2022 Vol. 21 No. 2 Previous Issue    Next Issue

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

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    Recent advances in immunocastration in sheep and goat and its animal welfare benefits: A review
    ZENG Fan-mei, DING Yi, Teketay WASSIE, JING Hai-jing, Sohail AHMED, LIU Gui-qiong, JIANG Xun-ping
    2022, 21(2): 299-309.  DOI: 10.1016/S2095-3119(21)63670-5
    Abstract ( )   PDF in ScienceDirect  
    Castration of male animals is a common practice in the meat industry aimed at reducing aggressive behavior, preventing unpleasant flavor, and controlling undesirable breeding.  For many years, mechanical castration and surgical castration have been practiced to sterilize the animals.  However, these castration methods are not humane because of the associated risk of death, pain, and stress.  Recently, immunocastration targeting the hypothalamic-pituitary-gonadal axis (HPG) axis has been reported as an animal-friendly approach that circumvents many of the concerns with conventional castration, and suggested by researches as an alternative to surgical castration.  However, there is no compilation of updated information on the use of immunocastration in sheep and goats.  Therefore, this review aims to summarize the developmental process from traditional surgical castration to immunocastration and to screen the process of immune targets.  It also compares the respective advantages and disadvantages of traditional castration technologies and immunocastration, in particular including analyses in the characteristics, features application and welfare benefits of immunocastration in sheep and goats were also analyzed.
    Factors affecting hydraulic conductivity and methods to measure in plants
    GENG Da-li, LI Lei, YANG Yu-sen, MA Feng-wang, GUAN Qing-mei
    2022, 21(2): 310-315.  DOI: 10.1016/S2095-3119(20)63396-2
    Abstract ( )   PDF in ScienceDirect  
    The plant hydraulic network faces several challenges under drought stress.  Hydraulic conductivity is one of the major indicators of the hydraulic network’s response to drought stress.  Here, we review our current understanding of the factors directly affecting hydraulic conductivity and the methods used to measure it.   
    Crop Science
    Characterization and fine mapping of RTMS10, a semi-dominant reverse thermo-sensitive genic male sterile locus in rice
    NI Jin-long, WANG De-zheng, NI Da-hu, SONG Feng-shun, YANG Jian-bo, YAO Da-nian
    2022, 21(2): 316-325.  DOI: 10.1016/S2095-3119(20)63563-8
    Abstract ( )   PDF in ScienceDirect  
    The discovery and application of environment-sensitive genic male sterile (EGMS) rice germplasm provide an easy method for hybrid rice breeding and have made great contributions to hybrid rice production.  Typically, the photoperiod- and thermo-sensitive GMS (P/TGMS) lines utilized in two-line hybrid systems are male sterile under long day or/and high temperature but fertile under short day or/and low temperature conditions.  However, YannongS (YnS), a reverse TGMS (rTGMS) line, is sterile under low temperature (<29°C) and fertile under high temperature (>29.5°C).  Here, we report a genetic study on the rTGMS trait in YnS.  Interestingly, the F1 plants of the cross between YnS and a cultivar, L422, were male sterile at 22°C and completely fertile at 27°C.  Moreover, the segregation ratio of fertile and sterile individuals in YnS/L422 F2 populations changed from 1:3.05 to 2.95:1 when the ambient temperature increased, showing that the rTGMS trait exhibits semi-dominance in YnS.  We further found a locus on chromosome 10, termed RTMS10, which controls the rTGMS trait in YnS.  We then finely mapped RTMS10 to a ~68 kb interval between markers ID13116 and ID1318 by YnS/L422 BC6F2 populations.  A near iso-genic line (NIL) NL1 from the BC6F3 generation was developed and the pollen of NL1 became abnormal from the meiosis stage under low temperature.  In summary, we identified an rTGMS locus, RTMS10, and provided co-segregated markers, which could help to accelerate molecular breeding of rTGMS lines and better understand the rTGMS trait in rice.

    Co-silencing E1 and its homologs in an extremely late-maturing soybean cultivar confers super-early maturity and adaptation to high-latitude short-season regions
    LIU Li-feng, GAO Le, ZHANG Li-xin, CAI Yu-peng, SONG Wen-wen, CHEN Li, YUAN Shan, WU Ting-ting, JIANG Bing-jun, SUN Shi, WU Cun-xiang, HOU Wen-sheng, HAN Tian-fu
    2022, 21(2): 326-335.  DOI: 10.1016/S2095-3119(20)63391-3
    Abstract ( )   PDF in ScienceDirect  
    Soybean (Glycine max (L.) Merr.), a typical short-day plant, is sensitive to photoperiod, which limits the geographical range for its cultivation.  In the flowering pathway regulated by photoperiod, E1, a flowering inhibitor in soybean, plays the dominant role in flowering time regulation.  Two E1 homologs, E1-like-a (E1La) and E1-like-b (E1Lb), play overlapping or redundant roles in conjunction with E1.  In the present study, E1 and E1La/b were simultaneously silenced via RNA interference (RNAi) in Zigongdongdou (ZGDD), an extremely late-flowering soybean landrace from southern China.  As a result, RNAi lines showed a much earlier-flowering phenotype and obvious photoperiod insensitivity compared with wild-type (WT) plants.  In RNAi transgenic plants, the expression levels of flowering inhibitor GmFT4 and flowering promoters GmFT2a/GmFT5a were significantly down- and up-regulated, respectively.  Further, the maturity group (MG) of the RNAi lines was reduced from WT ZGDD’s MG VIII (extremely late-maturity) to MG 000 (super-early maturity), which can even grow in the northernmost village of China located at a latitude of 53.5°N.  Our study confirms that E1 and E1La/b can negatively regulate flowering time in soybean.  The RNAi lines generated in this study, with early flowering and maturity traits, can serve as valuable materials and a technical foundation for breeding soybeans that are adapted to high-latitude short-season regions.
