Scientia Agricultura Sinica ›› 2020, Vol. 53 ›› Issue (7): 1368-1380.doi: 10.3864/j.issn.0578-1752.2020.07.007

• PLANT PROTECTION • Previous Articles     Next Articles

Biologic and Transcriptomic Analysis of Citrus hystrix Responses to ‘Candidatus Liberibacter asiaticus’ at Different Infection Stages

CaiLing TENG1,Xi ZHONG1,HaoDi WU1,Yan HU2,ChangYong ZHOU1,XueFeng WANG1   

  1. 1. National Citrus Engineering Research Center, Citrus Research Institute, Chinese Academy of Agricultural Sciences, Chongqing 400712
    2. Ganzhou Bureau of Fruit Industry, Ganzhou 341000, Jiangxi
  • Received:2019-09-01 Accepted:2019-10-15 Online:2020-04-01 Published:2020-04-14

RichHTML

38

PDF

859

Abstract: 【Objective】 Citrus Huanglongbing (HLB), associated with phloem-colonized ‘Candidatus Liberibacter asiaticus’ (CLas), severely impedes worldwide citrus production. The objective of this study is to analyze the biological symptoms, microstructures and transcriptomes of Citrus hystrix in response to CLas infection at different stages, to reveal the tolerance mechanism of C. hystrix, and to provide a basis for further screening of resistance genes and HLB-tolerant/resistant citrus breeding. 【Method】| The budwoods of C. hystrix grafted on two-year-old Carrizo citrange rootstocks (C. sinensis× P. trifoliata) used in this study were graft-inoculated with budwoods from a CLas (strain GZBJT)-infected Guanximiyou pummelo maintained in a greenhouse at Citrus Research Institute. The budwoods used as inoculum were tested CLas positive and free of other potential phloem-limited pathogens, such as Citrus tristeza virus (CTV) or Citrus tatter leaf virus (CTLV) by PCR before grafting. Inoculated plants were kept in greenhouse along with mock-inoculated healthy control plants. Real-time quantitative PCR (qPCR) was performed every 15 days after inoculation. Four months after inoculation (the earliest establishment of CLas by qPCR) and 14 months after inoculation were defined as the early infection stage and the late infection stage, respectively. The biological symptoms and microstructures were observed to analyze the structural changes of different infection stages. Combined with comparative transcriptome and RT-qPCR validation, the response mechanism of C. hystrix against HLB was explored.【Result】 No typical symptom was observed in C. hystrix at the early and late stages of infection. Light microscopy observation from the midribs of HLB-affected and uninfected C. hystrix revealed that no significant structure change was found at the early infection stage and only a few sieves in the phloem were blocked at the late stage. By comparing the RNA-seq data, 181 and 1 384 genes were found to be differentially expressed at the early stage and late stage, respectively. Differentially expressed genes (DEGs) mainly involved in cell wall metabolism, host defense response, starch and sucrose metabolism, callose synthesis and signal transduction. Comparative transcriptome analysis showed that the expression of related genes in starch and sucrose metabolism and cell wall metabolism was down-regulated at the early infection stage, and the expression of related genes in salicylic acid metabolism, salicylic acid signal transduction pathway, pathogenesis-related protein and glutathione-S-transferases was up-regulated at the late infection stage.【Conclusion】 The early response of C. hystrix to CLas infection is mainly characterized by stable physical structure, undisturbed pathways such as starch synthesis and photosynthesis. Salicylic acid-mediated resistance signals, effector-triggered immunity (ETI), and glutathione-S-transferases mediated detoxification contribute to the tolerance of C. hystrix against CLas at the late infection stage.

Key words: citrus Huanglongbing, ‘Candidatus Liberibacter asiaticus’ (CLas);, Citrus hystrix, disease tolerance, transcriptome

Table 1

The genes and primers of RT-qPCR"

