2018 Vol. 17 No. 09 Previous Issue    Next Issue

    Crop Science
    Plant Protection
    Animal Science · Veterinary Medicine
    Agro-ecosystem & Environment
    Food Science

      Cover illustration

    For Selected: Toggle Thumbnails
    Agricultural remote sensing big data: Management and applications
    Yanbo Huang, CHEN Zhong-xin, YU Tao, HUANG Xiang-zhi, GU Xing-fa
    2018, 17(09): 1915-1931.  DOI: 10.1016/S2095-3119(17)61859-8
    Abstract ( )   PDF (13014KB) ( )  
    Big data with its vast volume and complexity is increasingly concerned, developed and used for all professions and trades. Remote sensing, as one of the sources for big data, is generating earth-observation data and analysis results daily from the platforms of satellites, manned/unmanned aircrafts, and ground-based structures. Agricultural remote sensing is one of the backbone technologies for precision agriculture, which considers within-field variability for site-specific management instead of uniform management as in traditional agriculture. The key of agricultural remote sensing is, with global positioning data and geographic information, to produce spatially-varied data for subsequent precision agricultural operations. Agricultural remote sensing data, as general remote sensing data, have all characteristics of big data. The acquisition, processing, storage, analysis and visualization of agricultural remote sensing big data are critical to the success of precision agriculture. This paper overviews available remote sensing data resources, recent development of technologies for remote sensing big data management, and remote sensing data processing and management for precision agriculture. A five-layer-fifteenlevel (FLFL) satellite remote sensing data management structure is described and adapted to create a more appropriate four-layer-twelve-level (FLTL) remote sensing data management structure for management and applications of agricultural remote sensing big data for precision agriculture where the sensors are typically on high-resolution satellites, manned aircrafts, unmanned aerial vehicles and ground-based structures. The FLTL structure is the management and application framework of agricultural remote sensing big data for precision agriculture and local farm studies, which outlooks the future coordination of remote sensing big data management and applications at local regional and farm scale.
    Crop Science
    A mitochondrial phosphate transporter, McPht gene, confers an acclimation regulation of the transgenic rice to phosphorus deficiency
    HAN Jiao, YU Guo-hong, WANG Li, LI Wei, HE Rui, WANG Bing, HUANG Sheng-cai, CHENG Xian-guo
    2018, 17(09): 1932-1945.  DOI: 10.1016/S2095-3119(17)61792-1
    Abstract ( )   PDF in ScienceDirect  
    Phosphate transporters play an important role in promoting the uptake and transport of phosphate in plants.  In this study, the McPht gene from the Mesembryanthemum crystallinum, a mitochondrial phosphate transporter, was isolated and constructed onto a constitutive expression vector carrying 35S::GFP, and the recombinant constructs were transferred into Oryza sativa japonica L. cv. Kitaake to investigate the regulatory role of the McPht gene under phosphorus deficiency.  The McPht gene encodes a protein of 357 amino acids with six transmembrane domains and is located to the mitochondria, and the mRNA transcripts of the McPht gene are highly accumulated in the shoots of M. crystallinum in response to phosphorus deficiency.  However, more mRNA transcripts of the McPht gene were accumulated in the roots of the transgenic rice under phosphorus deficiency.  Measurements showed that the transgenic rice demonstrated an enhanced promotion in the root development, the root activities, and phosphate uptake under phosphorus deficiency.  Transcriptome sequencing showed that the transgenic rice exhibited total of 198 differentially expressed genes.  Of these, total of 154 differentially expressed genes were up-regulated and total 44 genes were down-regulated comparing to the wild type in response to phosphorus deficiency.  The selective six genes of the up-regulated differentially expressed genes showed an enhanced increase in mRNA transcripts in response to phosphorus deficiency, however, the transcripts of the mitochondrial carrier protein transporter in rice, a homologous gene of the McPht,  in both the transgenic line and the wild type had no obvious differences.  Functional enrichment analyses revealed that the most of the up-regulated genes are involved in the cytoplasmic membrane-bounded vesicle, and most of the down-regulated genes are involved in the mitochondrion and cytoplasmic membrane-bounded vesicle.  The differentially expressed genes were highly enriched in plant secondary metabolisms and plant-pathogen interaction.  These results indicated that the overexpression of the McPht gene might participate in the physiological adaptive modulation of the transgenic rice to phosphorus deficiency by up- or down-regulating the differentially expressed genes.
