2022 Vol. 21 No. 1 Previous Issue    Next Issue

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

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    Recent advances in nutrient requirements of meat-type sheep in China: A review
    MA Tao, DENG Kai-dong, TU Yan, ZHANG Nai-feng, ZHAO Qi-nan, LI Chang-qing, JIN Hai, DIAO Qi-yu
    2022, 21(1): 1-14.  DOI: 10.1016/S2095-3119(21)63625-0
    Abstract ( )   PDF in ScienceDirect  
    China has the world’s largest sheep flock and the largest producer of sheep meat by far.  However, the nutrient requirements have not been systemically studied and there is a lack of knowledge of nutrient requirement for meat-type sheep in China.  Since 2008, the nutrient requirements of meat-type sheep in China has been systematically investigated.  In this review, we introduced the history of studies of nutrient requirements of meat-type sheep in China, summarized the recent advances in nutrient requirements of meat-type sheep, and highlighted the future directions of researches on nutrient requirements of meat-type sheep in China.
    Crop Science
    Reducing phosphorylation of nitrate reductase improves nitrate assimilation in rice
    HAN Rui-cai, LI Chen-yan, Adnan Rasheed, PAN Xiao-hua, SHI Qing-hua, WU Zi-ming
    2022, 21(1): 15-25.  DOI: 10.1016/S2095-3119(20)63386-X
    Abstract ( )   PDF in ScienceDirect  
    Nitrate reductase (NR) is an important enzyme for nitrate assimilation in plants, and post-translational phosphorylation regulates NR activity.  To evaluate the impact of the dephosphorylation of nitrate reductase 1 (NIA1) protein on NR activity, nitrogen metabolism and plant growth, NIA1 phosphorylation site directed mutant lines (S532D and S532A) and an OsNia1 over-expression line (OE) were constructed, and the phenotype, NIA1 protein and its phosphorylation level, NR activity, nitrate metabolism and reactive oxygen metabolism of the transgenic lines were analysed.  Exogenous NIA1 protein was not phosphorylated in S532D and S532A mutant lines, and their NR activities, activity states of NR and assimilation efficiencies of NO3–-N were higher than those in Kitaake (WT) and OE.  The changes in these physiological and biochemical indexes in the OE line were less than in S532D and S532A compared to WT.  These results suggest that the removal of transcriptional level control had little effect on nitrogen metabolism, but the removal of post-translational modification had a profound effect on it.  With the removal of NIA1 phosphorylation and the improvement in the nitrate assimilation efficiency, the plant height and chlorophyll content of S532D and S532A decreased and the hydrogen peroxide and malondialdehyde contents of rice seedlings increased, which may be related to the excessive accumulation of nitrite as an intermediate metabolite.  These results indicated that the phosphorylation of NR may be a self-protection mechanism of rice.  The reduced phosphorylation level of nitrate reductase improved the assimilation of nitrate, and the increased phosphorylation level reduced the accumulation of nitrite and prevented the toxic effects of reactive oxygen species in rice. 
    Analysis of combining ability for stem-related traits and its correlations with lodging resistance heterosis in hybrid wheat
    YANG Wei-bing, QIN Zhi-lie, SUN Hui, HOU Qi-ling, GAO Jian-gang, CHEN Xian-chao, ZHANG Li-ping, WANG Yong-bo, ZHAO Chang-ping, ZHANG Feng-ting
    2022, 21(1): 26-35.  DOI: 10.1016/S2095-3119(20)63408-6
    Abstract ( )   PDF in ScienceDirect  
    With the application of hybrid wheat, lodging is becoming one of the major factors limiting high yield in its production.  However, few studies have focused on combining ability and heterosis analysis of stem-related traits.  In this study, 24 crosses were made according to NCII genetic design, using the three (photo-sensitive male sterile lines)×eight (restorer lines) incomplete diallel crosses.  The length of basal second internode (LBSI) and breaking strength of basal second internode (BSBSI) as well as other stem-related traits were used to perform the principal component analysis (PCA), combining ability and heterosis analysis.  The PCA results showed that the variables could be classified into two main factors, which were named as the positive factor (factor 1) and the negative factor (factor 2), and accounted for 52.3 and 33.2%, respectively, of the total variance in different variables, combined with the analysis for index weight indicated that the factor 1-related traits play positive roles in lodging resistance formation of hybrids.  Combining ability variance analysis indicated that its genetic performance was mainly dominated by additive gene effects, and the hybrid combinations with higher lodging resistance can be selected by using of 14GF6085 (R1), 14GF6343-2 (R4), 14GF6937 (R6), 14GF7433-1 (R7), and BS1086 (M3), which are with the features with lower general combining ability (GCA) effects of factor 2-related traits whereas higher GCA effects of factor 1-related traits.  The heterosis analysis showed that the wide range of heterosis varied with the traits and combinations, and GCA or specific combining ability (SCA) effects of factor 1-related traits except wall thickness of basal second internode (WTBSI) were positively and closely related to the heterosis of lodging resistance.  Generally, the correlation coefficients of heterosis to GCA effects of sterile lines (GCAm) of factor 1-related traits are significantly higher than that to GCA of restorer lines (GCAr) and SCA, combined with the higher GCAm variance values of factor 1-related traits compared to GCAr, the GCAm of factor 1-related traits should be particularly considered when breeding hybrid combinations.  The heritability analysis showed that the narrow-sense heritability of the diameter of basal second internode (DBSI) and the center of gravity height (TCGH) were obviously lower (<60%) than other traits, suggesting that these two traits were suitable for selection in higher generation for parental breeding.  These could provide a theoretical basis for parental breeding and heterosis utilization of lodging resistance. 