基因标志
Gene symbol		 基因ID
Gene ID		 上游引物序列
Forward primer sequence (5′-3′)		 下游引物序列
Reverse primer sequence (5′-3′)		 基因功能描述
Description of gene function
CESA7 102616000 GGAGTAGGAATGGATGACGAC GGATGCTGGACTTGAGGAAG 纤维素合酶A催化亚基7
Cellulose synthase A catalytic subunit 7
EXPA5 102618439 TCCTGGAGGCTGGTGT CAAGGCGAGCATAAGAC 扩张蛋白A5 Expansin-A5
CalS3 102611841 GGTTGTGATTGCTCTGTGG GTGATTGAAAGCGAGACCTTAG 胼胝质合成酶3 Callose synthase 3
Susy 102616003 GTAGTGGGTGGTGATAGG AACAGTCAAGCCAAAGG 蔗糖合成酶 Sucrose synthase
glgC 102615570 TAGGTGGTGGTGCTGG ATTAAACTGGGTGAGGAT 葡萄糖-1-磷酸腺苷转移酶大亚基1
Glucose-1-phosphate adenylyltransferase large subunit 1-like
Rboh 102616720 AGGTACTTGCTGGCACA CGTCGGAAATCTGGTC 呼吸爆发氧化酶同源蛋白D
Respiratory burst oxidase homolog protein D
JAZ 102616825 CCCCACTTCAGTTCCC TGGTATGGTGCTCTTGC 蛋白质TIFY 10A Protein TIFY 10A-like
UGT74G1 102613233 TTCGTCATCCTCGTCC CCAACCAGCCCAAACT UDP葡萄糖基转移酶74G1
UDP-glycosyltransferase 74G1
SAMT 102624842 TGAAGCACATAACCCTAG AGAAGACCCACCACCT 水杨酸羧甲基转移酶
Salicylate carboxymethyltransferase
PR1 102627194 GACCGTATGGCGAGAA CACCCAATGCGAACC 病程相关蛋白1
Pathogenesis-related protein 1-like
R8L3 107176058 TGCGTTGGCTCTGGT AGTCCGTAGTCTTTGTCTCA 抗病性rpp8样蛋白3
Disease resistance RPP8-like protein 3
KTI 102621677 AACTCTTCTTCACCGAATG AGGCTAACTCCACCACC 21 kD种子蛋白21 kD seed protein

Fig. 1

Phenotypic identification and microstructure observation of C. hystrix infected by CLas at different stages"

Fig. 2

Comparative PageMan display of perturbed pathway of DEGs in C. hystrix infected by CLas at different stages"

Fig. 3

DEGs involved in sucrose-starch metabolism (A) and photosynthesis (B)"

Fig. 4

Biotic stress-related DEGs altered in response to CLas infection at different stages"

Fig. 5

RT-qPCR for the DEGs validation A: CH-M-VS-CH-HLB-E; B: CH-M-VS-CH-HLB-L; C: CH-HLB-E-VS-CH-HLB-L"