    Transcriptomic responses to aluminum (Al) stress in maize
    XU Li-ming, LIU Chan, CUI Bao-ming, WANG Ning, ZHAO Zhuo, ZHOU Li-na, HUANG Kai-feng, DING Jian-zhou, DU Han-mei, JIANG Wei, ZHANG Su-zhi
    2018, 17(09): 1946-1958.  DOI: 10.1016/S2095-3119(17)61832-X
    Abstract ( )   PDF in ScienceDirect  
    Aluminum (Al) toxicity is a major factor limiting crop production and plant growth in acid soils.  The complex inheritance of Al toxicity and tolerance mechanisms in maize has uncharacterized yet.  In this study, the maize inbred line 178 seedlings were treated with 200 μmol L–1 CaCl2+0 μmol L–1 AlCl3 (control) and 200 μmol L–1 CaCl2+60 μmol L–1 AlCl3 (Al treatment) for 1 and 6 h, respectively.  The experiment was repeated three times.  Then a detailed temporal analysis of root gene expression was performed using an Agilent GeneChip with 34 715 genes, only the genes showing more than 2.0-fold difference (P<0.01) between the control and the Al treatment maize seedlings were analyzed further.  Thus, a total of 832 different expression genes, 689 significantly up-regulated and 143 down-regulated, were identified after the seedlings were treated with Al for 6 h.  And 60 genes, 59 up-regulated and one down-regulated, were also detected after the seedlings were treated for 1 h.  Replicated transcriptome analyses further showed that about 61% of total significantly genes could be annotated based on plant genome resources.  Quantitative real-time PCR (qRT-PCT) of some selected candidate genes was used to demonstrate the microarray data, indicating significant differences between the control and Al-treated seedlings.  Exposure to Al for 6 h triggered changes in the transcript levels for several genes, which were primarily related to cell wall structure and metabolism, oxidative stress response, membrane transporters, organic acid metabolism, signaling and hormones, and transcription factors, etc.  After Al-treated for 1 h, differential abundance of transcripts for several transporters, kinase, and transcription factors were specifically induced.  In this study, the diversity of the putative functions of these genes indicates that Al stress for a short stage induced a complex transcriptome changes in maize.  These results would further help us to understand rapid and early mechanisms of Al toxicity and tolerance in maize regulated at the transcriptional level.
    Overexpression of GmBIN2, a soybean glycogen synthase kinase 3 gene, enhances tolerance to salt and drought in transgenic Arabidopsis and soybean hairy roots
    WANG Ling-shuang, CHEN Qing-shan, XIN Da-wei, QI Zhao-ming, ZHANG Chao, LI Si-nan, JIN Yang-mei, LI Mo, MEI Hong-yao, SU An-yu, WU Xiao-xia
    2018, 17(09): 1959-1971.  DOI: 10.1016/S2095-3119(17)61863-X
    Abstract ( )   PDF in ScienceDirect  
    Glycogen synthase kinase 3 (GSK3) is a kind of serine/threonine kinase widely found in eukaryotes.  Many plant GSK3 kinases play important roles in regulating stress responses.  This study investigated BRASSINOSTEROID-INSENSITIVE 2 (GmBIN2) gene, a member of the GSK3 protein kinase family in soybean and an orthologue of Arabidopsis BIN2/AtSK21GmBIN2 expression was increased by salt and drought stresses, but was not significantly affected by the ABA treatment.  To examine the function of GmBIN2, transgenic Arabidopsis and transgenic soybean hairy roots were generated.  Overexpression of GmBIN2 in Arabidopsis resulted in increased germination rate and root length compared with wild-type plants under salt and mannitol treatments.  Overexpression of GmBIN2 increased cellular Ca2+ content and reduced Na+ content, enhancing salt tolerance in transgenic Arabidopsis plants.  In the soybean hairy root assay, overexpression of GmBIN2 in transgenic roots also showed significantly higher relative root growth rate than the control when subjected to salt and mannitol treatments.  Measurement of physiological indicators, including proline content, superoxide dismutase (SOD) activity, and relative electrical conductivity, supported this conclusion.  Furthermore, we also found that GmBIN2 could up-regulate the expression of some stress-related genes in transgenic Arabidopsis and soybean hairy roots.  Overall, these results indicated that GmBIN2 improved tolerance to salt and drought in transgenic Arabidopsis and soybean hairy roots.
    A simple way to visualize detailed phylogenetic tree of huge genomewide SNP data constructed by SNPhylo
    YANG Hai-long, DONG Le, WANG Hui, LIU Chang-lin, LIU Fang, XIE Chuan-xiao
    2018, 17(09): 1972-1978.  DOI: 10.1016/S2095-3119(18)62023-4
    Abstract ( )   PDF (10046KB) ( )  
    Phylogenetic trees based on genome-wide single nucleotide polymorphisms (SNPs) among diverse inbreds could provide valuable and intuitive information for breeding and germplasm management in crops.  As a result of sequencing technology developments, a huge amount of whole genome SNP data have become available and affordable for breeders.  However, it is a challenge to perform quick and reliable plotting based on the huge amount of SNP data.  To meet this goal, a visualization pipeline was developed and demonstrated based on publicly available SNP data from the current important maize inbred lines, including temperate, tropical, sweetcorn, and popcorn.  The detailed phylogenetic tree plotted by our pipeline revealed the authentic genetic diversity of these inbreds, which was consistent with several previous reports and indicated that this straightforward pipeline is reliable and could potentially speed up advances in crop breeding.
