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    01 November 2019, Volume 52 Issue 21
    CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
    Identification and Characterization of the Expansin Gene Family in Upland Cotton (Gossypium hirsutum)
    ZHANG QiYan, LEI ZhongPing, SONG Yin, HAI JiangBo, HE DaoHua
    Scientia Agricultura Sinica. 2019, 52(21):  3713-3732.  doi:10.3864/j.issn.0578-1752.2019.21.001
    Abstract ( 436 )   HTML ( 90 )   PDF (3863KB) ( 629 )   Save
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    【Objective】 Expansins are a group of non-enzymatic proteins found in the plant cell wall, with important roles in plant growth, development, biotic and abiotic stress responses. To date, no systematic study on the molecular characterization, phylogeny and expression profiling of the upland cotton Expansin gene family has yet been conducted. In this study, a genome-wide identification, characterization and expression analysis of the Expansin gene family in upland cotton was performed. 【Method】 The members of the Expansin gene family in the upland cotton genome were identified by using the bioinformatics tools BLAST and HMMER, and were further analysed by using a combination of the bioinformatics softwares, such as ClustalW, MEGA, MCScanX, Prot Param, MEME, SignalP, Euk-mPLoc, Fancy Gene and DnaSP. The spatiotemporal expression patterns of the upland cotton Expansin gene family, and the differential expression of some Expansin homoeologs during the different stages of growth were determined by publicly available RNA-seq data. The expression patterns of some candidate Expansin genes were further validated by qRT-PCR. 【Result】 In the allotetraploid upland cotton, 72 expainsin-coding genes are identified, which is approximately twice as many as in the two diploid cotton species (Gossypium arboretum and G. raimondii), and these Expansin-coding genes are grouped into four subfamilies: 46 α-expansins (EXPAs), 8 β-expansins (EXPBs), 6 Expansin-like As (EXLAs), and 12 Expansin-like Bs (EXLBs). Except the two chromosomes GhA02 and GhD06, Expansin-coding genes are unevenly distributed across the other chromosomes ranging from 2 to 4, while the chromosomes GhA08 and GhD08 harbors 5 genes and 8 genes, respectively. Phylogenetic tree reveals that the members of the same subfamily are clustered together. In most cases, four Expansin members from the four (sub-)genomes of three cotton species (G. hirsutum, G. arboretum and G. raimondii) tends to cluster together within a given clade, for example, EXPA subfamily members Cotton_A_28454/Gh_A03G0885/Gh_D02G1269/Gorai.005G142200 which are located on collinear blocks are clustered into a clade. The computational prediction tool shows that all the Expansin proteins are predicted to be extracellular. The exon-intron structure analysis reveals that the upland cotton Expansin-coding genes typically consist of 3-5 exons interrupted by multiple introns, share an evolutionarily conserved exon-intron structure (consistent with the diversity of amino acid sequences), and have codon usage bias. RNA-seq data shows that different Expansin-coding genes are expressed in a stage- and tissue-specific manner during the developmental stages. For example, transcripts for GhEXPA19A and GhEXPA19D are highly abundant in the fire 10 days post anthesis (DPA) and 20 DPA when compared with other Expansin-coding genes. GhEXPA24D is highly expressed in few tissues, including cotyledons, new leaves, old leaves and bracts. Homoeologous genes exhibits different expression profiles, indicating the functional divergence and complementation. The qRT-PCR results are consistent with the RNA-seq data with the same trends for the expression of each Expansin-coding gene. For instance, GhEXLA3A and GhEXLA3D are highly expressed during the fiber elongation stage. GhEXPA19D and GhEXLA2D are highly expressed in the ovule at 3 DPA.【Conclusion】 The upland cotton genome contains 72 Expansin-coding genes which encode protein exhibiting the same structural diversity and evolutionary conservation as the coding DNA sequences of expansins, and which display diverse and dynamic expression patterns, implying functional conservation and divergence among the members of cotton Expansin genes.

    CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
    QTL Identification for Fatty Acid Content in Brassica napus Using the High Density SNP Genetic Map
    YE Sang,CUI Cui,GAO HuanHuan,LEI Wei,WANG LiuYan,WANG RuiLi,CHEN LiuYi,QU CunMin,TANG ZhangLin,LI JiaNa,ZHOU QingYuan
    Scientia Agricultura Sinica. 2019, 52(21):  3733-3747.  doi:10.3864/j.issn.0578-1752.2019.21.002
    Abstract ( 412 )   HTML ( 47 )   PDF (5693KB) ( 325 )   Save
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    【Objective】 Rapeseed oil is widely used in cooking, food processing and industrial production. Therefore, improving the fatty acid composition of rapeseed oil according to the specific production objective is an important goal of rapeseed breeding. In this study, QTL mapping of main fatty acid composition in Brassica napus under two environments was conducted, which was designed to search for the QTL and related candidate genes of fatty acid components in Brassica napus.【Method】 The high generation recombinant inbred lines (RILs) were used as experiment materials, which were derived from synthetic 10D130 and conventional variety Zhongshuang11, and field experiments were conducted in 2016-2017 and 2017-2018 with two different environments in Beibei District of Chongqing City, respectively. After self-pollinated seeds were harvested each year, fatty acid components of seeds were measured by GC with three technical repeats. Then, the RIL population genotype was analyzed with the rapeseed 6K SNP chip array. The DNA preparation and the chip preparation were processed strictly according to Infinium HD Assay Ultra manual of Illumina Inc. The SNP linkage map was constructed by using JoinMap 4.0 program with minimum LOD 2.0. QTL mapping of main fatty acid composition was conducted by composite interval mapping using software Windows QTL IciMapping V4.1.【Result】 In the two environments, the differences of parents’ traits and RILs population’s traits reached significant or extremely significant levels, and the contents of six fatty acids showed continuous distribution, which were suitable for the detection of QTLs. The reference SNP genetic map contains 1 897 polymorphic SNP markers, covering 3 214.19 cM of Brassica napus genome with an average map distance of 1.69 cM. Twenty-three QTLs loci of fatty acid components on 8 chromosomes were detected in two environments. The QTLs loci related to stearic acid, oleic acid, linoleic acid, linolenic acid, eicosapentaenoic acid and erucic acid contents were 6, 3, 4, 5, 2 and 3, respectively. And the “enrichment regions” of multiple fatty acid contents were found on chromosomes A05, A08 and C03. Meantime, the main QTL with overlapping linoleic acid and linolenic acid content was detected on A05 chromosome, showing the same additive effect. And the main effect QTLs, oleic acid with overlapping contents of eicosenic acid and erucic acid were detected on A08 and C03, which was opposite to the additive effect of eicosenic acid and erucic acid. Twenty-two candidate genes of fatty acid metabolic were found underlying confidence intervals of seventeen QTLs by comparing with homologous genes in Arabidopsis thaliana. These genes regulate lipid biosynthesis and metabolism through encoding fatty acid desaturase, total carboxylase synthase, carbon chain lengthening enzyme and participating in acyl coenzyme A biosynthesis. 【Conclusion】 The fatty acid composition QTL under two environments were mapped accurately with the 6K SNP chip of rapeseed, and the “enrichment regions” of multiple fatty acid QTLs on chromosomes A05, A08 and C03 were screened. Compared with Arabidopsis thaliana fatty acid metabolic genes, candidate genes for fatty acid metabolism in this population were detected, which could be used for improving fatty acid composition in rapeseed.

