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    2022 Vol. 21 No. 7 Previous Issue   

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


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    Review
    Roles of mushroom polysaccharides in chronic disease management
    ZHANG Shan, LEI Lin, ZHOU Yun, YE Fa-yin, ZHAO Guo-hua
    2022, 21(7): 1839-1866.  DOI: 10.1016/S2095-3119(21)63871-6
    Abstract ( )   PDF in ScienceDirect  
    Chronic diseases have drawn much attention as the primary cause of death and disability.  In exploring novel side-effect-free agents against chronic diseases, significant efforts have been devoted to mushroom polysaccharides due to their diverse biological activities.  This work reviewed the structural features, biological performances and molecular mechanisms of mushroom polysaccharides in managing cancers, diabetes mellitus and cardiovascular diseases.  The potentials of mushroom polysaccharides against chronic diseases highly depend on their structural features, including monosaccharide composition, molecular weight, the type and configuration of glycosidic bonds, degree of branching, the type of substituent pattern and chain conformation.  Regarding their working mechanisms, shared and disease-specific pathways were found.  The three chronic diseases shared the regulation of specific signalling pathways and the adjustment of gut microbiota.  In addition, the roles of transcription factors, receptors, enzymes, hormones and other functional proteins involved in the molecular mechanisms of mushroom polysaccharides against chronic diseases are first elaborated herein.  The present review describes the state of the art of mushroom polysaccharides in treating chronic diseases and addresses the perspectives, and will further promote research on this topic.
    Crop Science
    Influence of high-molecular-weight glutenin subunit deletions at the Glu-A1 and Glu-D1 loci on protein body development, protein components and dough properties of wheat (Triticum aestivum L.)
    LIU Da-tong, ZHANG Xiao, JIANG Wei, LI Man, WU Xu-jiang, GAO De-rong, BIE Tong-de, LU Cheng-bin
    2022, 21(7): 1867-1876.  DOI: 10.1016/S2095-3119(21)63605-5
    Abstract ( )   PDF in ScienceDirect  
    High-molecular-weight glutenin subunits (HMW-GSs) play a critical role in determining the viscoelastic properties of wheat.  As the organelle where proteins are stored, the development of protein bodies (PBs) reflects the status of protein synthesis and also affects grain quality to a great extent.  In this study, with special materials of four near-isogenic lines in a Yangmai 18 background we created, the effects of Glu-A1 and Glu-D1 loci deletions on the development and morphological properties of the protein body, protein components and dough properties were investigated.  The results showed that the deletion of the HMW-GS subunit delayed the development process of the PBs, and slowed the increases of volume and area of PBs from 10 days after anthesis (DAA) onwards.  In contrast, the areas of PBs at 25 DAA, the middle or late stage of endosperm development, showed no distinguishable differences among the four lines.  Compared to the wild type and single null type in Glu-A1, the ratios of HMW-GSs to low-molecular-weight glutenin subunits (LMW-GSs), glutenin macropolymer (GMP) content, mixograph parameters as well as extension parameters decreased in the single null type in Glu-D1 and double null type in Glu-A1 and Glu-D1, while the ratios of gliadins (Gli)/glutenins (Glu) in those types increased.  The absence of Glu-D1 subunits decreased both dough strength and extensibility significantly compared to the Glu-A1 deletion type.  These results provide a detailed description of the effect of HMW-GS deletion on PBs, protein traits and dough properties, and contribute to the utilization of Glu-D1 deletion germplasm in weak gluten wheat improvement for use in cookies, cakes and southern steamed bread in China and liquor processing. 
    Variations in the quality parameters and gluten proteins in synthetic hexaploid wheats solely expressing the Glu-D1 locus
    DAI Shou-fen, CHEN Hai-xia, LI Hao-yuan, YANG Wan-jun, ZHAI Zhi, LIU Qian-yu, LI Jian, YAN Ze-hong
    2022, 21(7): 1877-1885.  DOI: 10.1016/S2095-3119(21)63651-1
    Abstract ( )   PDF in ScienceDirect  
    This study evaluated the quality potential of seven synthetic hexaploid wheats (2n=6x=42, AABBDD) expressing only allelic variation at Glu-D1 of Aegilops tauschii (SHWSD).  Major quality parameters related to dough strength, gluten proteins (including high-molecular-weight glutenin subunits (HMW-GS) and low-molecular-weight glutenin subunits (LMW-GS), gliadins), and their ratios between SHWSD and the weak gluten wheat control Chuannong 16 (CN16) were measured in at least three environments (except STD7).  The zeleny sedimentation value (ZSV), dough development time (DDT), dough stability time (DST), and farinograph quality number (FQN) of SHWSD were considered stable under different environments, with their respective ranges being 8.00–17.67 mL, 0.57–1.50 min, 0.73–1.80 min, and 9.50–27.00.  The ZSV, DDT, DST, and FQN of SHWSD were smaller than those of CN16, suggesting that SHWSD had a weaker dough strength than CN16.  Although SHWSD had a lower gluten index than CN16, its wet and dry gluten contents were similar to or even higher than those of CN16 in all environments tested.  The protein content of grains (12.81–18.21%) and flours (14.20–20.31%) in SHWSD was higher than that in CN16.  The amount of HMW-GS in SHWSD sharply decreased under the expression of fewer HMW-GS genes, and the LMW-GS, gliadins, and total glutenins were simultaneously increased in SHWSD in comparison with CN16.  Moreover, SHWSD had higher ratios of LMW-GS/glutenin and gliadin/glutenin but a lower ratio of HMW-GS/glutenin than CN16.  These results provide necessary information for the utilization of SHWSD in weak-gluten wheat breeding.
