 10.1016/S2095-3119(17)61880-X
    Abstract ( )   PDF in ScienceDirect  
    Maize growth and development is affected by low temperature (LT) especially at the early stages of development.  To describe the response of different varieties to LT stress and determine an effective method to cope with LT stress, maize hybrids
    Zhengdan 958 (ZD 958) and Danyu 39 (DY 39) were planted and grown at 10 and 25°C, respectively.  Effects of the chemicals potassium chloride (KCl), gibberellin (GA3), 2-diethylaminoethyl-3,4-dichlorophenylether (DCPTA), and all three combined chemicals (KGD) on coping with LT stress were tested by seed priming.  The varieties performed significantly different at 10°C.  Compared to leaf, root growth was more severely affected by LT stress.  Root/leaf ratio is likely a more reliable parameter to evaluate cold tolerance based on its close correlation with leaf malondialdehyde (MDA) content (R=–0.8).  GA3 advanced seed germination by about 2 days compared with control treatment of water.  GA3 and DCPTA both resulted in lower leaf MDA content and higher leaf and root area, and root/leaf ratio.  KCl resulted in the highest evenness of plant height.  KGD performed the best in increasing cold tolerance of maize morphologically and physiologically.  Strategies to increase maize tolerance of cold stress, such as variety breeding or chemical selection, would increase maize yield especially at high-latitude regions and have great implications for food security.
    Abscisic acid induces differential expression of genes involved in wound-induced suberization in postharvest tomato fruit
    HAN Xue-yuan, MAO Lin-chun, LU Wen-jing, TAO Xiao-ya, WEI Xiao-peng, LUO Zi-sheng
    2018, 17(12): 2670-2682.  DOI: 10.1016/S2095-3119(18)62142-2
    Abstract ( )   PDF (9615KB) ( )  
    Fruit wounding occurred at harvest and transportation requires rapid suberization as a major part of the healing process to prevent infection and desiccation.  The focus of this work was to explore the mediation of abscisic acid (ABA) on wound-induced suberization and to determine expression profiles of specific genes involved in wound-induced suberization in tomato fruit.  The measurements of weight loss and fruit firmness suggested wound-induced suberization started at 2 d after wounding.  The suberization process with the accumulation of suberin polyphenolics (SPP) and polyaliphatics (SPA) observed through autofluorescence microscopy and Sudan IV staining was accelerated by ABA.  Expressions of SlPAL5 and Sl4CL involved in the synthesis of SPP reached the highest at 4 and 8 d after wounding following ABA application, respectively.  Associated with SPA biosynthesis, SlLACS1 and SlLACS2 showed the most abundant transcripts at 8 and 6 d in ABA group, respectively.  Transcript levels including SlKCSs, SlCYP86B1, SlFAR3, and SlGPATs were up-regulated at 2 d after wounding by ABA.  Activities of polyphenol oxidase and lipoxygenase were also enhanced during wound-induced suberization following ABA application. The results in this study proved that ABA accelerated the wound-induced suberization progress by increasing the transcript levels of relevant genes in postharvest tomato fruit. 
    Effects of short-term heat stress on PSII and subsequent recovery for senescent leaves of Vitis vinifera L. cv. Red Globe
    ZHANG Kun, CHEN Bai-hong, HAO Yan, YANG Rui, WANG Yu-an
    2018, 17(12): 2683-2693.  DOI: 10.1016/S2095-3119(18)62143-4
    Abstract ( )   PDF (501KB) ( )  
    Heat stress occurs frequently in energy-saving sunlight greenhouses (ESSG) at the late growth stage.  Three-year delayed cultivation (DC) of the Red Globe cultivar of Vitis vinifera L. was used to clarify the physiological mechanisms of short-term heat stress on PSII and subsequent recovery from heat stress.  By November, the photosynthetic function had declined and the fall in transpiration rate (E) with heating time increased the possibility of heat damage.  In July, the most obvious increase was in the relative variable fluorescence at J point at 40°C, and in November it changed to K point.  The 5 min of heat treatment resulted in a significant increase of the relative variable fluorescence at 0.3 ms (Wk), and after 10 min of heat treatment, the number of reactive centres per excited cross section (RC/CSo), probability that a trapped exciton moves an electron into the electron transport chain beyond QA– (at t=0) (Ψo) and quantum yield of electron transport at t=0 (φEo) decreased significantly (P<0.05), suggesting that the reaction centre, donor and acceptor side of photosystem II (PSII) were all significantly inhibited (P<0.05) and that the thermal stability of the photosynthetic mechanism was reduced.  The inhibition of energy fluxes for senescent leaves in November was earlier and more pronounced than that for healthy leaves, which did not recover from heat stress of more than 15 min after 2 h recovery at room temperature.