    SPECIAL FOCUS: MAIZE AND SOYBEAN RESPONSE TO LIGHT AND WATER IN STRIP INTERCROPPING
    Developing Maize-Soybean Strip Intercropping for Demand Security of National Food
    YANG WenYu,YANG Feng
    Scientia Agricultura Sinica. 2019, 52(21):  3748-3750.  doi:10.3864/j.issn.0578-1752.2019.21.003
    Abstract ( 335 )   HTML ( 55 )   PDF (239KB) ( 405 )   Save
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    Effects of Row Spacing on Dry Matter Accumulation, Grain Filling and Yield Formation of Different Nodulation Characteristic Soybeans in Intercropping
    PANG Ting,CHEN Ping,YUAN XiaoTing,LEI Lu,DU Qing,FU ZhiDan,ZHANG XiaoNa,ZHOU Ying,REN JianRui,WANG Tian,WANG Jin,YANG WenYu,YONG TaiWen
    Scientia Agricultura Sinica. 2019, 52(21):  3751-3762.  doi:10.3864/j.issn.0578-1752.2019.21.004
    Abstract ( 274 )   HTML ( 23 )   PDF (1359KB) ( 384 )   Save
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    【Objective】 Intercropping is an important way to increase the efficient utilization of resources and to solve the contradiction between grain supply and demand. Under intercropping system, crop symbiosis is influenced by interspecific interaction intensity between the species. In this study, maize-soybean intercropping system was used to investigate the effects of strength of root interaction between maize and soybean on the dry matter accumulation and yield formation of different nodule characteristic soybeans, so as to analyze variation trend dry matter accumulation and yield formation of soybean. 【Method】 Field experiments were carried out for two consecutive years from 2016 to 2017 with randomized complete block factorial design: factor A was different row spacing between maize and soybean, intercropped soybean followed by different row spacing (A2: 30 cm, A3: 45 cm, A4: 60 cm, A5: 75 cm); factor B was three soybean varieties (Gongxuan 1: Weak nodulation, Guixia 3: Moderate nodulation, Nandou 25: Strong nodulation).【Result】 The row spacing between soybean and maize had a significant effect on the biomass accumulation and distribution of soybean with different nodulation. Under monoculture, dry matter accumulation of soybean was significantly higher than that of intercropping, and reached the highest at R4 (full pod stage). The dry matter accumulation of intercropping soybean reached the highest at R5 stage, and was gradually higher than monoculture. Soybean had a highest amount of biomass accumulation when the row spacing was 45 cm and 60 cm. In intercropping, each variety had the longest grain filling time under A4, and the maximum grain filling rate, 100-seeds weight and yield were achieved under A4. Interestingly, there was no significant difference between monoculture and intercropping yield. Nandou 25 had the strongest grain filling capacity under all row spacing. Under A4, the average yield of Nandou 25 was 5.435% and 6.3% higher than that of Guixia 3 and Gongxuan 1, respectively. 【Conclusion】 Nandou 25 with strong nodulation could adapt to the intercropping environment well, and showed the best performance at 60 cm. It could promote dry matter accumulation and stabilize the yield through increasing grain filling rate and 100-seeds weight in intercropping. Furthermore, it could be useful to achieve the goal of stable and optimal yield in intercropping and monoculture.

    Effects of Irrigation Time and Ratio on Yield and Water Use Efficiency of Maize Under Monoculture and Intercropping
    PENG Xiao,PU Tian,YANG Feng,YANG WenYu,WANG XiaoChun
    Scientia Agricultura Sinica. 2019, 52(21):  3763-3772.  doi:10.3864/j.issn.0578-1752.2019.21.005
    Abstract ( 301 )   HTML ( 21 )   PDF (439KB) ( 351 )   Save
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    The effects of different irrigation proportion and irrigation time on yield and water use efficiency of monoculture and intercropping maize were studied to provide a basis for the high efficient water management technology for intercropped maize. 【Method】 The experiment was conducted with two factors randomized block by using automatic rain shelter from 2016-2017, the planting mode and irrigation ratio under the irrigation quota of 4 050 m 3·hm -2. Planting mode included monoculture and intercropping. The irrigation ratio included B1(sowing water (25%) + jointing water (25%) + tasseling water (25%) + filling water (25%)), B2(sowing water (25%) + jointing water (25%) + tasseling water (15%) + filling water (35%)), and B3(sowing water (25%) + jointing water (35%) + filling water (40%)). the effects of irrigation time and proportion on soil water content, inter-plant evaporation, water consumption characteristics, yield and water use efficiency of maize in different planting patterns were studied. 【Result】 The results showed that under the same irrigation quota, the soil moisture content for the monoculture maize at the jointing stage was 16.60% higher while it was 23.60% lower from jointing stage to maturity stage than that of intercropped maize. The peak stage of water consumption intensity of monoculture and intercropping was at jointing-tasseling stage, and the maximum daily water consumption intensity reached 7.21 mm·d -1, occupied by 21.62%-31.67% of the whole growth period. However, the water consumption intensity of intercropping after jointing stage was significantly higher than that of monoculture by 3.68%. The yield of monoculture maize reached the highest in B3 treatment, it was 16.49% higher than other monoculture treatments, and the water use efficiency was 11.71% higher. However, for intercropped maize, the kernels per spike and effective spike in B2 treatment was 4.47% and 6.97% higher than other irrigation treatments which lead the average yield increased 22.07%, and WUE increased 19.11%. 【Conclusion】 Under the irrigation quota of 4 050 m 3·hm -2 in this experiment, the monoculture maize get the highest yield when irrigated with 25%, 35% and 40% water at sowing, jointing and filling stages, respectively. For intercropped maize with wide and narrow rows and strips, the yield and water use efficiency get the highest, when the irrigated with 25%, 25%, 15% and 35% water at sowing, jointing, tasseling and filling stages, respectively.

    Influence of Light Intensity on Stoma and Photosynthetic Characteristics of Soybean Leaves
    CHEN JiYu,FENG LingYang,GAO Jing,SHI JianYi,ZHOU YuChen,TU FaTao,CHEN YuanKai,YANG WenYu,YANG Feng
    Scientia Agricultura Sinica. 2019, 52(21):  3773-3781.  doi:10.3864/j.issn.0578-1752.2019.21.006
    Abstract ( 565 )   HTML ( 42 )   PDF (1563KB) ( 437 )   Save
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    【Objective】 To reveal the response mechanism of photosynthetic and stomatal characteristics of soybean leaves to shade, it analyzed the stomatal characteristics, photosynthesis and carbohydrate changes of soybean leaves in seedling stage under different light intensity. 【Method】 A pot experiment was conducted to analyze the impact of four light-intensity levels including CK (normal light), LS (light shading, 20% shading), MS (medium shading, 40% shading) and SS (severe shading treatment, 75% shading) on stomata characteristics of upper and lower epidermis, photosynthetic fluorescence parameters, soluble sugar and starch content of two soybean varieties (Nandou-12, weak shade-sensitive and Guixiadou-7, high shade-sensitive).【Result】 Results revealed that the maximum number of stomata on the upper and lower epidermis of soybean leaves was observed with Nandou-12. Among shading treatments, LS and MS treatments significantly increased the number of stomata on the upper (by 26.9% and 18.5%) and lower (by 13.9% and 39.2%) epidermis as compared with CK. And between soybean varieties, the highest rate of photosynthesis was measured under LS treatment, whose average was 14.33 μmol CO2·m -2·s -1. In addition, the highest values of stomatal conductance in Nandou-12 (0.57 mm·m -2·s -1) and Guixiadou-7 (0.30 mm·m -2·s -1) were measured under LS treatment, and the maximum concentration of carbon dioxide under LS and SS treatments with Nandou-12 was significantly higher than that under CK. These results implied that increasing light intensity decreased the actual quantum yield, however, the actual quantum yield of Nandou-12 was significantly higher than that of Guixiadou-7. In contrast, the non-photochemical quenching coefficient of Nandou-12 and Guixiadou-7 was enhanced with a decline in light intensity. Moreover, the starch content of Nandou-12 and Guixiadou-7 was decreased by 59.0%, 77.8%, and 95.8%, and 47.5%, 67.3%, and 87.8%, respectively, under LS, MS, and SS treatments. Whereas, light shading (LS) significantly increased (72.7%) the soluble sugar content of Nandou-12 as compared with the corresponding values of Guixiadou-7.【Conclusion】 Overall, our results confirmed that shading conditions directly affect the stomata and photosynthetic characteristics of soybean leaves. However, by maintaining appropriate shading, the net photosynthetic rate of soybean leaves could be increased by increasing the rate of stomatal opening, which was conducive to increase the accumulation of carbohydrates and thus enhance the shade resistance of soybeans.