    Field mold stress induced catabolism of storage reserves in soybean seed and the resulting deterioration of seed quality in the field
    DENG Jun-cai, LI Xiao-man, XIAO Xin-li, WU Hai-jun, YANG Cai-qiong, LONG Xi-yang, ZHANG Qi-hui, Nasir Iqbal, WANG Xiao-chun, YONG Tai-wen, DU Jun-bo, YANG Feng, LIU Wei-guo, ZHANG Jing, WU Xiao-ling, WU Yu-shan, YANG Wen-yu, LIU Jiang
    2022, 21(2): 336-350.  DOI: 10.1016/S2095-3119(20)63594-8
    Abstract ( )   PDF in ScienceDirect  
    Excessive rainfall provides a favorable condition for field mold infection of plants, which triggers field mold (FM) stress.  If FM stress occurs during the late maturation stage of soybean seed, it negatively affects seed yield and quality.  To investigate the responses of soybean seed against FM stress and identify the underlying biochemical pathways involved, a greenhouse was equipped with an artificial rain producing system to allow the induction of mold growth on soybean seed.  The induced quality changes and stress responses were revealed on the levels of both transcriptome and metabolome.  The results showed that soybean seeds produced under FM stress conditions had an abnormal and inferior appearance, and also contained less storage reserves, such as protein and polysaccharide.  Transcriptional analysis demonstrated that genes involved in amino acid metabolism, glycolysis, tricarboxylic acid, β-oxidation of fatty acids, and isoflavone biosynthesis were induced by FM stress.  These results were supported by a multiple metabolic analysis which exhibited increases in the concentrations of a variety of amino acids, sugars, organic acids, and isoflavones, as well as reductions of several fatty acids.  Reprogramming of these metabolic pathways mobilized and consumed stored protein, sugar and fatty acid reserves in the soybean seed in order to meet the energy and substrate demand on the defense system, but led to deterioration of seed quality.  In general, FM stress induced catabolism of storage reserves and diminished the quality of soybean seed in the field.  This study provides a more profound insight into seed deterioration caused by FM stress.
    Optimal management of nitrogen fertilizer in the main rice crop and its carrying-over effect on ratoon rice under mechanized cultivation in Southeast China
    HUANG Jin-wen, WU Jia-yi, CHEN Hong-fei, ZHANG Zhi-xing, FANG Chang-xun, SHAO Cai-hong, LIN Wei-wei, WENG Pei-ying, Muhammad Umar KHAN, LIN Wen-xiong
    2022, 21(2): 351-364.  DOI: 10.1016/S2095-3119(21)63668-7
    Abstract ( )   PDF in ScienceDirect  
    This study attempted to clarify the carrying-over effect of different nitrogen treatments applied to the main crop on the crop population growth and yield formation of ratoon rice under mechanized cultivation in Southeast China.  Based on the constant total nitrogen application amounts (225.00 kg ha–1) in the main crop, an experiment with different ratios of basal and topdressing nitrogen fertilizer (the ratio of basal fertilizer:primary tillering fertilizer:secondary tillering fertilizer:booting fertilizer at 3:1:2:4 (N1), 3:2:1:4 (N2), 3:3:0:4 (N3), and 4:3:0:3 (N4), respectively, and a control without nitrogen treatment (N0)) was set up across two consecutive years in field using hybrid rice variety Yongyou 1540 as the test materials.  The results showed that the total tiller number and effective tillering percentage increased in the main crop under the N1 treatment, more nitrogen fertilizer applied in late growth stage of the main crop, and its effective tillering percentage of the main crop was the highest at up to 70.18%, which was 9.15% higher than that of conventional fertilization treatment (N4), more nitrogen fertilizer applied in early growth stage of the main crop.  The same tendency was observed in leaf area index (LAI) value of the main crop and its subsequent ratoon rice, which were 16.52 and 29.87% higher, respectively, in the N1 treatment than that in the N4 treatment at the full heading stage.  The same was true in the case of the transport rates of stem and sheath dry mater and the canopy light interception rates in both the main and its ratoon crops.  The transport rate of stem and sheath in main crop rice under N1 treatment increased by 50.57% compared with N4 treatment.  The canopy light interception rate of N1 treatment increased by 5.07% compared with N4 treatment at the full heading stage of the ratoon crop.  Therefore, the total actual yield was the highest in the main and its ratoon crops under N1 treatment, averaging 17 351.23 kg ha–1 in two-year trials, which was 23.00% higher than that in the conventional fertilization treatment (N4).  The results showed that appropriate nitrogen treatment was able to produce a good crop stand in the main crop, which was essential for producing a good ratoon crop population and high yield especially under mechanized cultivation with low stubble height of the main crop.  The study suggested that shifting the proper nitrogen application amounts to the late growth stage of the main crop, such as N1 treatment, not only had a higher productive effect on ensuring the yield of the main crop, but also had a positive effect on the axillary bud sprouts from the stubbles for ratoon rice, resulting in an increased percentage of productive panicles and achieving the goal of one planting with two good harvests under the conditions of our study.