[1] BOVÉ J M . Huanglongbing: A destructive, newly-emerging, century-old disease of citrus. Journal of Plant Pathology, 2006,88(1):7-37.
[2] 胡燕, 王雪峰, 周常勇 . 柑橘黄龙病菌亚洲种、虫媒及植物寄主互作研究进展. 园艺学报, 2016,43(9):1688-1698.
HU Y, WANG X F, ZHOU C Y . Recent advances in interactions among ‘ Candidatus Liberibacter asiaticus’, insect vector and plant host. Acta Horticulturae Sinica, 2016,43(9):1688-1698. (in Chinese)
[3] REINKING O A . Diseases of economic plants in Southern China. Philippine Agriculturist, 1919,8(4):109-134.
[4] SCHNEIDER H . Anatomy of greening-diseased sweet orange shoots. Phytopathology, 1968,58(1):1155-1160.
[5] ETXEBERRIA E, GONZALEZ P, ACHOR D, ALBRIGO G . Anatomical distribution of abnormally high levels of starch in HLB-affected Valencia orange trees. Physiological and Molecular Plant Pathology, 2009,74(1):76-83.
[6] ALBRECHT U, BOWMAN K D. Transcriptional response of susceptible and tolerant citrus to infection with ‘Candidatus Liberibacter asiaticus’. Plant Science, 2012,185/186:118-130.
[7] BOAVA L P, CRISTOFANI-YALY M, MACHADO M A . Physiologic, anatomic, and gene expression changes in Citrus sunki, Poncirus trifoliata and their hybrids after ‘Candidatus Liberibacter asiaticus’ infection. Phytopathology, 2017,107(5):590-599.
[8] FOLIMONOVA S Y, ROBERTSON C J, GARNSEY S M, GOWDA S, DAWSON W O . Examination of the responses of different genotypes of citrus to Huanglongbing (citrus greening) under different conditions. Phytopathology, 2009,99(12):1346-1354.
[9] SHOKROLLAH H, ABDULLAH T L, SIJAM K, ABDULLAH S N A, ABDULLAH N A P. Differential reaction of citrus species in Malaysia to Huanglongbing (HLB) disease using grafting method. American Journal of Agricultural and Biological Science, 2009,4(1):338.
[10] MARTINELLI F, URATSU S L, ALBRECHT U, REAGAN R L, PHU M L, BRITTON M, BUFFALO V, FASS J, LEICHT E, ZHAO W, LIN D, D’SOUZA R, DAVIS C E, BOWMAN K D, DANDEKAR A M. Transcriptome profiling of citrus fruit response to Huanglongbing disease. PLoS ONE, 2012,7(5):e38039.
[11] ALBRECHT U, BOWMAN K D . Gene expression in Citrus sinensis(L.) Osbeck following infection with the bacterial pathogen ‘Candidatus Liberibacter asiaticus’ causing Huanglongbing in Florida. Plant Science, 2008,175(3):291-306.
[12] KIM J S, SAGARAM U S, BURNS J K, LI J L, WANG N . Response of sweet orange ( Citrus sinensis) to ‘Candidatus Liberibacter asiaticus’ infection: Microscopy and microarray analyses. Phytopathology, 2009,99(1):50-57.
[13] FAN J, CHEN C, BRLANSKY R H, GMITTER F G, LI Z G . Changes in carbohydrate metabolism in Citrus sinensis infected with ‘Candidatus Liberibacter asiaticus’. Plant Pathology, 2010,59(6):1037-1043.
[14] FAN J, CHEN C, YU Q, BRLANSKY R H, LI Z G, GMITTER F G . Comparative iTRAQ proteome and transcriptome analyses of sweet orange infected by ‘ Candidatus Liberibacter asiaticus’. Physiologia Plantarum, 2011,143(3):235-245.
[15] ALBRECHT U, FIEHN O, BOWMAN K D . Metabolic variations in different citrus root stock cultivars associated with different responses to Huanglongbing. Plant Physiology and Biochemistry, 2016,107:33-44.
[16] ARITUA V, ACHOR D, GMITTER F G, ALBRIGO G, WANG N . Transcriptional and microscopic analyses of citrus stem and root responses to ‘ Candidatus Liberibacter asiaticus’ infection. PLoS ONE, 2013,8(9):e73742.
[17] MARTINELLI F, REAGAN R L, URATSU S L, PHU M L, ALBRECHT U, ZHAO W, DAVIS C E, BOWMAN K D, DANDEKAR A M . Gene regulatory networks elucidating Huanglongbing disease mechanisms. PLoS ONE, 2013,8(9):e74256.