    Effects of Maize Shading on Photosynthetic Characteristics, Vein and Stomatal Characteristics of Soybean
    LI ShengLan,TAN TingTing,FAN YuanFang,YANG WenYu,YANG Feng
    Scientia Agricultura Sinica. 2019, 52(21):  3782-3793.  doi:10.3864/j.issn.0578-1752.2019.21.007
    Abstract ( 335 )   HTML ( 21 )   PDF (2276KB) ( 442 )   Save
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    【Objective】 The aim of this study was to explore the effects of maize shading on the photosynthetic characteristics, leaf veins and stomatal characteristics of soybean during the symbiosis period under the maize-soybean intercropping system. 【Method】 Two factors were used in a completely randomized pot experiment under natural light, strong shade tolerant Nandou 12 and light shade tolerant Guixia 3, including the T1 (intercropping of 2 rows of maize and 2 rows of soybean), T2 (intercropping of 1 row of maize and 1 row of soybean) and CK (net for soybean) three treatments, respectively, to analyze photosynthetic parameters, veins and the porosity characteristic parameters’ responding under shading. 【Result】 By contrast with the net treatment, the far-red spectral irradiance of soybean canopy increased significantly under the shade of maize, and the light intensity under T1 and T2 treatment decreased by 48.62% and 77.39%, respectively. Photosynthetic rate, stomatal conductance, leaf vein density and stomatal density of soybean under maize shading were significantly less than those under CK (P<0.05), and the decrease rate increased with the increase of shade (from T1 to T2). Compared with CK, the net photosynthetic rate of Nandou 12 decreased significantly by 41.00% and 44.15% respectively under T1 and T2 treatment, the net photosynthetic rate of Guixia 3 decreased significantly by 44.62% and 47.93%, respectively, while stomatal conductance of Nandou 12 decreased significantly by 29.19% and 39.69%, and that of Guixia 3 decreased significantly by 26.83% and 49.50%, respectively. The vein density and stomatal density of Nandou 12 decreased by 14.99%, 20.01% and stomatal density decreased by 12.79%, 18.27% respectively under T1 and T2 treatment compared with CK; The vein density and stomatal density of Guixia 3 decreased by 10.38%, 27.62% and stomatal density decreased by 15.77%, 22.46% respectively under T1 and T2 treatment compared with CK. The net photosynthetic rate of soybean had significant positive correlation (P<0.05) with stomatal conductance, vein closure, stomatal density as well as vein density, and extremely negative correlation (P<0.01) with vein distance. In addition, there was an extremely significant positive correlation (P<0.01) between vein density and stomatal density. The vein density, vein length, veins closure, and the distance between the veins of Nandou 12 under maize shading were better than those of Guixia 3. In addition, the shade degree under T1 treatment was higher, while transpiration rate and vein closure, photosynthetic, vein and stomatal parameters of strong shade tolerant Nandou12 all change were less than those of Guixai 3, and Nandou had higher photosynthetic rate.【Conclusion】 In the maize-soybean intercropping system, the changes of canopy light environment, leaf vein and stomatal characteristics of soybean could reduce the photosynthetic ability of soybean, but the response of leaf vein and stomatal characteristics of different shade-tolerant soybean varieties to shading was different.

    PLANT PROTECTION
    Identification and Analysis of Differentially Expressed Genes Induced by Protein Elicitor PevD1 in Nicotiana benthamiana
    LIANG YingBo,LI Ze,QIU DeWen,ZENG HongMei,LI GuangYue,YANG XiuFen
    Scientia Agricultura Sinica. 2019, 52(21):  3794-3805.  doi:10.3864/j.issn.0578-1752.2019.21.008
    Abstract ( 367 )   HTML ( 12 )   PDF (1392KB) ( 169 )   Save
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    【Objective】 The objective of this study is to screen the differentially expressed genes (DEGs) induced by protein elicitor PevD1 of Verticillium dahliae in Nicotiana benthamiana by RNA-Seq, and to analyze the potential mechanism of PevD1-induced disease resistance. 【Method】 Leaves of 4-week-old N. benthamiana were infiltrated with 10 μmol·L -1 PevD1 solution, and samples were taken at 6, 12 and 24 h after PevD1 treatment, then RNA was extracted. The mRNA libraries were constructed and sequenced by BGISEQ-500 platform. The DEGs at each time point were screened for GO and KEGG analysis. The leucine-rich repeat receptor-like kinases (LRR-RLKs), transcription factors (TFs) and pathogenesis-related (PR) proteins family in DEGs were analyzed, and qRT-PCR was used to verify the expression levels of relevant DEGs.【Result】 GO functional enrichment and KEGG pathway enrichment analysis indicated that the DEGs at 6 h post infiltration (hpi) were mainly related to cell recognition, photosynthesis, light-harvesting, and were significantly enriched in photosynthesis-antenna protein pathways, terpenoid synthesis pathway, flavonoid and flavonol, and other secondary metabolite synthesis pathways. The DEGs at 12 hpi and 24 hpi were mainly associated with cell recognition and biological functions such as intracellular kinase activity, and were significantly enriched in plant-pathogen interaction pathway, sesquiterpene and triterpenoid biosynthetic pathway, flavonoid and flavonol biosynthetic pathway, linolenic acid metabolism. The unigenes in photosynthesis-antenna proteins, photosynthesis and porphyrin, chlorophyll metabolism pathway were mainly down-regulated, and the unigenes in sesquiterpenoid and triterpenoid biosynthesis, flavone and flavonol biosynthesis, plant-pathogen interaction, phenylpropanoid biosynthesis and terpenoid backbone biosynthesis pathway were mainly up-regulated. After PevD1 induction, a large number of LRR-RLKs, TFs and PR proteins family genes were significantly up-regulated, which were related to elicitor recognition, gene transcriptional regulation and disease resistance. qRT-PCR analysis showed that the expression pattern of the detected DEGs was consistent with the RNA-Seq results.【Conclusion】 PevD1 induced a large number of gene transcriptional rearrangements in N. benthamiana. Lots of LRR-RLKs, TFs and PR proteins family genes were up-regulated, which activated the plant immune system and conferred to plants disease resistant. These results can provide a basis for further study on the mechanism of PevD1-induced immunity in the future.