    Dynamics of maize grain drying in the high latitude region of Northeast China
    CHU Zhen-dong, MING Bo LI Lu-lu, XUE Jun, ZHANG Wan-xu, HOU Liang-yu, XIE Rui-zhi, HOU Peng, WANG Ke-ru, LI Shao-kun
    2022, 21(2): 365-374.  DOI: 10.1016/S2095-3119(20)63434-7
    Abstract ( )   PDF in ScienceDirect  
    A high grain moisture content at harvest has been an important problem in the high latitude region of Northeast China, and it is closely related to the genotypes of varieties, local meteorological factors and planting management.  However, delayed harvest at a low temperature could not effectively reduce the grain moisture content.  In this study, we continuously observed the grain drying during the late stage of different maturing types of maize varieties in Daqing, Heilongjiang Province, China in 2016 and 2017.  A two-segment linear model was used to analyze the different stages of the drying processes: 1) Two-segment linear model fitting can divide the grain drying process of all varieties into two separate linear drying processes with different slopes.  2) During the rapid drying stage, the drying was faster at a higher temperature.  The rate of slow drying was influenced by air vapor pressure.  3) The moisture content and meteorological factors when the drying rate turns from one stage into the other were not consistent between varieties and years.  After entering the frost period, temperatures below 0°C will significantly reduce the rate of grain drying.  4) Due to the short growth period of early-maturing varieties, the drying time was prolonged, and the grain moisture content was lower than that of the mid-late maturing varieties.  Local meteorological conditions do not allow the drying of mid-late maturing varieties to achieve a lower moisture content.  When the temperature falls below 0°C, the drying rate of grain decreases markedly.  Therefore, one feasible way to solve the problem of high moisture content is to replace the early-maturing varieties and implement the corresponding cultivation techniques.
    Differences in parameter estimates derived from various methods for the ORYZA (v3) Model
    TAN Jun-wei, DUAN Qing-yun, GONG Wei, DI Zhen-hua
    2022, 21(2): 375-388.  DOI: 10.1016/S2095-3119(20)63437-2
    Abstract ( )   PDF in ScienceDirect  
    Parameter estimation is always a difficult issue for crop model users, and inaccurate parameter values will result in deceptive model predictions.  Parameter values may vary with different inversion methods due to equifinality and differences in the estimating processes.  Therefore, it is of great importance to evaluate the factors which may influence parameter estimates and to make a comparison of the current widely-used methods.  In this study, three popular frequentist methods (SCE-UA, GA and PEST) and two Bayesian-based methods (GLUE and MCMC-AM) were applied to estimate nine cultivar parameters using the ORYZA (v3) Model.  The results showed that there were substantial differences between the parameter estimates derived by the different methods, and they had strong effects on model predictions.  The parameter estimates given by the frequentist methods were obviously sensitive to initial values, and the extent of the sensitivity varied with algorithms and objective functions.  Among the frequentist methods, the SCE-UA was recommended due to the balance between stable convergence and high efficiency.  All the parameter estimates remarkably improved the goodness of model-fit, and the parameter estimates derived from the Bayesian-based methods had relatively worse performance compared to the frequentist methods.  In particular, the parameter estimates with the highest probability density of posterior distributions derived from the MCMC-AM method (MCMC_Pmax) led to results equivalent to those derived from the frequentist methods, and even better in some situations.  Additionally, model accuracy was greatly influenced by the values of phenology parameters in validation.
    Genome-wide identification and expression analysis of GDSL esterase/lipase genes in tomato
    SUN Yao-guang, HE Yu-qing, WANG He-xuan, JIANG Jing-bin, YANG Huan-huan, XU Xiang-yang
    2022, 21(2): 389-406.  DOI: 10.1016/S2095-3119(20)63461-X
    Abstract ( )   PDF in ScienceDirect  
    The GDSL esterase/lipase family contains many functional genes that perform important biological functions in growth and development, morphogenesis, seed oil synthesis, and defense responses in plants.  The expression of GDSL esterase/lipase genes can respond to biotic and abiotic stresses.  Although GDSL esterase/lipase family genes have been identified and studied in other plants, they have not been identified and their functions remain unclear in tomato.  This study is the first to identify 80 GDSL esterase/lipase family genes in tomato, which were named SlGELP1–80.  These genes were mapped to their positions on the chromosomes and their physical and chemical properties, gene structure, phylogenetic relationships, collinear relationships, and cis-acting elements were analyzed.  The spatiotemporal expression characteristics of the SlGELP genes in tomato were diverse.  In addition, RNA-seq analysis indicated that the expression patterns of the SlGELP genes in tomato differed before and after inoculation with Stemphylium lycopersici.  qRT-PCR was used to analyze the expression of five SlGELP genes after treatments with S. lycopersici, salicylic acid and jasmonic acid.  Finally, this study was the first to identify and analyze GDSL esterase/lipase family genes in tomato via bioinformatics approaches, and these findings provide new insights for improving the study of plant disease resistance.