    Molecular cloning and functional identification of an apple flagellin receptor MdFLS2 gene
    QI Chen-hui, ZHAO Xian-yan, JIANG Han, LIU Hai-tao, WANG Yong-xu, HU Da-gang, HAO Yu-jin
    2018, 17(12): 2694-2703.  DOI: 10.1016/S2095-3119(18)62009-X
    Abstract ( )   PDF (4711KB) ( )  
    The leucine-rich repeat receptor kinase flagellin-sensing 2 gene (MdFLS2; Gene ID: MDP0000254112) was cloned from Royal Gala apple (Malus×domestica Borkh.).  This gene contained a complete open reading frame of 3 474 bp that encoded 1 158 amino acids.  The phylogenetic tree indicated that Prunus persica FLS2 exhibited the highest sequence similarity to MdFLS2.  The PlantCare database suggests that the promoter sequence of MdFLS2 contains several typical cis-acting elements, including ethylene-, gibberellin-, salicylic acid-, and drought-responsive elements.  Quantitative real-time PCR analysis showed that MdFLS2 was widely expressed in the different tissues of the apple and most highly expressed in the leaves.  Furthermore, MdFLS2 was significantly induced by the flagellin elicitor peptide flg22.  Treatment of the apple seedling leaves with flg22 resulted in an increase in leaf callose levels with increased treatment duration.  An increase in the production of O2 along with the expression of disease-related genes was also observed.  An oxidative burst was detected in the treated seedlings, but not in the control seedlings, indicating that flg22 had stimulated the expression of the MdFLS2 gene and its downstream target genes.  Furthermore, the ectopic expression of MdFLS2 complemented the function of the Arabidopsis fls2 mutant and conferred enhanced flg22 tolerance to the transgenic Arabidopsis, suggesting that MdFLS2 acts as a positive regulator in the response to pathogens in apple.
    Plant Protection
    Effects of UV-B radiation intensity and timing on epidemiological components of wheat stripe rust
    WANG Hui, QIN Feng, CHENG Pei, MA Zhan-hong, WANG Hai-guang
    2018, 17(12): 2704-2713.  DOI: 10.1016/S2095-3119(18)62020-9
    Abstract ( )   PDF (868KB) ( )  
    Stripe rust caused by Puccinia striiformis f. sp. tritici is an important wheat disease worldwide that is greatly influenced by environmental conditions.  Ultraviolet B (UV-B) radiation is one important environmental factor affecting the occurrence and epidemiology of wheat stripe rust.  Investigating UV-B radiation effects on the epidemiology of stripe rust may be conducive to monitoring and predicting this disease.  In this study, wheat seedlings were exposed to UV-B radiation during different periods under laboratory conditions and radiation effects on epidemiological components of wheat stripe rust were investigated.  Results showed that incubation period was shortened, and the infection efficiency, sporulation quantity and disease index increased when UV-B radiation was performed only pre-inoculation.  When the UV-B radiation was performed only post-inoculation or both pre- and post-inoculation, the incubation period was prolonged, and the infection efficiency, sporulation quantity and disease index were reduced.  When healthy wheat seedlings were inoculated using urediospores collected from wheat leaves irradiated by UV-B only post-inoculation or both pre- and post-inoculation, infection efficiency, sporulation quantity and disease index were also reduced.  However, in the latter, the disease incubation period did not differ under varying UV-B radiation intensities compared to that when wheat leaves were not treated with UV-B radiation.  Overall, the effects of direct exposure of wheat plants to UV-B radiation with different intensities in different periods on epidemiological components of wheat stripe rust were systematically explored, and the results suggest that the effects of UV-B radiation increased gradually with the increase of UV-B radiation intensity.  This information provides a basis for monitoring and predicting this disease as well as for conducting further studies on pathogen virulence variation.