    Identification of candidate genes related to soluble sugar contents in soybean seeds using multiple genetic analyses
    PAN Wen-jing, HAN Xue, HUANG Shi-yu, YU Jing-yao, ZHAO Ying, QU Ke-xin, ZHANG Ze-xin, YIN Zhen-gong, QI Hui-dong, YU Guo-long, ZHANG Yong, XIN Da-wei, ZHU Rong-sheng, LIU Chun-yan, WU Xiao-xia, JIANG Hong-wei, HU Zhen-bang, ZUO Yu-hu, CHEN Qing-shan, QI Zhao-ming
    2022, 21(7): 1886-1902.  DOI: 10.1016/S2095-3119(21)63653-5
    Abstract ( )   PDF in ScienceDirect  
    Soluble sugar content in seeds is an important quality trait of soybean.  In this study, 57 quantitative trait loci (QTLs) related to soluble sugar contents in soybean seeds were collected from databases and published papers.  After meta-overview-collinearity integrated analysis to refine QTL intervals, eight consensus QTLs were identified.  To further verify the consensus QTLs, a population of chromosome segment substitution lines (CSSLs) was analyzed.  Two lines containing fragments covering the regions of consensus QTLs and the recurrent parent were selected: one line showed high soluble sugar contents associated with a consensus QTL fragment, and the other line showed low soluble sugar contents.  Transcriptome sequencing was conducted for these two lines at the early, middle, and late stages of seed development, which identified 158, 109 and 329 differentially expressed genes, respectively.  Based on the analyses of re-sequencing data of the CSSLs and the consensus QTL region, three candidate genes (Glyma.19G146800, Glyma.19G122500, and Glyma.19G128500) were identified in the genetic fragments introduced from wild soybean.  Sequence comparisons between the two CSSL parents SN14 and ZYD00006 revealed a single nucleotide polymorphism (SNP) mutation in the coding sequence of Glyma.19G122500, causing a non-synonymous mutation in the amino acid sequence that affected the predicted protein structure.  A Kompetitive allele-specific PCR (KASP) marker was developed based on this SNP and used to evaluate the CSSLs.  These results lay the foundation for further research to identify genes related to soluble sugar contents in soybean seeds and for future soybean breeding.
    Identification and characterization of long-InDels through whole genome resequencing to facilitate fine-mapping of a QTL for plant height in soybean (Glycine max L. Merr.)
    LIU Chen, TIAN Yu, LIU Zhang-xiong, GU Yong-zhe, ZHANG Bo, LI Ying-hui, NA Jie, QIU Li-juan
    2022, 21(7): 1903-1912.  DOI: 10.1016/S2095-3119(21)63675-4
    Abstract ( )   PDF in ScienceDirect  
    With the development of sequencing technology, insertions-deletions (InDels) have been increasingly reported to be involved in the genetic deter mination of agronomical traits.  However, most studies have focused on the identification and application of short-InDels (1–15 bp) for genetic analysis.  The objective of this study was to deeply deploy long-InDels (>15 bp) for the genetic analysis of important agronomic traits in soybean.  A total of 13 573 polymorphic long-InDels were identified between parents Zhongpin 03-5373 (ZP) and Zhonghuang 13 (ZH), which were unevenly distributed on 20 chromosomes of soybean, varying from 321 in Chr11 to 1 246 in Chr18.  Consistent with the distribution pattern of annotated genes, the average density of long-InDels in arm regions was significantly higher than that in pericentromeric regions at the P=0.01 level.  A total of 2 704 (19.9% of total) long-InDels were located in genic regions, including 319 large-effect long-InDels, which resulted in truncated or elongated protein sequences.  A previously identified QTL (qPH16) underlying plant height was further analyzed, and it was found that 26 out of 35 (74.3%) long-InDel markers located in the qPH16 region showed clear polymorphisms between parents ZP and ZH.  Seven markers, including three long-InDels and four previously reported SNP markers, were used to genotype 242 recombinant inbred lines derived from ZP×ZH.  As a result, the qPH16 locus was narrowed from a 960-kb region to a 477.55-kb region, containing 65 annotated genes.  Therefore, these long-InDels are a complementary genetic resource of SNPs and short-InDels for plant height and can facilitate genetic studies and molecular assisted selection breeding in soybean.
    Photosynthetic properties of the mid-vein and leaf lamina of field-grown, high-yield hybrid rice during senescence
    GAO Zhi-ping, XU Min-li, ZHANG Hai-zi, LÜ Chuan-gen, CHEN Guo-xiang
    2022, 21(7): 1913-1926.  DOI: 10.1016/S2095-3119(21)63676-6
    Abstract ( )   PDF in ScienceDirect  
    Previous studies with rice (Oryza sativa L.) have shown that the different components of the photosynthetic apparatus are not uniformly synthesized or degraded during senescence.  However, while most of those studies have focused on the leaf lamina, few have addressed senescence-associated chloroplast function or leaf physiology.  Here, we investigated the photosynthetic properties of the mid-vein and leaf lamina in a high-yield hybrid rice cultivar (Liangyoupei 9, LYP9) during the senescence stage.  Assimilation and transpiration decreased more slowly in the mid-vein than in the lamina during senescence, suggesting more sustained photosynthesis in the mid-vein, as well as stronger heat dissipation.  Two-dimensional gel electrophoresis suggested that photosynthesis and energy metabolism were less affected by senescence in the mid-vein than in the leaf lamina.  During late senescence, the excess energy dissipation in the mid-vein through the xanthophyll cycle had a higher active photosynthetic capacity than in the leaf lamina, and we inferred that the mid-vein and leaf lamina of LYP9 rice differed in terms of their maturation.  Taken together, these results provide new insights into the underlying mechanisms of senescence of the rice mid-vein and associated physiology.