    Effects of zinc fertilizer and short-term high temperature stress on wheat grain production and wheat flour proteins
    TAO Zhi-qiang, WANG De-mei, CHANG Xu-hong, WANG Yan-jie, YANG Yu-shuang, ZHAO Guang-cai
    2018, 17(09): 1979-1990.  DOI: 10.1016/S2095-3119(18)61911-2
    Abstract ( )   PDF in ScienceDirect  
    Content of wheat flour proteins affects the quality of wheat flour.  Zinc nutrition in wheat can change the protein content of the flour.  The inconsistency and instability of wheat grain quality during grain filling while under high temperature stress (HTS) are major problems in the production of high quality wheat.  At present, there is a lack of studies on zinc fertilizer and HTS effects on wheat flour protein and the content of its components.  For this study, treatment combinations of four levels of zinc fertilizers and exposure to a short-term HTS, at 20 d after flowering (D20), were tested on two wheat cultivars with different gluten levels.  Individuals of a strong gluten wheat, Gaoyou 2018 (GY2018), and a medium gluten wheat, Zhongmai 8 (ZM8), were grown in pots at the Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing in 2015–2017.  We measured grain yield and weight and the activities of two enzymes (nitrate reductase and glutamine synthetase) from the flag leaves, collected at D10 and D20.  Total protein content, protein yield, and content of four protein components (albumin, gliadin, glutenin, and globulin) were measured from flour produced from the pot-grown plants.  HTS significantly increased the contents of total protein, albumin, gliadin, and glutenin in wheat grains, and reduced the grain yield, grain weight, protein yield, globulin content, and flag leaf nitrate reductase (NR) and glutamine synthetase (GS) activities.  The results showed that HTS and zinc fertilizer had greater impacts on the strong gluten cultivar compared to the medium gluten cultivar.  Under HTS, grain yield decreased by 13 and 8% in GY2018 and ZM8, respectively; protein yield decreased by 7 and 8% in GY2018 and ZM8, respectively.  Zinc fertilizer increased: grain and protein yields; grain weight; total protein, albumin, gliadin, and glutenin contents; protein yield; and NR and GS activities.  In contrast, zinc fertilizer reduced the content of globulin.  The addition of 15 mg Zn kg–1 soil had the strongest effect on grain yield and quality as compared to the other three treatments (additions of 0, 30, and 45 mg Zn kg–1 soil).  Zinc fertilizer also reduced the negative effects of HTS on protein yield, content, and components’ content.  Therefore, wheat grown with additional zinc in the soil can improve the quality of the flour.
    Dynamics of Bt cotton Cry1Ac protein content under an alternating high temperature regime and effects on nitrogen metabolism
    ZHANG Xiang, RUI Qiu-zhi, LIANG Pan-pan, WEI Chen-hua, DENG Guo-qiang, CHEN Yuan, CHEN Yuan, DONG Zhao-di, CHEN De-hua
    2018, 17(09): 1991-1998.  DOI: 10.1016/S2095-3119(17)61878-1
    Abstract ( )   PDF in ScienceDirect  
    This study was conducted to investigate the effects of alternating high temperature on Cry1Ac protein content on Bt cotton cultivars Sikang 1 (SK-1, a conventional cultivar) and Sikang 3 (SK-3, a hybrid cultivar). In 2011 and 2012, cotton plants were subjected to high temperature treatments ranging from 32 to 40°C in climate chambers to investigate the effects of high temperature on boll shell insecticidal protein expression. The experiments showed that significant decline of the boll shell insecticidal protein was detected at temperatures higher than 38°C after 24 h. Based on the results, the cotton plants were treated with the threshold temperature of 38°C from 6:00 a.m. to 6:00 p.m. followed by a normal temperature of 27°C during the remaining night hours (DH/NN) in 2012 and 2013. These treatments were conducted at peak boll growth stage for both cultivars in study periods of 0, 4, 7, and 10 d. Temperature treatment of 32°C from 6:00 a.m. to 6:00 p.m. and 27°C in the remaining hours was set as control. The results showed that, compared with the control, after the DH/NN stress treatment applied for 7 d, the boll shell Cry1Ac protein content level was significantly decreased by 19.1 and 17.5% for SK-1 and by 15.3 and 13.7% for SK-3 in 2012 and 2013, respectively. Further analysis of nitrogen metabolic physiology under DH/NN showed that the soluble protein content and the glutamic pyruvic transaminase (GPT) activities decreased slightly after 4 d, and then decreased sharply after 7 d. The free amino acid content and the protease content increased sharply after 7 d. The changes in SK-1 were greater than those in SK-3. These results suggest that under DH/NN stress, boll shell Cry1Ac protein content decline was delayed. Reduced protein synthesis and increased protein degradation in the boll shell decreased protein content, including Bt protein, which may reduce resistance to the cotton bollworm.
