A field survey: Distinctive composition of core and keystone taxa in root microbiota of Carex cepillacea on the Qinghai-Tibet Plateau

Abstract

The understanding of plant-microbe interactions in terms of core and/or keystone taxa is crucial for enhancing plant stress tolerance. Nevertheless, the investigation of this key component of microbiome associated with plants thriving in extreme environments, like non-mycorrhizal sedges on the Qinghai-Tibet Plateau, has been relatively limited. In this study, we employed frequency-abundance methods and molecular ecological network analysis to identify the core and keystone taxa of fungi and bacteria in both rhizosphere soil and root endosphere of Carex cepillacea. The results revealed a substantial number of unique taxa in both core and keystone taxa, with Sphingomonas and Gibberella representing core taxa, while Nocardioides and Truncatella serve as the keystone taxa. Specifically, there was a considerably higher proportion of exclusive taxa in the keystone taxa (bacteria: 48.8%, fungi: 55.4%) compared to that observed in core taxa (bacteria: 16.3%, fungi: 10.7%). Regarding microorganisms inhabiting rhizosphere soil, total nitrogen (TN) primarily influenced the assembly of core communities while available phosphorus (AP) played a major role in shaping the keystone communities. Within the root endosphere, both the core and keystone microbial communities were significantly more influenced by soil carbon and TN nutrients compared to other factors. It is noteworthy that certain “common core” taxa, such as Actinoplanes, Blastococcus, Penicillium, and Fusarium, exhibited high interconnectedness within the entire microbiome network. Considering the contribution of keystone taxa is significantly enhanced when they are part of the core taxa, these findings can provide a foundation for the development of microbial formulations based on key constituents of the microbiome.

Graphical abstract

Keywords

core taxa / keystone taxa / nonmycorrhizal plant / soil nutrient / Tibetan grassland

Highlight

	● A substantial number of distinct taxa were found in both core and keystone taxa.
	● The soil properties exert distinct influences on the assemblage of core and key taxa.
	● A set of key component microbiome that belong to both core and key taxa were selected.

References

[1] Acuña, J.J., Rilling, J.I., Inostroza, N.G., Manquian, J., Zhang, Q., Gupta, V.V.S.R., Jorquera, M.A., 2023. Diversity, community structure, and potential functions of root-associated bacterial communities of different wheat (Triticum aestivum) cultivars under field conditions. Agronomy13, 1392.

[2] Agler, M.T., Ruhe, J., Kroll, S., Morhenn, C., Kim, S.T., Weigel, D., Kemen, E.M., 2016. Microbial hub taxa link host and abiotic factors to plant microbiome variation. PLoS Biology14, e1002352.

[3] Almario, J., Jeena, G., Wunder, J., Langen, G., Zuccaro, A., Coupland, G., Bucher, M., 2017. Root-associated fungal microbiota of nonmycorrhizal Arabis alpina and its contribution to plant phosphorus nutrition. Proceedings of the National Academy of Sciences of the United States of America114, E9403–E9412.

[4] Amit, G., Bashan, A., 2023. Top-down identification of keystone taxa in the microbiome. Nature Communications14, 3951.

[5] Archer, E., 2021. rfPermute: estimate permutation p-values for random forest importance metrics. R Package Version 2.2.

[6] Bai, B., Liu, W.D., Qiu, X.Y., Zhang, J., Zhang, J.Y., Bai, Y., 2022. The root microbiome: community assembly and its contributions to plant fitness. Journal of Integrative Plant Biology64, 230–243.

[7] Banerjee, S., Kirkby, C.A., Schmutter, D., Bissett, A., Kirkegaard, J.A., Richardson, A.E., 2016. Network analysis reveals functional redundancy and keystone taxa amongst bacterial and fungal communities during organic matter decomposition in an arable soil. Soil Biology and Biochemistry97, 188–198.

[8] Banerjee, S., Schlaeppi, K., Van Der Heijden, M.G.A., 2018. Keystone taxa as drivers of microbiome structure and functioning. Nature Reviews Microbiology16, 567–576.

