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    2023 Vol. 22 No. 11 Previous Issue    Next Issue

    Special Focus: Germplasm and Molecular Breeding in Horticultural Crops
    Crop Science
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    Special Focus: Germplasm and Molecular Breeding in Horticultural Crops
    Editorial — Germplasm and molecular breeding in horticultural crops
    WU Jun, GUAN Qing-mei, WANG Li-rong, LUAN Fei-shi, DUAN Qiao-hong, SONG Chuan-kui
    2023, 22(11): 3237-3243.  DOI: 10.1016/j.jia.2023.10.041
    Abstract ( )   PDF in ScienceDirect  
    A high-quality genome of Actinidia eriantha provides new insight into ascorbic acid regulation
    LIAO Guang-lian, HUANG Chun-hui, JIA Dong-feng, ZHONG Min, TAO Jun-jie, QU Xue-yan, XU Xiao-biao
    2023, 22(11): 3244-3255.  DOI: 10.1016/j.jia.2023.07.018
    Abstract ( )   PDF in ScienceDirect  

    Actinidia eriantha is one of the species of kiwifruit with a particularly high ascorbic acid (AsA) content.  However, the molecular mechanism driving AsA richness in fruit remains unclear.  In order to reveal the molecular mechanism of AsA richness in Aeriantha, this study constructed a regulatory network related to AsA metabolism by combining genomics, metabolomics and transcriptomics.  We assembled a high-quality genome of Aeriantha ‘Ganlv 1’ with only five remaining gaps.  The assembly is comprised of 29 pseudochromosomes with a total size of 615.95 Mb, and contig N50 of 20.35 Mb. Among them, 24 of the pseudochromosomes were obtained directly from telomere-to-telomere.  The LTR assembly index score and consensus quality value were 21.34 and 39.90%, respectively.  Subsequently, 61 metabolites and 2 092 genes were found to be differentially accumulated/expressed during fruit development by metabolome and transcriptome assays, respectively.  AsA metabolism and the cyclic regeneration pathway were found to have high expression levels throughout fruit growth and development, suggesting its crucial role in the regulation of AsA.  Furthermore, the AsA contents are highly associated with ascorbate peroxidase genes.  The genome obtained in this study provides genomic resources for the genetic and breeding research of Aeriantha, and the constructed regulatory network can provide a public data platform for future research on kiwifruit.

    The PcHY5 methylation is associated with anthocyanin biosynthesis and transport in ‘Max Red Bartlett’ and ‘Bartlett’ pears
    WEI Wei-lin, JIANG Fu-dong, LIU Hai-nan, SUN Man-yi, LI Qing-yu, CHANG Wen-jing, LI Yuan-jun, LI Jia-ming, WU Jun
    2023, 22(11): 3256-3268.  DOI: 10.1016/j.jia.2023.07.017
    Abstract ( )   PDF in ScienceDirect  

    The red coloring of pear fruits is mainly caused by anthocyanin accumulation.  Red sport, represented by the green pear cultivar ‘Bartlett’ (BL) and the red-skinned derivative ‘Max Red Bartlett’ (MRB), is an ideal material for studying the molecular mechanism of anthocyanin accumulation in pear.  Genetic analysis has previously revealed a quantitative trait locus (QTL) associated with red skin color in MRB.  However, the key gene in the QTL and the associated regulatory mechanism remain unknown.  In the present study, transcriptomic and methylomic analyses were performed using pear skin for comparisons between BL and MRB.  These analyses revealed differential PcHY5 DNA methylation levels between the two cultivars; MRB had lower PcHY5 methylation than BL during fruit development, and PcHY5 was more highly expressed in MRB than in BL.  These results indicated that PcHY5 is involved in the variations in skin color between BL and MRB.  We further used dual luciferase assays to verify that PcHY5 activates the promoters of the anthocyanin biosynthesis and transport genes PcUFGT, PcGST, PcMYB10 and PcMYB114, confirming that PcHY5 not only regulates anthocyanin biosynthesis but also anthocyanin transport.  Furthermore, we analyzed a key differentially methylated site between MRB and BL, and found that it was located in an intronic region of PcHY5.  The lower methylation levels in this PcHY5 intron in MRB were associated with red fruit color during development, whereas the higher methylation levels at the same site in BL were associated with green fruit color.  Based on the differential expression and methylation patterns in PcHY5 and gene functional verification, we hypothesize that PcHY5, which is regulated by methylation levels, affects anthocyanin biosynthesis and transport to cause the variations in skin color between BL and MRB.

    Development and application of KASP marker for high throughput detection of the seedless trait in grapevine
    WANG Fu-qiang, BIAN Lu, QIU Peng-peng, GUO Shuo, GUO Jing-han, GUO Chen-shuo, JIANG Jian-fu, LIU Chong-huai, WANG Yong, LIU Guo-tian, WANG Yue-jin, XU Yan
    2023, 22(11): 3269-3283.  DOI: 10.1016/j.jia.2023.10.014
    Abstract ( )   PDF in ScienceDirect  

    Molecular marker-assisted selection (MAS) can significantly accelerate and improve the efficiency of the breeding process in seedless grape cultivars.  In this study, we developed the KASP_VviAGL11 and VviAGL11_410 markers based on a single nucleotide polymorphism (SNP) site (Chr18: 26889437 (A/C)) of the VviAGL11 gene, and compared them with previously reported SSR markers p3_VvAGL11 and 5U_VviAGL11 by testing 101 cultivars and 81 F1 hybrid progenies.  The results showed that both of the proposed markers obtained 100% accuracy rates in detecting allele A, which was closely associated with the seedless trait in grapes, while p3_VvAGL11 and 5U_VviAGL11 had lower accuracy rates due to their tendency to produce false positives.  After careful evaluation of the technical advantages and disadvantages associated with these markers, we concluded that KASP_VviAGL11 was superior in terms of simplicity, cost-effectiveness, efficiency, and accuracy.  Thus, we optimized the process of molecular MAS for seedless grapes, focusing on the KASP_VviAGL11 marker as a central component, to provide key technical support for the development of new seedless grape cultivars.