    Wheat growth, photosynthesis and physiological characteristics under different soil Zn levels
    LI Si-ping, ZENG Lu-sheng, SU Zhong-liang
    2022, 21(7): 1927-1940.  DOI: 10.1016/S2095-3119(21)63643-2
    Abstract ( )   PDF in ScienceDirect  
    In recent years, heavy metal hazards in the soil have seriously affected agricultural production.  This study aims to examine the effects of different levels of heavy metal Zn on the growth, photosynthesis and physiological characteristics of wheat, and provide a theoretical basis for the diagnosis and control of heavy metal pollution in agricultural production.  The field test method was used to explore the changes of wheat agronomic traits, photosynthetic capacity, chlorophyll fluorescence parameters, spectral characteristic curve, active oxygen metabolism system, cell ultrastructure, and yield, under different Zn levels (0, 250, 500, 750, and 1 000 mg kg–1).  The results show that, low-level Zn treatments can effectively promote the synthesis of wheat chlorophyll, improve photosynthetic capacity, and increase yield.  The yield of ZnL1 (250 mg kg–1) was the highest in the two-year test, which increased by 20.4% in 2018 and 13.9% in 2019 compared with CK (0 mg kg–1).  However, a high Zn level had a significant stress effect on the photosystem of wheat.  PIabs (reaction center performance index) and Fv/Fm (maximum photochemical efficiency) were significantly reduced, the active oxygen metabolism system was damaged, and the photosynthetic capacity was reduced, which in turn led to reduced yield.  Among them, the yield of ZnL4 (1 000 mg kg–1) was the lowest in the two-year test, which was 28.1 and 16.4% lower than CK in 2018 and 2019, respectively.  The green peak position of ZnL3 and ZnL4 had “red shift” to the long wave direction, while the red valley position of ZnL4 had “blue shift” to the short wave direction.  Under ZnL4, some wheat leaf organelles began to decompose, vacuoles increased, cytoplasm decreased, cell walls thickened, chloroplast basal lamellae were disordered, and mitochondrial membranes disintegrated.  Stepwise regression and Path analysis showed that Pn (net photosynthetic rate) played a leading role in the formation of yield.  Redundancy (RDA) analysis showed that the optimal Zn level for wheat growth was about 250 mg kg–1, and wheat would be stressed when the soil Zn level exceeded 500 mg kg–1 in the test condition of this study.  Findings of this study provide a theoretical basis for the diagnosis and prevention of heavy metal (Zn) pollution in the soil.
    Grain yield and grain moisture associations with leaf, stem and root characteristics in maize
    XU Chen-chen, ZHANG Ping, WANG Yuan-yuan, LUO Ning, TIAN Bei-jing, LIU Xi-wei, WANG Pu, HUANG Shou-bing
    2022, 21(7): 1941-1951.  DOI: 10.1016/S2095-3119(20)63598-5
    Abstract ( )   PDF in ScienceDirect  
    Improving grain yield (GY) and reducing grain moisture (GM) are urgent demands for directly harvesting kernels with combine harvesters in maize production.  GY and GM are both related to leaf, stem and root characteristics, but the relationships are not fully understood.  To better understand these relationships, we conducted a field trial involving 12 maize hybrids with two sowing dates in 2017 and 10 maize hybrids with one sowing date in 2019.  GY ranged from 6.5–14.6 t ha–1 in early-sown varieties and 9.3–12.7 t ha–1 in late-sown varieties in 2017, and 5.9–7.4 t ha–1 in 2019, respectively, with corresponding GM variations of 29.8–34.9%, 29.4–34.5% and 31.9–37.1% at harvest.  A large maximum leaf area contributed to a high yield, a fast leaf senescence rate accelerated grain dehydration in the late growth period, and a compact root structure resulted in both of high-yield and fast-grain dehydration.  A strong stem improved lodging resistance but maintained a high GM at harvest, and it is challenging to combine high GY and low GM in maize.  High GY co-existed with low GM in some varieties that should have a rapid grain filling, a relatively long grain-filling duration, and a rapid grain dehydration in the late growth period.  A high daily temperature in the late growth period also improved GY and reduced GM by influencing grain filling and dehydration, suggesting that adjusting the sowing date should be an alternative strategy to combine high GY and low GM in kernel harvesting. 
    Horticulture
    Comparative transcriptome analysis provides insights into the mechanism of pear dwarfing
    TANG Zi-kai, SUN Man-yi, LI Jia-ming, SONG Bo-bo, LIU Yue-yuan, TIAN Yi-ke, WANG Cai-hong, WU Jun
    2022, 21(7): 1952-1967.  DOI: 10.1016/S2095-3119(21)63774-7
    Abstract ( )   PDF in ScienceDirect  
    Dwarfism is an important trait which is closely related to the efficiency of fruit orchard management and production.  However, dwarfing cannot be widely applied in the cultivation of pears, especially Asian pears.  Developing varieties with dwarf characteristics is a goal of paramount importance in pear breeding.  In the present study, dwarf phenotype pears (DPPs) and arborescent phenotype pears (APPs) were obtained from the offspring of a cross between ‘Aiyuxiang’ and ‘Cuiguan’ pear cultivars, which exhibited dwarfed and arborescent statures, respectively.  When compared with APPs, the heights of DPPs showed a 62.8% reduction, and the internode lengths were significantly shorter.  Cross-grafting between DPPs and APPs demonstrated that the dwarfed phenotype of DPPs was primarily induced by the aerial portions of the plant, and independent of the root system.  Observations of stem tissue sections showed that DPP cells were arranged chaotically with irregular shapes, and the average length was larger than that of the APP cells.  A total of 1 401 differently expressed genes (DEGs) in shoot apices between DPPs and APPs were identified by RNA-sequencing (RNA-Seq), and these DEGs were mainly enriched in the ‘phytohormone-related pathways, cell wall metabolism and cell division’ categories.  Moreover, 101 DEGs were identified as transcription factors (TFs).  In DPPs, several brassinosteroids (BR) signaling and cell cycle-related genes were significantly down-regulated, while genes involved in BR and GA degradation were up-regulated.  Comprehensive analysis of RNA-Seq data and stem tissue sections suggested that the dwarfed phenotype of DPPs could be primarily attributed to deficiencies in cell division.  Previous work using simple sequence repeat (SSR) markers narrowed the location of the gene responsible for the dwarf phenotype of ‘Le Nain Vert’.  Through combined analysis of our transcriptomic data with the SSR results, we identified four genes as promising candidates for the dwarf phenotype, among which, a DELLA gene could be the most promising.  The results presented in this study provide a sound foundation for further exploration into the genetic and molecular mechanisms underlying pear dwarfing.