[9] Bastian, M., Heymann, S., Jacomy, M., 2009. Gephi: an open source software for exploring and manipulating networks. In: Proceedings of the Third International AAAI Conference on Web and Social Media. San Jose: AAAI361–362.

[10] Berendsen, R.L., Pieterse, C.M.J., Bakker, P.A.H.M., 2012. The rhizosphere microbiome and plant health. Trends in Plant Science17, 478–486.

[11] Bez, C., Esposito, A., Musonerimana, S., Nguyen, T.H., Navarro-Escalante, L., Tesfaye, K., Turello, L., Navarini, L., Piazza, S., Venturi, V., 2023. Comparative study of the rhizosphere microbiome of Coffea arabica grown in different countries reveals a small set of prevalent and keystone taxa. Rhizosphere25, 100652.

[12] Bhatti, A.A., Haq, S., Bhat, R.A., 2017. Actinomycetes benefaction role in soil and plant health. Microbial Pathogenesis111, 458–467.

[13] Bodenhausen, N., Horton, M.W., Bergelson, J., 2013. Bacterial communities associated with the leaves and the roots of Arabidopsis thaliana. PLoS One8, e56329.

[14] Bolger, A.M., Lohse, M., Usadel, B., 2014. Trimmomatic: a flexible trimmer for Illumina sequence data. Bioinformatics30, 2114–2120.

[15] Boukhatem, Z.F., Merabet, C., Tsaki, H., 2022. Plant growth promoting actinobacteria, the most promising candidates as bioinoculants? Frontiers in Agronomy 4, 849911.

[16] Bragina, A., Berg, C., Berg, G., 2015. The core microbiome bonds the alpine bog vegetation to a transkingdom metacommunity. Molecular Ecology24, 4795–4807.

[17] Bulgarelli, D., Garrido-Oter, R., Münch, P.C., Weiman, A., Dröge, J., Pan, Y., Mchardy, A.C., Schulze-Lefert, P., 2015. Structure and function of the bacterial root microbiota in wild and domesticated barley. Cell Host & Microbe17, 392–403.

[18] Camargo, A.P., De Souza, R.S.C., Jose, J., Gerhardt, I.R., Dante, R.A., Mukherjee, S., Huntemann, M., Kyrpides, N.C., Carazzolle, M.F., Arruda, P., 2023. Plant microbiomes harbor potential to promote nutrient turnover in impoverished substrates of a Brazilian biodiversity hotspot. The ISME Journal17, 354–370.

[19] Chelius, M.K., Triplett, E.W., 2001. The diversity of archaea and bacteria in association with the roots of Zea mays L. Microbial Ecology41, 252–263.

[20] Chen, H.B., Boutros, P.C., 2011. VennDiagram: a package for the generation of highly-customizable Venn and Euler diagrams in R. BMC Bioinformatics12, 35.

[21] Chen, L.J., Jiang, Y.J., Liang, C., Luo, Y., Xu, Q.S., Han, C., Zhao, Q.G., Sun, B., 2019. Competitive interaction with keystone taxa induced negative priming under biochar amendments. Microbiome7, 77.

[22] Coleman-Derr, D., Desgarennes, D., Fonseca-Garcia, C., Gross, S., Clingenpeel, S., Woyke, T., North, G., Visel, A., Partida-Martinez, L.P., Tringe, S.G., 2016. Plant compartment and biogeography affect microbiome composition in cultivated and native Agave species. New Phytologist209, 798–811.

[23] Compant, S., Cassan, F., Kostić, T., Johnson, L., Brader, G., Trognitz, F., Sessitsch, A., 2025. Harnessing the plant microbiome for sustainable crop production. Nature Reviews Microbiology23, 9–23.

[24] Custer, G.F., Gans, M., Van Diepen, L.T.A., Dini-Andreote, F., Buerkle, C.A., 2023. Comparative analysis of core microbiome assignments: implications for ecological synthesis. mSystems8, e0106622.