    Comprehensive analysis of the full-length transcripts and alternative splicing involved in clubroot resistance in Chinese cabbage
    SU He-nan, YUAN Yu-xiang, YANG Shuang-juan, WEI Xiao-chun, ZHAO Yan-yan, WANG Zhi-yong, QIN Liu-yue, YANG Zhi-yuan, NIU Liu-jing, LI Lin, ZHANG Xiao-wei
    2023, 22(11): 3284-3295.  DOI: 10.1016/j.jia.2022.09.014
    Abstract ( )   PDF in ScienceDirect  

    Chinese cabbage is an economically important Brassica vegetable worldwide, and clubroot, which is caused by the soil-borne protist plant pathogen Plasmodiophora brassicae is regarded as a destructive disease to Brassica crops.  Previous studies on the gene transcripts related to Chinese cabbage resistance to clubroot mainly employed RNA-seq technology, although it cannot provide accurate transcript assembly and structural information.  In this study, PacBio RS II SMRT sequencing was used to generate full-length transcriptomes of mixed roots at 0, 2, 5, 8, 13, and 22 days after Pbrassicae infection in the clubroot-resistant line DH40R.  Overall, 39 376 high-quality isoforms and 26 270 open reading frames (ORFs) were identified from the SMRT sequencing data.  Additionally, 426 annotated long noncoding RNAs (lncRNAs), 56 transcription factor (TF) families, 1 883 genes with poly(A) sites and 1 691 alternative splicing (AS) events were identified.  Furthermore, 1 201 of the genes had at least one AS event in DH40R.  A comparison with RNA-seq data revealed six differentially expressed AS genes (one for disease resistance and five for defensive response) that are potentially involved in Pbrassicae resistance.  The results of this study provide valuable resources for basic research on clubroot resistance in Chinese cabbage.

    Blue light induces leaf color change by modulating carotenoid metabolites in orange-head Chinese cabbage (Brassica rapa L. ssp. pekinensis)
    ZHANG Rui-xing, ZHANG Ni-nan, WANG Ya-xiu, Khan ABID, MA Shuai, BAI Xue, ZENG Qi, PAN Qi-ming, LI Bao-hua, ZHANG Lu-gang
    2023, 22(11): 3296-3311.  DOI: 10.1016/j.jia.2023.09.029
    Abstract ( )   PDF in ScienceDirect  

    Carotenoids are involved in the formation of plant leaf color as well as photosystem photoprotection.  This study showed that blue light significantly induced up-regulation of the total carotenoid content in the inner leaves of orange-head Chinese cabbage (OHCC).  Furthermore, the transcriptomic analysis revealed that blue light treatment induced up-regulation of genes in photosynthesis (BrHY5-2, BrCOP1 and BrDET1) and the methylerythritol 4-phosphate pathways (BrGGPS, BrDXS and BrHDR) upstream of the carotenoid metabolic pathway.  Carotenoid metabolomic analysis revealed that the accumulation of several orange and red carotenoids (lycopene, zeaxanthin, β-carotene, lutein, and β-cryptoxanthin) after blue light treatment contributed to the deepening of the leaf coloration, suggesting that short-term blue light treatment could be used to boost nutritional quality.  The light signal gene BrHY5-2 participated in the blue light-induced transcriptional regulation of carotenoid biosynthesis in OHCC.  Overexpression of BrHY5-2 in Arabidopsis significantly increased the total carotenoid content and the sensitivity to blue light.  The above findings revealed new insights about blue-light-induced carotenoid synthesis and accumulation in OHCC lines.  They suggested a new engineering approach to increase the nutritional value of vegetables.

    A novel mutation in ACS11 leads to androecy in cucumber
    WANG Jie, LI Shuai, CHEN Chen, ZHANG Qi-qi, ZHANG Hui-min, CUI Qing-zhi, CAI Guang-hua, ZHANG Xiao-peng, CHAI Sen, WAN Li, YANG Xue-yong, ZHANG Zhong-hua, HUANG San-wen, CHEN Hui-ming, SUN Jin-jing
    2023, 22(11): 3312-3320.  DOI: 10.1016/j.jia.2023.03.003
    Abstract ( )   PDF in ScienceDirect  

    Sex determination in plants gives rise to unisexual flowers.  A better understanding of the regulatory mechanism underlying the production of unisexual flowers will help to clarify the process of sex determination in plants and allow researchers and farmers to harness heterosis.  Androecious cucumber (Cucumis sativus L.) plants can be used as the male parent when planted alongside a gynoecious line to produce heterozygous seeds, thus reducing the cost of seed production.  The isolation and characterization of additional androecious genotypes in varied backgrounds will increase the pool of available germplasm for breeding.  Here, we discovered an androecious mutant in a previously generated ethyl methanesulfonate (EMS)-mutagenized library of the cucumber inbred line ‘406’.  Genetic analysis, whole-genome resequencing, and molecular marker-assisted verification demonstrated that a nonsynonymous mutation in the ethylene biosynthetic gene 1-AMINOCYCLOPROPANE-1-CARBOXYLATE SYNTHASE 11 (ACS11) conferred androecy.  The mutation caused an amino acid change from serine (Ser) to phenylalanine (Phe) at position 301 (S301F).  In vitro enzyme activity assays revealed that this S301F mutation leads to a complete loss of enzymatic activity.  This study provides a new germplasm for use in cucumber breeding as the androecious male parent, and it offers new insights into the catalytic mechanism of ACS enzymes.