    Non-target-site and target-site resistance to AHAS inhibitors in American sloughgrass (Beckmannia syzigachne)
    WANG Jing-jing, LI Xiang-ju, LI Dan, HAN Yu-jiao, LI Zheng, YU Hui-lin, CUI Hai-lan
    2018, 17(12): 2714-2723.  DOI: 10.1016/S2095-3119(18)62021-0
    Abstract ( )   PDF in ScienceDirect  
    American sloughgrass (Beckmannia syzigachne (Steud.) Fernald) is one of the most competitive and malignant weeds in rice-wheat rotation fields in China.  American sloughgrass populations in the Jiangsu Province of China became less sensitive to acetohydroxyacid synthase (AHAS) inhibitors after repeated application for many years in these areas.  Two suspected resistant American sloughgrass populations (R1 and R2) collected in the field were detected the resistance to inhibitors of AHAS in whole-plant dose-response assays, compared to the susceptible (S) population.  These assays indicated that R1 showed low resistance to mesosulfuron-methyl (3.32-fold), imazapic (2.84-fold) and pyroxsulam (1.55-fold), moderate resistance to flazasulfuron (4.67-fold) and pyribenzoxim (7.41-fold), and high resistance to flucarbazone (11.73-fold).  However, using a combination of the cytochrome P450 inhibitor, malathion, with mesosulfuron-methyl resulted in a reduction in R1 resistance relative to mesosulfuron-methyl alone.  Furthermore, R2 was highly resistant to flazasulfuron (34.90-fold), imazapic (11.30-fold), flucarbazone (49.20-fold), pyribenzoxim (12.94-fold), moderately resistant to mesosulfuron-methyl (9.77-fold) and pyroxsulam (6.26-fold), and malathion had no effect on R2 resistance to mesosulfuron-methyl.  The full-length of AHAS genes was sequenced and the AHAS enzymes were assayed in vitro in order to clarify the mechanism of resistance to AHAS inhibitors in R1 and R2 populations.  The results demonstrated that R2 had a Pro-197-Ser mutation in the AHAS gene, and the sensitivity of R2 to the five AHAS inhibitors was decreased, which may result in R2 resistance to AHAS inhibitors.  There was no mutation in the AHAS gene of R1, and there were no significant differences in enzyme sensitivity between susceptible (S) and resistant (R1) populations.  An enhanced metabolism may be the main mechanism of R1 resistance to AHAS inhibitors.
    Morphological and molecular characterization of the rice root-knot nematode, Meloidogyne graminicola, Golden and Birchfeild, 1965 occurring in Zhejiang, China
    TIAN Zhong-ling, Munawar Maria, Eda Marie Barsalote, Pablo Castillo, ZHENG Jing-wu
    2018, 17(12): 2724-2733.  DOI: 10.1016/S2095-3119(18)61971-9
    Abstract ( )   PDF in ScienceDirect  
    The rice root-knot nematode Meloidogyne graminicola is a severe pest of rice.  In China, it was first reported from Hainan Province, and later from several other provinces.  In the present study, a rice root-knot nematode population found from the rice cultivation areas of Zhejiang Province, China is characterized via molecular analysis using internal transcribed spacer (ITS) and cytochrome c oxidase subunit II (coxII)-16S rRNA genes and scanning electron microscopy (SEM) observations of males and the second-stage juveniles.  Morphometric data and molecular sequence comparisons for all M. graminicola populations occurring in China are also provided.  The overall morphology of M. graminicola found in Zhejiang match well with the original description, though males have a slightly longer body and stylet, and a shorter tail, while the second-stage juvenile is also slightly longer than in the original description.  This is the first report of M. graminicola from Zhejiang.  Phylogenetic studies based on coxII suggest that all the Chinese populations belong to Type B.  This study expands knowledge of the increasing distribution and phylogenetic relationships of M. graminicola that occur in China. 