    Overexpression of MdMIPS1 enhances drought tolerance and water-use efficiency in apple
    HU Ling-yu, YUE Hong, ZHANG Jing-yun, LI Yang-tian-su, GONG Xiao-qing, ZHOU Kun, MA Feng-wang
    2022, 21(7): 1968-1981.  DOI: 10.1016/S2095-3119(21)63822-4
    Abstract ( )   PDF in ScienceDirect  
    Myo-inositol and its derivatives play important roles in the tolerance of higher plants to abiotic stresses, and myo-inositol-1-phosphate synthase (MIPS) is the rate-limiting enzyme in myo-inositol biosynthesis.  In this study, we found that increased myo-inositol biosynthesis enhanced drought tolerance in MdMIPS1-overexpressing apple lines under short-term progressive drought stress.  The effect of myo-inositol appeared to be mediated by the increased accumulation of osmoprotectants such as glucose, sucrose, and proline, and by the increased activities of antioxidant enzymes that eliminate reactive oxygen species.  Moreover, enhanced water-use efficiency (WUE) was observed in MdMIPS1-overexpressing apple lines under long-term moderate water deficit conditions that mimicked the water availability in the soil of the Loess Plateau.  Enhanced WUE may have been associated with the synergistic regulation of osmotic balance and stomatal aperture mediated by increased myo-inositol biosynthesis.  Taken together, our findings shed light on the positive effects of MdMIPS1-mediated myo-inositol biosynthesis on drought tolerance and WUE in apple.
    Genome-wide identification and characterization of the abiotic-stress-responsive lipoxygenase gene family in diploid woodland strawberry (Fragaria vesca)
    LI Zhi-qi, Xie Qian, YAN Jia-hui, CHEN Jian-qing, CHEN Qing-xi
    2022, 21(7): 1982-1996.  DOI: 10.1016/S2095-3119(21)63819-4
    Abstract ( )   PDF in ScienceDirect  
    Lipoxygenase (LOXs) is a kind of dioxygenase without heme and iron, which plays an important role in the development and adaptation of many plants to the environment.  However, the study of strawberry LOX gene family has not been reported.  In this study, 14 LOX genes were identified from the diploid woodland strawberry genome.  The phylogenetic tree divides the FvLOX gene into two subfamilies: 9-LOX and 13-LOX.  Gene duplication event analysis showed that whole-genome duplication (WGD)/segmental duplication and dispersed duplication effectively promoted the expansion of strawberry LOX family.  QRT-PCR analysis showed that FvLOX genes were expressed in different tissues.  Expression profile analysis showed that FvLOX1 and FvLOX8 were up-regulated under low temperature stress, FvLOX3 and FvLOX7 were up-regulated under drought stress, FvLOX6 and FvLOX9 were up-regulated under salt stress, FvLOX2, FvLOX3 and FvLOX6 were up-regulated under salicylic acid (SA) treatment, FvLOX3, FvLOX11 and FvLOX14 were up-regulated under methyl jasmonate (MeJA) treatment, FvLOX4 and FvLOX14 were up-regulated under abscisic acid (ABA) treatment.  Promoter analysis showed that FvLOX genes were involved in plant growth and development and stress response.  We analyzed and identified the whole genome of strawberry FvLOX family and characterized a variety of FvLOX candidate genes involved in abiotic stress response.  This study laid a theoretical and empirical foundation for the response mechanism of strawberry to abiotic stress.
    Identifying potential flavonoid biosynthesis regulator in Zanthoxylum bungeanum Maxim. by genome-wide characterization of the MYB transcription factor gene family
    WANG Xiang-yuan, TIAN Lu, FENG Shi-jing, WEI An-zhi
    2022, 21(7): 1997-2018.  DOI: 10.1016/S2095-3119(21)63747-4
    Abstract ( )   PDF in ScienceDirect  
    Plant MYB transcription factors (TFs) play crucial roles in regulating the biosynthesis of flavonoids but current analysis on their role in Zanthoxylum bungeanum Maxim. (ZBM) is far from comprehensive.  In this study, we identified 270 MYB genes in ZBM and divided them into four subfamilies.  The R2R3-MYB (ZbMYB) category contained 251 genes and was classified into 33 subfamilies according to their phylogenetic results and sequence similarity.  These subfamilies included 24 subgroups containing both MYBs of ZBM plants and AtMYBs, and nine subgroups containing only ZBM MYBs or AtMYBs.  ZbMYBs with similar functions clustered into the same subgroup, indicating functional conservation.  The subcellular localization analysis predicted that most ZbMYB genes were found in the nucleus.  The transposed duplications appeared to play a major role in the expansion of the MYB gene family in ZBM.  Through phylogenetic analysis and transcriptome profiling, it was found that 28 ZbMYB genes may regulate the biosynthesis of flavonoids in ZBM, and these genes expression presented distinct temporal and spatial expression patterns.  In different fruit development stages of ZBM, the expression patterns of EVM0042160 and EVM0033809 genes obtained by qRT-PCR analysis are very similar to the flavonoid and anthocyanin content curves in ZBM.  Further correlation analysis showed that the content of flavonoids in different fruit development stages and the transcript abundance levels of 28 ZbMYB genes have different degrees of correlation relationship.  These results indicated that the ZbMYB genes might be involved in the flavonoid metabolic pathway.  This comprehensive and systematic analysis of MYB family genes provided a solid foundation for further functional analysis of MYB TFs in ZBM.