    Transcriptomic profiling of watermelon (Citrullus lanatus) provides insights into male flowers development
    ZHU Ying-chun, YUAN Gao-peng, JIA Sheng-feng, AN Guo-lin, LI Wei-hua, SUN De-xi, LIU Jun-pu
    2022, 21(2): 407-421.  DOI: 10.1016/S2095-3119(21)63615-8
    Abstract ( )   PDF in ScienceDirect  
    Watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) is an important cucurbit crop grown worldwide.  Watermelon fruit quality, fertility, and seed-setting rate are closely related to male flower development.  In this study, the different developmental stages of flower buds of the watermelon cultivar ‘Xinteda Zhengkang 9’ were distinguished by cytological observation, and transcriptome sequencing analysis was performed subsequently.  Acetocarmine staining of anthers was performed and the longitudinal and transverse diameters of the unopened male flower buds were measured.  Cytological observations of anthers at different developmental stages showed that the anther grew from the tetrad to the mature stage, and the longitudinal and transverse diameters of the flower buds increased.  The length of the male flower buds also changed significantly during development.  Transcriptome sequencing analysis at four periods, the tetrad (A group), mononuclear (B group), dikaryophase (C group), and mature stages (D group).  A total of 16 288 differentially expressed genes (DEGs) were detected in the four stages, with the prolongation of developmental stages, the number of DEGs increased gradually in the comparison groups, there was 2 014, 3 259, 4 628, 1 490, 3 495 and 1 132 DEGs revealed in six comparison groups (A-vs.-B, A-vs.-C, A-vs-D, B-vs.-C, B-vs.-D, and C-vs.-D), respectively.  Gene Ontology (GO) and KEGG enrichment analysis showed that the DEGs were mainly enriched in cellular component and starch and sucrose metabolism, phenylpropanoid biosynthesis and pentose sugar, etc.  Finally, we completely screened 59 DEGs in the six comparison groups, interestingly, we found one pollen-specific protein (Cla001608) that was significantly down-regulated (the value of log2Fold Change up to 17.32), which indicated that it may play an important role in the development of male flowers.  This work provides insight into the molecular basis of the developmental stages of male flowers in watermelon and may aid in dominant cross breeding.

    Response of carbohydrate metabolism-mediated sink strength to auxin in shoot tips of apple plants
    SU Jing, CUI Wei-fang, ZHU Ling-cheng, LI Bai-yun, MA Feng-wang, LI Ming-jun
    2022, 21(2): 422-433.  DOI: 10.1016/S2095-3119(20)63593-6
    Abstract ( )   PDF in ScienceDirect  
    Auxin (indole-3-acetic acid, IAA) has a considerable impact on the regulation of plant carbohydrate levels and growth, but the mechanism by which it regulates sugar levels in plants has received little attention.  In this study, we found that exogenous IAA altered fructose (Fru), glucose (Glc), and sucrose (Suc) concentrations in shoot tips mainly by regulating MdSUSY1, MdFRK2, MdHxK1 and MdSDH2 transcript levels.  Additionally, we used 5-year-old ‘Royal Gala’ apple trees to further verify that these genes play primary roles in regulating sink strength.  The results showed that MdSUSY1, MdFRK2, MdHxK1/3 and MdSDH2 might be major contributors to sink strength regulation.  Taken together, these results provide new insight into the regulation of the carbohydrate metabolism mechanism, which will be helpful for regulating sink strength and yield.
    Comprehensive evaluation of 20 pomegranate (Punica granatum L.) cultivars in China 
    CHEN Yan-hui, GAO Hui-fang, WANG Sa, LIU Xian-yan, HU Qing-xia, JIAN Zai-hai, WAN Ran, SONG Jin-hui, SHI Jiang-li
    2022, 21(2): 434-445.  DOI: 10.1016/S2095-3119(20)63389-5
    Abstract ( )   PDF in ScienceDirect  
    Recent investigations on pomegranate products have significantly increased and successfully drawn consumers’ attention to nutritional and medicinal values, promoting the pomegranate industry’s development worldwide.  However, little information on pomegranates grown in China is available.  Morphological and chemical characterizations of fruits and arils from 20 pomegranate cultivars in six regions of China were investigated.  Combined with overall scores by principal component analysis, ‘Yushiliu No. 1’, ‘Taishanhong No. 2’, ‘Tunisia’ and ‘Mollar’ were promising cultivars, and Chinese researchers bred the first two.  It was surprising that ‘Mollar’ had bigger fruit size and more aril moisture grown in China than in Spain.  Cultivars with higher anthocyanin content in arils were ‘Turkey’, ‘Moyu’ and ‘Red Angel’, which might be used as the source of natural red food colourants.  While red husk ‘Hongruyi’ and ‘Hongshuangxi’ with higher vitamin C, aril moisture and lower titratable acid in arils, might also be promising cultivars for further various utilization.  Furthermore, the comparison of ‘Tunisia’ fruits from four regions revealed that cultivation locations had more influence on fruit traits than genotypes.  Maturity index classification was established for Chinese pomegranate cultivars.  Therefore, the results would provide a valuable guide for agricultural cultivation, industrial utilization, and breeding. 