    Sexual compatibility of transgenic soybean and different wild soybean populations
    HU Yu-qi, SHENG Ze-wen, LIU Jin-yue, LIU Qi, QIANG Shen, SONG Xiao-ling, LIU Biao
    2022, 21(1): 36-48.  DOI: 10.1016/S2095-3119(20)63385-8
    Abstract ( )   PDF in ScienceDirect  
    The introduction of genetically modified (GM) soybean into farming systems raises great concern that transgenes from GM soybean may flow to endemic wild soybean via pollen.  This may increase the weediness of transgenic soybean by increasing the fitness of hybrids under certain conditions and threaten the genetic diversity of wild soybean populations.  Although pollen-mediated gene flow between GM crops and wild relatives is dependent on many factors, the sexual compatibility (SC) determined by their genetic backgrounds is the conclusive factor.  The considerable genetic variation among wild soybean populations may cause compatibility differences between different wild and cultivated soybeans.  Thus, an evaluation of the SC between transgenic soybean and different wild soybeans is essential for assessing the environmental consequences of cultivated soybean–wild soybean transgene flow.  The podding and seed sets were assessed after artificial hybridization using transgenic glyphosate-resistant soybean as the paternal parent and 18 wild soybean populations as the maternal parents.  Then, the average number of filled seeds produced in 200 flowers (AFS) was calculated for each wild soybean under natural self-pollination as well as under artificial crossing with transgenic soybean.  Finally, the index of cross-SC was calculated (ICSC) as the ratio of the AFS of wild soybean artificially crossed with transgenic soybean and the AFS of naturally self-pollinated wild soybean.  The results demonstrated that after self-pollination and crossing with transgenic soybean, the average podding rates of 18 wild soybean populations ranged within 96.50–99.50% and 4.92–18.03%, and the average filled seed numbers per pod varied from 1.70 to 2.69 and 0.20 to 0.48, respectively.  The results showed that approximately 89% of wild soybeans displayed either medium or higher than medium SC with transgenic soybean (ICSC>1.0%).  This implied the high possibility of gene flow via pollen from transgenic soybean to wild soybean.

    Overexpression of Brassica napus cytosolic fructose-1,6-bisphosphatase and sedoheptulose-1,7-bisphosphatase genes significantly enhanced tobacco growth and biomass
    LI Yan-yan, GUO Li-na, LIANG Cheng-zhen, MENG Zhi-gang, Syed Tahira, GUO San-dui, ZHANG Rui
    2022, 21(1): 49-59.  DOI: 10.1016/S2095-3119(20)63438-4
    Abstract ( )   PDF in ScienceDirect  
    Elevated activities of cytosolic fructose-1,6-bisphosphatase (cyFBPase) and sedoheptulose-1,7-bisphosphatase (SBPase) are associated with higher yields in plants.  In this study, the expression levels of the cyFBPase and SBPase genes were increased by overexpressing rape (Brassica napus) cDNA in tobacco (Nicotiana tabacum) plants.  The transgenic plants co-expressing cyFBPase and SBPase (TpFS), or expressing single cyFBPase (TpF) or SBPase (TpS) had 1.77-, 1.55-, 1.23-fold cyFBPase and 1.45-, 1.12-, 1.36-fold SBPase activities as compared to the wild-type (WT), respectively.  Photosynthesis rates of TpF, TpS and TpFS increased 4, 20 and 25% compared with WT plants.  The SBPase and cyFBPase positively regulated each other and functioned synergistically in transgenic tobacco plants.  In addition, the sucrose contents of the three transgenic plants were higher than that of WT plants.  The starch accumulation of the TpFS and TpS plants was improved by 53 and 37%, but slightly decreased in TpF plants.  Moreover, the transgenic tobacco plants harbouring SBPase and/or cyFBPase genes showed improvements in their growth, biomass, dry weight, plant height, stem diameter, leaf size, flower number, and pod weight.  In conclusion, co-expression of SBPase and cyFBPase may pave a new way for improving crop yield in agricultural applications.
    Modeling leaf color dynamics of winter wheat in relation to growth stages and nitrogen rates 
    ZHANG Yong-hui, YANG Yu-bin, CHEN Chun-lei, ZHANG Kui-ting, JIANG Hai-yan, CAO Wei-xing, ZHU Yan
    2022, 21(1): 60-69.  DOI: 10.1016/S2095-3119(20)63319-6
    Abstract ( )   PDF in ScienceDirect  
    The objective of this work was to develop a model for simulating the leaf color dynamics of winter wheat in relation to crop growth stages and leaf positions under different nitrogen (N) rates.  RGB (red, green and blue) data of each main stem leaf were collected throughout two crop growing seasons for two winter wheat cultivars under different N rates.  A color model for simulating the leaf color dynamics of winter wheat was developed using the collected RGB values.  The results indicated that leaf color changes went through three distinct stages, including early development stage (ES), early maturity stage (MS) and early senescence stage (SS), with respective color characteristics of light green, dark green and yellow for the three stages.  In the ES stage, the R and G colors gradually decreased from their initial values to steady values, but the B value generally remained unchanged.  RGB values remained steady in the MS, but all three gradually increased to steady values in the SS.  Different linear functions were used to simulate the dynamics of RGB values in time and space.  A cultivar parameter of leaf color matrix (MRGB) and a nitrogen impact factor (FN) were added to the color model to quantify their respective effects.  The model was validated with an independent experimental dataset.  RMSEs (root mean square errors) between the observed and simulated RGB values ranged between 7.0 and 10.0, and relative RMSEs (RRMSEs) ranged between 7 and 9%.  In addition, the model was used to render wheat leaves in three-dimensional space (3D).  The 3D visualizations of leaves were in good agreement with the observed leaf color dynamics in winter wheat.  The developed color model could provide a solid foundation for simulating dynamic crop growth and development in space and time. 