    Chemical mutagenesis and soybean mutants potential for identification of novel genes conferring resistance to soybean cyst nematode
    GE Feng-yong, ZHENG Na, ZHANG Liu-ping, HUANG Wen-kun, PENG De-liang, LIU Shi-ming
    2018, 17(12): 2734-2744.  DOI: 10.1016/S2095-3119(18)62105-7
    Abstract ( )   PDF (5218KB) ( )  
    The resistance of soybean (Glycine max (L.) Merr.) to soybean cyst nematode (SCN, Heterodera glycines Ichinohe), which is a devastating pathogen in soybean production and causes a large quantity of annual yield loss worldwide, can shift during the long-term interaction and domestication.  It is vital to identify more new resistance genetic sources for identification of novel genes underlying resistance to SCN for management of this pathogen.  In the present study, first, two ethane methylsulfonate-mutagenesis soybean M2 populations of PI 437654, which shows a broad resistance to almost all of SCN races, and Zhonghuang 13, which is a soybean cultivar in China conferring strong resistance to lodging, were developed.  Many types of morphological phenotypes such as four- and five-leaflet leaves were observed from these two soybean M2 populations.  Second, 13 mutants were identified and confirmed to exhibit alteration of resistance to SCN race 4 through the forward genetic screening of 400 mutants of the PI 437654 M2 population, the rate of mutants with alteration of SCN-infection phenotype is 3.25%.  Third, these identified mutants were further verified not to show any changes in the genomic sequences of the three known SCN-resistant genes, GmSHMT08, GmSNAP18 and GmSANP11, compared to the wild-type soybean; and all of them were still resistant to SCN race 3 similar to the wild-type soybean.  Taken together, we can conclude that the 13 mutants identified in the present study carry the mutations of the new gene(s) which contribute(s) to the resistance to SCN race 4 in PI 437654 and can be potentially used as the genetic soybean sources to further identify the novel SCN-resistant gene(s).   
    Assessment of suitable reference genes for qRT-PCR analysis in Adelphocoris suturalis
    LUO Jing, MA Chao, LI Zhe, ZHU Bang-qin, ZHANG Jiang, LEI Chao-liang, JIN Shuang-xia, J. Joe Hull, CHEN Li-zhen
    2018, 17(12): 2745-2757.  DOI: 10.1016/S2095-3119(18)61926-4
    Abstract ( )   PDF (1312KB) ( )  
    Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is the most commonly-used tool for measurement of gene expression, but its accuracy and reliability depend on appropriate data normalization with the use of one or more stable reference genes.  Adelphocoris suturalis is one of the most destructive pests of cotton, but until recently knowledge of its underlying molecular physiology had been hindered by a lack of molecular resources.  To facilitate research on this pest, we evaluated 12 common housekeeping genes studied in insects (GAPDH, ACT, βACT, TBP, SDH, βTUB, EF1γ, EF1α, EF1δ, RPL32, RPS15, and RPL27) for their expression stability in A. suturalis when subjected to various experimental treatments, including three biotic (developmental stage and sex, tissue type, and metathoracic scent gland for varying developmental stages and sexes) and one abiotic (RNA interference injection) conditions.  Four dedicated algorithms (ΔCt method, geNorm, BestKeeper and NormFinder) were used to analyze gene expression stability.  In addition, RefFinder provided an overall ranking of the stability/suitability of these candidates.  This study is the first to provide a comprehensive list of suitable reference genes for gene expression analyses in A. suturalis, which can serve to facilitate transcript expression study of related biological processes in this and related species.