    Selection for high quality pepper seeds by machine vision and classifiers
    TU Ke-ling, LI Lin-juan, YANG Li-ming, WANG Jian-hua, SUN Qun
    2018, 17(09): 1999-2006.  DOI: 10.1016/S2095-3119(18)62031-3
    Abstract ( )   PDF in ScienceDirect  
    This research aimed to improve selection of pepper seeds for separating high-quality seeds from low-quality seeds. Past research has shown that seed vigor is significantly related to the seed color and size, thus several physical features were identified as candidate predictors of high seed quality. Image recognition software was used to automate recognition of seed feature quality using 400 kernels of pepper cultivar 101. In addition, binary logistic regression and a neural network were applied to determine models with high predictive value of seed germination. Single-kernel germination tests were conducted to validate the predictive value of the identified features. The best predictors of seed vigor were determined by the highest correlation observed between the physical features and the subsequent fresh weight of seedlings that germinated from the 400 seeds. Correlation analysis showed that fresh weight was significantly positively correlated with eight physical features: three color features (R, a*, brightness), width, length, projected area, and single-kernel density, and weight. In contrast, fresh weight significantly negatively correlated with the feature of hue. In analyses of two of the highest correlating single features, germination percentage increased from 59.3 to 71.8% when a*≥3, and selection rate peaked at 57.8%. Germination percentage increased from 59.3 to 79.4%, and the selection rate reached 76.8%, when single-kernel weight ≥0.0064 g. The most effective model was based on a multilayer perceptron (MLP) neural network, consisting of 15 physical traits as variables, and a stability calculated as 99.4%. Germination percentage in a calibration set of seeds was 79.1% and the selection rate was 90.0%. These results indicated that the model was effective in predicting seed germination based on physical features and could be used as a guide for quality control in seed selection. Automated systems based on machine vision and model classifiers can contribute to reducing the costs and labor required in the selection of pepper seeds.
    Isolation and characterization of the secondary wall-related SND1 gene in hawthorn
    CHEN Ke-qin, GUO Yun-na, SONG Meng-ru, DAI Hong-yan, ZHANG Zhi-hong
    2018, 17(09): 2007-2014.  DOI: 10.1016/S2095-3119(17)61791-X
    Abstract ( )   PDF in ScienceDirect  
    Secondary wall-associated NAC domain protein1 (SND1) is a key regulator directly regulating the expression levels of MYB46 and MYB83 in the regulation network for secondary wall synthesis, especially in plant fibres.  In this study,  a SND1 gene was isolated from hawthorn (Crataegus pinnatifida) and named as CpSND1 because it has a conservative N-terminal DNA-binding domain with AtSND1.  Arabidopsis plants overexpressing CpSND1 had similar phenotypes as plants overexpressing AtSND1, including inhibited growth, upward-curling leaves, sepal dysplasia and sterility.  In addition, overexpressing CpSND1 in Arabidopsis also induced the expression of downstream genes, including lignin, cellulose and xylan biosynthesis genes as well as MYB genes.  Our results provided functional information of CpSND1 for future genetic engineering in hawthorn.
    Effect of pre-culture on virus elimination from in vitro apple by thermotherapy coupled with shoot tip culture
    HU Guo-jun, DONG Ya-feng, ZHANG Zun-ping, FAN Xu-dong, REN Fang, LI Zheng-nan
    2018, 17(09): 2015-2023.  DOI: 10.1016/S2095-3119(18)61913-6
    Abstract ( )   PDF in ScienceDirect  

    We evaluated the role of pre-culture on survival rate of in vitro apple plants treated by thermotherapy.  Two apple cultivars, Malus×domestica cv. Pink Lady and Huafu, were used in the experiment and both have widely grown in China and infected with Apple chlorotic leaf spot virus (ACLSV) and Apple stem grooving virus (ASGV).  Results in growth and virus titer of apple plants did not exhibit clear trends during five different periods of pre-culture.  Whilst, pre-culture increased the survival rate of the two cultivars during thermotherapy.  The survival rate of plants pre-cultured for 13 d (P-13d) was 14 and 51% higher than that of P-1d plants for Pink Lady and Huafu, respectively.  Moreover, pre-culture positively influenced regeneration of Huafu plants.  The average survival rate of plants regenerated from P-1d and P-4d was 20% lower than that regenerated from P-7d, P-10d, and P-13d.  The efficiency of virus eradication was determined by reverse-transcription PCR with two primer pairs for each virus, and the detection results showed that pre-culture scarcely affected apple virus elimination.  Despite the fact that the two viruses were hardly detected at 5 d of thermotherapy, no virus-free plants were found in the two cultivars of regenerated apple plantlets after 30-d treatment. 
    Plant Protection
    Germination and appressorium formation of Pyricularia oryzae Cavara can be inhibited by reduced concentration of Blasin®Flowable with carbon dioxide microbubbles
    Tamaki Masahiko, Kobayashi Fumiyuki, Suehiro Keisuke, Ohsato Shuichi, Sato Michio
    2018, 17(09): 2024-2030.  DOI: 10.1016/S2095-3119(18)61962-8
    Abstract ( )   PDF in ScienceDirect  
    We investigated the possibility to reduce the usage of Blasin®Flowable (BF), a disinfectant inhibiting the germination and appressorium formation of Pyricularia oryzae Cavara conidia, by using carbon dioxide microbubbles (CO2MB).  Germination was significantly inhibited by 10 000-fold diluted BF solution containing CO2MB generated by the decompression-type generator compared to CO2 millibubbles (CO2MMB) and CO2MB generated by the gas-water circulating-type generator.  Appressorium formation in the 10 000-fold diluted BF solution containing both CO2MBs was less than that in CO2MMB.  Scanning electron microscopy showed wrinkles and dents on the surface of conidia treated with 5 000-fold diluted BF solution containing both CO2MBs.  Via transmission electron microscopy, we observed the expansion of the vacuole and the intracellular space and bloated or absent lipid granules in the conidia treated with BF solution containing both CO2MBs.  Our results show that inhibition of the conidium germination and appressorium formation of P. oryzae Cavara by 10 000-fold diluted BF solution could be achieved by using the decompression-type CO2MB.