    Study of corn kernel breakage susceptibility as a function of its moisture content by using a laboratory grinding method 
    GUO Ya-nan, HOU Liang-yu, LI Lu-lu, GAO Shang, HOU Jun-feng, MING Bo, XIE Rui-zhi, XUE Jun, HOU Peng, WANG Ke-ru, LI Shao-kun
    2022, 21(1): 70-77.  DOI: 10.1016/S2095-3119(20)63250-6
    Abstract ( )   PDF in ScienceDirect  
    The rate of corn kernel breakage in the grain combine harvesters is a crucial factor affecting the quality of the grain shelled in the field.  The objective of the present study was to determine the susceptibility of corn kernels to breakage based on the kernel moisture content in order to determine the moisture content that corresponds to the lowest rate of breakage.  In addition, we evaluated the resistance to breakage of various corn cultivars.  A total of 17 different corn cultivars were planted at two different sowing dates at the Beibuchang Experiment Station, Beijing and the Xinxiang Experiment Station (Henan Province) of the Chinese Academy of Agricultural Sciences.  The corn kernel moisture content was systematically monitored and recorded over time, and the breakage rate was measured by using the grinding method.  The results for all grain samples from the two experimental stations revealed that the breakage rate y is quadratic in moisture content x, y=0.0796x2−3.3929x+78.779; R2=0.2646, n=512.  By fitting to the regression equation, a minimum corn kernel breakage rate of 42.62% was obtained, corresponding to a corn kernel moisture content of 21.31%.  Furthermore, in the 90% confidence interval, the corn kernel moisture ranging from 19.7 to 22.3% led to the lowest kernel breakage rate, which was consistent with the corn kernel moisture content allowing the lowest breakage rate of corn kernels shelled in the field with combine grain harvesters.  Using the lowest breakage rate as the critical point, the correlation between breakage rate and moisture content was significantly negative for low moisture content but positive for high moisture content.  The slope and correlation coefficient of the linear regression equation indicated that high moisture content led to greater sensitivity and correlation between grain breakage and moisture content.  At the Beibuchang Experiment Station, the corn cultivars resistant to breakage were Zhengdan 958 (ZD958) and Fengken 139 (FK139), and the corn cultivars non-resistant to breakage were Lianchuang 825 (LC825), Jidan 66 (JD66), Lidan 295 (LD295), and Jingnongke 728 (JNK728).  At the Xinxiang Experiment Station, the corn cultivars resistant to breakage were HT1, ZD958 and FK139, and the corn cultivars non-resistant to breakage were ZY8911, DK653 and JNK728.  Thus, the breakage classifications of the six corn cultivars were consistent between the two experimental stations.  In conclusion, the results suggested that the high stability of the grinding method allowed it to be used to determine the corn kernel breakage rates of different corn cultivars as a function of moisture content, thus facilitating the breeding and screening of breakage-resistant corn.

    Effects of chemical topping on cotton development, yield and quality in the Yellow River Valley of China
    ZHU Ling-xiao, LIU Lian-tao, SUN Hong-chun, ZHANG Yong-jiang, ZHANG Ke, BAI Zhi-ying, LI An-chang, DONG He-zhong, LI Cun-dong
    2022, 21(1): 78-90.  DOI: 10.1016/S2095-3119(20)63559-6
    Abstract ( )   PDF in ScienceDirect  
    Topping is a cultivation method that is widely practiced due to the indeterminate growth character of cotton (Gossypium hirsutum L.).  Among the different methods of accomplishing topping, manual topping is common in the Yellow River Valley of China, although it is time- and labor-intensive.  The objective of this study was to characterize the responses of cotton to different topping treatments with respect to development, yield and quality.  This study included field experiments from 2015 to 2016 with three different topping methods: manual topping (MT), chemical topping (CT) using mepiquat chloride, and a non-decapitation treatment (NT).  We found that the plant height, the number of fruiting branches and the length of upper fruiting branches of cotton treated with CT were significantly lower than NT.  The chlorophyll content of cotton treated with CT was not significantly different from NT, but was higher than that of MT in the later season.  CT enhanced plant development with reduced endogenous gibberellic acid and abscisic acid contents, and the apical development of the main stem was inhibited.  Compared with MT, CT significantly increased the biomass of the vegetative parts.  Most importantly, there were no significant differences in the yield or fiber quality between MT and CT.  These findings suggested that CT, a simplified and effective topping method, could be utilized as an alternative in the Yellow River Valley of China.
    Versatile physiological functions of the Nudix hydrolase family in berry development and stress response in grapevine
    WANG Pei-pei, WANG Zhao-ke, GUAN Le, Muhammad Salman HAIDER, Maazullah NASIM, YUAN Yong-bing, LIU Geng-sen, LENG Xiang-peng
    2022, 21(1): 91-112.  DOI: 10.1016/S2095-3119(20)63490-6
    Abstract ( )   PDF in ScienceDirect  
    Nudix hydrolases are widely distributed across all classes of organisms and provide the potential capacity to hydrolyze a wide range of organic pyrophosphates.  Although Nudix hydrolases are involved in plant detoxification processes in response to abiotic and biotic stresses, the biological functions of Nudix hydrolases remain largely unclear in grapevine.  In the present study, a total of 25 putative grapevine Nudix hydrolases (VvNUDXs) were identified by bioinformatics analysis and classified into eight subfamilies based to their preferred substrates.  Both tandem and segmental duplications were responsible for the evolution and expansion of the NUDX gene family in grapevine.  To investigate the regulatory roles of VvNUDX genes during growth and development, as well as in response to abiotic and biotic stresses in grapevine, the expression patterns were revealed in publicly available microarray data.  The spatial and temporal expression patterns of the VvNUDX genes indicated that they might play important roles in multiple developmental processes.  Transcriptome and qRT-PCR analyses showed that ten VvNUDX genes were specifically expressed in grapevine berries, suggesting potential roles in grapevine berry development.  Expression and phylogenetic analyses demonstrated that VvNUDX1 and VvNUDX3 might be involved in terpenoid biosynthesis in grapevine.  Furthermore, most VvNUDX genes active toward the ADP-ribose/NADH showed different patterns in response to various abiotic and biotic stresses, such as salinity and drought, as well as different types of biotic treatments, such as Erysiphe necator, Bois Noir phytoplasma and leaf-roll-associated virus-3 (GLRaV-3).  These results indicated that VvNUDX genes were associated with plant detoxification processes in response to abiotic and biotic stresses, and regulate the disease immunity and resistance pathways.  The information obtained here may provide good opportunities to explore the physiological functions of VvNUDX genes in berry development and stress response networks in grapevine. 