    Plant Protection
    Proteomic analysis of pathogen-responsive proteins from maize stem apoplast triggered by Fusarium verticillioides
    Hafiz ABDUL HASEEB, ZHANG Jun, GUO Yu-shuang, GAO Mei-xu, GUO Wei
    2022, 21(2): 446-459.  DOI: 10.1016/S2095-3119(21)63657-2
    Abstract ( )   PDF in ScienceDirect  
    During the attack of a pathogen, a variety of defense-associated proteins are released by the host plant in the apoplast to impede the perceived attack.  This study utilized the mass spectrometry (LC-MS/MS) and label-free quantification method to analyze the apoplastic fluid (APF) from maize stalk and identified the proteins responsive to the Fusarium verticillioides infection.  We have identified 742 proteins, and among these, 119 proteins were differentially accumulated (DAPs), i.e., 35 up-regulated, 18 down-regulated, and 66 proteins were only induced by the pathogen infection.  The differentially accumulated proteins were analyzed for their Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes (KEGG) pathway enrichment.  The highly enriched Biological Process (BP) term was the L-serine biosynthesis process, whereas the most enriched Molecular Function (MF) term was the cysteine-type endopeptidase inhibitor activity.  It was also found that the pathways related to the biosynthesis of amino acid, biosynthesis of secondary metabolites, protein processing in the endoplasmic reticulum, and carbohydrate metabolic pathways were significantly enriched.  Moreover, 61 out of 119 differentially accumulated proteins were predicted as secretory proteins.  The secretory pathways analysis showed that a greater number of proteins were secreted through the conventional secretion system compared to the unconventional secretion system.  The identified secreted proteins were related to a variety of pathways in defense responses including cell redox homeostasis, cell wall modification, signal transduction, carbohydrate metabolism, binding proteins (metal ion binding, RNA binding and heme-binding), maintenance and stabilization of other proteins, indicating a complex response from the plant to the fungal infection.  Our data suggested that a number of host proteins belonging to various pathways have been modulated in the apoplastic region.
    A rapid, low-cost deep learning system to classify strawberry disease based on cloud service
    YANG Guo-feng, YANG Yong, HE Zi-kang, ZHANG Xin-yu, HE Yong
    2022, 21(2): 460-473.  DOI: 10.1016/S2095-3119(21)63604-3
    Abstract ( )   PDF in ScienceDirect  
    Accurate and timely classification of diseases during strawberry planting can help growers deal with them in timely manner, thereby reducing losses.  However, the classification of strawberry diseases in real planting environments is facing severe challenges, including complex planting environments, multiple disease categories with small differences, and so on.  Although recent mobile vision technology based deep learning has achieved some success in overcoming the above problems, a key problem is how to construct a non-destructive, fast and convenient method to improve the efficiency of strawberry disease identification for the multi-region, multi-space and multi-time classification requirements.  We develop and evaluate a rapid, low-cost system for classifying diseases in strawberry cultivation.  This involves designing an easy-to-use cloud-based strawberry disease identification system, combined with our novel self-supervised multi-network fusion classification model, which consists of a Location network, a Feedback network and a Classification network to identify the categories of common strawberry diseases.  With the help of a novel self-supervision mechanism, the model can effectively identify diseased regions of strawberry disease images without the need for annotations such as bounding boxes.  Using accuracy, precision, recall and F1 to evaluate the classification effect, the results of the test set are 92.48, 90.68, 86.32 and 88.45%, respectively.  Compared with popular Convolutional Neural Networks (CNN) and five other methods, our network achieves better disease classification effect.  Currently, the client (mini program) has been released on the WeChat platform.  The mini program has perfect classification effect in the actual test, which verifies the feasibility and effectiveness of the system, and can provide a reference for the intelligent research and application of strawberry disease identification.

    Expression profiles and functional prediction of ionotropic receptors in Asian corn borer, Ostrinia furnacalis (Lepidoptera: Crambidae)
    ZHANG Yu, YANG Bin, YU Jie, PANG Bao-ping, WANG Gui-rong
    2022, 21(2): 474-485.  DOI: 10.1016/S2095-3119(20)63427-X
    Abstract ( )   PDF in ScienceDirect  
    Genes involved in chemosensation are essential for odorant-mediated insect behaviors.  Odorant receptors (ORs) bind and respond to pheromones and plant volatiles, regulating insect behaviors such as mating and host-plant selection, while ionotropic receptors (IRs), which are present at lower levels in insects than ORs, influence ion channels, especially in agricultural pests.  Asian corn borer, Ostrinia furnacalis, is the main pest of maize that causes huge economic losses in Asia.  Twenty-one OfurIRs have been identified, but none has been characterized.  In this study, tissue-specific expression profiling, phylogenetic analysis, and electroantennography (EAG) analysis were applied to characterize the evolution, expression, and the potential function of OfurIRs.  It was found that 20 OfurIRs were highly expressed in the antennae, except for OfurIR75p3, whereas 10 and nine OfurIRs were highly expressed in the proboscis and genitalia, respectively, indicating that these OfurIRs were functionally associated with feeding and oviposition.  EAG results showed that seven acids elicited responses in the antennae of O. furnacalis and that 2-oxopentanoic acid displayed a significant female-biased response.  Combined with the phylogenetic analysis, 10 OfurIRs in clade 4 were roughly predicted to be candidate receptors for 2-oxopentanoic acid and other tested acids.  These results provide basic information about OfurIRs and may help advance the knolwedge on the olfactory system of O. furnacalis
    Animal Science · Veterinary Medicine
    A comprehensive evaluation of factors affecting the accuracy of pig genotype imputation using a single or multi-breed reference population
    ZHANG Kai-li, PENG Xia, ZHANG Sai-xian, ZHAN Hui-wen, LU Jia-hui, XIE Sheng-song, ZHAO Shu-hong, LI Xin-yun, MA Yun-long
    2022, 21(2): 486-495.  DOI: 10.1016/S2095-3119(21)63695-X
    Abstract ( )   PDF in ScienceDirect  
    Genotype imputation has become an indispensable part of genomic data analysis.  In recent years, imputation based on a multi-breed reference population has received more attention, but the relevant studies are scarce in pigs.  In this study, we used the Illumina PorcineSNP50 Bead Chip to investigate the variations of imputation accuracy with various influencing factors and compared the imputation performance of four commonly used imputation software programs.  The results indicated that imputation accuracy increased as either the validation population marker density, reference population sample size, or minor allele frequency (MAF) increased.  However, the imputation accuracy would have a certain extent of decrease when the pig reference population was a mixed group of multiple breeds or lines.  Considering both imputation accuracy and running time, Beagle 4.1 and FImpute are excellent choices among the four software packages tested.  This work visually presents the impacts of these influencing factors on imputation and provides a reference for formulating reasonable imputation strategies in actual pig breeding.