    QTL analysis of early flowering of female flowers in zucchini (Cucurbita pepo L.)
    QU Shu-ping, YANG Dan, YU Hai-yang, CHEN Fang-yuan, WANG Ke-xin, DING Wen-qi, XU Wen-long, WANG Yun-li
    2023, 22(11): 3321-3330.  DOI: 10.1016/j.jia.2022.09.009
    Abstract ( )   PDF in ScienceDirect  

    Early flowering promotes early maturity, production, and the capacity to counteract biotic and abiotic stresses, making it an important agronomic trait in zucchini.  The present study demonstrated that the zucchini inbred line ‘19’ consistently flowered early, taking significantly fewer days to bloom the first female flower (DFF) than the inbred line ‘113’.  Genetic analysis revealed that DFF, an inheritable quantitative trait, is controlled by multiple genes.  Based on the strategy of quantitative trait locus (QTL) sequencing (QTL-seq) combined with linkage analysis, three QTLs for DFF were identified on chromosomes 4, 11, and 20.  This study used additional F2 populations grown under different environmental conditions for QTL mapping analysis of DFF with insertion/deletion (InDel) markers to validate these results.  Using the composite interval mapping (CIM) method of R/qtl software, we only identified one major locus under all environmental conditions, located in a 117-kb candidate region on chromosome 20.  Based on gene annotation, gene sequence alignment, and qRT-PCR analysis, we found that the Cp4.1LG20g08050 gene encoding a RING finger protein may be a candidate gene for the opposite regulation of early flowering in zucchini.  In summary, these results lay a foundation for a better understanding of early flowering and improving early flowering-based breeding strategies in zucchini.

    SLAF marker based QTL mapping of fruit-related traits reveals a major-effect candidate locus ff2.1 for flesh firmness in melon
    CHEN Ke-xin, DAI Dong-yang, WANG Ling, YANG Li-min, LI Dan-dan, WANG Chao, JI Peng, SHENG Yun-yan
    2023, 22(11): 3331-3345.  DOI: 10.1016/j.jia.2023.02.014
    Abstract ( )   PDF in ScienceDirect  

    Flesh firmness (FF) is an important and complex trait for melon breeders and consumers.  However, the genetic mechanism underlying FF is unclear.  Here, a soft fruit melon (P5) and a hard fruit melon (P10) were crossed to generate F2, and the FF and fruit-related traits were recorded for two years.  By performing quantitative trait locus (QTL) specific-locus amplified fragment (SLAF) (QTL-SLAF) sequencing and molecular marker-linkage analysis, 112 844 SLAF markers were identified, and 5 919 SNPs were used to construct a genetic linkage map with a total genetic distance of 1 356.49 cM.  Ten FF- and fruit-related QTLs were identified.  Consistent QTLs were detected for fruit length (FL) and fruit diameter (FD) in both years, and QTLs for single fruit weight (SFW) were detected on two separate chromosomes in both years.  For FF, the consistent major locus (ff2.1) was located in a 0.17-Mb candidate region on chromosome 2.  Using 429 F2 individuals derived from a cross between P5 and P10, we refined the ff2.1 locus to a 28.3-kb region harboring three functional genes.  These results provide not only a new candidate QTL for melon FF breeding but also a theoretical foundation for research on the mechanism underlying melon gene function.

    Differential metabolites and their transcriptional regulation in seven major tea cultivars (Camellia sinensis) in China
    GAO Ting, HOU Bing-hao, SHAO Shu-xian, XU Meng-ting, ZHENG Yu-cheng, JIN Shan, WANG Peng-jie, YE Nai-xing
    2023, 22(11): 3346-3363.  DOI: 10.1016/j.jia.2023.02.009
    Abstract ( )   PDF in ScienceDirect  

    Various genetic and biochemical characteristics exist in tea plant cultivars, and they largely determine production suitability and tea quality.  Here, we performed transcriptomic and metabolomic analyses of young shoots of seven tea cultivars and identified major regulatory transcription factors (TFs) for the characteristic metabolites in different cultivars based on weighted gene co-expression network analysis (WGCNA).  Phenotypically, we found that ‘Tieguanyin’ (TGY) and ‘Fujian Shuixian’ (FJSX), which are suitable for oolong tea, had higher catechin contents.  The metabolites of ‘Jinxuan’ (JX) were more prominent, especially the contents of phenolic acids, flavonoids, terpenes, and tannins, which were higher than those of the other six cultivars.  Moreover, ‘Fudingdabai’ (FDDB), which is suitable for white tea, was rich in amino acids, linolenic acid, and saccharides.  At the molecular level, hydroxycinnamoyl CoA quinate hydroxycinnamoyl transferase (HCT) (CsTGY12G0001876, and CsTGY06G0003042) led to the accumulation of chlorogenic acid in TGY.  The main reason for the higher l-ascorbic acid content in FJSX was the high expression levels of L-galactono-1,4-lactone hydrogenase (GalLDH) (CsTGY13G0000389) and Myo-inositol oxygenase (MIOX) (CsTGY14G0001769, and CsTGY14G0001770), which were regulated by WRKY (CsTGY11G0001197).  Furthermore, FDDB, ‘Longjing 43’ (LJ43), ‘Shuchazao’ (SCZ)  and ‘Baihaozao’ (BHZ) had higher free fatty acid contents, among which MYB (CsTGY14G0002344) may be a hub gene for the regulation of palmitoleic acid accumulation.  More importantly, we found that the shoots of TGY were green with purple, mainly due to the accumulation of anthocyanins and the downregulation of the Mg-protoporphyrin IX nonomethyl ester cyclase (MPEC) (CsTGY10G0001989) gene that affects chlorophyll synthesis.  These results will provide a theoretical reference for tea cultivar breeding and suitability.

    Genome-wide association studies reveal the genetic basis of amino acid content variation in tea plants
    GUO Ya-fei, LI Dai-li, QIU Hai-ji, ZHANG Xiao-liang, LIU Lin, ZHAO Jing-jing, JIANG De-yuan
    2023, 22(11): 3364-3379.  DOI: 10.1016/j.jia.2023.10.002
    Abstract ( )   PDF in ScienceDirect  