    Genome-wide analysis of the CCCH zinc finger family in longan: Characteristic identification and expression profiles in Dimocarpus longan Lour
    SU Li-yao, XIAO Xue-chen, JIANG Meng-qi, HUANG Shu-qi, XUE Xiao-dong, LI Xue, LAI Zhong-xiong, LIN Yu-ling
    2022, 21(1): 113-130 .  DOI: 10.1016/S2095-3119(20)63460-8
    Abstract ( )   PDF in ScienceDirect  
    CCCH (C3H) Zinc finger (Znf) transcription factors (TFs), as a novel type of Znf gene, regulate the expression of genes by binding to their mRNAs and play important roles in plant growth and development and abiotic stress resistance.  Longan (Dimocarpous longan) is a tropical/subtropical fruit tree of great economic importance in Southeast Asia.  However, genomic information on C3H and their functions in longan are still unknown.  In this study, a comprehensive analysis of the longan C3H (DlC3H) gene family was carried out.  A total of 49 DlC3H genes in three clades were identified from the longan genome database.  Characteristics of the genes were analyzed with respect to gene structure, motif composition, phylogenetic tree and potential functions.  The analysis of alternative splicing (AS) events suggested that AS events in DlC3H genes were related to the transformation from longan non-embryonic to embryonic cultures.  Promoter analysis indicated that most of the DlC3H genes included cis-acting elements associated with hormones and stresses responses.  Quantitative real-time PCR (qRT-PCR) analysis indicated that 26 of the 49 DlC3Hs, which possess methyl jasmonate (MeJA) and abscisic acid (ABA) responsive cis-acting elements, showed differential expression patterns under treatment with ABA, MeJA and their endogenous inhibitors, suggesting that DlC3Hs might be involved in the ABA and MeJA signaling pathways.  The expression profiles of 17 of the 49 DlC3Hs in non-embryonic callus and three tissues of embryonic cultures showed that only five of the 17 DlC3Hs had the same expression trends as the FPKM trends in transcriptome data; the expression levels of DlC3H07/14/16/36/49 in embryogenic callus and DlC3H04/38 in globular embryos were high, suggesting that they have different functions in embryonic development.  Further, we verified that DlC3H01/03/05/11/19/39 were regulated by sRNAs by a modified 5´ RLM-RACE method.  This study provides the first systematic analysis of C3H genes in longan, and found that C3H genes may be involved in hormone and stress responses, and somatic embryogenesis.  Our preliminary investigation may provide clues to further studies on the characteristics and functions of this family in longan.
    Constructing the wolfberry (Lycium spp.) genetic linkage map using AFLP and SSR markers
    YIN Yue, AN Wei, ZHAO Jian-hua, LI Yan-long, FAN Yun-fang, CHEN Jin-huan, CAO You-long, ZHAN Xiang-qiang
    2022, 21(1): 131-138.  DOI: 10.1016/S2095-3119(21)63610-9
    Abstract ( )   PDF in ScienceDirect  
    Genetic linkage maps are important for quantitative trait locus (QTL) and marker-assisted selection breeding.  The wolfberry (Lycium spp.) is an important food and traditional medicine in China.  However, few construction genetic linkage maps have been reported because of the lack of genomic and genetic resources.  In this study, a population of 89 F1 seedings was derived from a cross between two heterozygous parents, L. chinense var. potaninii ‘BF-01’ (female) and L. barbarum var. auranticarpum ‘NH-01’ (male), in order to construct a genetic linkage map using simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) markers based on the double pseudo-test cross mapping strategy.  The resulting genetic map consisted of 165 markers (74 AFLPs and 91 SSRs) distributed across 12 linkage groups and spanned a total length of 557.6 cM with an average distance of 3.38 cM between adjacent markers.  The 12 linkage groups contained 3 to 21 markers and ranged in length from 8.6 to 58.3 cM.  Twenty-nine segregated markers distributed in the map were mainly located on LG4 and LG9 linkage groups at P<0.05.  This is the first linkage map of Lycium species using SSR and AFLP markers, which can serve as basis for improving genes and selective breeding of the genome assembly.
    Plant Protection
    iTRAQ-based quantitative proteomics analysis of defense responses triggered by the pathogen Rhizoctonia solani infection in rice
    FENG Zhi-ming, GAO Peng, ZHAO Jian-hua, WANG Guang-da, ZHANG Hui-min, CAO Wen-lei, XUE Xiang, ZHANG Ya-fang, Ma Yu-yin, Hua Rong, CHEN Zong-xiang, CHEN Xi-jun, HU Ke-ming, ZUO Shi-min
    2022, 21(1): 139-152.  DOI: 10.1016/S2095-3119(20)63499-2
    Abstract ( )   PDF in ScienceDirect  
    The soil-borne necrotrophic fungus Rhizoctonia solani is one of destructive fungi causing severe yield losses in various important crops.  However, the host defense mechanisms against the invasion of this pathogen are poorly understood.  In this study, we employed an iTRAQ-based quantitative proteomic approach to investigate host proteins responsive to R. solani using the resistant rice cultivar YSBR1.  As a whole, we identified 319 differentially accumulated proteins (DAPs) after inoculation of rice plants with R. solani.  Functional categorization analysis indicates that these DAPs cover a broad range of functions.  Notably, a substantial portion of the DAPs are involved in cell redox homeostasis, carbohydrate metabolism, and phenylpropanoid biosynthesis, or belong to pathogenesis-related proteins, indicating that these processes/proteins play important roles in host defense against R. solani.  Interestingly, all of the DAPs involved in photosynthesis and chlorophyll biosynthetic processes, and part of the DAPs involved in phenylpropanoid biosynthesis, show reduced accumulation after R. solani infection, suggesting that R. solani probably inhibits host photosynthetic system and phenylpropanoid biosynthesis to facilitate infection and colonization.  In conclusion, our results provide both valuable resources and new insights into the molecular mechanisms underlying rice and R. solani interaction.