    Strawberry vein banding virus P6 protein intracellular transport and an important domain identification
    PAN Yuan, ZHOU Xiu-hong, LI Shuai, FENG Ming-feng, SHI Man-ling, ZUO Deng-pan, JIANG Xi-zi, CHEN Jing, HU Ya-hui, ZHANG Xiang-xiang, JIANG Tong
    2018, 17(09): 2031-2041.  DOI: 10.1016/S2095-3119(18)61978-1
    Abstract ( )   PDF (13957KB) ( )  
    Strawberry vein banding virus (SVBV)-infected strawberry cells contain cytoplasmic inclusions with isometric particles.  To identify the components of the inclusions, green fluorescent protein (GFP) was fused to the carboxy-terminus (C-terminus) of SVBV open reading frames, these constructs were separately transformed into Agrobacterium tumefaciens and infiltrated into Nicotiana benthamiana leaves.  Results showed that the SVBV P6 protein assembled into prominent and amorphous inclusion bodies (IBs).  To investigate P6 subcellular localization, P6-GFP was ectopically expressed in N. benthamiana leaves by agroinfiltration and then stained with 4´,6-diamidino-2-phenylindole (DAPI).  We found the P6 protein accumulated in the nuclei and also formed cytoplasmic IBs with different sizes.  To further determine the location of P6 IBs in the cytoplasm, and explore whether the P6 IBs move freely or depend on cytoskeleton and endoplasmic reticulum (ER), the microfilament marker protein (GFP-ABD2-GFP), microtubules marker protein (mCherry-MAP65-1) and ER marker protein (mCherry-HDEL) were separately coexpressed with P6-GFP and into N. benthamiana leaves by agroinfiltration, exhibiting that P6 IBs aligned with cytoskeleton and endoplasmic reticulum.  Meanwhile, coinfiltration of P1 and P6 indicated the P6 colocalized with the P1 protein at periphery of cells.  The P6 protein contains one C-terminal nuclear localization signal (NLS) region, a P6 protein mutant with a deleted NLS did not localize in the nucleus, did not form IBs, and was unable to facilitate exogenous GFP expression.  These results demonstrate that the deleted NLS region is an important P6 domain required for biological functions.  In summary, the mobile P6 IBs are associated with ER, microfilaments and microtubules and move along microfilaments to the SVBV P1 protein in the PD. 
    Conidia of one Fusarium solani isolate from a soybean-production field enable to be virulent to soybean and make soybean seedlings wilted
    ZHENG Na, ZHANG Liu-ping, GE Feng-yong, HUANG Wen-kun, KONG Ling-an, PENG De-liang, LIU Shi-ming
    2018, 17(09): 2042-2053.  DOI: 10.1016/S2095-3119(17)61891-4
    Abstract ( )   PDF (22206KB) ( )  
    Fusarium is usually thought to cause soybean root rot, which results in a large quantity of annual yield loss in soybean production, by its secretions including Fusarium toxins and cell wall degrading enzymes, but not by the conidia themselves that do not underlie any virulence so far.  Here we report that the conidia of one Fusarium solani isolate are able to be virulent to soybean and make soybean seedlings wilted alone.  We isolated them from the wilted plants in a soybean-production field and molecularly identified 17 Fusarium isolates through phylogenetic analysis.  Of them, except for one isolate that showed diversity of virulence to different soybeans (virulent to one soybean whereas avirulent to another soybean), the others were all virulent to the two tested soybeans: both conidia cultures and secretions could make soybean seedlings wilted at 5 days post infection, and their virulence had dosage effects that only conidia cultures of at least 5×106 conidia mL–1 could show virulence to soybean; however, the sole conidia of the F. solani isolate #4 also exhibited virulence to soybean and could make soybean seedlings wilted.  Finally, we developed the specific cleaved amplified polymorphic sequences (CAPS) markers to easily differentiate Fusarium isolates.  The isolate #4 in this work will likely be used to investigate the new mechanism of virulence of Fusarium to soybean.     