    Tea is one of the most popular non-alcoholic beverages in the world, and free amino acids, especially theanine, make a major contribution to the umami taste of tea.  However, the genetic basis of the variation in amino acid content in tea plants remains largely unknown.  Here, we measured the free amino acid content in fresh leaves of 174 tea accessions over two years using a targeted metabolomics approach and obtained genotype data via RNA sequencing.  Genome-wide association studies were conducted to investigate loci affecting the content of free amino acids.  A total of 69 quantitative trait loci (–log10(P-value)>5) were identified.  Functional annotation revealed that branched-chain amino acid aminotransferase, glutamine synthetase, nitrate transporter, and glutamate decarboxylase might be important for amino acid metabolism.  Two significant loci, glutamine synthetase (Glu1, P=3.71×10–4; Arg1, P=4.61×10–5) and branched-chain amino acid aminotransferase (Val1, P=4.67×10–5; I_Leu1, P=3.56×10–6), were identified, respectively.  Based on the genotyping result, two alleles of CsGS (CsGS-L and CsGS-H) and CsBCAT (CsBCAT-L and CsBCAT-H) were selected to perform function verification.  Overexpression of CsGS-L and CsGS-H enhanced the contents of glutamate and arginine in transgenic plants, and overexpression of CsBCAT-L and CsBCAT-H promoted the accumulation of valine, isoleucine and leucine.  Enzyme activity assay uncovered that SNP1054 is important for CsGS catalyzing glutamate into glutamine.  Furthermore, CsGS-L and CsGS-H differentially regulated the accumulation of glutamine, and CsBCAT-L and CsBCAT-H differentially regulated the accumulation of branched-chain amino acids.  In summary, the findings in our study would provide new insights into the genetic basis of amino acids contents variation in tea plants and facilitate the identification of elite genes to enhance amino acids content.

    Crop Science
    Genome-wide association and linkage mapping strategies reveal the genetic loci and candidate genes of important agronomic traits in Sichuan wheat
    ZHANG Zhi-peng, LI Zhen, HE Fang, LÜ Ji-juan, XIE Bin, YI Xiao-yu, LI Jia-min, LI Jing, SONG Jing-han, PU Zhi-en, MA Jian, PENG Yuan-ying, CHEN Guo-yue, WEI Yu-ming, ZHENG You-liang, LI Wei
    2023, 22(11): 3380-3393.  DOI: 10.1016/j.jia.2023.02.030
    Abstract ( )   PDF in ScienceDirect  

    Increasing wheat yield is a long-term goal for wheat breeders around the world.  Exploiting elite genetic resources and dissecting the genetic basis of important agronomic traits in wheat are the necessary methods for high-yield wheat breeding.  This study evaluated nine crucial agronomic traits found in a natural population of 156 wheat varieties and 77 landraces from Sichuan, China in seven environments over two years.  The results of this investigation of agronomic traits showed that the landraces had more tillers and higher kernel numbers per spike (KNS), while the breeding varieties had higher thousand-kernel weight (TKW) and kernel weight per spike (KWS).  The generalized heritability (H2) values of the nine agronomic traits varied from 0.74 to 0.95.  Structure analysis suggested that the natural population could be divided into three groups using 43 198 single nucleotide polymorphism (SNP) markers from the wheat 55K SNP chip.  A total of 67 quantitative trait loci (QTLs) were identified by the genome-wide association study (GWAS) analysis based on the Q+K method of a mixed linear model.  Three important QTLs were analyzed in this study.  Four haplotypes of QFTN.sicau-7BL.1 for fertile tillers number (FTN), three haplotypes of QKNS.sicau-1AL.2 for KNS, and four haplotypes of QTKW.sicau-3BS.1 for TKW were detected.  FTN-Hap2, KNS-Hap1, and TKW-Hap2 were excellent haplotypes for each QTL based on the yield performance of 42 varieties in regional trials from 2002 to 2013.  The varieties with all three haplotypes showed the highest yield compared to those with either two haplotypes or one haplotype.  In addition, the KASP-AX-108866053 marker of QTL QKNS.sicau-1AL.2 was successfully distinguished between three haplotypes (or alleles) in 63 varieties based on the number of kernels per spike in regional trials between 2018 and 2021.  These genetic loci and reliable makers can be applied in marker-assisted selection or map-based gene cloning for the genetic improvement of wheat yield. 

    Genetic dissection of crown root traits and their relationships with aboveground agronomic traits in maize
    SHA Xiao-qian, GUAN Hong-hui, ZHOU Yu-qian, SU Er-hu, GUO Jian, LI Yong-xiang, ZHANG Deng-feng, LIU Xu-yang, HE Guan-hua, LI Yu, WANG Tian-yu, ZOU Hua-wen, LI Chun-hui
    2023, 22(11): 3394-3407.  DOI: 10.1016/j.jia.2023.04.022
    Abstract ( )   PDF in ScienceDirect  
    The crown root system is the most important root component in maize at both the vegetative and reproductive stages.  However, the genetic basis of maize crown root traits (CRT) is still unclear, and the relationship between CRT and aboveground agronomic traits in maize is poorly understood.  In this study, an association panel including 531 elite maize inbred lines was planted to phenotype the CRT and aboveground agronomic traits in different field environments.  We found that root traits were significantly and positively correlated with most aboveground agronomic traits, including flowering time, plant architecture and grain yield.  Using a genome-wide association study (GWAS) coupled with resequencing, a total of 115 associated loci and 22 high-confidence candidate genes were identified for CRT.  Approximately one-third of the genetic variation in crown root was co-located with 46 QTLs derived from flowering and plant architecture.  Furthermore, 103 (89.6%) of 115 crown root loci were located within known domestication- and/or improvement-selective sweeps, suggesting that crown roots might experience indirect selection in maize during domestication and improvement.  Furthermore, the expression of Zm00001d036901, a high-confidence candidate gene, may contribute to the phenotypic variation in maize crown roots, and Zm00001d036901 was selected during the domestication and improvement of maize.  This study promotes our understanding of the genetic basis of root architecture and provides resources for genomics-enabled improvements in maize root architecture.