    Design and selection of an artificial diet for the coconut black-headed caterpillar, Opisina arenosella, based on orthogonal array analysis
    JIN Tao, LIN Yu-ying, JIN Qi-an, WEN Hai-bo, PENG Zheng-qiang
    2018, 17(12): 2758-2757.  DOI: 10.1016/S2095-3119(17)61889-6
    Abstract ( )   PDF (412KB) ( )  
    Opisina arenosella has been an outbreak pest of coconut trees in southern China since 2013.  To develop efficient control methods for this invasive pest, adequate rearing protocols are desirable.  In this study, an orthogonal array of artificial diets with 11 factors at 3 levels was deployed for both 2nd–4th and 5th–6th instar larvae of O. arenosella.  Biological parameters including survival time of larvae, development time from larva to pupa, pupation rate, emergence rate, and pupal weight were monitored to reveal the most important components in the diet formulas.  Biological parameters in O. arenosella were most affected by brewer’s yeast, sucrose, ascorbic acid, and wheat germ.  Statistical analysis indicated that different diet combinations supported optimum performance of biological parameters for 2nd–4th and 5th–6th instar larvae.  The validity of the optimization predicted by the orthogonal array analysis was confirmed in a follow-up bioassay with similar optimized diets for both 2nd–4th and 5th–6th instar larvae.  The optimal artificial diet has great potential for the mass rearing technique, and can provide valuable results for using parasitoids in biological control of O. arenosella.
    Animal Science · Veterinary Medicine
    Influence of lactic acid bacteria, cellulase, cellulase-producing Bacillus pumilus and their combinations on alfalfa silage quality
    LI Dong-xia, NI Kui-kui, ZHANG Ying-chao, LIN Yan-li, YANG Fu-yu
    2018, 17(12): 2768-2782.  DOI: 10.1016/S2095-3119(18)62060-X
    Abstract ( )   PDF in ScienceDirect  
    This study assessed the effects of lactic acid bacteria (LAB), cellulase, cellulase-producing Bacillus pumilus and their combinations on the fermentation characteristics, chemical composition, bacterial community and in vitro digestibility of alfalfa silage.  A completely randomized design involving a 8 (silage additives)×3 or 2 (silage days) factorial arrangement of treatments was adopted in the present study.  The 8 silage additive treatments were: untreated alfalfa (control); two commercial additives (GFJ and Chikuso-1); an originally selected LAB (Lactobacillus plantarum a214) isolated from alfalfa silage; a cellulase-producing Bacillus (CB) isolated from fresh alfalfa; cellulase (C); and the combined additives (a214+C and a214+CB).  Silage fermentation characteristics, chemical composition and microorganism populations were analysed after 30, 60 and 65 days (60 days followed by exposure to air for five additional days).  In vitro digestibility was analysed for 30 and 60 days.  Compared with the other treatments, selected LAB a214, a214 combined with either C or CB, and Chikuso-1 had the decreased (P<0.001) pH and increased (P<0.001) lactic acid concentrations during the ensiling process, and there were no differences (P>0.05) among them.  Fiber degradation was not significant (P≥0.054) in any C or CB treatments.  The a214 treatment showed the highest (P=0.009) in vitro digestibility of dry matter (595.0 g kg–1 DM) after ensiling and the highest abundance of Lactobacillus (69.42 and 79.81%, respectively) on days 60 and 65, compared to all of other treatments.  Overall, the silage quality of alfalfa was improved with the addition of a214, which indicates its potential as an alfalfa silage inoculant.