[25] Dasgupta, D., Richardson, A.E., Camuy-Vélez, L.A., Kirkby, C., Kirkegaard, J.A., Banerjee, S., 2024. Microbial dynamics during in-situ organic matter decomposition reveals the importance of keystone taxa in the core microbiome. Applied Soil Ecology199, 105396.

[26] Delgado-Baquerizo, M., Oliverio, A.M., Brewer, T.E., Benavent-González, A., Eldridge, D.J., Bardgett, R.D., Maestre, F.T., Singh, B.K., Fierer, N., 2018. A global atlas of the dominant bacteria found in soil. Science359, 320–325.

[27] Deng, Y., Jiang, Y.H., Yang, Y.F., He, Z.L., Luo, F., Zhou, J.Z., 2012. Molecular ecological network analyses. BMC Bioinformatics13, 113.

[28] Dhondge, H.V., Barvkar, V.T., Paul, D., Dastager, S.G., Pable, A.A., Nadaf, A.B., 2022. Exploring the core microbiota in scented rice (Oryza sativa L.) rhizosphere through metagenomics approach. Microbiological Research263, 127157.

[29] Ding, G.G., Zeng, W.J., Sun, L.J., Chen, F.S., Lyu, Y., Xu, J., Yan, T., Wang, H.M., Ma, Z.Q., 2024. Root acquisitive traits mirror the functional modules of root-associated fungi. Soil Biology and Biochemistry190, 109317.

[30] Durán, P., Thiergart, T., Garrido-Oter, R., Agler, M., Kemen, E., Schulze-Lefert, P., Hacquard, S., 2018. Microbial interkingdom interactions in roots promote Arabidopsis survival. Cell175, 973–983.e14.

[31] Emsens, W.J., De Weyer, M., Fuentes, I., Liczner, Y., Van Diggelen, R., Verbruggen, E., 2022. Strong conditionality in plant-fungal community assembly after soil inoculation in post-agricultural grasslands. Soil Biology and Biochemistry166, 108580.

[32] Fan, J.H., Liu, T.Y., Liao, Y., Li, Y.Y., Yan, Y., Lu, X.Y., 2021. Distinguishing stoichiometric homeostasis of soil microbial biomass in alpine grassland ecosystems: evidence from 5,000 km belt transect across Qinghai-Tibet Plateau. Frontiers in Plant Science12, 781695.

[33] Feng, K., Peng, X., Zhang, Z., Gu, S.S., He, Q., Shen, W.L., Wang, Z.J., Wang, D.R., Hu, Q.L., Li, Y., Wang, S., Deng, Y., 2022. iNAP: an integrated network analysis pipeline for microbiome studies. iMeta1, e13.

[34] Feng, K., Zhang, Y.G., He, Z.L., Ning, D.L., Deng, Y., 2019. Interdomain ecological networks between plants and microbes. Molecular Ecology Resources19, 1565–1577.

[35] Gao, Q., Yang, Z.L., 2016. Diversity and distribution patterns of root-associated fungi on herbaceous plants in alpine meadows of southwestern China. Mycologia108, 281–291.

[36] Geml, J., Wagner, M.R., 2018. Out of sight, but no longer out of mind-towards an increased recognition of the role of soil microbes in plant speciation. New Phytologist217, 965–967.

[37] Genre, A., Lanfranco, L., Perotto, S., Bonfante, P., 2020. Unique and common traits in mycorrhizal symbioses. Nature Reviews Microbiology18, 649–660.

[38] Großkopf, T., Soyer, O.S., 2014. Synthetic microbial communities. Current Opinion in Microbiology18, 72–77.

[39] Gu, S.S., Xiong, X.Y., Tan, L., Deng, Y., Du, X.F., Yang, X.X., Hu, Q.L., 2022. Soil microbial community assembly and stability are associated with potato (Solanum tuberosum L.) fitness under continuous cropping regime. Frontiers in Plant Science13, 1000045.