[18] ZHONG Y, CHENG C Z, JIANG B, JIANG N H, ZHANG Y Y, HU M L, ZHONG G Y . Digital gene expression analysis of Ponkan mandarin (Citrus reticulata Blanco) in response to Asia citrus psyllid-vectored Huanglongbing infection. International Journal of Molecular Sciences, 2016,17(7):1063.
[19] FAN J, CHEN C, YU Q, KHALAF A, ACHOR D S, BRLANSKY R H, MOORE G A, LI Z G, GMITTER F G . Comparative transcriptional and anatomical analyses of tolerant rough lemon and susceptible sweet orange in response to ‘ Candidatus Liberibacter asiaticus’ infection. Molecular Plant-Microbe Interactions, 2012,25(11):1396-1407.
[20] ZHONG Y, CHENG C Z, JIANG N H, JIANG B, ZHANG Y Y, WU B, HU M L, ZENG J W, YAN H X, YI G J, ZHONG G Y . Comparative transcriptome and iTRAQ proteome analyses of citrus root responses to ‘ Candidatus Liberibacter asiaticus’ infection. PLoS ONE, 2015,10(6):e0126973.
[21] LIAO H L, BURNS J K . Gene expression in Citrus sinensis fruit tissues harvested from Huanglongbing-infected trees: Comparison with girdled fruit. Journal of Experimental Botany, 2012,63(8):3307-3319.
[22] DUAN Y P, ZHOU L J, HALL D G, LI W B, DODDAPANENI H, LIN H, LIU L, VAHLING C M, GABRIEL D W, WILLIAMS K P, DICKERMAN A, SUN Y J, COTTWALD T . Complete genome sequence of citrus Huanglongbing bacterium, ‘ Candidatus Liberibacter asiaticus’ obtained through metagenomics. Molecular Plant-Microbe Interactions, 2009,22(8):1011-1020.
[23] LU H, ZHANG C, ALBRECHT U, SHIMIZU R, WANG G, BOWMAN K D . Overexpression of a citrus NDR1 ortholog increases disease resistance in Arabidopsis. Frontiers in Plant Science, 2013,4:157.
[24] ROSALES R, BURNS J K . Phytohormone changes and carbohydrate status in sweet orange fruit from Huanglongbing-infected trees. Journal of Plant Growth Regulation, 2011,30(3):312-321.
[25] NEHELA Y, HIJAZ F, ELZAAWELY A A, EL-ZAHABY H M, KILLINY N. Citrus phytohormonal response to ‘ Candidatus Liberibacter asiaticus’ and its vector Diaphorina citri. Physiological and Molecular Plant Pathology, 2018,102:24-35.
[26] HU Y, ZHONG X, LIU X L, LOU B H, ZHOU C Y, WANG X F . Comparative transcriptome analysis unveils the tolerance mechanisms of Citrus hystrix in response to ‘Candidatus Liberibacter asiaticus’ infection. PLoS ONE, 2017,12(12):e0189229.
[27] KOH E J, ZHOU L, WILLIAMS D S, PARK J, DING N, DUAN Y P, KANG B H . Callose deposition in the phloem plasmodesmata and inhibition of phloem transport in citrus leaves infected with ‘ Candidatus Liberibacter asiaticus’. Protoplasma, 2012,249(3):687-697.
[28] FAN J, CHEN C, ACHOR D S, BRLANSKY R H, LI Z G, GMITTER F G . Differential anatomical responses of tolerant and susceptible citrus species to the infection of ‘ Candidatus Liberibacter asiaticus’. Physiological and Molecular Plant Pathology, 2013,83:69-74.
[29] DENG H, ACHOR D S, EXTEBERRIA E, YU Q, DU D, STANTON D, LIANG G, GMITTER FG . Phloem regeneration is a mechanism for Huanglongbing-tolerance of ‘Bearss’ lemon and ‘LB8-9’ sugar Belle® mandarin. Frontiers in Plant Science, 2019,10:277.
[30] WANG Y S, ZHOU L J, YU X Y, STOVER E, LUO F, DUAN Y P . Transcriptome profiling of Huanglongbing (HLB) tolerant and susceptible citrus plants reveals the role of basal resistance in HLB tolerance. Frontiers in Plant Science, 2016,7:933.
[31] LIONETTI V . PECTOPLATE: The simultaneous phenotyping of pectin methylesterases, pectinases, and oligogalacturonides in plants during biotic stresses. Frontiers in Plant Science, 2015,6:331.
[32] OWENS R A, BLACKBURN M, DING B . Possible involvement of the phloem lectin in long-distance viroid movement. Molecular Plant-Microbe Interactions, 2001,14(7):905-909.
[33] FOLIMONOVA S Y, ACHOR D S . Early events of citrus greening (Huanglongbing) disease development at the ultrastructural level. Phytopathology, 2010,100(9):949-958.