    Overexpression of CsGH3.6 Enhanced Resistance to Citrus Canker Disease by Inhibiting Auxin Signaling Transduction
    ZOU XiuPing,LONG JunHong,PENG AiHong,CHEN Min,LONG Qin,CHEN ShanChun
    Scientia Agricultura Sinica. 2019, 52(21):  3806-3818.  doi:10.3864/j.issn.0578-1752.2019.21.009
    Abstract ( 230 )   HTML ( 6 )   PDF (2855KB) ( 218 )   Save
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    【Background】 Citrus canker, induced by Xanthomonas citri subsp. citri (Xcc), is one of the most destructive disease in citrus production. Auxin plays an important role in regulating Xcc-induced pustule formation in citrus. GH3, an early auxin response gene, regulates plant hormone homeostasis through acylating indole-3-acetic acid (IAA). The previous study found that CsGH3.6 had a vital role in response to Xcc infection. 【Objective】 Here, to explore the internal mechanism of CsGH3.6 in regulating the dynamic balance of auxin and affecting the plant resistance to citrus canker, disease resistance evaluation, phenotype analysis, hormone determination and transcriptome sequencing of Wanjingcheng orange (Citrus sinensis) overexpressing CsGH3.6 were performed in this study.【Method】 To evaluate resistance to citrus canker in transgenic plants overexpressing CsGH3.6, fully expanded intact leaves gathered from transgenic plants were infected with Xcc by the pin-prick inoculation, and the diseased areas and disease severity index were investigated 10 d after inoculation, the wild type (WT) plant was used as the control. To detect hormone levels in transgenic plants, different hormones were isolated from leaves before and after Xcc infection and their contents were determined through high performance liquid chromatography (HPLC). Compared with WT plant, changes of phenotypes (plant types and leaf longitudinal diameter, transverse diameter and thickness) in transgenic plants were investigated in the greenhouse, and the length of epidermal cell and stomata density were further analyzed using optical microscopy. RNA sequencing was performed to investigate transcript changes in transgenic plant, and gene functions were annotated based on Nr, Nt, Pfam, COG, SwissProt and gene ontology (GO) databases. To elucidate the molecular mechanism of CsGH3.6 in regulating the canker resistance in citrus, the important genes, functions and pathways affected significantly by overexpressing CsGH3.6 were investigated using the KEGG database and MapMan software.【Result】 Overexpression of CsGH3.6 significantly enhanced citrus canker resistance in transgenic plants. The branches of transgenic plants increased and drooped, the leaves curled upward, became smaller and lighter in color. The stomata density of transgenic plants increased and the length of epidermal cells became shorter. Hormone analyses showed that the contents of free auxin IAA and jasmonic acid (JA) in transgenic plants decreased significantly, while the content of salicylic acid (SA) increased significantly. Transcriptome sequencing showed that overexpression of CsGH3.6 significantly inhibited the expression of auxin signal transduction related genes, especially the expression level of all the predicted Aux/IAA genes was down-regulated in transgenic plant. Conversely, the expression level of genes related to biological stress was up-regulated, most of which were pathogenesis-related genes. 【Conclusion】 Overexpression of CsGH3.6 can inhibit auxin signal transduction through acylating free IAA, regulate the homeostasis of JA and SA, change the morphogenesis of cells and plants, and finally enhance the plant resistance to citrus canker. The results suggest that the regulation of hormone homeostasis has potential value in citrus disease resistance breeding.

    The Structure of Day-Age of Male Spodoptera litura Moths by Sex Pheromone Trapping in the Field
    CHEN QingHua,ZENG Juan,YANG Ling,JIA Yong,LI Qing,FENG ChuanHong,CHEN XiaoJuan,HU RongPing
    Scientia Agricultura Sinica. 2019, 52(21):  3819-3827.  doi:10.3864/j.issn.0578-1752.2019.21.010
    Abstract ( 295 )   HTML ( 8 )   PDF (650KB) ( 275 )   Save
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    【Objective】 It is of great significance to determine the developmental status of male moths trapped by sex pheromone for objective evaluation of the effect of mass trapping. This study aims to research the internal reproductive system and developmental age of Spodoptera litura, determine the development situation of male moths captured in the field and the nature of insect source, and to provide a theoretical basis for the application of sex pheromone trapping of S. litura.【Method】 In 2014 and 2015, after eclosion from the laboratory-reared pupae, 1-10 day-old male moths were dissected under the microscope. The criterion of the developmental age of male S. litura moths was determined by the long semi-axis of testis. Using this criterion, the day-old of male moths captured daily with sex pheromone trapping in the fields of Dongpo and Jintang counties of Sichuan Province from 2015 to 2017 was identified. The effect of trapping male moths on mating behaviors and patterns was then analyzed.【Result】 The internal reproductive system of male S. litura moths was composed of testis, vas deferens, seminal vesicle, ejaculatory duct and accessory gland. The structure of testis was stable, elastic and easily-measured. With the increase of age, the length of long semi-axis of testis gradually decreased. The mean value of long semi-axis of testis of 10-day-old males decreased by 44.71%, compared with that of 1-day-old male testis (1 103.54 μm). The relationship equation between the long semi-axis (y) and day-old (x) was y=-48.52x+1084 (R 2=0.9472, RMSE=36.8). There were significant differences in the length of long semi-axis of testis among the age groups of 1-5, 6-8 and 9-10 day-old. The criterion table displaying the relationship between the day-old of male moths and the length of long semi-axis of testis was built to identify the age of male moths captured by pheromone trapping in the field. Similar day-age structures of male moths were found in Jintang from 2015 to 2017 and in Dongpo in 2017, with lower percentages of older male moths. Specifically, the mean percentage of 1-day-old male moths captured by sex pheromone trapping in Jintang was 39.89%, and that of 2- and 3 day-old was 21.42% and 15.75%, respectively. In other words, 1-3 day-old male moths accounted for 72.22%-79.02% in total, and the percentage from 5- to 10-day-old male moths was below 10%. In Dongpo, the percentage of 1-, 2- and 3-day-old male moths was 39.93%, 20.79% and 19.54%, respectively, as a total of 80.26%, after 5-day-old of age, the percentage was relatively small. The mean percentage of male moths of each day-old decreased exponentially with age. The daily trapping dynamic showed the 3 generations of adults in the fields of Jintang and Dongpo from the end of April to the end of August. The male moths of the 1st and 2nd generations were mainly between ages of 1-3 day-old, and the ratio of younger moths (1-3 day-old) of Jintang to older moths (4-10 day-old) was 3.32 and 1.54, and that of younger moth to older moths in Dongpo was 3.34 and 1.58, respectively. With increased numbers of adults in Dongpo, the majority of 3rd generation was older moths, with the ratio of younger moths to older moths of 0.76, which was lower than that of Jintang (2.34).【Conclusion】 The size of the testis of male S. litura moth can reflect its day-age. Male moths captured through sex pheromone trapping are mainly composed of 1-3 day-old, which is beneficial to reduce mating rate in the current generation and the whole population in the next ones.