    Genome-wide identification and analysis of the regulation wheat DnaJ family genes following wheat yellow mosaic virus infection
    LIU Ting-ting, XU Miao-ze, GAO Shi-qi, ZHANG Yang, HU Yang, JIN Peng, CAI Lin-na, CHENG Ye, CHEN Jian-ping, YANG Jian, ZHONG Kai-li
    2022, 21(1): 153-169.  DOI: 10.1016/S2095-3119(21)63619-5
    Abstract ( )   PDF in ScienceDirect  
    The co-chaperone DnaJ plays an important role in protein folding and regulation of various physiological activities, and participates in several pathological processes.  DnaJ has been extensively studied in many species including humans, drosophila, mushrooms, tomatoes, and Arabidopsis.  However, few studies have examined the role of DnaJ in wheat (Triticum aestivum), and the interaction mechanism between TaDnaJs and plant viruses.  Here, we identified 236 TaDnaJs and performed a comprehensive genome-wide analysis of conserved domains, gene structure and protein motifs, chromosomal positions and duplication relationships, and cis-acting elements.  We grouped these TaDnaJs according to their domains, and randomly selected six genes from the groups for tissue-specific analysis, and expression profiles analysis under hormone stress, and 17 genes for plant virus infection stress.  In qRT-PCR, we found that among the 17 TaDnaJ genes tested, 16 genes were up-regulated after wheat yellow mosaic virus (WYMV) infection, indicating that the TaDnaJ family is involved in plant defense response.  Subsequent yeast two-hybrid assays verified the WYMV NIa, NIb and 7KD proteins interacted with TaDJC (TraesCS7A02G506000), which had the most significant changes in gene expression levels after WYMV infection.  Insights into the molecular mechanisms of TaDnaJ-mediated stress tolerance and sensitivity could inform different strategies designed to improve crop resistance to abiotic and biotic stress.  This study provides a basis for future investigation of the TaDnaJ family and plant defense mechanisms.
    Using transcriptome Shannon entropy to evaluate the off-target effects and safety of insecticidal siRNAs
    MA Wei-hua, WU Tong, ZHANG Zan, LI Hang, SITU Gong-ming, YIN Chuan-lin, YE Xin-hai, CHEN Meng-yao, ZHAO Xian-xin, HE Kang, LI Fei
    2022, 21(1): 170-177.  DOI: 10.1016/S2095-3119(20)63394-9
    Abstract ( )   PDF in ScienceDirect  
    A recent breakthrough in agricultural biotechnology is the introduction of RNAi-mediated strategies in pest control.  However, the off-target effects of RNAi pest control are still not fully understood.  Here, we studied the off-target effects of two insecticidal siRNAs in both target and non-target insects.  The results revealed that off-target effects of insecticidal siRNAs occur widely in both target and non-target insects.  We classified the expression-changed genes according to their homology to the siRNA-targeted gene, related KEGG pathways with the siRNA-targeted gene and continuous matches with siRNAs.  Surprisingly, the unintended significant changes in gene expression levels did not strictly match with the number of contiguous nucleotides in the siRNAs.  As expected, the expression of small portions of the homologous and KEGG-related genes were significantly changed.  We calculated the Shannon entropy of the transcriptome profile of the insects after injecting them with insecticidal siRNAs.  Though hundreds of genes were affected in their expression levels post siRNA-treatment, the Shannon entropy of the transcriptome remained unchanged, suggesting that the transcriptome expression was balanced.  Our results provide evidence that siRNAs cross-reacted with individual genes in non-target species, but did not have significant effects on the integrity of the transcriptome profiles in either target or non-target species on a genomic scale.  The metric we proposed can be used to estimate the off-target effects of insecticidal siRNAs, which might be useful for evaluating the safety of RNAi in pest control.  
    Population genetic structure of Sitobion miscanthi in China
    SUN Jing-xuan, LI Qian, TAN Xiao-ling, FAN Jia, ZHANG Yong, QIN Yao-guo, Frédéric FRANCIS, CHEN Ju-lian
    2022, 21(1): 178-187.  DOI: 10.1016/S2095-3119(20)63445-1
    Abstract ( )   PDF in ScienceDirect  
    The wheat aphid, Sitobion miscanthi, is one of the most destructive pests of wheat plants in the temperate regions of China.  Little is known about the genetic structure evolution of  the different geographic populations of S. miscanthi with its migration.  In this study, we investigated the population genetic structure and demographic history of S. miscanthi by analysing 18 geographical populations across China using one mitochondrial gene, COI; one nuclear gene, EF-1α; and two endosymbiont Buchnera genes, gnd and trpA.  Analysis of data from the various groups showed high haplotype diversity and low nucleotide variation.  SAMOVA analysis did not find a correlation between genetic distance and geographic distance.  However, areas with high population diversity exhibited high haplotype diversity.  Therefore, we speculate that there are two main natural migration pathways of S. miscanthi in China.  One is from Yunnan to the Sichuan Basin, and the other is from Wuhan, Xinyang and Jiaodong Peninsula areas to the northwest.  Based on this hypothesis, we inferred that these aphid populations appear first in the southwestern and southern regions and spread to the north with the help of the southeastern and southwestern monsoons, which occur in spring and summer.  In autumn, the aphids spread southward with the northeastern and northwestern monsoons.