[34] CHISHOLM S T, COAKER G, DAY B, STASKAWICA B J . Host-microbe interactions: Shaping the evolution of the plant immune response. Cell, 2006,124(4):803-814.
[35] JONES J D, DANGL J L . The plant immune system. Nature, 2006,444(7117):323-329.
[36] ZOU H, GOWDA S, ZHOU L, HAJERI S, CHEN G, DUAN Y . The destructive citrus pathogen, ‘ Candidatus Liberibacter asiaticus’ encodes a functional flagellin characteristic of a pathogen-associated molecular pattern. PLoS ONE, 2012,7(9):e46447.
[37] HAO G X, BOYLE M, ZHOU L J, DUAN Y P . The intracellular citrus Huanglongbing bacterium, ‘ Candidatus Liberibacter asiaticus’ encodes two novel autotransporters. PLoS ONE, 2013,8(7):e68921.
[38] SHI Q C, FEBRES V J, ZHANG S J, YU F H, MCCOLLUM G, HALL D G, MOORE G A, STOVER E . Identification of gene candidates associated with Huanglongbing tolerance, using ‘ Candidatus Liberibacter asiaticus’ flagellin 22 as a proxy to challenge citrus. Molecular Plant-Microbe Interactions, 2017,31(2):200-211.
[39] DA GRACA J V, DOUHAN G W, HALBERT S E, KEREMANE M L, LEE R F, VIDALAKIS G, ZHAO H . Huanglongbing: An overview of a complex pathosystem ravaging the world’s citrus. Journal of Integrative Plant Biology, 2016,58(4):373-387.
[40] ZHANG Y, LI X . Salicylic acid: Biosynthesis, perception, and contributions to plant immunity. Current Opinion in Plant Biology, 2019,50:29-36.
[41] ZHU F, XI D H, YUAN S, XU F, ZHANG D W, LIN H H . Salicylic acid and jasmonic acid are essential for systemic resistance against Tobacco mosaic virus in Nicotiana benthamiana. Molecular Plant-Microbe Interactions, 2014,27(6):567-577.
[42] ZOU X, BAI X, WEN Q, XIE Z, WU L, PENG A, HE Y, XU L, CHEN S . Comparative analysis of tolerant and susceptible citrus reveals the role of methyl salicylate signaling in the response to Huanglongbing. Journal of Plant Growth Regulation, 2019,38:1516-1528.
[43] VAN LOON L C, REP M, PIETERSE C M J . Significance of inducible defense-related proteins in infected plants. Annual Reviews of Phytopathology, 2006,44(1):135-162.
[44] WU J, ALFREZ F M, JOHNSON E G, GRAHAM J H . Up-regulation of PR 1 and less disruption of hormone and sucrose metabolism in roots is associated with lower susceptibility to ‘ Candidatus Liberibacter asiaticus’. Plant Pathology, 2018,67(6):1426-1435.
[45] FU S, SHAO J, ZHOU C, HARTUNG J S . Transcriptome analysis of sweet orange trees infected with ‘ Candidatus Liberibacter asiaticus’ and two strains of Citrus tristeza virus. BMC Genomics, 2016,17:349.
[46] NWUGO C C, DUAN Y, LIN H . Study on citrus response to Huanglongbing highlights a down-regulation of defense-related proteins in lemon plants upon ‘ Ca. Liberibacter asiaticus’ infection. PLoS ONE, 2013,8(6):e67442.
[47] MARTINELLI F, REAGAN R L, DOLAN D, FILECCIA V, DANDEKAR A M . Proteomic analysis highlights the role of detoxification pathways in increased tolerance to Huanglongbing disease. BMC Plant Biology, 2016,16(1):167.
[1] WANG ZhongNi, LEI Yue, LI JiaLi, GONG YanLong, ZHU SuSong. Functions of ABC Transporter OsARG1 in Rice Heading Date Regulation [J]. Scientia Agricultura Sinica, 2026, 59(1): 1-16.
[2] WANG SiQi, ZOU LiRen, BAI RuiWen, YAN Ke, WANG SiYang, QI XiaoGuang, SHEN HaiLin, WEN JingHui. Screening of Key Genes Related to Gibberellic Acid Regulation of Rachis Hardening in Honey Grapes [J]. Scientia Agricultura Sinica, 2026, 59(1): 179-189.
[3] ZOU XiaoWei, XIA Lei, ZHU XiaoMin, SUN Hui, ZHOU Qi, QI Ji, ZHANG YaFeng, ZHENG Yan, JIANG ZhaoYuan. Analysis of Disease Resistance Induced by Ustilago maydis Strain with Overexpressed UM01240 Based on Transcriptome Sequencing [J]. Scientia Agricultura Sinica, 2025, 58(6): 1116-1130.