    Analysis of genetic diversity and population structure in sweetpotato using SSR markers
    LIU Cheng, ZHAO Ning, JIANG Zhi-cheng, ZHANG Huan, ZHAI Hong, HE Shao-zhen, GAO Shao-pei, LIU Qing-chang
    2023, 22(11): 3408-3415.  DOI: 10.1016/j.jia.2023.02.004
    Abstract ( )   PDF in ScienceDirect  
    Sweetpotato, Ipomoea batatas (L.) Lam., is an important food crop worldwide.  Large scale evaluation of sweetpotato germplasm for genetic diversity is necessary to determine the genetic relationships between them and effectively use them in the genetic improvement.  In this study, the genetic diversity of 617 sweetpotato accessions, including 376 landraces and 162 bred varieties from China and 79 introduced varieties from 11 other countries, was assessed using 30 simple sequence repeat (SSR) primer pairs with high polymorphism.  Based on the population structure analysis, these sweetpotato accessions were divided into three groups, Group 1, Group 2 and Group 3, which included 228, 136 and 253 accessions, respectively.  Consistent results were obtained by phylogenic analysis and principal coordinate analysis (PCoA).  Of the three groups, Group 2 showed the highest level of genetic diversity and its accessions were mainly distributed in low-latitude regions.  The accessions from South China exhibited the highest level of genetic diversity, which supports the hypothesis that Fujian and Guangdong were the first regions where sweetpotato was introduced to China.  Analysis of molecular variance (AMOVA) indicated significant genetic differentiations between the different groups, but low levels of genetic differentiation existed between the different origins and accession types.  These results provide valuable information for the better utilization of these accessions in sweetpotato breeding.
    No-tillage with straw mulching boosts grain yield of wheat via improving the eco-physiological characteristics in arid regions
    YIN Wen, FAN Zhi-long, HU Fa-long, FAN Hong, HE Wei, SUN Ya-li, WANG Feng, ZHAO Cai, YU Ai-zhong, CHAI Qiang
    2023, 22(11): 3416-3429.  DOI: 10.1016/j.jia.2023.02.041
    Abstract ( )   PDF in ScienceDirect  
    Straw returning to the field is a technical measure of crop production widely adopted in arid areas.  It is unknown whether crop yield can be further increased by improving the eco-physiological characteristics when straw returning is applied in the crop production system.  So, a three-year field experiment was conducted with various straw returning treatments for wheat production: (i) no-tillage with straw mulching (NTSM), (ii) no-tillage with straw standing (NTSS), (iii) conventional tillage with straw incorporation (CTS), and (iv) conventional tillage with no straw returning (CT, control).  The eco-physiological and yield formation indicators were investigated to provide the basis for selecting the appropriate straw returning method to increase wheat yield and clarifying its regulation mechanism on eco-physiology.  The results showed that NTSM and NTSS treatments had better regulation of eco-physiological characteristics and had a higher yield increase than CTS and CT.  Meanwhile, NTSM had a relatively higher yield than NTSS through better regulation of eco-physiological characteristics.  Compared to CT, the leaf area index of NTSM was decreased by 6.1–7.6% before the Feekes 10.0 stage of wheat, but that of NTSM was increased by 38.9–45.1% after the Feekes 10.0 stage.  NTSM effectively regulated the dynamics of the photosynthetic source of green leaves during the wheat growth period.  NTSM improved net photosynthetic rate by 10.2–21.4% and 11.0–21.6%, raised transpiration rate by 4.4–10.0% and 5.3–6.1%, increased leaf water use efficiency by 5.6–10.4% and 5.4–14.6%, at Feekes 11.0 and 11.2 stages of wheat, compared to CT, respectively.  NTSM had higher leaf water potential (LWP) by 7.5–12.0% and soil water potential (SWP) by 8.9–24.0% from Feekes 10.3 to 11.2 stages of wheat than CT.  Meanwhile, the absolute value of difference on LWP and SWP with NTSM was less than that with CT, indicating that NTSM was conducive to holding the stability of water demand for wheat plants and water supply of soil at arid conditions.  Thus, NTSM had a greater grain yield of wheat by 18.6–27.3% than CT, and the high yield was attributed to the synchronous increase and cooperative development of ear number, grain number per ear, and 1 000-grain weight.  NTSM had a positive effect on regulating the eco-physiological characteristics and can be recommended to enhance wheat grain yield in arid conditions.
    Inclusion of peanut in wheat–maize rotation increases wheat yield and net return and improves soil organic carbon pool by optimizing bacterial community
    ZOU Xiao-xia, HUANG Ming-ming, LIU Yan, SI Tong, ZHANG Xiao-jun, YU Xiao-na, GUO Feng, WAN Shu-bo
    2023, 22(11): 3430-3443.  DOI: 10.1016/j.jia.2023.04.018
    Abstract ( )   PDF in ScienceDirect  

    Improving soil quality while achieving higher productivity is the major challenge in the agricultural industry.  Wheat (Triticum aestivum L.)–maize (Zea mays L.) (W–M) rotation is the dominant planting pattern in the Huang-Huai-Hai  Plain and is important for food security in China.  However, the soil quality is deteriorating due to the W–M rotation’s long-term, intensive, and continuous cultivation.  Introducing legumes into the W–M rotation system may be an effective way to improve soil quality.  In this study, we aimed to verify this hypothesis by exploring efficient planting systems (wheat–peanut (Arachis hypogaea L.) (W–P) rotation and wheat rotated with maize and peanut intercropping (W–M/P)) to achieve higher agricultural production in the Huang-Huai-Hai   Plain.  Using traditional W–M rotation as the control, we evaluated crop productivity, net returns, soil microorganisms (SMs), and soil organic carbon (SOC) fractions for three consecutive years.  The results indicated that wheat yields were significantly increased under W–P and W–M/P (382.5–579.0 and 179.8–513.1 kg ha−1, respectively) compared with W–M.  W–P

    and W–M/P provided significantly higher net returns (58.2 and 70.4%, respectively) than W–M.  W–M/P and W–M retained the SOC stock more efficiently than W–P, increasing by 25.46–31.03 and 14.47–27.64%, respectively, in the 0–20 cm soil layer.  Compared with W–M, W–M/P improved labile carbon fractions; the sensitivity index of potentially mineralizable carbon, microbial biomass carbon (MBC), and dissolved organic carbon was 31.5, 96.5–157.2, and 17.8% in 20–40, 10–40, and 10–20 cm soil layers, respectively.  The bacterial community composition and bacteria function were altered as per the soil depth and planting pattern.  W–M/P and W–M exhibited similar bacterial community composition and function in 0–20 and 20–40 cm soil layers.  Compared with W–P, a higher abundance of functional genes, namely, contains mobile elements and stress-tolerant, and a lower abundance of genes, namely, potentially pathogenic, were observed in the 10–20 cm soil layer of W–M and the 0–20 cm soil layer of W–M/P.  SOC and MBC were the main factors affecting soil bacterial communities, positively correlated with Sphingomonadales and Gemmatimonadales and negatively correlated with Blastocatellales.  Organic input was the main factor affecting SOC and SMs, which exhibited feedback effects on crop productivity.  In summary, W–M/P improved productivity, net returns, and SOC pool compared with traditional W–M rotation systems, and it is recommended that plant–soil–microbial interactions be considered while designing high-yield cropping systems.