    C-type natriuretic peptide stimulates chicken myoblast differentiation through NPRB/NPRC receptors and metabolism pathway
    HUANG Hua-yun, LIANG Zhong, LIU Long-zhou, LI Chun-miao, HUANG Zhen-yang, WANG Qian-bao, LI Shou-feng, ZHAO Zhen-hua
    2022, 21(2): 496-503.  DOI: 10.1016/S2095-3119(21)63694-8
    Abstract ( )   PDF in ScienceDirect  
    Skeletal muscle development is closely related with the amount of meat production and its quality in chickens.  Natriuretic peptides (NPs) play an important role in myotube formation and fat oxidation of skeletal muscle in animals.  The effect of C-type natriuretic peptide (CNP), an important member of the NPs, and its underlying molecular mechanisms in skeletal muscle are incompletely understood.  Treatment of myoblasts with CNP led to enhanced proliferation/differentiation and significantly upregulated (P<0.05) mRNA expression of the CNP receptors natriuretic peptide receptor B (NPRB) and the clearance receptor C (NPRC).  In cells exposed to CNP, 142 differentially expressed genes (84 up-regulation and 58 down-regulation) (P<0.05) were identified by RNA-sequencing compared with those in control cells.  Sixteen genes were significantly enriched (P<0.05) in the metabolic pathway, and six of them (phospholipase C β4, phospholipase C β2, phosphoglycerate mutase 1, creatine kinase B, peroxiredoxin 6 and CD38) were closely related to skeletal muscle development and differentially expressed.  In conclusion, CNP stimulated differentiation of myoblasts by upregulating expression of the NPRB and NPRC receptors and enriching key genes in the metabolic pathway.  
    Construction of a telomerase-immortalized porcine tracheal epithelial cell model for swine-origin mycoplasma infection
    XIE Xing,  HAO Fei, WANG Hai-yan, PANG Mao-da, GAN Yuan, LIU Bei-bei, ZHANG Lei, WEI Yan-na, CHEN Rong, ZHANG Zhen-zhen, BAO Wen-bin, BAI Yun, SHAO Guo-qing, XIONG Qi-yan, FENG Zhi-xin
    2022, 21(2): 504-520.  DOI: 10.1016/S2095-3119(21)63644-4
    Abstract ( )   PDF in ScienceDirect  
    Primary porcine tracheal epithelial cells (PTECs) are an appropriate model for studying the molecular mechanism of various porcine respiratory diseases, including swine-origin mycoplasmas, which are isolated from respiratory tract of pigs and mainly found on the mucosal surface surrounding swine trachea.  However, the short proliferation ability of primary PTECs greatly limits their lifespan.  In this study, primary PTECs were carefully isolated and cultured, and immortal PTECs were constructed by transfecting primary PTECs with the recombinant constructed plasmid pEGFP-hTERT containing human telomerase reverse transcriptase (hTERT).  Immortal PTECs (hTERT-PTECs) maintained both the morphological and functional characteristics of primary PTECs, as indicated by the expression of cytokeratin 18, cell-cycle analysis, proliferation assay, Western blotting, telomerase activity assay, karyotype analysis and quantitative RT-PCR.  Compared to primary PTECs, hTERT-PTECs had an extended replicative lifespan, higher telomerase activity, and enhanced proliferative activity.  In addition, this cell line resulted in a lack of transformed and grown tumors in nude mice, suggesting that it could be safely applied in further studies.  Moreover, hTERT-PTECs were vulnerable to all swine-origin mycoplasmas through quantitative analysis as indicated by 50% color changing unit (CCU50) calculation, and no significant differences of adhesion ability between primary and immortal PTECs were observed.  For the representative swine mycoplasma Mycoplasma hyopneumoniae (Mhp), except for DNA copies quantitative real-time PCR assay, indirect immunofluorescence assay and Western blotting analysis also depicted that hTERT-PTECs was able to adhere to different Mhp strains of different virulence.  In summary, like primary PTECs, hTERT-PTECs could be widely used as an adhesion cell model for swine-origin mycoplasmas and in infection studies of various porcine respiratory pathogens.  
    Agro-ecosystem & Environment
    Long-term straw return influenced ammonium ion retention at the soil aggregate scale in an Anthrosol with rice-wheat rotations in China
    ZHANG Wen-zhao, CHEN Xiao-qin, WANG Huo-yan, WEI Wen-xue, ZHOU Jian-min
    2022, 21(2): 521-531.  DOI: 10.1016/S2095-3119(20)63592-4
    Abstract ( )   PDF in ScienceDirect  
    Soil aggregates are an important controlling factor for the physico-chemical and biological processes such as ammonium (NH4+) retention.  Straw return to the field is increasingly recommended to promote soil carbon (C) sequestration and improve crop yields.  However, the effects of straw return on NH4+ retention at soil aggregate level in agricultural soils have seldom been investigated.  This study aimed to evaluate the influences of long-term straw return on NH4+ adsorption and fixation in microaggregates (<0.25 mm) with or without soil organic carbon (SOC) oxidization.  Soil samples were collected from plots of three treatments, i.e., no fertilizer (CK), inorganic NPK fertilizers (NPK), and inorganic NPK fertilizers with rice straw return (NPKS), from a 20-year-old field trial with rice-wheat rotations in Taihu Lake Region, China.  Soil aggregates were separated using wet-sieving method.  The SOC of microaggregates was oxidized by H2O2.  The results showed that long-term straw return significantly increased SOC and NH4+ adsorption, but inhibited NH4+ fixation in microaggregates.  NH4+ adsorption potential and strength - obtained from adsorption isotherms - increased, but NH4+ fixation decreased along with increasing SOC in microaggregates, indicating the important role of SOC in NH4+ adsorption and fixation.  This was verified by the SOC oxidization test that showed a relative decrease in NH4+ adsorption potential for the NPKS treatment and an increase in NH4+ fixation in all three treatments.  Therefore, long-term straw return influences NH4+ adsorption and fixation by enhancing SOC content and could improve N availability for crop uptake and minimize applied N fertilizer losses in rice-wheat cropping systems.