    Animal Science · Veterinary Medicine
    Targeted myostatin loss-of-function mutation increases type II muscle fibers in Meishan pigs
    QIAN Li-li, XIE Jing-yi, GAO Ting, CAI Chun-bo, JIANG Sheng-wang, BI Han-fang, XIE Shan-shan, CUI Wen-tao
    2022, 21(1): 188-198.  DOI: 10.1016/S2095-3119(21)63669-9
    Abstract ( )   PDF in ScienceDirect  
    Myostatin (MSTN) is a negative regulator of skeletal muscle growth and development.  The skeletal muscle in MSTN–/– mice is significantly hypertrophied, with muscle fiber type II increasing significantly while muscle fiber type I decreasing.  However, it is still not clear how the skeletal muscle types change in MSTN–/– pigs, and how the mechanism for MSTN regulates fiber types, especially in large animals like pigs.  This study conducted a comprehensive analysis of the composition of skeletal muscle fibers in MSTN–/– pigs produced in our laboratory.  It was observed that, compared with wild-type (WT) pigs, both the total mass of skeletal muscle and type IIb muscle fibers increased significantly (P<0.01), while the type I and type IIa muscle fibers decreased significantly (P<0.01), in MSTN–/– Meishan pigs.  In addition, to explore the influence of MSTN on muscle fiber type and its regulation mechanism in the embryonic stage, this study selected a few genes (Myf5, Mef2d, MyoD and Six1) associated with muscle fiber type and validated their expression by quantitative RT-PCR.  Herein, it was found that Myh7, Myh2, Myh4 and Myh1 can be detected in the skeletal muscle of pigs at 65 days of gestation (dg).  Compared with WT pigs, in MSTN–/– Meishan pigs, Myh7 decreased significantly (P<0.01), while Myh4 (P<0.001) and Myh1 (P<0.05) increased significantly.  Meanwhile, the increased expression of Myf5 (P<0.05), Mef2d (P<0.01) and Six1 (P<0.05) in MSTN–/– Meishan pigs suggested that MSTN should regulate the directional development of muscle fiber types in the early stage of embryonic development.  Thus, at the embryonic stage, the type II muscle fibers began to increase in MSTN–/– pigs.  These results can provide valuable information not only for pig meat quality improvement, but also for the study of human skeletal muscle development and disease treatment.  
    Development of a cELISA for effective detection of the antibody against H7 subtype of avian influenza virus
    WANG Cong-cong, WANG Si-wen, ZHANG Ying, SHI Jian-zhong, YIN Xin, LI Cheng-jun, WANG Xiu-rong
    2022, 21(1): 199-207.  DOI: 10.1016/S2095-3119(21)63645-6
    Abstract ( )   PDF in ScienceDirect  
    H7 avian influenza viruses (AIVs) normally circulated among birds before.  From 1996 to 2012, human infections with H7 AIVs (H7N2, H7N3, and H7N7) were reported in Canada, Italy, Mexico, the Netherlands, the United Kingdom and the USA.  Until March 2013, human infections with H7N9 AIVs were reported in China.  Since then, H7N9 AIVs have continued to circulate in both humans and birds.  Therefore, the detection of antibodies against the H7 subtype of AIVs has become an important topic.  In this study, a competitive enzyme-linked immunosorbent assay (cELISA) method for the detection of antibody against H7 AIVs was established.  The optimal concentration of antigen coating was 5 μg mL–1, serum dilution was 1/10, and enzyme-labeled antibody was 1/3 000.  To determine the cut-off value of cELISA, percent inhibition (PI) was determined by using receiver operating characteristic (ROC) curve analysis in 178 AIVs negative samples and 368 AIVs positive serum samples (n=546).  When PI was set at 40%, the specificity and sensitivity of cELISA were 99.4 and 98.9%, respectively.  This method could detect the antibodies against H7Nx (N1–N4, N7–N9) AIVs, and showed no reaction with AIVs of H1–H6 and H8–H15 subtypes or common avian viruses such as Newcastle disease virus (NDV), Infectious bronchitis virus (IBV) and Infectious bursal disease virus (IBDV), exhibiting good specificity.  This method showed a coincidence rate of 98.56% with hemagglutinin inhibition (HI) test.  And the repeatability experiment revealed that the coefficients of variation (CV) of intra- and inter-batch repetition were all less than 12%.  The data indicated that the cELISA antibody-detection method established in this study provided a simple and accurate technical support for the detection of a large number of antibody samples of H7-AIV.
    Agro-ecosystem & Environment
    Bentonite-humic acid improves soil organic carbon, microbial biomass, enzyme activities and grain quality in a sandy soil cropped to maize (Zea mays L.) in a semi-arid region
    ZHOU Lei, XU Sheng-tao, Carlos M. MONREAL, Neil B. MCLAUGHLIN, ZHAO Bao-ping, LIU Jing-hui, HAO Guo-cheng
    2022, 21(1): 208-221.  DOI: 10.1016/S2095-3119(20)63574-2
    Abstract ( )   PDF in ScienceDirect  
    A bentonite-humic acid (B-HA) mixture added to degraded soils may improve soil physical and hydraulic properties, due to effects such as improved soil structure and increased water and nutrient retention, but its effect on soil physicochemical and biological properties, and grain quality is largely unknown.  The effect of B-HA, added at 30 Mg ha−1, was studied at 1, 3, 5 and 7 years after its addition to a degraded sandy soil in a semi-arid region of China.  The addition of B-HA significantly increased water-filled pore space and soil organic carbon, especially at 3 to 5 years after its soil addition to the soil.  Amending the sandy soil with B-HA also increased the content of microbial biomass (MB)-carbon, -nitrogen and -phosphorus, and the activities of urease, invertase, catalase and alkaline phosphatase.  The significant effect of maize (Zea mays L.) growth stage on soil MB and enzyme activities accounted for 58 and 84% of their total variation, respectively.  In comparison, B-HA accounted for 8% of the total variability for each of the same two variables.  B-HA significantly enhanced soil properties and the uptake of N and P by maize in semi-arid areas.  The use of B-HA product would be an effective management strategy to reclaim degraded sandy soils and foster sustainable agriculture production in northeast China and regions of the world with similar soils and climate.