    Selection and evaluation of potential reference genes for gene expression analysis in greenbug (Schizaphis graminum Rondani)
    ZHANG Bai-zhong, LIU Jun-jie, YUAN Guo-hui, CHEN Xi-ling, GAO Xi-wu
    2018, 17(09): 2054-2065.  DOI: 10.1016/S2095-3119(18)61903-3
    Abstract ( )   PDF in ScienceDirect  
    In order to precisely assess gene expression level, a suitable internal reference gene must be chosen to quantify real-time reverse transcription polymerase chain reaction (RT-qPCR) data.  For greenbug, Schizaphis graminum, a suitable reference gene for assessing the level of transcriptional expression of target genes has yet to be explored.  In our study, eight reference genes, elongation fator 1 beta (Ef1β), TATA box binding protein (TBP), alpha-tubulin (α-TUB), 18S ribosomal (18S), 28S ribosomal (28S), glyceraldehyde-3-phosphate (GAPDH), actin (ACT), and ribosomal protein L18 (RPL18) were evaluated in S. graminum at different developmental stages, tissues, and insecticide treatments.  To further explore whether these genes are suitable to serve as internal control, three software-based approaches (geNorm, BestKeeper, and NormFinder), ?Ct method, and one web-based comprehensive tool (RefFinder) were employed to analyze and rank the tested genes.  The optimal number of reference genes was determined using the geNorm program, and the suitability of particular reference genes was empirically validated according to normalized gene expression data of three target genes, heat shock protein gene (HSP70), cytocrome P450 gene (SgraCYP18A1), and glutathione S-transferase (GST).  We found that the most suitable reference genes varied considerably under different experimental conditions.  For developmental stages, α-TUB and 28S were the optimal reference genes; for different tissues, 18S and ACT were suitable reference genes; for insecticide treatments, 28S and α-TUB were suitable for normalizations of expression data.  In addition, 28S and α-TUB were the suitable reference gene as they had the most stable expression among different developmental stages, tissues and insecticide treatments.  This should be useful for the selection of the suitable reference genes to obtain reliable RT-qPCR data in the gene expression of S. graminum.
    The biotypes and host shifts of cotton-melon aphids Aphis gossypii in northern China
    ZHANG Shuai, LUO Jun-yu, WANG Li, WANG Chun-yi, Lü Li-min, ZHANG Li-juan, ZHU Xiang-zhen, CUI Jin-jie
    2018, 17(09): 2066-2073.  DOI: 10.1016/S2095-3119(17)61817-3
    Abstract ( )   PDF in ScienceDirect  
    Aphis gossypii is a globally distributed species and therefore has a highly variable life cycle.  Populations of A. gossypii in northern China exhibit greater genotypic diversity and a broader host range, yet the details of life cycles of different biotypes is still unclear.  In this study, the Cytb and 16S gene regions of A. gossypii collected from 5 common summer hosts and 4 primary hosts were analyzed.  A total of 57 haplotypes were obtained from 1 046 individual A. gossypii sequences.  The sequence included 44 variable sites, 27 of which were parsimony informative sites and 17 of which were singleton variable sites.  The most frequent 3 haplotypes were found in 896 individuals, representing a total of 85.7% of all individuals and 36 haplotypes were found in 1 individual.  A neighbor-joining tree was constructed using 21 haplotypes that were found in more than 2 individuals.  Considering the individual host plant, 5 biotypes were identified.  Type 1 corresponded exactly to the cucurbit host-race and the other 4 biotypes were found as cotton host-races.  Type 3 was the most abundant biotype in cotton fields in northern China.
    Animal Science · Veterinary Medicine
    Synonymous codon usage pattern in model legume Medicago truncatula
    SONG Hui, LIU Jing, CHEN Tao, NAN Zhi-biao
    2018, 17(09): 2074-2081.  DOI: 10.1016/S2095-3119(18)61961-6
    Abstract ( )   PDF in ScienceDirect  
    Synonymous codon usage pattern presumably reflects gene expression optimization as a result of molecular evolution.  Though much attention has been paid to various model organisms ranging from prokaryotes to eukaryotes, codon usage has yet been extensively investigated for model legume Medicago truncatula.  In present study, 39 531 available coding sequences (CDSs) from M. truncatula were examined for codon usage bias (CUB).  Based on analyses including neutrality plots, effective number of codons plots, and correlations between optimal codons frequency and codon adaptation index, we conclude that natural selection is a major driving force in M. truncatula CUB.  We have identified 30 optimal codons encoding 18 amino acids based on relative synonymous codon usage.  These optimal codons characteristically end with A or T, except for AGG and TTG encoding arginine and leucine respectively.  Optimal codon usage is positively correlated with the GC content at three nucleotide positions of codons and the GC content of CDSs.  The abundance of expressed sequence tag is a proxy for gene expression intensity in the legume, but has no relatedness with either CDS length or GC content.  Collectively, we unravel the synonymous codon usage pattern in M. truncatula, which may serve as the valuable information on genetic engineering of the model legume and forage crop.