    Plant Protection
    Characterization of laccase gene StLAC6 involved in the pathogenicity and peroxisome function in Setosphaeria turcica
    LIU Ning, ZHANG Qian-qian, JIA Hui, ZHAO Bin, ZHU Zi-ping , CAO Zhi-yan, DONG Jin-gao
    2022, 21(7): 2019-2030.  DOI: 10.1016/S2095-3119(21)63855-8
    Abstract ( )   PDF in ScienceDirect  

    Laccases, as a kind of multicopper oxidase, play an important role in pigment synthesis and growth in fungi and are involved in their interactions with host plants.  In Setosphaeria turcica, 9 laccase-like multicopper oxidases have been identified, and StLAC2 is involved in the synthesis of the melanin that accumulates in the cell wall.  The function of another major laccase gene, StLAC6, was studied here.  The knockout of StLAC6 had no effect on the growth, morphology or invasion ability of S. turcica, but the morphology and function of peroxisomes of knockout mutants were abnormal.  The knockout of the StLAC6 gene resulted in increased contents of phenolic compounds and melanin and the sensitivity to fungicides increased compared with wild type strains.  In the mutants of StLAC6, there is a significant change of the expression levels of other laccase genes.  This study provides a new insight into laccase functions and the relationship of the laccase gene family in plant pathogenic fungi.   

    Apple stem grooving virus is associated with leaf yellow mottle mosaic disease on Citrus grandis cv. Huangjinmiyou in China
    XUAN Zhi-you, ZHANG Song, LI Ping, YANG Fang-yun, CHEN Hong-ming, LIU Ke-hong, ZHOU Yan, LI Zhong-an, ZHOU Chang-yong, CAO Meng-ji
    2022, 21(7): 2031-2041.  DOI: 10.1016/S2095-3119(21)63823-6
    Abstract ( )   PDF in ScienceDirect  
    Although it is usually latent on citrus, apple, and pear, apple stem grooving virus (ASGV) poses a great risk to many sensitive cultivars.  Since severe leaf yellow mottle mosaic (LYMM) symptoms have been observed on Huangjinmiyou (HJY) pummelos (Citrus grandis cv. Huangjinmiyou), a commercial variety that is widely cultivated in South China, high throughput sequencing (HTS) was used to find potential pathogens and only three divergent ASGV variants were identified.  The three ASGV variants shared 81.03–82.34% genome-wide pairwise identities with each other, and were separately closest to other ASGV variants from different hosts and/or geographical regions, as indicated by viral phylogenies.  However, these new variants may have developed from viral interstrain interactions, based on the results of recombination analysis.  A large-scale survey using reverse transcription-PCR (RT-PCR) protocols designed for the three ASGV variants revealed a high incidence (92.7–100%) of ASGV in symptomatic HJY trees from 11 major citrus-producing regions in China.  None of ASGV were detected in asymptomatic trees.  Temperature treatments applied to the symptomatic HJY plants showed that ASGV is sensitive to high temperatures (30–35°C), at which not only the plants recovered, but also the viruses were not detected by RT-PCR, while at low temperatures (20–24°C), both the symptoms and viruses remained detectable.  These data show that ASGV is associated with the LYMM disease prevalent on HJY in China, and this is the significant basis especially of taking appropriate measures timely to manage the disease.  
    A conserved odorant receptor identified from antennal transcriptome of Megoura crassicauda that specifically responds to cis-jasmone
    WANG Bo, HUANG Tian-yu, YAO Yuan, Frederic FRANCIS, YAN Chun-cai, WANG Gui-rong, WANG Bing
    2022, 21(7): 2042-2054.  DOI: 10.1016/S2095-3119(21)63712-7
    Abstract ( )   PDF in ScienceDirect  
    Herbivore-induced plant volatiles (HIPVs) play a key role in the interactions between plants and herbivorous insects, as HIPVs can promote or deter herbivorous insects’ behavior.  While aphids are common and serious phloem-feeding pests in farmland ecosystems, little is known about how aphids use their sensitive olfactory system to detect HIPVs.  In this study, the antennal transcriptomes of the aphid species Megoura crassicauda were sequenced, and expression level analyses of M. crassicauda odorant receptors (ORs) were carried out.  To investigate the chemoreception mechanisms that M. crassicauda uses to detect HIPVs, we performed in vitro functional studies of the ORs using 11 HIPVs reported to be released by aphid-infested plants.  In total, 54 candidate chemosensory genes were identified, among which 20 genes were ORs.  McraOR20 and McraOR43 were selected for further functional characterization because their homologs in aphids were quite conserved and their expression levels in antennae of M. crassicauda were relatively high.  The results showed that McraOR20 specifically detected cis-jasmone, as did its ortholog ApisOR20 from the pea aphid Acyrthosiphon pisum, while McraOR43 did not respond to any of the HIPV chemicals that were tested.  This study characterized the ability of the homologous OR20 receptors in the two aphid species to detect HIPV cis-jasmone, and provides a candidate olfactory target for mediating aphid behaviors.  
    A sublethal concentration of afidopyropen suppresses the population growth of the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae)
    MA Kang-sheng, TANG Qiu-ling, LIANG Ping-zhuo, LI Jian-hong, GAO Xi-wu
    2022, 21(7): 2055-2064.  DOI: 10.1016/S2095-3119(21)63714-0
    Abstract ( )   PDF in ScienceDirect  
    The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is an important insect pest of cotton crops worldwide.  The objectives of this study were to determine the acute toxicity of afidopyropen and whether there are any effects of sublethal concentrations of afidopyropen on the biological characteristics of A. gossypii.  The results showed that afidopyropen possesses high acute toxicity to adult A. gossypii with a 72 h LC50 value of 1.062 mg L–1.  A sublethal concentration (LC10) of afidopyropen significantly decreased adult longevity, fecundity and oviposition days of female adults in both F0 and F1 generations.  The total pre-adult survival of F1 progeny was also significantly reduced by 30% at the LC10 of afidopyropen.  In addition, the nymph developmental time, pre-adult period, adult pre-reproductive period (APRP), and total pre-reproductive period (TPRP) of the F1 progeny were significantly prolonged compared with the control.  Several population parameters, including the net reproductive rate (R0), intrinsic rate of increase (r) and finite rate of increase (λ) of F1 progeny were significantly decreased by a sublethal afidopyropen concentration exposure.  These results indicated that sublethal concentration of afidopyropen can significantly suppress A. gossypii population growth.  It would be useful for assessing the overall effects of afidopyropen on A. gossypii.  