[40] Hamonts, K., Trivedi, P., Garg, A., Janitz, C., Grinyer, J., Holford, P., Botha, F.C., Anderson, I.C., Singh, B.K., 2018. Field study reveals core plant microbiota and relative importance of their drivers. Environmental Microbiology20, 124–140.

[41] Hao, X.L., Zhu, Y.G., Nybroe, O., Nicolaisen, M.H., 2020. The composition and phosphorus cycling potential of bacterial communities associated with hyphae of Penicillium in soil are strongly affected by soil origin. Frontiers in Microbiology10, 2951.

[42] Hartman, K., Schmid, M.W., Bodenhausen, N., Bender, S.F., Valzano-Held, A.Y., Schlaeppi, K., Van Der Heijden, M.G.A., 2023. A symbiotic footprint in the plant root microbiome. Environmental Microbiome18, 65.

[43] Hiruma, K., Gerlach, N., Sacristán, S., Nakano, R.T., Hacquard, S., Kracher, B., Neumann, U., Ramírez, D., Bucher, M., O'Connell, R.J., Schulze-Lefert, P., 2016. Root endophyte Colletotrichum tofieldiae confers plant fitness benefits that are phosphate status dependent. Cell165, 464–474.

[44] Hol, W.H.G., De Boer, W., De Hollander, M., Kuramae, E.E., Meisner, A., Van Der Putten, W.H., 2015. Context dependency and saturating effects of loss of rare soil microbes on plant productivity. Frontiers in Plant Science6, 485.

[45] Huang, C.L., Sarkar, R., Hsu, T.W., Yang, C.F., Chien, C.H., Chang, W.C., Chiang, T.Y., 2020. Endophytic microbiome of biofuel plant Miscanthus sinensis (Poaceae) interacts with environmental gradients. Microbial Ecology80, 133–144.

[46] Ibrahim, M.M., Guo, L.M., Zhang, H.X., Wu, F.Y., Zou, S.Q., Xing, S.H., Mao, Y.L., 2022. Comparative impact of Bacillus spp. on long-term N supply and N-cycling bacterial distribution under biochar and manure amendment. Journal of Soil Science and Plant Nutrition22, 882–895.

[47] Ji, N.N., Liang, D., Clark, L.V., Sacks, E.J., Kent, A.D., 2023. Host genetic variation drives the differentiation in the ecological role of the native Miscanthus root-associated microbiome. Microbiome11, 216.

[48] Jiang, L.L., Wang, S.P., Pang, Z., Wang, C.S., Meng, F.D., Lan, Z.C., Zhou, X.Q., Li, Y.M., Zhang, Z.H., Luo, C.Y., Jones, D.L., Rui, Y.C., Wang, Y.F., 2021. Abiotic and biotic controls of soil dissolved organic nitrogen along a precipitation gradient on the Tibetan Plateau. Plant and Soil459, 65–78.

[49] Jiao, S., Chen, W.M., Wei, G.H., 2022. Core microbiota drive functional stability of soil microbiome in reforestation ecosystems. Global Change Biology28, 1038–1047.

[50] Jin, Z.X., Jiang, F.Y., Wang, L.T., Declerck, S., Feng, G., Zhang, L., 2024. Arbuscular mycorrhizal fungi and Streptomyces: brothers in arms to shape the structure and function of the hyphosphere microbiome in the early stage of interaction. Microbiome12, 83.

[51] Jones, P., Garcia, B.J., Furches, A., Tuskan, G.A., Jacobson, D., 2019. Plant host-associated mechanisms for microbial selection. Frontiers in Plant Science10, 862.

[52] Kumar, M., Ansari, W.A., Zeyad, M.T., Singh, A., Chakdar, H., Kumar, A., Farooqi, M.S., Sharma, A., Srivastava, S., Srivastava, A.K., 2023. Core microbiota of wheat rhizosphere under upper indo-Gangetic plains and their response to soil physicochemical properties. Frontiers in Plant Science14, 1186162.