    Comparison of forage yield, silage fermentative quality, anthocyanin stability, antioxidant activity, and in vitro rumen fermentation of anthocyanin-rich purple corn (Zea mays L.) stover and sticky corn stover
    TIAN Xing-zhou, Pramote Paengkoum, Siwaporn Paengkoum, Sorasak Thongpea, BAN Chao
    2018, 17(09): 2082-2095.  DOI: 10.1016/S2095-3119(18)61970-7
    Abstract ( )   PDF in ScienceDirect  
    The objective of this study was to observe the forage yield, silage fermentative quality, anthocyanin stability, and antioxidant activity during the storage period and in vitro rumen fermentation of anthocyanin-rich purple corn (Zea mays L.) stover (PS) and sticky corn stover (SS).  Forage yield of corn stover was weighed and ensiled with two treatments: (1) hybrid sticky waxy corn stover (control), and (2) hybrid purple waxy corn stover (treatment).  Samples were stored in mini-silos for periods of 0, 7, 14, 21, 42, 63, 84, and 105 d.  The results showed that PS had significantly higher (P<0.05) yields of dry matter (DM), organic matter (OM), gross energy (GE), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and total anthocyanins than that of the SS.  Anthocyanin-rich purple corn stover silage (PSS) showed higher (P<0.05) levels of DM and CP relative to the sticky corn stover silage (SSS).  Although anthocyanin-rich PSS displayed a lower (P<0.05) level of pelargonidin-3-glucoside (P3G), it had higher (P<0.05) levels of peonidin (Peo) and pelargonidin (Pel) compared to the control.  Delphinidin (Del) and malvidin (Mal) were not detected in SSS during the ensilage period; in PSS, Del was no longer detected after 7 d of ensilage.  Specifically, total anthocyanins in anthocyanin-rich PSS decreased rapidly (P<0.05) prior to 7 d of ensilage, and then remained at relatively stable (P>0.05) constants.  Compared to the anthocyanin-rich PSS, SSS displayed significantly higher P<0.05) pH value and ammonia nitrogen (NH3-N) content.  Propionic acid (PA) at 0 d and butyric acid (BA) during the entire study period were not detected, whereas anthocyanin-rich PSS showed a higher (P<0.05) level of lactic acid (LA) than that of the SSS.  Compared with the SSS extract, anthocyanin-rich PSS extract showed a higher (P<0.05) level of 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and displayed a lower (P<0.05) half maximal inhibitory concentration (IC50) value.  Moreover, anthocyanin-rich PSS reduced (P<0.05) gas production (GP), and displayed lower levels of immediately soluble fraction and ratio of acetic acid (AA) to PA at 12 h, but the other parameters were unaffected (P>0.05) relative to the control.  Taken together, the results indicated that: (1) anthocyanins could be stable in silage; (2) anthocyanin-rich PSS showed better silage fermentative quality and stronger antioxidant activity; and (3) anthocyanin-rich PSS had no negative effect on rumen fermentation parameters.
    Agro-ecosystem & Environment
    Design of a spatial sampling scheme considering the spatial autocorrelation of crop acreage included in the sampling units
    WANG Di, ZHOU Qing-bo, YANG Peng, CHEN Zhong-xin
    2018, 17(09): 2096-2106.  DOI: 10.1016/S2095-3119(17)61882-3
    Abstract ( )   PDF in ScienceDirect  
    Information on crop acreage is important for formulating national food polices and economic planning.  Spatial sampling, a combination of traditional sampling methods and remote sensing and geographic information system (GIS) technology, provides an efficient way to estimate crop acreage at the regional scale.  Traditional sampling methods require that the sampling units should be independent of each other, but in practice there is often spatial autocorrelation among crop acreage contained in the sampling units.  In this study, using Dehui County in Jilin Province, China, as the study area, we used a thematic crop map derived from Systeme Probatoire d’Observation de la Terre (SPOT-5) imagery, cultivated land plots and digital elevation model data to explore the spatial autocorrelation characteristics among maize and rice acreage included in sampling units of different sizes, and analyzed the effects of different stratification criteria on the level of spatial autocorrelation of the two crop acreages within the sampling units.  Moran’s I, a global spatial autocorrelation index, was used to evaluate the spatial autocorrelation among the two crop acreages in this study.  The results showed that although the spatial autocorrelation level among maize and rice acreages within the sampling units generally decreased with increasing sampling unit size, there was still a significant spatial autocorrelation among the two crop acreages included in the sampling units (Moran’s I varied from 0.49 to 0.89), irrespective of the sampling unit size.  When the sampling unit size was less than 3 000 m, the stratification design that used crop planting intensity (CPI) as the stratification criterion, with a stratum number of 5 and a stratum interval of 20% decreased the spatial autocorrelation level to almost zero for the maize and rice area included in sampling units within each stratum.  Therefore, the traditional sampling methods can be used to estimate the two crop acreages.  Compared with CPI, there was still a strong spatial correlation among the two crop acreages included in the sampling units belonging to each stratum when cultivated land fragmentation and ground slope were used as stratification criterion.  As far as the selection of stratification criteria and sampling unit size is concerned, this study provides a basis for formulating a reasonable spatial sampling scheme to estimate crop acreage.