    SPECIAL FOCUS: CHANGE OF SOIL PHOSPHRUS AND ITS EFFICIENT UTILIZATION
    Change of Soil Phosphrus and Its Efficient Utilization
    ZHANG ShuXiang,XU MingGang
    Scientia Agricultura Sinica. 2019, 52(21):  3828-3829.  doi:10.3864/j.issn.0578-1752.2019.21.011
    Abstract ( 338 )   HTML ( 19 )   PDF (218KB) ( 375 )   Save
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    Change of Phosphorus in Red Soil and Its Effect to Grain Yield Under Long-Term Different Fertilizations
    LI DongChu,WANG BoRen,HUANG Jing,ZHANG YangZhu,XU MingGang,ZHANG ShuXiang,ZHANG HuiMin
    Scientia Agricultura Sinica. 2019, 52(21):  3830-3841.  doi:10.3864/j.issn.0578-1752.2019.21.012
    Abstract ( 360 )   HTML ( 24 )   PDF (749KB) ( 349 )   Save
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    【Objective】 Change characteristic of phosphorus (P) in red soil were quantified under long term different fertilizations, and effects of P on soil productivity were studied, so as to provide a theoretical basis for P management in red soil regions in southern China. 【Method】 Change of soil Olsen-P and total P content was compared under long term no P fertilization (CK, N, NK), chemical P fertilizer (PK, NP, NPK), application of chemical fertilizer combined with half crop straw return (NPKS) and application of organic manure and chemical fertilizer combined with organic manure (1.5NPKM, NPKM, M) using long term trial platform in the upland red soil (from 1991-2016). Responses of soil P to P balance were analyzed. Different models were used to fit the response curve of crops yield to Olsen-P in the red soil. The critical P value of soil Olsen-P for crop yield (CV) was calculated. 【Result】 The Olsen-P and total P increased, and P activation coefficient (PAC) promoted under long term P fertilization in the red soil. PAC was higher under application of organic manure and chemical fertilizer combined with organic manure (1.5NPKM, NPKM, M) than that under application of chemical fertilizer combined with half crop straw return (NPKS) and chemical P fertilizer (PK, NP, NPK). Changes of Olsen-P and total P were significantly affected by P balance (P<0.01). Soil Olsen-P increased by 3.00-5.22 mg·kg -1, and total P increased by 0.02-0.06 g·kg -1 with 100 kg P·hm -2 cumulative surplus in the red soil. The Olsen-P decreased with years under long term no P fertilization (CK, N, NK), and they decreased by 1.85 mg·kg -1, 0.40 mg·kg -1, and 1.76 mg·kg -1, respectively, with 100 kg P·hm -2 cumulative deficiency in the red soil. Grain yields of wheat and maize were significant higher under application of organic manure and chemical fertilizer combined with organic manure (1.5NPKM, NPKM, M) than that under application of chemical fertilizer combined with half crop straw return (NPKS) and chemical P fertilizer (PK, NP, NPK) than under no P fertilizations (CK, N, NK). Sustainability index of grain yield (SYI) were higher under application of organic manure and chemical fertilizer combined with organic manure (1.5NPKM, NPKM, M) than that under the other treatments. Three models (linear-linear model, linear-platform model and Michelice model) were better fit the response of crop yield to Olsen-P in red soil (P<0.01). Linear-linear model was recommended for the higher R 2. The critical value of Olsen-P content in agronomic in red soil of wheat and maize were 13.5 mg·kg -1, and 23.4 mg·kg -1, respectively, calculated by linear-linear mode. 【Conclusion】 Application of chemical fertilizer combined with organic manure were recommended in red soil region of southern China. That had the beneficial for P accumulation and promoting P availability. Applications of chemical fertilizer combined with organic manure were also used to keep the high and stable production. Linear-linear model was recommended to calculate the critical value of Olsen-P content in agronomic. Application rates of P fertilizer should be adjusted timely according to the difference between actual Olsen-P content in the soil and critical value of Olsen-P content in agronomic in productivity.

    Phosphorus Profit and Loss and Its Effect on Inorganic Phosphorus in Fluvo-Aquic Soil Under Long-Term Located Fertilization
    WANG BoHan,HUANG ShaoMin,GUO DouDou,ZHANG ShuiQing,SONG Xiao,YUE Ke,ZHANG KeKe
    Scientia Agricultura Sinica. 2019, 52(21):  3842-3851.  doi:10.3864/j.issn.0578-1752.2019.21.013
    Abstract ( 282 )   HTML ( 8 )   PDF (1689KB) ( 401 )   Save
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    【Objective】 In this study, the changes of phosphorus profit and loss as well as various forms of inorganic phosphorus in fluvo-aquic soil under long-term fertilizer application, and the effect of soil phosphorus profit and loss on inorganic phosphorus were discussed, which provided a theoretical basis for the rational application of phosphorus fertilizer in fluvo-aquic soil.【Method】 Based on the “National Long-term Monitoring Station for Soil Fertility and Fertilizer Benefit in Fluvo-aquic Soil”, the four fertilization modes in North China including NPK (single chemical fertilizer), SNPK (straw return), MNPK (organic-inorganic combined application), 1.5 MNPK (high amount of organic-inorganic combined application), were studied with the control of NK (non-phosphate fertilizer) to study the changes of apparent phosphorus profit and loss, cumulative phosphorus profit and loss, the content and relative content of each form of inorganic phosphorus, and the effect of soil phosphorus profit and loss on each form of inorganic phosphorus.【Result】 Under the condition of not applying phosphate fertilizer for 25 years, the phosphorus in the soil was always in a state of deficit, the cumulative deficit of phosphorus in soil was 431.8 kg·hm -2, after 25 years, the cumulative surplus of soil phosphorus on four phosphate fertilizer models (NPK, SNPK, MNPK, and1.5MNPK) was 291.2, 398.4, 1 742.4, and 2 676.9 kg·hm -2, respectively. When phosphorus fertilizer was not applied for a long time, Ca2-P decreased most in soil inorganic phosphorus by 49.0%. In the first 13 years, the soil Ca2-P of the above four fertilizer models increased by 1.2-5.4 times, with an average annual increase of 1.26-5.73 mg·kg -1. In the latter 12 years, the growth rate of soil Ca2-P decreased by 99.2%-112.6% by applying chemical fertilizer single, straw returning and organic-inorganic combined application model; and the content of Ca2-P in the soil decreased by 2.0 mg·kg -1 per year. The relative content of soil Ca2-P increased by 1.0%-3.5% in 25 years above four fertilizer models. After 25 years of application of phosphate fertilizer, the content of Ca8-P, Al-P, and Fe-P in soil increased 1.4-6.5, 1.8-3.3, and 1.1-2.2 times, respectively, with an average annual increase of 4.69-19.81, 1.67-3.10, and 1.23-2.37 mg·kg -1, respectively; the relative content increased 8.4%-3.0%, 3.3%-4.0%, 1.8%-3.3%, respectively. The contents of Ca10-P and O-P were oscillatory between 350-410 and 100-160 mg·kg -1 for a long time, but their relative contents decreased by 11.4%-29.7% and 3.1%-8.9%, respectively. Under the condition of not applying phosphate fertilizer for 25 years, for every 100 kg P·hm -2 cumulative deficit, Ca2-P, Ca8-P, Al-P, Fe-P, Ca10-P, and O-P in soil decreased by 1.2, 2.7, 1.1, 1.5, 0.8, and 7.5 mg·kg -1, respectively. Under the mode of single fertilizer and straw returning for 25 years, for every 100 kg P·hm -2 cumulative surplus, Ca2-P, Ca8-P, Al-P, Fe-P, Ca10-P, and O-P in soil increased by 3.9-5.0, 21.5-21.6, 6.5-7.4, 4.8-5.6, 4.0-7.5, and 2.4-7.2 mg·kg -1, respectively. Under the mode of organic and inorganic combined application for 25 years, for every 100 kg P·hm -2 cumulative surplus, Ca2-P, Ca8-P, Al-P, Fe-P, Ca10-P, and O-P in soil increased by 1.8-2.8, 14.2-16.4, 2.5-3.2, 1.9-2.6, -0.2-1.2, and 0.3-1.9 mg·kg -1, respectively. 【Conclusion】 The long-term application of phosphorus fertilizer could increase the surplus of phosphorus and the content and its relative content of Ca2-P, Ca8-P, Al-P, and Fe-P in fluvo-aquic soil, and the effect of organic and inorganic combined application was higher than that of single chemical fertilizer and straw returning. When the surplus of phosphorus in fluvo-aquic soil was the same, the increment of Ca8-P was the most in all fertilizer models, followed by Al-P and Fe-P, and the increment of Ca2-P, Ca8-P, Al-P, and Fe-P in soil with single chemical fertilizer was higher than that of straw returning and organic and inorganic combined application.