    Plant Protection
    FgGyp8 as a putative FgRab1 GAP is required for growth and pathogenesis by regulating FgSnc1-mediated secretory vesicles fusion in Fusarium graminearum
    ZHANG Xing-zhi, CHEN Shuang, Yakubu Saddeeq ABUBAKAR, MAO Xu-zhao, MIAO Peng-fei, WANG Zong-hua, ZHOU Jie, ZHENG Hua-wei
    2023, 22(11): 3444-3457.  DOI: 10.1016/j.jia.2023.04.005
    Abstract ( )   PDF in ScienceDirect  

    Fusarium graminearum is an important plant pathogenic fungus that causes disease and yield reduction in many cereal crops, such as wheat and barley.  Gyp8 stimulates GTP hydrolysis on Ypt1 in yeast.  However, the functions of Gyp8 in plant pathogenic fungi are still unknown.  In this study, we investigated the roles of FgGyp8 in Fgraminearum by genetic and pathological analyses.  Through gene knockout and phenotypic analyses, we found that FgGyp8 is required for vegetative growth in Fgraminearum.  The conidiation, conidial size and number of septa per conidium of ΔFggyp8 mutant are significantly reduced when compared to the wild type PH-1.  Furthermore, FgGyp8 is crucial for pathogenicity on wheat coleoptiles and wheat heads.  FgGyp8 contains a conserved TBC domain.  Domain deletion analysis showed that the TBC domain, C- and N-terminal regions of FgGyp8 are all important for its biological functions in Fgraminearum.  Moreover, we showed that FgGyp8 catalyzes the hydrolysis of the GTP on FgRab1 to GDP in vitro, indicating that FgGyp8 is a GTPase-activating protein (GAP) for FgRab1.  In addition, we demonstrated that FgGyp8 is required for FgSnc1-mediated fusion of secretory vesicles with the plasma membrane in Fgraminearum.  Finally, we showed that FgGyp8 has functional redundancy with another FgRab1 GAP, FgGyp1, in Fgraminearum.  Taken together, we conclude that FgGyp8 is required for vegetative growth, conidiogenesis, pathogenicity and acts as a GAP for FgRab1 in Fgraminearum.

    Identification and expression analysis of sugar transporter family genes reveal the role of ZmSTP2 and ZmSTP20 in maize disease resistance
    MA Yu-xin, ZHOU Zhi-jun, CAO Hong-zhe, ZHOU Fan, SI He-long, ZANG Jin-ping, XING Ji-hong, ZHANG Kang, DONG Jin-gao
    2023, 22(11): 3458-3473.  DOI: 10.1016/j.jia.2022.12.014
    Abstract ( )   PDF in ScienceDirect  

    Sugar is an indispensable source of energy for plant growth and development, and it requires the participation of sugar transporter proteins (STPs) for crossing the hydrophobic barrier in plants.  Here, we systematically identified the genes encoding sugar transporters in the genome of maize (Zea mays L.), analyzed their expression patterns under different conditions, and determined their functions in disease resistance.  The results showed that the mazie sugar transporter family contained 24 members, all of which were predicted to be distributed on the cell membrane and had a highly conserved transmembrane transport domain.  The tissue-specific expression of the maize sugar transporter genes was analyzed, and the expression level of these genes was found to be significantly different in different tissues.  The analysis of biotic and abiotic stress data showed that the expression levels of the sugar transporter genes changed significantly under different stress factors.  The expression levels of ZmSTP2 and ZmSTP20 continued to increase following Fusarium graminearum infection.  By performing disease resistance analysis of zmstp2 and zmstp20 mutants, we found that after inoculation with Cochliobolus carbonum, Setosphaeria turcica, Cochliobolus heterostrophus, and Fgraminearum, the lesion area of the mutants was significantly higher than that of the wild-type B73 plant.  In this study, the genes encoding sugar transporters in maize were systematically identified and analyzed at the whole genome level.  The expression patterns of the sugar transporter-encoding genes in different tissues of maize and under biotic and abiotic stresses were revealed, which laid an important theoretical foundation for further elucidation of their functions.

    Possible source and migration pathway for early-summer immigrants of the oriental armyworm, Mythimna separata, arriving in northern Japan
    Akira OTUKA, Tokumitsu NIIYAMA, JIANG Xing-fu
    2023, 22(11): 3474-3488.  DOI: 10.1016/j.jia.2023.06.001
    Abstract ( )   PDF in ScienceDirect  

    The first generation of the oriental armyworm, Mythimna separata (Walker), arrives every year in northern Japan in mainly late May to early June.  Analyses of weather maps suggested that this moth’s immigration source could be eastern China, but the accuracy of those analyses was very limited due to the lack of a current standard trajectory analysis.  The management of migratory insect pests such as Mseparata benefits from the identification of the migration source(s) and pathway(s) of the pests.  The present study provides a trajectory analysis for Mseparata.  Backward trajectories from trap sites in northern Japan were calculated with the HYSPLIT System developed by the U.S. National Oceanic and Atmospheric Administration, taking the flight speed of M. separata and the limitation of low ambient temperature at flight height into account.  The ending times of the moth’s short and long trajectories were set at dusk on the day before and two days before the possible arrival date, respectively.  The results suggested two types of possible migration pathway: a multi-step pathway from Northeast China, the Korean Peninsula, and eastern Russia, which are destination areas of the first-generation’s migration, and a direct pathway from seasonal main emigration areas in eastern China such as Jiangsu and Shandong provinces.  These findings contribute to our understanding of the migration ecology of Mseparata and can be used for the development of methods to predict the migration of this insect.