    Pharmacokinetics of oral ethanamizuril solution in chickens
    CHENG Pei-pei, HU Xing-xing, WANG Chun-mei, LIU Ying-chun, WANG Mi, ZHANG Ke-yu, FEI Chenzhong, ZHANG Li-fang, WANG Xiao-yang, ZHENG Wen-li, XUE Fei-qun
    2018, 17(12): 2783-2789.  DOI: 10.1016/S2095-3119(18)62056-8
    Abstract ( )   PDF (895KB) ( )  
    Ethanamizuril (EZL) is a novel triazine anticoccidial compound that has high anticoccidial activity in chickens.  In order to treat coccidiosis rationally in poultry, a detection method was developed for ethanamizuril in broiler plasma, and then the pharmacokinetics studies were performed in broilers after oral administration of different dose levels.  Ethanamizuril was administered as single oral doses at low (0.67 mg kg–1 BW), medium (1.33 mg kg–1 BW) and high (6.67 mg kg–1 BW) levels in which the medium dose was that recommended in clinics.  Plasma concentrations of ethanamizuril were determined using ultra-high performance liquid chromatography and the data were analyzed with a non-compartmental model.  Peak plasma concentrations of ethanamizuril were (2.16±0.57), (3.91±0.71), and (23.71±5.02) mg L–1 at (5.17±1.80), (4.60±2.12), and (4.60±2.12) h, respectively.  The terminal elimination half-lives (t1/2λz) for ethanamizuril were (10.84±2.59), (10.66±2.47), and (13.34±3.10) h after oral administration at low, medium and high doses, respectively.  The areas under the concentration-time curve (AUC0–t) were (37.68±6.87), (73.19±9.18), and (485.76±125.10) mg L–1 h with mean residence times (MRT0–t) of (14.79±3.03), (15.57±3.69), and (20.22±4.01) h at the 3 dosages, respectively.  Ethanamizuril was absorbed rapidly and eliminated slowly.  A comparison across the dose range indicated that the time to reach peak plasma concentration (Tmax) values were similar while peak plasma concentration (Cmax) and AUC0–t were positively correlated with increasing dosages.  This study of the pharmacokinetics of an ethanamizuril solution in chickens provides a theoretical basis for the rational use in the clinic.
    Agricultural Economics and Management
    Suitability of the DNDC model to simulate yield production and nitrogen uptake for maize and soybean intercropping in the North China Plain
    ZHANG Yi-tao, LIU Jian, WANG Hong-yuan, LEI Qiu-liang, LIU Hong-bin, ZHAI Li-mei, REN Tian-zhi, ZHANG Ji-zong
    2018, 17(12): 2790-2801.  DOI: 10.1016/S2095-3119(18)61945-8
    Abstract ( )   PDF (577KB) ( )  
    Intercropping is an important agronomic practice.  However, assessment of intercropping systems using field experiments is often limited by time and cost.  In this study, the suitability of using the DeNitrification DeComposition (DNDC) model to simulate intercropping of maize (Zea mays L.) and soybean (Glycine max L.) and its aftereffect on the succeeding wheat (Triticum aestivum L.) crop was tested in the North China Plain.  First, the model was calibrated and corroborated to simulate crop yield and nitrogen (N) uptake based on a field experiment with a typical double cropping system.  With a wheat crop in winter, the experiment included five treatments in summer: maize monoculture, soybean monoculture, intercropping of maize and soybean with no N topdressing to maize (N0), intercropping of maize and soybean with 75 kg N ha–1 topdressing to maize (N75), and intercropping of maize and soybean with 180 kg N ha–1 topdressing to maize (N180).  All treatments had 45 kg N ha–1 as basal fertilizer.  After calibration and corroboration, DNDC was used to simulate long-term (1955 to 2012) treatment effects on yield.  Results showed that DNDC could stringently capture the yield and N uptake of the intercropping system under all N management scenarios, though it tended to underestimate wheat yield and N uptake under N0 and N75.  Long-term simulation results showed that N75 led to the highest maize and soybean yields per unit planting area among all treatments, increasing maize yield by 59% and soybean yield by 24%, resulting in a land utilization rate 42% higher than monoculture.  The results suggest a high potential to promote soybean production by intercropping soybean with maize in the North China Plain, which will help to meet the large national demand for soybean.