    Grain zinc and iron concentrations of Chinese wheat landraces and cultivars and their responses to foliar micronutrient applications
    JIANG Li-na, MA Jing-li, WANG Xiao-jie, LIU Gang-gang, ZHU Zhao-long, QI Chen-yang, ZHANG Ling-fang, LI Chun-xi, WANG Zhi-min, HAO Bao-zhen
    2022, 21(2): 532-541.  DOI: 10.1016/S2095-3119(21)63614-6
    Abstract ( )   PDF in ScienceDirect  
    Grain zinc (Zn) and iron (Fe) concentrations and their responses to foliar application of micronutrients in 28 Chinese wheat landraces and 63 cultivars were investigated in a two-year field experiment.  The average grain Zn and Fe concentrations were 41.8 mg kg–1 (29.0−63.3 mg kg–1) and 39.7 mg kg–1 (27.9−67.0 mg kg–1), respectively.  Compared with cultivars, landraces had greater grain Zn (11.0%) and Fe (4.8%) concentrations but lower harvest index (HI), grain weight per spike (GWS), grain number per spike (GNS) and thousand grain weight (TGW).  Both Zn and Fe concentrations were negatively and significantly correlated with HI, GWS, and GNS, while showed a poor association with TGW, suggesting that lower HI, GWS, and GNS, but not TGW, accounted for higher Zn and Fe concentrations for landraces than for cultivars.  Grain Zn concentrations of both cultivars and landraces significantly increased after foliar Zn spray and the increase was two-fold greater for landraces (12.6 mg kg–1) than for cultivars (6.4 mg kg–1).  Foliar Fe spray increased grain Fe concentrations of landraces (3.4 mg kg–1) and cultivars (1.2 mg kg–1), but these increases were not statistically significant.  This study showed that Chinese wheat landraces had higher grain Zn and Fe concentrations than cultivars, and greater increases occurred in grain Zn concentration than in grain Fe concentration in response to fertilization, suggesting that Chinese wheat landraces could serve as a potential genetic source for enhancing grain mineral levels in modern wheat cultivars.

    Preparation and efficacy evaluation of Paenibacillus polymyxa KM2501-1 microbial organic fertilizer against root-knot nematodes
    CHENG Wan-li, ZENG Li, YANG Xue, HUANG Dian, YU Hao, CHEN Wen, CAI Min-min, ZHENG Long-yu, YU Zi-niu, ZHANG Ji-bin
    2022, 21(2): 542-551.  DOI: 10.1016/S2095-3119(20)63498-0
    Abstract ( )   PDF in ScienceDirect  
    Root-knot nematodes (RKNs) cause huge yield losses to agricultural crops worldwide.  Meanwhile, livestock manure is often improperly managed by farmers, which leads to serious environmental pollution.  To resolve these two problems, this study developed a procedure for the conversion of chicken manure to organic fertilizer by larvae of Hermetia illucens L. and Bacillus subtilis BSF-CL.  Chicken manure organic fertilizer was then mixed thoroughly with Paenibacillus polymyxa KM2501-1 to a final concentration of 1.5×108 CFU g–1.  The efficacy of KM2501-1 microbial organic fertilizer in controlling root-knot nematodes was evaluated in pot and field experiments.  In pot experiments, applying KM2501-1 microbial organic fertilizer either as a base fertilizer or as a fumigant at the dose of 40 g/pot suppressed root-knot disease by 61.76 and 69.05% compared to the corresponding control treatments, respectively.  When applied as a fumigant at the dose of 1 kg m–2 in field experiments, KM2501-1 microbial organic fertilizer enhanced the growth of tomato plants, suppressed root-knot disease by 49.97%, and reduced second stage juveniles of RKN in soil by 88.68%.  KM2501-1 microbial organic fertilizer controlled RKNs better than commercial bio-organic fertilizer in both pot and field experiments.  These results demonstrate that this co-conversion process efficiently transforms chicken manure into high value-added larvae biomass and KM2501-1 microbial organic fertilizer with potential application as a novel nematode control agent.

    Agricultural Economics and Management
    Black tea markets worldwide: Are they integrated?
    XU Yong-mei, QIAO Fang-bin, HUANG Ji-kun
    2022, 21(2): 552-565.  DOI: 10.1016/S2095-3119(21)63850-9
    Abstract ( )   PDF in ScienceDirect  
    Global tea consumption has risen significantly alongside rapid expansion of international trade in recent years.  However, few studies have systematically examined the relationship among the major tea markets worldwide.  Using weekly data from 2012–2019, this study empirically analyzed the price series of the world’s major black tea auction markets.  The estimation results showed that these markets are connected, even though heterogeneities vary.  This finding holds not only for regional markets but also for international markets.  The findings offer important implications for tea-producing countries with millions of smallholder farmers.