    Animal Science · Veterinary Medicine
    High serum reproductive hormone levels at mid-pregnancy support Meishan pig prolificacy
    ZHOU Rong, YANG Yalan, LIU Ying, CHEN Jie, YANG Bing, TANG Zhong-lin
    2023, 22(11): 3489-3499.  DOI: 10.1016/j.jia.2023.05.014
    Abstract ( )   PDF in ScienceDirect  
    Increasing prolificacy is an important aim in the pig industry.  Regions associated with litter size have been revealed, but detailed molecular mechanisms are unclear.  The Meishan pig is one of the most prolific breeds, with higher prolificacy than the Yorkshire pig, which exhibits high feeding efficiency and lean meat yield.  The ovary is the key organ determining reproductive traits during pregnancy by synthesizing and secreting reproductive hormones essential for conceptus maintenance.  In this comparative multi-omics study of the ovary transcriptome, proteome, and metabolome on day 49 of pregnancy, we aimed to identify genomic, proteomic, and metabolomic differences between the ovaries of Meishan and Yorkshire pigs to reveal potential molecular mechanisms conferring high prolificacy.  Meishan pigs demonstrated general downregulation of steroid biosynthesis and butanoate metabolism in the ovary during mid-pregnancy at both transcriptome and proteome levels but exhibited higher serum cholesterol, estradiol, and progesterone levels than Yorkshire pigs.  We also identified several single-nucleotide polymorphisms in the genes of the steroid hormone pathway associated with litter number, average birth weight, and total litter weight.  Lower biosynthesis rates but elevated serum levels of reproductive hormones during mid- and late pregnancy are essential for the greater prolificacy of Meishan pigs.
    miR-27b-5p regulates chicken liver disease via targeting IRS2 to suppress the PI3K/AKT signal pathway
    ZHAO Jing, WU Ya-mei, ZHANG Yao, TANG Shu-yue, HAN Shun-shun, CUI Can, TAN Bo, YU Jie, KANG Hou-yang, CHEN Guang-deng, MA Meng-gen, ZHU Qing, YIN Hua-dong
    2023, 22(11): 3500-3516.  DOI: 10.1016/j.jia.2023.04.010
    Abstract ( )   PDF in ScienceDirect  

    The liver is a vital organ in chickens that performs a number of crucial physiological functions, including the storage of hepatic glycogen, protein synthesis, detoxification, and deoxidation.  The growth and metabolism of the liver are complex processes influenced by factors such as environment, diet, and genetics.  MicroRNAs (miRNAs), as post-transcriptional regulatory molecules, play a role in various biological processes.  There is growing evidence that miR-27b-5p plays a key role in the regulation of liver development and metabolism in various species.  However, its role in chicken livers has yet to be determined.  In our experiment, we found that chickens with fatty livers had significantly higher levels of serum triglyceride (TG) and total cholesterol (TC) compared to the normal chickens, while the control group had significantly higher levels of very low-density lipoprotein (VLDL) and serum hormones.  Further research showed that the mRNA of miR-27b-5p was highly expressed in fatty livers.  By exploring the function of miR-27b-5p in chicken livers, we discovered that it promotes lipogenesis, oxidative stress, and inflammatory responses, leading to hepatocyte apoptosis.  Our study also established the mechanism by which miR-27b-5p interacts with its target gene, and found that miR-27b-5p targets insulin receptor substrate 2 (IRS2) and modulates the PI3K/AKT signaling pathway.  Additionally, our investigation of IRS2 in chicken hepatocytes revealed that knocking down IRS2 has the same effects as overexpressing miR-27b-5p.  In conclusion, our study revealed that miR-27b-5p directly binds to IRS2, inhibiting the PI3K/AKT signaling pathway and causing steatosis, oxidative stress, inflammation, and apoptosis in chicken liver.

    Agro-ecosystem & Environment
    Effects of the combined application of organic and chemical nitrogen fertilizer on soil aggregate carbon and nitrogen: A 30-year study
    BAI Jin-shun, ZHANG Shui-qing, HUANG Shao-min, XU Xin-peng, ZHAO Shi-cheng, QIU Shao-jun, HE Ping, ZHOU Wei
    2023, 22(11): 3517-3534.  DOI: 10.1016/j.jia.2023.09.012
    Abstract ( )   PDF in ScienceDirect  

    To understand the long-term effects of combined organic and chemical nitrogen fertilization on soil organic C (SOC) and total N (TN), we conducted a 30-year field experiment with a wheat–maize rotation system on the Huang-Huai-Hai Plain during 1990–2019.  The experimental treatments consisted of five fertilizer regimes: no fertilizer (control), chemical fertilizer only (NPK), chemical fertilizer with straw (NPKS), chemical fertilizer with manure (NPKM), and 1.5 times the rate of NPKM (1.5NPKM).  The NPK, NPKS, and NPKM treatments had equal N inputs.  The crop yields were measured over the whole experimental duration.  Soil samples were collected from the topsoil (0–10 and 10–20 cm) and subsoil (20–40 cm) layers for assessing soil aggregates and taking SOC and TN measurements.  Compared with the NPK treatment, the SOC and TN contents increased significantly in both the topsoil (24.1–44.4% for SOC and 22.8–47.7% for TN) and subsoil layers (22.0–47.9% for SOC and 19.8–41.8% for TN) for the organically amended treatments (NPKS, NPKM and 1.5NPKM) after 30 years, while no significant differences were found for the average annual crop yields over the 30 years of the experiment.  The 0–10 cm layer of the NPKS treatment and the 20–40 cm layer of the NPKM treatment had significantly higher macroaggregate fraction mass proportions (19.8 and 27.0%) than the NPK treatment.  However, the 0–10 and 20–40 cm layers of the 1.5NPKM treatment had significantly lower macroaggregate fraction mass proportions (–19.2 and –29.1%) than the control.  The analysis showed that the higher SOC and TN in the soil of organically amended treatments compared to the NPK treatment were related to the increases in SOC and TN protected in the stable fractions (i.e., free microaggregates and microaggregates within macroaggregates), in which the contributions of the stable fractions were 81.1–91.7% of the increase in SOC and 83.3–94.0% of the increase in TN, respectively.  The relationships between average C inputs and both stable SOC and TN stocks were significantly positive with R2 values of 0.74 and 0.72 (P<0.01) for the whole 40 cm soil profile, which indicates the importance of N for soil C storage.  The results of our study provide key evidence that long-term combined organic and chemical nitrogen fertilization, while maintaining reasonable total N inputs, benefited soil C and N storage in both the topsoil and subsoil layers.