    Spatial-temporal evolution of vegetation evapotranspiration in Hebei Province, China
    WANG Qian-feng, TANG Jia, ZENG Jing-yu, QU Yan-ping, ZHANG Qing, SHUI Wei, WANG Wu-lin, YI Lin, LENG Song
    2018, 17(09): 2107-2117.  DOI: 10.1016/S2095-3119(17)61900-2
    Abstract ( )   PDF in ScienceDirect  
    Evapotranspiration (ET) is the sum of soil or water body evaporation and plant transpiration from the earth surface and ocean to the atmosphere, and thus plays a significant role in regulating carbon and water resource cycles.  The time-series data set from the remote sensing MOIDS product (MOD16) was used to study the spatial-temporal evolution of vegetation evapotranspiration in salinized areas during 2000–2014 by analyzing the variability, spatial patterns and Mann-Kendall (MK) nonparametric trends for the time series.  The results indicate that inter-annual and intra-annual variations of ET across various vegetated areas show seasonal changes, with the abnormal months identified.  The cultivated land displays a greater degree of spatial heterogeneity and the spatial pattern of ET in the area covered by broadleaved deciduous forests corresponds to a higher ET rate and increased water consumption.  A widespread decline of ET is observed only in cultivated areas.  However, agricultural cultivation doesn’t worsen water shortage and soil salinization problems in the region, and water shortage problems are worsening for other vegetated areas.  This research provides a basis of reference for the reasonable allocation of water resources and restructuring of vegetation patterns in salinized areas.
    Food Science
    Implications of step-chilling on meat color investigated using proteome analysis of the sarcoplasmic protein fraction of beef longissimus lumborum muscle
    ZHANG Yi-min, ZHANG Xiu-ze, WANG Tian-tian, David L. Hopkins, MAO Yan-wei, LIANG Rong-rong, YANG Guang-fu, LUO Xin, ZHU Li-xian
    2018, 17(09): 2118-2125.  DOI: 10.1016/S2095-3119(18)62028-3
    Abstract ( )   PDF (5571KB) ( )  
    In order to improve beef color and color stability, step-chilling (SC) was applied on excised bovine longissimus lumborum muscle, with chilling starting at 0–4°C for 5 h, then holding the temperature at 12–18°C for 6 h, followed by 0–4°C again until 24 h post-mortem.  pH and temperature were measured during rigor on SC loins as well as those subjected to routine chilling (RC, 0–4°C, till 24 h post-mortem).  Color L*, a*, b* values, metmyoglobin (MetMb) content, MetMb reducing ability (MRA) and NADH content were determined on samples aged for 1, 7, and 14 d.  Sarcoplasmic proteome analysis was only conducted on d 1 samples.  The results showed muscles subjected to SC maintained a temperature at around 15°C for 5 to 10 h post-mortem, and exhibited a slow temperature decline, but rapid pH decline.  Beef steaks treated with SC had higher L*, a*, b* and chroma values than those of RC samples at 1 and 7 d chilled storage (0–4°C), while showing no significant difference for a*, b* and chroma values at d 14.  The SC samples also exhibited a lower relative content of surface MetMb, higher MRA and NADH content, compared with RC beef steaks during storage, indicating the SC-treated beef showed an improved color stability.  Eleven differential protein spots/nine proteins were identified by two-dimensional gel electrophoresis and mass spectrometry, and those proteins were mainly involved in redox, chaperone binding, metabolic and peroxidase activity.  Oxidoreductases play a role in decreasing the oxidation-induced myoglobin oxidation and benefiting the production of NADH, and finally improving the colour of beef.  Of these, pyruvate dehydrogenase E1 component subunit beta showed a positive correlation with color L*, a*, b* values and accounted for more than 60% of the variation in color values; this protein can be considered as a potential beef color biomarker.  The present study provided valuable information for studies on the molecular mechanism of color improvement from step-chilling, as well as for identifying markers associated with beef color.
    Identification and characterization of Pichia membranifaciens Hmp-1 isolated from spoilage blackberry wine
    WANG Ying, ZHAO Yan-cun, FAN Lin-lin, XIA Xiu-dong, LI Ya-hui, ZHOU Jian-zhong
    2018, 17(09): 2126-2136.  DOI: 10.1016/S2095-3119(18)62027-1
    Abstract ( )   PDF in ScienceDirect  
    The pellicle-forming yeast could cause the quality deterioration of wine.  In this study, a pellicle-forming strain Hmp-1 was isolated from the spoilage blackberry wine, and identified as Pichia membranifaciens based on the morphology and partial nucleotide sequence of 26S rDNA.  The effects of fermentation conditions (ethanol, sulfur dioxide, sugar, and temperature) on the growth of P. membranifaciens strain Hmp-1 and Saccharomyces cerevisiae strain FM-S-115 (a strain used for the blackberry wine fermentation) were investigated, respectively.  The results indicated that Hmp-1 had lower resistance to these factors compared to FM-S-115, and the growth of Hmp-1 was completely inhibited by 10% (v/v) or 50 mg L–1 SO2 during the fermentation of blackberry wine.  These results suggested that Hmp-1 could effectively be controlled by increasing ethanol or SO2 concentration during the fermentation and storage of blackberry wine.  Furthermore, the analysis based on gas chromatography-mass spectrometry (GC-MS) showed that Hmp-1 remarkably decreased kinds of volatile compounds in blackberry wine, especially aldehydes and esters.  In addition, some poisonous compounds were detected in the blackberry wine fermented by FM-S-115 and Hmp-1.  These results suggested that Hmp-1 was a major cause leading to the quality deterioration of blackberry wine.