    Changes in paddy cropping system enhanced economic profit and ecological sustainability in central China
    ZHOU Yong, YAN Xiao-yuan, GONG Song-ling, LI Cheng-wei, ZHU Rong, ZHU Bo, LIU Zhang-yong, WANG Xiao-long, CAO Peng
    2022, 21(2): 566-577.  DOI: 10.1016/S2095-3119(21)63841-8
    Abstract ( )   PDF in ScienceDirect  
    In China, the traditional early and late season double rice (DR) system is declining accompanied by the fast increase of two newly developed cropping systems: ratoon rice (RR) and rice–crawfish (RC).  Three methodologies: economic analysis, emergy evaluation and life cycle assessment (LCA) were employed to evaluate the economics and sustainability of this paddy cropping system change.  Economic analysis indicated that the income and profit of the RC system were far larger than those of RR and DR.  The income to costs ratio of RR and RC increased by 25.5 and 122.7% compared with that of DR, respectively.  RC had the highest emergy input thanks to increasing irrigation water, electricity, juvenile crawfish and forage input while RR showed a lower total emergy and nonrenewable emergy input, such as irrigation water, electricity, fertilizers and pesticides than DR.  The environmental loading ratios decreased by 16.7–50.4% when cropping system changed from DR to RR or from DR to RC while the emergy sustainability indexes increased by 22.6–112.9%.  The life cycle assessment indicated lower potential environmental impacts of RR and RC, whose total environmental impact indexes were 35.0–61.0% lower than that of DR.  Grain yield of RR was comparable with that of DR in spite of less financial and emergy input of RR, but RC had a much lower grain yield (a 53.6% reduction compared to DR).  These results suggested that RR is a suitable cropping system to achieve the food security, economic and environmental goals.
    Short Communication
    Waxy allele diversity in waxy maize landraces of Yunnan Province, China
    WU Xiao-yang, LONG Wen-jie, CHEN Dan, ZHOU Guo-yan, DU Juan, WU Shao-yun, CAI Qing
    2022, 21(2): 578-585.  DOI: 10.1016/S2095-3119(20)63471-2
    Abstract ( )   PDF in ScienceDirect  
    Waxy maize is one of the main fresh-eating maize types, and a mutation of the waxy gene causes the waxy character of maize grains.  China is rich in waxy maize landraces, and Yunnan and its surrounding areas, are the place of origin and genetic diversity center of Chinese waxy maize.  The six known waxy alleles of Chinese waxy maize are wx-D7, wx-D10, wx-Cin4, wx-124, wx-Reina, and wx-Xuanwei.  The mutation sites of these alleles all occur in the coding region of the waxy gene, however, the mechanism by which the waxy characteristic is caused by the mutation in the regulatory region has only been reported rarely in maize.  In this study, 405 waxy maize landraces from Yunnan were used as materials to identify the insertion and deletion of a large sequence fragment in the upstream ~3.5 kb regulatory region of the waxy gene by molecular marker detection.  Three different waxy alleles were identifed in this study: wx-PIF/Harbinger, wx-hAT and wxElote2.  These three types of mutations all represented transposons inserted into the regulatory region of the waxy gene.  Wx-PIF/Harbinger was a 304-bp MITE class transposon insertion belonging to the PIF/Harbinger family, while wx-hAT was a 560-bp MITE class transposon insertion belonging to the hAT family, and wx-Elote2 was a 6 560-bp LTR-like transposon insertion.  In this study, the alleles were identifed for more than 70% of the waxy maize landraces in Yunnan, which provids a basis for the utilization of these waxy maize landraces.
    Molecular and morphological characterization of stunt nematodes of wheat, maize, and rice in the savannahs of northern Nigeria
    Sulaiman ABDULSALAM, , PENG Huan, LIU Shi-ming, HUANG Wen-kun, KONG Ling-an, PENG De-liang
    2022, 21(2): 586-595.  DOI: 10.1016/S2095-3119(21)63696-1
    Abstract ( )   PDF in ScienceDirect  
    Stunt nematodes (Tylenchorhynchus spp.) are obligate migratory root ecto-parasitic nematodes found in the fields of many cultivated crops.  These nematodes, with phyto-sanitary potential, are frequently ignored or misdiagnosed as pests, and this may pose a threat to food security.  The accuracy of its identification based on a morphological approach has been challenged recently, due to the overlapping of the morphological and morphometric characters of the species.  Consequently, the objective of this study is to identify and characterize stunt nematodes present in 54 fields cultivated with cereal crops (wheat, maize and rice) in the savannahs of northern Nigeria, using integrative taxonomy and molecular approaches.  The molecular and morphological studies identified and confirmed the presence of T. annulatus as the occurring specie in the savannahs of northern Nigeria.  The phylogenetic analysis was carried out using the internal transcribed spacer (ITS) and 28S genes of ribosomal DNA further confirmed the presence of T. annulatus.  The first molecular characterization and sequences of the ITS and 28S rDNA gene for T. annulatus from Nigeria were provided by this research.  Also, according to our literature search, this is the first report on T. annulatus in wheat, maize and rice in the savannahs of northern Nigeria.  Further study to test the pathogenicity of the parasitic nematode species found in this survey is recommended for the prioritization and development of efficient management strategies.