    Fate of fertilizer nitrogen and residual nitrogen in paddy soil in Northeast China
    BI Shi-ting, LUO Xiang-yu, ZHANG Chen, LI Peng-fei, YU Cai-lian, LIU Zhi-lei, PENG Xian-long
    2023, 22(11): 3535-3548.  DOI: 10.1016/j.jia.2023.06.010
    Abstract ( )   PDF in ScienceDirect  

    The relationship between the fate of nitrogen (N) fertilizer and the N application rate in paddy fields in Northeast China is unclear, as is the fate of residual N.  To clarify these issues, paddy field and 15N microplot experiments were carried out in 2017 and 2018, with N applications at five levels: 0, 75, 105, 135 and 165 kg N ha–1 (N0, N75, N105, N135 and N165, respectively).  15N-labeled urea was applied to the microplots in 2017, and the same amount of unlabeled urea was applied in 2018.  Ammonia (NH3) volatilization, leaching, surface runoff, rice yield, the N contents and 15N abundances of both plants and soil were analyzed.  The results indicated a linear platform model for rice yield and the application rate of N fertilizer, and the optimal rate was 135 kg N ha–1.  N uptake increased with an increasing N rate, and the recovery efficiency of applied N (REN) values of the difference subtraction method were 45.23 and 56.98% on average in 2017 and 2018, respectively.  The REN was the highest at the N rate of 135 kg ha–1 in 2017 and it was insignificantly affected by the N application rate in 2018, while the agronomic efficiency of applied N (AEN) and physiological efficiency of applied N (PEN) decreased significantly when excessive N was applied.  N loss through NH3 volatilization, leaching and surface runoff was low in the paddy fields in Northeast China.  NH3 volatilization accounted for 0.81 and 2.99% of the total N application in 2017 and 2018, respectively.  On average, the leaching and surface runoff rates were 4.45% and less than 1.05%, respectively, but the apparent denitrification loss was approximately 42.63%.  The residual N fertilizer in the soil layer (0–40 cm) was 18.37–31.81 kg N ha–1 in 2017, and the residual rate was 19.28–24.50%.  Residual 15N from fertilizer in the soil increased significantly with increasing N fertilizer, which was mainly concentrated in the 0–10 cm soil layer, accounting for 58.45–83.54% of the total residual N, and decreased with increasing depth.  While the ratio of residual N in the 0–10 cm soil layer to that in the 0–40 cm soil layer was decreased with increasing N application.  Furthermore, of the residual N, approximately 5.4% was taken up on average in the following season and 50.2% was lost, but 44.4% remained in the soil.  Hence, the amount of applied N fertilizer should be reduced appropriately due to the high residual N in paddy fields in Northeast China.  The appropriate N fertilizer rate in the northern fields in China was determined to be 105–135 kg N ha–1 in order to achieve a balance between rice yield and high N fertilizer uptake.

    Assessment of the crucial factors influencing the responses of ammonia and nitrous oxide emissions to controlled release nitrogen fertilizer: A meta-analysis
    LÜ Hui-dan, WANG Xi-ya, PAN Zhao-long, ZHAO Shi-cheng
    2023, 22(11): 3549-3559.  DOI: 10.1016/j.jia.2023.07.008
    Abstract ( )   PDF in ScienceDirect  

    Reducing ammonia (NH3) and nitrous oxide (N2O) emissions have great effects on mitigating nitrogen (N) nutrient loss and greenhouse gas emissions.  Controlled release urea (CRU) can control the N release rate, which reduces reactive N loss and increases nitrogen use efficiency relative to conventional urea (CU).  However, the crucial factors influencing the responses of NH3 and N2O emissions to CRU relative to CU are still unclear.  In this study, we evaluated the responses of NH3 and N2O emissions to CRU based on collected field data with a meta-analysis.  CRU reduced the NH3 and N2O emissions by 32.7 and 25.0% compared with CU, respectively.  According to subgroup analysis, CRU presented better mitigation of NH3 and N2O emissions in soils with pH 6.5–7.5 (–47.9 and –23.7%) relative to either pH<6.5 (–28.5 and –21.4%) or pH>7.5 (–29.3 and –17.3%), and in the rice season (–34.8 and –29.1%) relative to the wheat season (–19.8 and –22.8%).  The responses of NH3 and N2O emissions to CRU increased from rainfed (–30.5 and –17.0%) to irrigated (–32.5 and –22.9%), and then to paddy (–34.8 and –29.1%) systems.  In addition, the response of N2O emission mitigation increased with increases in soil total nitrogen (TN); however, soil TN did not significantly affect the response of NH3 volatilization.  The reduction in NH3 emission was greater in sandy-textured soil (–57.7%) relative to loam-textured (–32.9%) and clay-textured (–32.3%) soils, whereas soil texture did not affect N2O emission.  Overall, CRU was a good option for reducing the NH3 and N2O emissions relative to CU in agricultural production.  This analysis improves our understanding of the crucial environmental and management factors influencing the mitigation of NH3 and N2O emissions under CRU application, and these site-specific factors should be considered when applying CRU to reduce reactive N loss and increase NUE.

    Letter
    Virucidal activity of MICRO-CHEM PLUS against African swine fever virus
    JIANG Cheng-gang, SUN Ying, ZHANG Fan, AI Xin, LU Ming, QIN Jia-lin, ZHANG Xian-feng, WANG Jing-fei, BU Zhi-gao, ZHAO Dong-ming, HE Xi-jun
    2023, 22(11): 3560-3563.  DOI: 10.1016/j.jia.2023.09.021
    Abstract ( )   PDF in ScienceDirect