    Relationship Between Soil Available Phosphorus and Inorganic Phosphorus Forms Under Equivalent Organic Matter Condition in a Tier Soil
    LI RuoNan,WANG ZhengPei,BATBAYAR Javkhlan,ZHANG DongJie,ZHANG ShuLan,YANG XueYun
    Scientia Agricultura Sinica. 2019, 52(21):  3852-3865.  doi:10.3864/j.issn.0578-1752.2019.21.014
    Abstract ( 281 )   HTML ( 10 )   PDF (2244KB) ( 394 )   Save
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    【Objective】 Investigating the contribution of inorganic phosphorus (P) fractions to soil available phosphorus under equivalent soil organic matter content might be helpful in development of phosphate fertilizer management strategy whereby to improve phosphorus use efficiency in a given soil.【Method】 We collected and screened the soils with a gradient of Olsen P level but the quite similar soil organic matter content (SOC ranges from 10.03 to 10.68 g·kg -1) in a Tier soil under winter wheat-summer maize cropping in Guanzhong Plain of Shaanxi Province. The Olsen P contents of the selected soil samples were 10.73 mg·kg -1, 18.06 mg·kg -1, 20.61 mg·kg -1, 24.01 mg·kg -1, 30.73 mg·kg -1, 43.69 mg·kg -1, and 58.58 mg·kg -1, respectively. We then analyzed the soil inorganic phosphorus forms with the phosphorus fractionation method developed by Chang & Jackson and modified by Jiang & Gu.【Result】 The results showed that the calcium bounded phosphorus fraction was the dominant form in the cultivated soil in the northwestern winter wheat-summer maize planting area, accounting for 66.67% of the total amount of inorganic phosphorus, of which dicalcium phosphate (Ca2-P), octa-calcium phosphate (Ca8-P) and apatite (Ca10-P) account for 2.80%, 16.80% and 47.09%, respectively, on average; and aluminum bounded phosphate (Al-P), iron bounded phosphate (Fe-P) and occluded phosphate (O-P) composed of 16.28%, 5.23% and 11.81%, respectively. Soil Olsen P was increased significantly and linearly with the increasing content of Ca2-P, Ca8-P, Ca10-P, Al-P, Fe-P and O-P; while the phosphorus activation coefficients, defined as the ratio of soil Olsen P to total P, were correlated significantly positively and linearly to the content of Ca2-P, Ca8-P, Al-P, Fe-P and O-P. The results of path analysis showed that the contribution of inorganic phosphorus to soil available phosphorus (Olsen P) in Guanzhong Plain area of Shaanxi Province was in the order of Ca2-P (0.974)>Al-P (0.186)>Ca8-P (0.182)>Fe-P (0.150)>Ca10-P (0.007)>O-P (-0.074), the contribution of inorganic phosphorus to phosphorus activation coefficient (PAC) was Ca2-P (0.768)>Al-P (0.082)>Ca8-P (0.071)>Fe-P (-0.018)>Ca10-P (-0.055)>O-P (-0.388), which was consistent with the contribution of soil phosphorus component to available phosphorus. The results of stepwise regression analysis showed that Ca2-P and Ca8-P were the major two contributors to Olsen P, but the Ca2-P contributed the most to PAC.【Conclusion】 Under the same or similar soil organic matter condition, Ca2-P was the most effective phosphorus source in Tier soil of wheat-maize growing area in Guanzhong Plain of Shaanxi Province. The increase of soil phosphorus availability was mainly achieved by increasing the proportion of phosphorus forms of readily available and relatively high availability such as Ca2-P, Ca8-P and Al-P, and reducing the proportion of very low availability forms, i.e. Ca10-P. Generally, under current cropping system, the application of phosphate fertilizers mainly kept the soil phosphorus in pools of available forms in the Guanzhong Plain.

    Phosphorus Adsorption and Desorption Characteristics and Its Response to Soil Properties of Black Soil Under Long-Term Different Fertilization
    WANG Qiong,ZHAN XiaoYing,ZHANG ShuXiang,PENG Chang,GAO HongJun,ZHANG XiuZhi,ZHU Ping,GILLES Colinet
    Scientia Agricultura Sinica. 2019, 52(21):  3866-3877.  doi:10.3864/j.issn.0578-1752.2019.21.015
    Abstract ( 405 )   HTML ( 13 )   PDF (761KB) ( 454 )   Save
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    【Objective】 Fertilizer is generally added to agricultural soil to meet the needs of crop production, but long-term over fertilization changes soil phosphorus (P) pool and soil properties. This study evaluated the characteristics change of P adsorption and desorption and its response to soil properties under long-term fertilization, to do a favor to provide theoretical basis of rational fertilizer application and improve the P availability of black soil.【Method】 Four treatments, including no fertilizer (CK), urea and potash sulphate (NK), urea, super-calcium phosphate and potash sulphate (NPK), and NPK plus pig manure (NPKM), were investigated in a 21-year (1989-2010) long-term fertilization experiment at Gongzhuling (Jilin Province) of China. The crop of cropping system was maize. Soil samples were collected in 1990, 2000 and 2010 at 0-20 cm depth to analyze soil properties and to measure soil P adsorption and desorption characteristics. Langmuir equation was used to fit the P adsorption curve, and then the maximum adsorption capacity (Qmax), adsorption constant (K), buffering capacity of soil P (MBC), and P sorption saturation (DPS) were calculated according to Langmuir equation.【Result】 There was a good fitness between the P adsorption curve and Langmuir equation (R 2=0.93-0.99, P<0.01). There existed difference for P adsorption and desorption characteristic under the four treatments. Over time, compared with initial year, for CK and NK treatments, the Qmax value increased by 1.83 and 1.61 times, MBC value increased by 0.80% and 49.40%, DPS value decreased by 92.04% and 87.50%, Readily Desorbable Phosphorus (RDP) value decreased by 20.00% and 82.83%, respectively; for NPK treatment, Qmax and DPS value increased by 81.87% and 79.56%, MBC and RDP value decreased by 79.37% and 48.57%, respectively, while under NPKM treatment, the Qmax and MBC value decreased by 33.35% and 78.52%, DPS and RDP values increased by 11.36 and 1.48 times, respectively. After 21 years experiments, compared with CK and NPK treatments, the Qmax and MBC value of NPKM treatment decreased by 64.66% and 49.52%, 81.87% and 79.56%, respectively; the DPS and RDP value of NPKM treatment increased by 110 and 3.81 times, 4.36 times and 78.57%, respectively. Compared with other treatments, the Total-P, Olsen-P, soil organic matter (SOM) and CaCO3 contents increased and SSA decreased significantly, but the pH, free Fe2O3 and Al2O3 value kept unchanged under NPKM treatment. RDA test showed that SOM and Total-P were the main factors that explained 49.5% and 18.7% of the total variation (P<0.05) which caused the difference of P adsorption desorption characteristic parameters among four treatments.【Conclusion】 Long-term combination of NPK fertilizers with manures could significantly increase SOM and P accumulation contents, decrease the soil adsorption capacity and increase desorption capacity, and improve P availability in soil, but it significantly increased the DPS value, easily thereby caused the risk of phosphorus loss. Therefore, various management practices and inorganic and organic P fertilizer input amounts should be considered to reduce P losses from this area.