[4] SUN Ping, ZHU WenCan, LIN XianRui, WU JiaQi, CAO YiWen, CHEN ChenFei, WANG Yi, ZHU JianXi, JIA HuiJuan, QIAN MinJie, SHEN JianSheng. Effects of Rainy and Low Light Conditions on Coloration and Flavonoid Accumulation in Peach Peel Based on Metabolomic and Transcriptomic Analyses [J]. Scientia Agricultura Sinica, 2025, 58(6): 1173-1194.
[5] XIE LuLu, LI Fu, ZHANG SiYuan, GAO JianChang. Analysis of Conserved Genes in Adventitious Root Formation Based on Cross Species Transcriptomes [J]. Scientia Agricultura Sinica, 2025, 58(6): 1195-1209.
[6] GAO YanHao, WANG TingTing, BAI WeiWei, DU XingJie, LIU Xian, QIN BenYuan, FU Tong, SUN Yu, GAO TengYun, ZHANG TianLiu. The Combination of Lipidome and Transcriptome Revealed the Differential Expression Patterns of Lipid Characteristics in Different Muscle Tissues for Nanyang Cattle [J]. Scientia Agricultura Sinica, 2025, 58(6): 1239-1258.
[7] WANG Fan, LIU ChenWei, LU HongChen, XU RenChao, BIAN XiaoChun. Transcriptome Analysis of Vicia faba Response to Alternaria alternata Infection and Validation of the Disease Resistance Function of VfPR4 [J]. Scientia Agricultura Sinica, 2025, 58(22): 4656-4672.
[8] MU YingTong, LU JingShi, ZHANG YuTong, SHI FengLing. Identification of Key Drought-Responsive Genes in Upright Medicago ruthenica Sojak cv. Zhilixing Based on Transcriptome Sequencing and WGCNA [J]. Scientia Agricultura Sinica, 2025, 58(21): 4528-4543.
[9] PAN Yuan, WANG De, LIU Nan, MENG XiangLong, DAI PengBo, LI Bo, HU TongLe, WANG ShuTong, CAO KeQiang, WANG YaNan. Evaluation of the Effectiveness of Two High-Throughput Sequencing Techniques in Identifying Apple Viruses and Identification of Two Novel Viruses [J]. Scientia Agricultura Sinica, 2025, 58(2): 266-280.
[10] LIN Yan, ZHENG LingLing, TIAN Jia, WEN Yue, CHEN Chen, WANG Lei. Based on Transcriptomics and Proteomics to Provide Insights into the Molecular Mechanisms of Calyx Abscission in Korla Xiangli [J]. Scientia Agricultura Sinica, 2025, 58(18): 3744-3765.
[11] DONG Xue, CHEN MengQiu, SHAO Jin, WU XueYou, TANG PeiAn. Construction of a Differential Gene Expression and Quality Regulation Network in Stored Rice Grain Using WGCNA [J]. Scientia Agricultura Sinica, 2025, 58(14): 2885-2903.
[12] CAO YanYong, CHENG ZeQiang, MA Juan, YANG WenBo, ZHU WeiHong, SUN XinYan, LI HuiMin, XIA LaiKun, DUAN CanXing. Integrating Transcriptomic and Metabolomic Analyses Reveals Maize Responses to Stalk Rot Caused by Fusarium proliferatum [J]. Scientia Agricultura Sinica, 2025, 58(1): 75-90.
[13] QI RenJie, NING Yu, LIU Jing, LIU ZhiYang, XU Hai, LUO ZhiDan, CHEN LongZheng. Identification and Analysis of Genes Related to Bitter Gourd Saponin Synthesis Based on Transcriptome Sequencing [J]. Scientia Agricultura Sinica, 2024, 57(9): 1779-1793.
[14] LIN Wei, WU ShuiJin, LI YueSen. Transcriptome and Proteome Association Analysis to Revealthe Molecular Mechanism of Baxi Banana Seedlings in Response to Low Temperature [J]. Scientia Agricultura Sinica, 2024, 57(8): 1575-1591.
[15] GAO ChenXi, HAO LuYang, HU Yue, LI YongXiang, ZHANG DengFeng, LI ChunHui, SONG YanChun, SHI YunSu, WANG TianYu, LI Yu, LIU XuYang. Analysis of Transposable Element Associated Epigenetic Regulation under Drought in Maize [J]. Scientia Agricultura Sinica, 2024, 57(6): 1034-1048.
Viewed
Full text


Abstract

Cited
  Shared   
  Discussed   
No Suggested Reading articles found!
京ICP备09089781号-30
Copyright 2018 © Editorial office of Scientia Agricultura Sinica
Tel: 86-010-82106279    E-mail: zgnykx@mail.caas.net.cn
Supported by Beijing Magtech Co.Ltd