    Animal Science · Veterinary Medicine
    Integration of genome-wide association study and selection signatures reveals genetic determinants for skeletal muscle production traits in an F2 chicken population
    LI Yu-dong, BAI Xue, LIU Xin , WANG Wei-jia, LI Zi-wei, WANG Ning, XIAO Fan, GAO Hai-he, GUO Huai-shun, LI Hui, WANG Shou-zhi
    2022, 21(7): 2065-2075.  DOI: 10.1016/S2095-3119(21)63805-4
    Abstract ( )   PDF in ScienceDirect  

    Improving the production of broiler chicken meat has been a goal of broiler breeding programs worldwide for many years.  However, the genetic architectures of skeletal muscle production traits in chickens have not yet been fully elucidated.  In the present study, a total of 519 F2 birds, derived from a cross of Arbor Acres broiler and Baier layer, were re-sequenced (26 F0 individuals were re-sequenced at a 10-fold depth; 519 F2 individuals were re-sequenced at a 3-fold depth) and the coupling of genome-wide association study (GWAS) and selection signatures (FST (fixation index) and θπ (nucleotide diversity)) was carried out to pinpoint the associated loci and genes that contribute to pectoral muscle weight (PMW) and thigh muscle weight (TMW).  A total of 7 890 258 single nucleotide polymorphisms (SNPs) remained to be analyzed after quality control and imputation.  The integration of GWAS and selection signature analyses revealed that genetic determinants responsible for skeletal muscle production traits were mainly localized on chromosomes 1 (168.95–172.43 Mb) and 4 (74.37–75.23 Mb).  A total of 17 positional candidate genes (PCGs) (LRCH1, CDADC1, CAB39L, LOC112531568, LOC112531569, FAM124A, FOXO1, NBEA, GPALPP1, RUBCNL, ARL11, KPNA3, LHFP, GBA3, LOC112532426, KCNIP4, and SLIT2) were identified in these regions.  In particular, KPNA3 and FOXO1 were the most promising candidates for meat production in chickens.  These findings will help enhance our understanding of the genetic architecture of chicken muscle production traits, and the significant SNPs identified could be promising candidates for integration into practical breeding programs such as genome-wide selection (GS) to improve the meat yield of chickens.

    Effect of the gene silencing of phosphorus transporters on phosphorus absorption across primary cultured duodenal epithelial cell monolayers of chick embryos
    LI Ting-ting, LU Na, SHAO Yu-xin, ZHANG Li-yang, LU Lin, LIU Zong-ping, LUO Xu-gang, LIAO Xiu-dong
    2022, 21(7): 2076-2085.  DOI: 10.1016/S2095-3119(21)63771-1
    Abstract ( )   PDF in ScienceDirect  
    The aim of the study was to investigate whether phosphorus (P) transporters, type IIb sodium-dependent phosphate cotransporter (NaP-IIb) and inorganic phosphate transporter 2 (PiT2), were directly involved in P absorption across primary cultured duodenal epithelial cell monolayers of chick embryos.  The siRNAs against NaP-IIb or PiT2 were designed, synthesized and transfected into primary cultured duodenal epithelial cells of chick embryos.  Then, the inhibitory efficiency of siRNAs against NaP-IIb or PiT2 was analyzed, and the most efficacious siRNAs were selected to be used for subsequent P absorption experiments.  Briefly, primary cultured duodenal epithelial cells of chick embryos were transfected with either NaP-IIb or PiT2 siRNAs and grown in confluent monolayers on transwell plates.  The untransfected or transfected cell monolayers were then incubated in an uptake medium containing 0 or 0.25 mmol L–1 of P as KH2PO4 to measure the P absorption across duodenal epithelial cell monolayers.  The results showed that among the siRNAs designed, si-1372 and si-890 were demonstrated to be the most effective in inhibiting the NaP-IIb and PiT2 expressions, respectively.  Supplemental P increased (P=0.065) the protein abundance of PiT2 and enhanced (P<0.0001) P absorption in primary cultured duodenal epithelial cell of chick embryos.  Furthermore, NaP-IIb silencing decreased (P=0.07) P absorption across duodenal epithelial cell monolayers, while PiT2 silencing had no effect (P=0.345).  It is concluded that the NaP-IIb, but not PiT2, might be directly involved in the P absorption of chick duodenal epithelial cells.