    Comparison of nitrogen losses by runoff from two different cultivating patterns in sloping farmland with yellow soil during maize growth in Southwest China 
    HE Shu-qin, MA Rui, WANG Na-na, WANG Shuang, LI Ting-xuan, ZHENG Zi-cheng
    2022, 21(1): 222-234.  DOI: 10.1016/S2095-3119(20)63496-7
    Abstract ( )   PDF in ScienceDirect  
    The loss of N in farmland is an important cause of agricultural non-point source pollution, which seriously impacts the aquatic environment.  A two-year (2017–2018) experiment was conducted to investigate the characteristics of runoff and N losses under different tillage practices.  Taking downslope ridge planting and cross ridge planting as the experimental treatments, the characteristics of surface runoff, interflow, and N losses in sloping farmlands with yellow soil were studied throughout the maize growth period.  As the rainfall increased, the surface runoff and interflow also increased.  The surface runoff and N losses in the surface runoff of downslope ridge planting were significantly higher than those of cross ridge planting.  The interflow volumes and N losses in the 0–20 and 20–40 cm soil layers of the cross ridge planting were significantly higher than those of the downslope ridge planting.  The total N (TN) losses from surface runoff accounted for 54.95–81.25% of the N losses from all pathways.  Therefore, we inferred that surface runoff is the main pathway of N losses.  Dissolved total N (DTN) was the main form of N loss under different tillage measures, as it accounted for 55.82–94.41% of the TN losses, and dissolved organic N accounted for 52.81–87.06% of the DTN losses.  Thus, we inferred that dissolved N is the main form of N loss.  Future research must focus on the prevention and control of the N losses during the maize seedling stage to reduce the environmental pollution caused by ammonium N through runoff.
    Effects of land use/cover change (LUCC) on the spatiotemporal variability of precipitation and temperature in the Songnen Plain, China
    CHU Xiao-lei, LU Zhong, WEI Dan, LEI Guo-ping
    2022, 21(1): 235-248.  DOI: 10.1016/S2095-3119(20)63495-5
    Abstract ( )   PDF in ScienceDirect  
    Understanding the effects of land use/cover change (LUCC) on regional climate is critical for achieving land use system sustainability and global climate change mitigation.  However, the quantitative analysis of the contribution of LUCC to the changes of climatic factors, such as precipitation & temperature (P&T), is lacking.  In this study, we combined statistical methods and the gravity center model simulation to quantify the effects of long-term LUCC on P&T in the Songnen Plain (SNP) of Northeast China from 1980–2018.  The results showed the spatiotemporal variability of LUCC. For example, paddy field had the largest increase (15 166.43 km2) in the SNP, followed by dry land, while wetland had the largest decrease (19 977.13 km2) due to the excessive agricultural utilization and development.  Annual average precipitation decreased at a rate of –9.89 mm per decade, and the warming trends were statistically significant with an increasing rate of 0.256°C per decade in this region since 1980.  The model simulation revealed that paddy field, forestland, and wetland had positive effects on precipitation, which caused their gravity centers to migrate towards the same direction accompanied by the center of precipitation gravity, while different responses were seen for building land, dry land and unused land.  These results indicated that forestland had the largest influence on the increase of precipitation compared with the other land use types.  The responses in promoting the temperature increase differed significantly, being the highest in building land, and the lowest in forestland.  In general, the analysis of regional-scale LUCC showed a significant reduction of wetland, and the increases in building land and cropland contributed to a continuous drying and rapid warming in the SNP.

    Food Science
    Polypropylene crisper and 1-MCP delay the softening, lignification and transcription levels of related enzyme genes of golden needle mushrooms (Flammulina velutipes)
    WANG Wen-jun, LI Yao, LI Fu-hua, ZENG Kai-fang, MING Jian
    2022, 21(1): 249-260.  DOI: 10.1016/S2095-3119(21)63764-4
    Abstract ( )   PDF in ScienceDirect  
    The fresh postharvest golden needle mushroom (Flammulina velutipes) sporocarp has a high moisture content and crisp texture, but it still has high physiological activity and respiration, leading to senescence and quality deterioration.  Treatments with 1-methylcyclopropene (1-MCP) and polypropylene (PP) crispers were used to study the changes of lignification and softening of F. velutipes during storage.  The main findings were as follows: the crisper packaging could effectively prolong the storage time of F. velutipes; either the 1-MCP treatment, crisper packaging or the combination of the two treatments could significantly inhibit the accumulation of lignin and the decreases in the contents of cellulose and pectin, and had certain inhibitory effects on the activities of enzymes involved in lignification and softening including phenylalanine ammonia-lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), cellulase (Cx), pectin methylesterase (PME) and polygalacturonase (PG).  Among them, the inhibitory effect of the crisper packaging was higher than the 1-MCP treatment, while the combination of the two treatments was the best.  The results of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed that the crisper packaging in combination with the 1-MCP treatment could effectively maintain the integrity and stability of the F. velutipes cellular structure and inhibit the emergence of plasmolysis to prevent cell membrane rupture.  The transcription levels showed that the crisper packaging and the combination of the 1-MCP treatment and crisper packing could effectively affect the expression of genes for enzymes related to lignification and softening of Fvelutipes.  In conclusion, 1-MCP and PP crispers could delay the lignification and softening of F. velutipes during storage.