    Sunflower response to potassium fertilization and nutrient requirement estimation
    LI Shu-tian, DUAN Yu, GUO Tian-wen, ZHANG Ping-liang, HE Ping, Kaushik Majumdar
    2018, 17(12): 2802-2812.  DOI: 10.1016/S2095-3119(18)62074-X
    Abstract ( )   PDF (909KB) ( )  
    Field experiments were conducted in oil and edible sunflower to study the effects of potassium (K) fertilization on achene yield and quality, and to estimate the nutrient internal efficiency (IE) and nutrient requirement in sunflower production.  All trials in edible sunflower and 75% trials in oil sunflower showed positive yield responses to K fertilization.  Compared with control without K fertilization, the application of K increased achene yield by an average of 406 kg ha–1 for oil sunflower and 294 kg ha–1 for edible sunflower.  K application also increased 1 000-achene weight and kernel rate of both oil and edible sunflower.  K fertilization improved the contents of oil, oleic acid, linoleic acid and linolenic acid in achenes of oil sunflower, and increased contents of oil, total unsaturated fatty acid and protein in achenes of edible sunflower.  The average agronomic efficiency of K fertilizer was 4.0 for oil sunflower and 3.0 kg achene kg–1 K2O for edible sunflower.  The average IE of N, P and K under balanced NPK fertilization was 22.9, 82.8, and 9.9 kg kg–1 for oil sunflower, and 27.3, 138.9, and 14.3 kg kg–1 for edible sunflower.  These values were equivalent to 45.5, 14.1, and 108.1 kg, and 39.0, 8.0, and 71.7 kg of N, P and K, respectively, in above-ground dry matter required for production per ton of achenes.  The average harvest index of N, P and K was 0.47, 0.56 and 0.05 kg kg–1 in oil sunflower, and 0.58, 0.58 and 0.14 kg kg–1 in edible sunflower.   
    High potassium to magnesium ratio affected the growth and magnesium uptake of three tomato (Solanum lycopersicum L.) cultivars
    LI Hui-xia, CHEN Zhu-jun, ZHOU Ting, LIU Yan, ZHOU Jian-bin
    2018, 17(12): 2813-2821.  DOI: 10.1016/S2095-3119(18)61949-5
    Abstract ( )   PDF in ScienceDirect  
    Potassium (K) and magnesium (Mg) levels and their balances are two factors affecting the growth of plant.  However, the responses of different crop cultivars to K/Mg ratios are less clear.  This study was aimed at assessing the different responses of tomato (Solanum Lycopersicum L.) cultivars to the different K/Mg supply ratios.  Three tomato cultivars (Zhongza 9 (ZZ), Gailiangmaofen (MF), and Jinpengchaoguan (JP)) were grown in pots with three different K+/Mg2+ ratios (4:0, 4:1 and 8:1, represented by K/Mg4:0, K/Mg4:1, and K/Mg8:1, respectively).  Compared with K/Mg4:1 treatment, the leaf chlorophyll content, net photosynthetic rate, and total biomass of tomato seedlings under K/Mg4:0 treatments were decreased by 69.7, 89.1, and 53.1%, respectively.  The Mg deficiency symptoms were observed when the Mg content in shoot became lower than 4 mg g–1 DW.  Compared with K/Mg4:1 treatment, total biomass of tomato seedlings of K/Mg8:1 treatment was decreased by 21.6%; the shoot and root Mg contents were decreased by 10.4 and 21.8%, respectively; and Mg uptake of tomato was reduced by 34.1%.  There were significant differences in biomass and Mg uptake for the three cultivars between the different K+/Mg2+ treatments.  The Mg uptake of the three different cultivars ranked as ZZ>JP>MF under Mg deficiency and high K condition.  In conclusion, the growth and Mg uptake and allocation of tomato were influenced significantly by imbalance K and Mg supply. JP and ZZ were the cultivars with the highest efficiency in Mg uptake. 