    Characteristics of Soil Phosphorus in Winter Wheat/Summer Maize Cropping in Shaanxi Guanzhong Plain
    LIU Lin,JI BingJie,LI RuoNan,BATBAYAR Javkhlan,ZHANG ShuLan,YANG XueYun
    Scientia Agricultura Sinica. 2019, 52(21):  3878-3889.  doi:10.3864/j.issn.0578-1752.2019.21.016
    Abstract ( 320 )   HTML ( 15 )   PDF (694KB) ( 291 )   Save
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    【Objective】 It is of great significance to maintain and improve soil quality and land productivity, meanwhile enhance the phosphorus (P) use efficiency by studying the distribution characteristics and changes of soil phosphorus in winter wheat/summer maize cropping in Shaanxi Guanzhong Plain in recent 30 years. 【Method】 Based on 458 soil samples collected in total in 2011 from 10 typical counties in winter wheat/summer maize cropping in Guanzhong Plain analysis data, we compared its Olsen P content with the soil survey data in 1980s, and also explored the distribution characteristics of the current soil phosphorus pools at the regional level.【Result】 The results showed that the soil Olsen P content in the plough layer soils significantly increased during the past 30 years. The mean values of soil Olsen P in Baoji, Xianyang and Weinan were 26.09 mg·kg -1, 27.50 mg·kg -1 and 21.53 mg·kg -1, respectively, compared with soil survey data in 1980s, the corresponding increasing rate were 334.83%, 276.71% and 231.23%, respectively. The proportions of cultivated land with higher soil Olsen P levels were significantly increased, with the largest increase was observed in 15-30 mg·kg -1 and the largest decrease in Olsen P<10 mg·kg -1. The total distribution of soil Olsen P and inorganic phosphorus was higher in the west (Baoji City) and the middle (Xianyang City) than in the east (Weinan City), and organic phosphorus content was opposite. At present, the soil Olsen P level in the large area of Guanzhong Plain under winter wheat/summer maize cropping was higher than the agronomic threshold, which could meet the supply of phosphorus in high yield crops. Meanwhile, the cumulative distribution probability of soil Olsen P content (greater than 37 mg·kg -1) was more than 20% in Baoji and Xianyang, the cumulative distribution probability of water-soluble P content (greater than 2 mg·kg -1) was more than 22%, so there would be a higher risk of water environment pollution. 【Conclusion】 Excessive application of phosphorus fertilizer under long-term intensive and high-intensity planting conditions significantly increased the Olsen P content in soil. Considering the protection of environment and rational utilization of limited phosphorus resources, the application of phosphorus fertilizer should be regulated reasonably, so as to apply fertilizer according to soil and supply fertilizer according to demand.

    HORTICULTURE
    Effects of Ethephon and 1-MCP on the Expression of AheAAT Gene and AheERF Transcription Factors in Jackfruit Fruit
    REN XueYan,LIU GuangCai,LI GuoPeng,YE ChunHai,FENG Feng,WANG JunNing
    Scientia Agricultura Sinica. 2019, 52(21):  3890-3902.  doi:10.3864/j.issn.0578-1752.2019.21.017
    Abstract ( 402 )   HTML ( 18 )   PDF (4912KB) ( 245 )   Save
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    【Objective】 The effects of Ethephon (ETH) and 1-methylcyclopropene (1-MCP) on AAT activities, the expression of AheAAT gene and AheERF1/2 transcription factor were studied during ripening of jackfruit to provide a theoretical basis for further understanding the role of AATS in the synthesis of esters and its regulation. 【Method】 The test material was jackfruit of Haida2. During the full bloom period, the fruit with the representative flowering period was labeled and harvested about 150 days after flowering. The fruits with the same size and maturity and no disease and insect damage were selected to divide into three groups for treatment. The first group was immersed in 1 000 mg?L -1 ETH solution for 2-3 min; the second group was fumigated with 0.5 mg?L -1 1-MCP for 15 h; the third group, as a control group, was naturally matured at 22℃ and 90% relative humidity conditions. During fruit ripening, samples were taken periodically with 3-5 fruits per times. The flesh of the jackfruit was frozen in liquid nitrogen and then stored in an ultra-low temperature refrigerator at -80℃ for determination of AAT activities, the expression of AheAAT gene and AheERF1/2 of jackfruit.【Result】 By analyzing the activity of AAT enzyme, it was found that ETH treatment promoted the ripening and senescence of jackfruit, advanced the peak of the activity peak of AAT, but reduced AAT enzyme activity. 1-MCP treatment inhibited the ripening and senescence of fruits by inhibiting the AAT activity in the pre-storage period, delaying the time of peak AAT activity, and significantly reducing the activity of AAT enzyme. Sequence analysis of AheAAT gene showed that the total length of AheAAT gene was 1 380 bp, encoding 459 amino acids. AheAAT had a conserved domain H-x-x-x-D and an L-x-x-YYPLAGR active site motif, a D(N)F(V) GWG add-on motif. The AheAAT gene belonged to the BAHD alcohol acyltransferase family, and its amino acid sequence had the highest similarity to apples and pears. At the same time, two ERF transcription factors, named AheERF1/2, were cloned from the fruit of jackfruit, of which AheERF1 was 648 bp in length, encoding 215 amino acids, and had the highest homology with apple and kidney bean. AheERF2 was 657 bp in length, encoding 218 amino acids, with the highest homology with apples, papaya. The amino acid sequence of AheERF1/2 contained an AP2/ERF conserved sequence consisting of 64/65 amino acid residues and had a characteristic sequence of an ERF family transcription factor. ETH treatment advanced the expression peak of AheAAT gene in jackfruits and down-regulated its expression. The effects of ETH treatment on the expression of AheERF1/2 transcription factor were identical to that of AheAAT gene. ETH treatment decreased the correlation between AheAAT gene and AheERF2 transcription factor. 1-MCP treatment prolonged the storage period of jackfruit fruit. 1-MCP treatment prolonged the storage period of jackfruit fruit. The expression of AheAAT gene and AheERF1/2 transcription factors were significantly reduced during the pre-storage period after 1-MCP treatment. 1-MCP down-regulated the expression levels of AheAAT and AheERF1/2 transcription factor at the peak of their expressions. However, 1-MCP had little effect on the correlations of the AheERF1/2 transcription factor with the AheAAT gene. 【Conclusion】 ETH treatment advanced the peak activity of AAT enzyme, the peak expression of AheAAT and AheERF1/2 transcription factors, down-regulated the expression of AheAAT and AheERF1/2 transcription factors, and decreased the activity of AAT enzyme and the correlation between AheAAT and AheERF2 transcription factors. Compared with the control group, 1-MCP treatment inhibited the activity of AAT enzyme, the expression of AheAAT gene and AheERF1/2 transcription factors in the pre-storage phase, decreased the activity of AAT enzyme and down-regulated the expression levels of AheAAT and AheERF1/2 transcription factors during the late storage period.

    FOOD SCIENCE AND ENGINEERING
    Effect of Ultra-High Pressure and High Temperature Short-Time Sterilization on the Quality of NFC Apple Juice During Storage
    DENG Hong,LEI JiaLei,YANG TianGe,LIU MinHao,MENG YongHong,GUO YuRong,XUE Jia
    Scientia Agricultura Sinica. 2019, 52(21):  3903-3923.  doi:10.3864/j.issn.0578-1752.2019.21.018
    Abstract ( 338 )   HTML ( 29 )   PDF (1908KB) ( 318 )   Save
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    【Objective】 In order to provide an experimental basis for regulating the shelf life of not from concentrate (NFC) juice products in Chinese market and formulating standard of NFC juice products in China, the quality changes of NFC apple juice treated by different sterilization methods (e.g., high temperature short-time (HTST) and Ultra-high pressure (UHP)) during storage periods were compared. 【Method】 NFC apple juice was prepared by using Fuji apple as raw material and treated by HTST at 98℃ for 50 s and UHP at 400 MPa for 15 min, respectively, before refrigerated at 4℃. Then the changes of microbial, physical and chemical indicators, polyphenols, enzymes (polyphenol oxidase and peroxidase) activity, antioxidant activity and aroma components were studied using various methods (e.g., microbial and chemical methods, principal component analysis (PCA), instrumental analysis methods of HPLC, and GC-MS). 【Result】 The sterilization rates of total bacteria, Escherichia coli, mold and yeast in NFC apple juice were 100% through HTST and UHP treatment, however, the total number of colonies increased significantly (89.15%, 58.65%) at the 10 th and 5 th week of storage, respectively. No obvious proliferation of Escherichia coli, mold and yeast was observed. The microbial communities of NFC apple juice treated by HTST and UHP during storage were of no significant changes, but the increases of dominant bacteria were different. The TSS, pH, TA, and the sensory quality (storage for 4 and 8 weeks) of NFC apple juices treated by HTST and UHP did not change significantly, but not the total color significantly (P<0.05). During the storage period, the content of epicatechin in NFC apple juice treated by HTST and UHP decreased by 33% and 53%, respectively. The total antioxidant capacity of FRAP, scavenging rate of DPPH free radical were kept at 76%, 73%, and 77%, 76%, respectively. PPO and POD of NFC apple juice were completely inactivated after HTST treatment, but the enzymes activity (PPO and POD) in samples processed by UHP showed a trend of first increasing and then decreasing. The polyphenol content and antioxidant activity of HTST treated NFC apple juice were significantly higher than those of UHP treated samples. The total retention rate of 18 characteristic aroma substances in HTST treated NFC apple juice was 52%, but the aroma components remained stable during storage. In contrast, the aroma content of UHP treated NFC apple juice (57.75 mg/100 mL) was close to the control sample (57.17 mg/100 mL), but the aroma components significantly changed and reduced by 26.13% during storage. 【Conclusion】 NFC apple juice with HTST and UHP sterilization could maintain the commercial quality stored at 4℃ for 9 and 4 weeks, respectively, but the shelf life of HTST treated NFC apple juice was longer than that treated by UHP.