    Effect of harvest time on the chemical composition and antioxidant capacity of Gannan navel orange (Citrus sinensis L. Osbeck ‘Newhall’) juice
    ZHANG Jun, ZHANG Jing-yi, SHAN You-xia, GUO Can, HE Lian, ZHANG Lin-yan, LING Wei, LIANG Yan, ZHONG Ba-lian
    2022, 21(1): 261-272.  DOI: 10.1016/S2095-3119(20)63395-0
    Abstract ( )   PDF in ScienceDirect  
    The present study investigates the chemical composition and antioxidant capacity of juice from the Gannan navel orange, which is harvested at one- to two-week intervals during the ripening period.  The total soluble solid (TSS), total polyphenol content (TPC), total flavonoid content (TFC), sucrose and hesperidin contents gradually increase with the ripening of the fruit, followed by slight declines at the late maturity stage.  Contrary to these observations, the contents of titratable acid (TA), vitamin C (Vc), and limonin trend downward throughout the ripening period.  However, the contents of fructose, glucose, and narirutin fluctuate throughout the harvest time.  Three in vitro antioxidant assays consistently indicate that the harvest time exerts no significant influence (P>0.01) on the antioxidant capacity.  Furthermore, principal component analysis (PCA) and Pearson’s correlation test are performed to provide an overview of the complete dataset. This study provides valuable information for evaluating the fruit quality and determining when to harvest the fruit in order to meet the preferences of consumers.  Meanwhile, our observations suggest that the fruits subjected to juice processing should be harvested at the late maturity stage to alleviate the “delayed bitterness” problem without compromising the antioxidant capacity and the flavonoid content in the juice.
    Agricultural Economics and Management
    The relationship between farm size and fertilizer use efficiency: Evidence from China
    ZHU Wei, QI Li-xia, WANG Rui-mei
    2022, 21(1): 273-281.  DOI: 10.1016/S2095-3119(21)63724-3
    Abstract ( )   PDF in ScienceDirect  
    Low fertilizer use efficiency is commonly found in China’s agriculture sector.  It is critical to understand the drivers of fertilizer use in order to increase fertilizer use efficiency (FUE).  The purpose of this paper is to investigate the relationship between farm size and FUE based on farm-level data in China.  The results suggest a positive farm size–FUE relationship.  The estimated elasticities of farm size for rice, maize, wheat–maize, and rice–maize are similar, and the average elasticity of farm size is around 0.2.  Statistically, a 1% increase in farm size is associated with a 0.2% increase in FUE.  The positive effect of farm size on FUE is not due to the increase in yield, but the reduction in fertilizer use while keeping yield largely unchanged.  The findings suggest that promoting the expansion of farm size may increase FUE, and thus reduce environmental pollution caused by fertilizer overuse.
    Does Internet use promote the adoption of agricultural technology?  Evidence from 1 449 farm households in 14 Chinese provinces
    ZHENG Yang-yang, ZHU Tie-hui, JIA Wei
    2022, 21(1): 282-292.  DOI: 10.1016/S2095-3119(21)63750-4
    Abstract ( )   PDF in ScienceDirect  
    China is characterized as ‘a large country with many smallholder farmers’ whose participation in modern agriculture is key to the country’s modern agriculture development.  Promoting smallholder farmers’ adoption of modern agricultural production technology is one effective way to improve the capabilities of smallholder farmers.  This paper aims to explore the impact of Internet use on the adoption of agricultural production technology by smallholder farmers based on a survey of 1 449 smallholders across 14 provinces in China.  The results suggest that Internet use can significantly promote technology adoption, with the probability of adopting new crop varieties, water-saving irrigation technology and straw-returning technology increasing by 0.200, 0.157 and 0.155, respectively.  Furthermore, the effect of Internet use is found to be heterogeneous with a greater effect on smallholder farmers having low education levels, limited training, and high incomes.  To increase agricultural production technology adoption by smallholders, rural Internet infrastructure and Internet use promotion should be the focus for the Chinese government.
    Short Communication
    New geographic distribution and molecular diversity of Citrus chlorotic dwarf-associated virus in China
    YANG Zhen, ZHANG Lan, ZHAO Jin-fa, ZHANG Xing-kai, WANG Ying, LI Tai-sheng, ZHANG Wei, ZHOU Yan
    2022, 21(1): 293-298.  DOI: 10.1016/S2095-3119(20)63601-2
    Abstract ( )   PDF in ScienceDirect  
    In 2009, an emerging citrus viral disease caused by Citrus chlorotic dwarf-associated virus (CCDaV) was discovered in Yunnan Province of China.  However, the occurrence and spread of CCDaV in other citrus-growing provinces in China is unknown to date.  To better understand the distribution and molecular diversity of CCDaV in China, a total of 1 772 citrus samples were collected from 11 major citrus-growing provinces and were tested for CCDaV by PCR.  Among these, 134 citrus samples from Guangxi, Yunnan and Guangdong were tested positive for CCDaV, demonstrating that the occurrence and spread of CCDaV are increasing in China.  The complete genome sequences of 17 CCDaV isolates from different provinces and hosts were sequenced.  Comparisons of the whole-genome sequences of the 17 CCDaV isolates as well as the 15 isolates available in GenBank revealed that the sequence identity was about 99–100%, showing that the CCDaV isolates were highly conserved.  Phylogenetic studies showed that the 32 CCDaV isolates belonged to four different groups based on geographical origins and host species, and that CCDaV isolates from China and Turkey were clustered into different groups.  The results provide important information for clarifying the distribution and genetic diversity of CCDaV in China.