    Protective efficacy of an H5/H7 trivalent inactivated vaccine (H5-Re13, H5-Re14, and H7-Re4 strains) in chickens, ducks, and geese against newly detected H5N1, H5N6, H5N8, and H7N9 viruses
    ZENG Xian-ying, HE Xin-wen, MENG Fei, MA Qi, WANG Yan, BAO Hong-mei, LIU Yan-jing, DENG Guo-hua, SHI Jian-zhong, LI Yan-bing, TIAN Guo-bin, CHEN Hua-lan
    2022, 21(7): 2086-2094.  DOI: 10.1016/S2095-3119(22)63904-2
    Abstract ( )   PDF in ScienceDirect  

    Some H5 viruses isolated in poultry or wild birds between 2020 and 2021 were found to be antigenically different from the vaccine strains (H5-Re11 and H5-Re12) used in China.  In this study, we generated three new recombinant vaccine seed viruses by using reverse genetics and used them for vaccine production.  The vaccine strain H5-Re13 contains the hemagglutinin (HA) and neuraminidase (NA) genes of an H5N6 virus that bears the clade 2.3.4.4h HA gene, H5-Re14 contains the HA and NA genes of an H5N8 virus that bears the clade 2.3.4.4b HA gene, and H7-Re4 contains the HA and NA genes of H7N9 virus detected in 2021.  We evaluated the protective efficacy of the novel H5/H7 trivalent inactivated vaccine in chickens, ducks, and geese.  The inactivated vaccine was immunogenic and induced substantial antibody responses in the birds tested.  Three weeks after vaccination, chickens were challenged with five different viruses detected in 2020 and 2021: three viruses (an H5N1 virus, an H5N6 virus, and an H5N8 virus) bearing the clade 2.3.4.4b HA gene, an H5N6 virus bearing the clade 2.3.4.4h HA gene, and an H7N9 virus.  All of the control birds shed high titers of virus and died within 4 days post-challenge, whereas the vaccinated chickens were completely protected from these viruses.  Similar protective efficacy against H5 viruses bearing the clade 2.3.4.4h or 2.3.4.4b HA gene was observed in ducks and geese.  Our study indicates that the newly updated H5/H7 vaccine can provide solid protection against the H5 and H7N9 viruses that are currently circulating in nature.  

    Generation and application of two monoclonal antibodies targeting conserved linear epitopes in the NP protein of influenza A virus
    ZHAO Yu-hui, WEN Xia, LI Qi-bing, JIANG Li, WANG Guang-wen, LIANG Li-bin, WANG Xiu-rong, CHEN Hua-lan, LI Cheng-jun
    2022, 21(7): 2095-2105.  DOI: 10.1016/S2095-3119(21)63840-6
    Abstract ( )   PDF in ScienceDirect  
    Monoclonal antibodies (mAbs) are widely used in virus research and disease diagnosis.  The nucleoprotein (NP) of influenza A virus (IAV) plays important roles in multiple stages of the virus life cycle.  Therefore, generating conserved mAbs against NP and characterizing their properties will provide useful tools for IAV research.  In this study, two mAbs against the NP protein, 10E9 and 3F3, were generated with recombinant truncated NP proteins (NP-1 and NP-2) as immunogens.  The heavy-chain subclass of both 10E9 and 3F3 was determined to be IgG2α, and the light-chain type was κ.  Truncation and site-specific mutation analyses showed that the epitopes of mAbs 10E9 and 3F3 were located in the N terminal 84–89 amino acids and the C terminal 320–324 amino acids of the NP protein, respectively.  We found that mAbs 10E9 and 3F3 reacted well with the NP protein of H1–H15 subtypes of IAV.  Both 10E9 and 3F3 can be used in immunoprecipitation assay, and 10E9 was also successfully applied in confocal microscopy.  Furthermore, we found that the 10E9-recognized 84SAGKDP89 epitope and 3F3-recognized 320ENPAH324 epitope were highly conserved in NP among all avian and human IAVs.  Thus, the two mAbs we developed could be used as powerful tools in the development of diagnostic methods of IAV, and also surely promote the basic research in understanding the replication mechanisms of IAV.

    Agro-ecosystem & Environment
    Increase in yield and nitrogen use efficiency of double rice with long-term application of controlled-release urea
    TIAN Chang, SUN Ming-xue, ZHOU Xuan, LI Juan, XIE Gui-xian, YANG Xiang-dong, PENG Jian-wei
    2022, 21(7): 2106-2118.  DOI: 10.1016/S2095-3119(21)63734-6
    Abstract ( )   PDF in ScienceDirect  
    Controlled-release urea (CRU) has better characteristics than conventional urea for synchronizing nitrogen (N) release with plant uptake.  Understanding the effects of CRU on crop yield and N use efficiency (NUE) has long been the key to evaluate the performance of CRU.  A long-term experiment over five consecutive years was conducted in Changsha, Hunan Province, China, to investigate the effects of polyethylene-coated urea with a 90-d release period on the yield and NUE of double rice (early and late crops are grown in the same year), the amount of residual soil mineral N and the soil–plant N balance, as well as on the economic benefits.  Four N fertilizer treatments including CK (no N fertilizer), U (conventional urea), CRU1 (polyethylene-coated urea with equal N application rate to U) and CRU2 (20% reduction in N application rate of CRU1) were established.  The results indicated that CRU1 application increased the yield and NUE of double rice by 11.0 and 13.5%, respectively, compared with U.  Higher yield and NUE of late rice were found than in early rice in CRU treatments.  Compared with conventional U, the yield and NUE of early rice in the CRU1 treatment were increased by 6.0 and 10.2%, respectively, and those of late rice were increased by 15.4 and 13.8%, respectively.  There was no significant difference between CRU1 and CRU2 in double rice yield.  Furthermore, CRU treatments (including CRU1 and CRU2) had higher apparent residual Nmin rate (ARNR) and apparent N recovery rate (ANRR), but lower apparent N loss (NS) than the conventional U treatment.  Concentrations of NH4+-N and NO3-N were greater in the surface soil (0–20 cm) and lower in the deeper soil layer (40–60 cm) with CRU treatments than in the U treatment after harvest.  Moreover, CRU application produced a greater economic benefit than conventional U application.  In general, CRU outperformed U fertilizer in terms of rice yield, NUE, soil–plant N balance, economic benefit, and CRU2 provided greater comprehensive benefits than CRU1.  It is suggested that CRU application is beneficial for solving N management challenges in the production of rice.