    ANIMAL SCIENCE·VETERINARY SCIENCE·RESOURCE INSECT
    Effects of Tannic Acid Addition in Milk Replacer on Development of Gastrointestinal Tract of 7 to 28 Days Old Hu Lambs
    ZHENG Chen,LI FaDi,LI Fei,ZHOU JuWang,DUAN PengWei,LIU HuiHui,FAN HaiMiao,ZHU WeiLi,LIU Ting
    Scientia Agricultura Sinica. 2019, 52(21):  3924-3933.  doi:10.3864/j.issn.0578-1752.2019.21.019
    Abstract ( 283 )   HTML ( 20 )   PDF (461KB) ( 224 )   Save
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    【Objective】 This study was conducted to investigate the effects of tannic acid supplementation to milk replacer on the development of gastrointestinal tract of 7 to 28 day-old Hu lambs. 【Method】 Thirty 7 day-old Hu male lambs were chosen and divided into 2 groups, fifteen lambs in each group and each lamb as a duplication. Lambs were fed milk replacer with or without 0.2% tannic acid, respectively. The test lasted 21 days. Eight lambs were selected from each group randomly and slaughtered at 28 day-old. The weights of the compound stomach and the intestinal tract with and without content, and lengths of the intestinal tract were measured, then the relative quality and length were calculated. While the tissue samples from fundus gland region of the abomasum, the middle part of duodenum, jejunum and ileum were fixed in paraformaldehyde to analyse the histomorphology, and the apoptotic rate of intestinal epithelial cells as well. And the mRNA expression of occludin, ZO-1 and claudin 1 protein of duodenum, jejunum and ileum mucosa were measured.【Result】 The results showed that except relative weights of duodenum (% body weight, P=0.012; % intestinal tract weight, P=0.034; % gastrointestinal tract weight, P=0.017), relative length of jejunum and colon (% intestinal tract length, P=0.030, P=0.004), and content of colon (% body weight, P=0.039), the relative weights (% body weight, % stomach weight, % intestinal tract weight, and % gastrointestinal tract weight), relative lengths (% intestinal tract length), content of stomach and intestinal tract (% body weight, % stomach content weight, % intestinal tract content weight, and % gastrointestinal tract content weight), and mRNA expression of claudin 1 protein in intestinal tract of lambs were not affected by tannic acid (P>0.05). However, tannic acid elongated the muscular thickness of duodenum and decreased the villus width of lamb duodenum significantly (P=0.013,P=0.001), and up-regulated mRNA expression of ZO-1 protein of jejunum (P=0.003). And there was a tendency that tannic acid up-regulated mRNA expression of occludin protein of jejunum (P=0.077), and decreased villus width and crypt depth of jejunum and the apoptotic rate of jejunum and ileum cells (P=0.073, P=0.062, P=0.097, P=0.052). 【Conclusion】 In conclusion, tannic acid decreased the relative weights of duodenum and relative length of jejunum of 7-28 day-old Hu lambs, but improved the barrier function of intestinal tract via elongating the muscular thickness of duodenum, up-regulating the mRNA expression of ZO-1 and occludin protein of jejunum, and decreasing the crypt depth of jejunum and the apoptotic rate of jejunum and ileum cells.

    Whole-Industry Chain Loss and Edible Rate of Chinese Meats
    ZHOU Lin,YANG ZhenNi,ZHANG Min,CHENG GuangYan
    Scientia Agricultura Sinica. 2019, 52(21):  3934-3942.  doi:10.3864/j.issn.0578-1752.2019.21.020
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    【Objective】 China is a country with both high meat production and high consumption. In 2017, China’s meat production reached 85.581 million tons. From the perspective of the whole industry chain, the meat from the farmer to table must go through a variety of links, such as breeding, slaughtering, precooling, segmentation, transportation, retail, and storage, etc., degrees of food loss happens within each link mentioned above, especially from the links after slaughtering to retail which caused a huge waste of resources and environment. This study focused on five main links, including segmentation, precooling, transportation, retail/wholesale, and storage regarding to four products, including pork, beef, mutton, and chicken, to define the loss of pork, beef, mutton, and chicken in their respective industry chains, from production and consumption through whole-industry meat investigation, and to calculate their edible proportions based on consumption habits.【Method】 Based on the idea of systematically analysis, this study divided the whole meat supply chain into five links as segmentation, transportation, retail/wholesale, precooling, and frozen storage, which may be loss of meat. Under the consideration that the supply chain of consumption patterns as warm fresh pork, chilled fresh pork and frozen pork differs greatly, we first calculated the loss of the whole industry chain of each consumption pattern, and then calculated the weighted average of meat loss named comprehensive loss rate for each type of meat. The edible ratio has been collected based on the actual data after a long-term slaughter and deboning experience of slaughter plant. The research areas is mainly centralized in the main producing area for each type of meat, and selected typical enterprises, supermarkets and local markets in different scale as interview objects, and obtain first-hand data through one-on-one interviews and investigations.【Result】 Through field survey in 10 provinces/cities of Beijing, Sichuan, Chongqing, Shandong, Henan, Guangdong, Guangxi, Jilin, Inner Mongolia, Xinjiang, and 19 integrated enterprises, 7 slaughter enterprises and 16 terminal sales markets, the results showed that the current whole-link loss rates of pork, chicken, beef, and mutton in China were 8.1%, 11.22%, 1.47%, and 7.45%, respectively. In terms of meat circulation forms, the loss rates of warm fresh pork, chilled fresh pork and frozen pork were 2.69%, 4.12%, and 8.10%, respectively. The loss rates of warm fresh beef, chilled fresh beef and frozen beef were 7.17%, 8.68%, and 11.47%, respectively; the loss rates of warm fresh mutton, chilled fresh mutton and frozen mutton were 4.63%, 6.53%, and 7.45%, respectively; and the loss rates of chilled fresh poultry and frozen poultry were 6.31% and 11.22%, respectively. Combining the proportions of different consumption patterns, comprehensive whole-industry-chain loss rates of pork, beef, mutton, and poultry: 4.36%, 9.55%, 5.94%, and 9.30%, respectively, the carcass edible rates were 78.48%, 81.26%, 73.72%, and 68.55%, respectively; and the whole edible rates are 90.29%, 94.48%, 96.46%, and 78.91%, respectively.【Conclusion】 Due to varying eating habits, meat loss in China was significantly lower than that in European countries, the US, Japan, and other countries with high food consumption rates. The main causes of current Chinese meat loss included relatively low processing and the cutting technology of middle and small enterprises, lacking of refrigeration equipment in wholesale and retail links, the nature of frozen meat, and consumers’ preference for warm, fresh meat in many regions of China. In the long run, with the increase in the market share of cold fresh meat consumption, the improvement of the technical level of slaughtering and segmentation, and the improvement of refrigeration and storage facilities, meat loss within supply chain should have high potential to decrease.