    Agro-ecosystem & Environment
    A joint use of emergy evaluation, carbon footprint and economic analysis for sustainability assessment of grain system in China during 2000–2015
    WANG Xiao-long, WANG Wei, GUAN Yue-shan, XIAN Yuan-ran, HUANG Zhi-xin, FENG Hai-yi, CHEN Yong
    2018, 17(12): 2822-2835.  DOI: 10.1016/S2095-3119(18)61928-8
    Abstract ( )   PDF in ScienceDirect  
    The rapid growth of grain yield in China accelerates a discussion on whether the grain system in China is sustainable.  To answer the question, a comprehensive assessment from economic and environmental points is necessary.  This study jointly used economic analysis (ECA), emergy evaluation (EME) and carbon footprint (CF) to analyze the environmental and economic sustainability of the grain production system in China based on the national statistical data during 2000–2015.  Results showed that the costs of maize, wheat, rice and soybean had increased by 252−346% from 2000 to 2015, causing the lower profit of grain system in recent years.  The situation resulted in a serious problem on economic sustainability of grain system in China.  Meanwhile, the emergy sustainability index (ESI) of maize, wheat, rice and soybean systems were increasing during 2000–2015, and the CF on unit yield of the crops had been reduced by 10−30% in the study period.  The results reflected the improved environmental sustainability of grain system in China during 2000–2015.  Nevertheless, the emergy flow of industrial inputs for the crops were increased by 4−22% in the study period, and the CF from the inputs presented a growth rate of 16−23% as well during the same period.  The results implied that the grain system in China was relying more on fossil-based inputs.  Finally, according to the key points of cost, emergy and CF, we suggest that improving labor efficiency, advanced agricultural practices and optimizing cropping pattern will be effective ways to further improve the economic and environmental sustainability of grain system in China.  
    Short Communication
    Soil tillage methods by years interaction for dry matter of plant yield of maize (Zea mays L.) using additive main effects and multiplicative interaction model
    Jan Bocianowski, Piotr Szulc, Kamila Nowosad
    2018, 17(12): 2836-2839.  DOI: 10.1016/S2095-3119(18)62085-4
    Abstract ( )   PDF (873KB) ( )  
    The objective of this study was to assess soil tillage methods by years interaction for dry matter of plant yield of maize (Zea mays L.) grown in West Poland by the additive main effects and multiplicative interaction model.  The study comprised four soil tillage methods, analysed in 12 years through field trials arranged in a randomized complete block design, with four replicates.  Dry matter of plant yield of the tested soil tillage methods varied from 86.7 dt ha–1 (for no-plough tillage in 2005) to 246.4 dt ha–1 (for complete conventional tillage in 2012), with an average of 146.6 dt ha–1.  In the variance analysis, 49.07% of the total dry matter of plant yield variation was explained by years, 12.69% by differences between soil tillage methods, and 10.53% by soil tillage methods by years interaction.  Dry matter of plant yield is highly influenced by soil tillage methods by years factors.
    China launches the “IAS1000 Project”
    QIAN Wan-qiang, WAN Fang-hao
    2018, 17(12): 2840-2841.  DOI: 10.1016/S2095-3119(18)62144-6
    Abstract ( )   PDF in ScienceDirect  
    The rapid development of omics provides new technologies and methodologies for the study of invasion biology. Agricultural Genomics Institute at Shenzhen (CAAS-AGIS) and Institute of Plant Protection, Chinese Academy of Agricultural Sciences (CAAS-IPP) initiated the “IAS1000 project” (A genome project of 1000 invasive alien species) and established the “IAS1000 alliance” in Shenzhen on November 14, 2018. Via deep-mining of omics data, the project aims for better understanding the ecological processes and molecular mechanisms of biological invasion, and developing new technologies and products for prevention and management of invasive alien species. Up to now, there have been more than 40 research institutes, universities and enterprises participating in this project, forming an omics team with multi-disciplinary members.

    The main tasks of “IAS1000 project” include: (i) building a global collaboration platform for an in-depth research on molecular mechanisms of invasiveness; (ii) developing new technologies and products for prevention and control of invasive alien species, including RNA interference, gene editing, molecular pesticides with specific target carried by new physical/chemical materials, intelligent recognition of molecular odor, utilization of molecule-induced immunity, creation of new vaccines, and the restorer of soil ecological network; (iii) cultivating new elite talents in the integrated subjects encompassing omics, invasion biology, entomology and botany, etc.