    Effects of a decade of organic fertilizer substitution on vegetable yield and soil phosphorus pools, phosphatase activities, and the microbial community in a greenhouse vegetable production system
    ZHANG Yin-Jie, GAO Wei, LUAN Hao-an, TAND Ji-wei, LI Ruo-nan, LI Ming-Yue, ZHANG Huai-zhi, HUANG Shao-wen
    2022, 21(7): 2119-2133.  DOI: 10.1016/S2095-3119(21)63715-2
    Abstract ( )   PDF in ScienceDirect  
    Partial substitution of chemical fertilizers by organic amendments is adopted widely for promoting the availability of soil phosphorus (P) in agricultural production.  However, few studies have comprehensively evaluated the effects of long-term organic substitution on soil P availability and microbial activity in greenhouse vegetable fields.  A 10-year (2009–2019) field experiment was carried out to investigate the impacts of organic fertilizer substitution on soil P pools, phosphatase activities and the microbial community, and identify factors that regulate these soil P transformation characteristics.  Four treatments included 100% chemical N fertilizer (4CN), 50% substitution of chemical N by manure (2CN+2MN), straw (2CN+2SN), and combined manure with straw (2CN+1MN+1SN).  Compared with the 4CN treatment, organic substitution treatments increased celery and tomato yields by 6.9−13.8% and 8.6−18.1%, respectively, with the highest yields being in the 2CN+1MN+1SN treatment.  After 10 years of fertilization, organic substitution treatments reduced total P and inorganic P accumulation, increased the concentrations of available P, organic P, and microbial biomass P, and promoted phosphatase activities (alkaline and acid phosphomonoesterase, phosphodiesterase, and phytase) and microbial growth in comparison with the 4CN treatment.  Further, organic substitution treatments significantly increased soil C/P, and the partial least squares path model (PLS-PM) revealed that the soil C/P ratio directly and significantly affected phosphatase activities and the microbial biomass and positively influenced soil P pools and vegetable yield.  Partial least squares (PLS) regression demonstrated that arbuscular mycorrhizal fungi positively affected phosphatase activities.  Our results suggest that organic fertilizer substitution can promote soil P transformation and availability.  Combining manure with straw was more effective than applying these materials separately for developing sustainable P management practices. 
    Interaction of soil microbial communities and phosphorus fractions under long-term fertilization in paddy soil 
    Muhammad QASWAR, Waqas AHMED, HUANG Jing, LIU Kai-lou, ZHANG Lu, HAN Tian-fu, DU Jiang-xue, Sehrish ALI, Hafeez UR-RAHIM, HUANG Qing-hai, ZHANG Hui-min
    2022, 21(7): 2134-2144.  DOI: 10.1016/S2095-3119(21)63733-4
    Abstract ( )   PDF in ScienceDirect  
    Understanding the impact of biological activities on the soil phosphorus (P) distribution under long-term fertilizer application can facilitate better soil P fertility management.  Therefore, the primary objectives of this study were to investigate the effect of long-term (since 1981) fertilizer application on the soil P fractions and microbial community and to evaluate correlations between the microbial community structure and P distribution.  The following treatments were implemented in a long-term field trial: no fertilization (CK), inorganic N and K (NK), inorganic P and K (PK), inorganic N, P and K (NPK) and manure+NPK (MNPK) fertilization.  The study showed that the soil pH, soil organic carbon and total and available N and P concentrations were considerably higher in the MNPK treatment than in the CK treatment.  The soil microbial biomass C, N and P concentrations were also significantly higher in the MNPK treatment than in the CK treatment.  Among fertilization treatments, the β-1,4-glucosidase, α-1,4-glucosidase, urease, acid phosphatase and phosphodiesterase activities were the highest in the MNPK treatment.  Compared to inorganic fertilization, the MNPK treatment increased the labile soil P fractions and decreased the residual soil P concentration.  Continuous fertilization significantly affected the soil microbial composition.  The total phospholipid fatty acid (PLFA) concentrations in the NK, PK, NPK and MNPK treatments were 23.3, 43.1, 48.7 and 87.7% higher, respectively, than in the CK treatment.  A significant correlation was observed between the microbial community and soil P fractions.  Moreover, the aggregated boosted tree (ABT) model showed that among the various soil biochemical properties, the total PLFA concentration was the factor that most influenced the active P pool, accounting for 35.4% of the relative influence of all soil biochemical properties examined.  These findings reveal that combined manure and inorganic fertilizer application is a better approach than applying inorganic fertilizer alone for sustaining long-term P fertility by mediating soil biological activity.


    The effects of soil properties, cropping systems and geographic location on soil prokaryotic communities in four maize production regions across China 
    TIAN Xue-liang, LIU Jia-jia, LIU Quan-cheng, XIA Xin-yao, PENG Yong, Alejandra I. HUERTA, YAN Jian-bing, LI Hui, LIU Wen-de
    2022, 21(7): 2145-2157.  DOI: 10.1016/S2095-3119(21)63772-3
    Abstract ( )   PDF in ScienceDirect  
    The diversity of prokaryotic communities in soil is shaped by both biotic and abiotic factors.  However, little is known about the major factors shaping soil prokaryotic communities at a large scale in agroecosystems.  To this end, we undertook a study to investigate the impact of maize production cropping systems, soil properties and geographic location (latitude and longitude) on soil prokaryotic communities using metagenomic techniques, across four distinct maize production regions in China.  Across all study sites, the dominant prokaryotes in soil were Alphaproteobacteria, Gammaproteobacteria, Betaproteobacteria, Gemmatimonadetes, Acidobacteria, and Actinobacteria.  Non-metric multidimensional scaling revealed that prokaryotic communities clustered into the respective maize cropping systems in which they resided.  Redundancy analysis (RDA) showed that soil properties especially pH, geographic location and cropping system jointly determined the diversity of the prokaryotic communities.  The functional genes of soil prokaryotes from these samples were chiefly influenced by latitude, soil pH and cropping system, as revealed by RDA analysis.  The abundance of genes in some metabolic pathways, such as genes involved in microbe–microbe interactions, degradation of aromatic compounds, carbon fixation pathways in prokaryotes and microbial metabolism were markedly different across the four maize production regions.  Our study indicated that the combination of soil pH, cropping system and geographic location significantly influenced the prokaryotic community and the functional genes of these microbes.  This work contributes to a deeper understanding of the composition and function of the soil prokaryotic community across large-scale production systems such as maize.