[53] Layeghifard, M., Hwang, D.M., Guttman, D.S., 2017. Disentangling interactions in the microbiome: a network perspective. Trends in Microbiology25, 217–228.

[54] Li, J., Liu, Y.X., Lü, P.P., Wang, Y.L., Li, Z.F., Zhang, Y., Gan, H.Y., Li, X.C., Mandal, D., Cai, J., Guo, Z.X., Yao, H., Guo, L.D., 2022. Community assembly of fungi and bacteria along soil-plant continuum differs in a Zoige wetland. Microbiology Spectrum10, e0226022.

[55] Liaw, A., Wiener, M., 2002. Classification and regression by randomForest. R News2, 18–22.

[56] Ling, N., Wang, T.T., Kuzyakov, Y., 2022. Rhizosphere bacteriome structure and functions. Nature Communications13, 836.

[57] Lundberg, D.S., Lebeis, S.L., Paredes, S.H., Yourstone, S., Gehring, J., Malfatti, S., Tremblay, J., Engelbrektson, A., Kunin, V., Rio, T.G.D., Edgar, R.C., Eickhorst, T., Ley, R.E., Hugenholtz, P., Tringe, S.G., Dangl, J.L., 2012. Defining the core Arabidopsis thaliana root microbiome. Nature488, 86–90.

[58] Lynch, M.D.J., Neufeld, J.D., 2015. Ecology and exploration of the rare biosphere. Nature Reviews Microbiology13, 217–229.

[59] Magoč, T., Salzberg, S.L., 2011. FLASH: fast length adjustment of short reads to improve genome assemblies. Bioinformatics27, 2957–2963.

[60] Meier, M.A., Lopez-Guerrero, M.G., Guo, M., Schmer, M.R., Herr, J.R., Schnable, J.C., Alfano, J.R., Yang, J.L., 2021. Rhizosphere microbiomes in a historical maize-soybean rotation system respond to host species and nitrogen fertilization at the genus and subgenus levels. Applied and Environmental Microbiology87, e0313220.

[61] Miller, R.M., Jastrow, J.D., Reinhardt, D.R., 1995. External hyphal production of vesicular-arbuscular mycorrhizal fungi in pasture and tallgrass prairie communities. Oecologia103, 17–23.

[62] Moreno-Mateos, D., Alberdi, A., Morriën, E., Van Der Putten, W.H., Rodríguez-Uña, A., Montoya, D., 2020. The long-term restoration of ecosystem complexity. Nature Ecology & Evolution4, 676–685.

[63] Niu, B., Paulson, J.N., Zheng, X.Q., Kolter, R., 2017. Simplified and representative bacterial community of maize roots. Proceedings of the National Academy of Sciences of the United States of America of the United States of America114, E2450–E2459.

[64] Olsen, S.R., 1954. Estimation of Available Phosphorus in Soils by Extraction with Sodium Bicarbonate. Washington, D.C.: U.S. Dept. of Agriculture.

[65] Pan, Y.X., Li, X.R., Wang, Z.R., Feng, L., Huang, L., Wang, B.Y., Sun, J.Y., 2023. Soil extracellular enzymes characteristics and their controlling factors along the elevation gradient in Qinghai-Tibet Plateau, China. Applied Soil Ecology188, 104862.

[66] Peter, H., Beier, S., Bertilsson, S., Lindström, E.S., Langenheder, S., Tranvik, L.J., 2011. Function-specific response to depletion of microbial diversity. The ISME Journal5, 351–361.

[67] Poole, P., Ramachandran, V., Terpolilli, J., 2018. Rhizobia: from saprophytes to endosymbionts. Nature Reviews Microbiology16, 291–303.

[68] Richardson, A.E., Lynch, J.P., Ryan, P.R., Delhaize, E., Smith, F.A., Smith, S.E., Harvey, P.R., Ryan, M.H., Veneklaas, E.J., Lambers, H., Oberson, A., Culvenor, R.A., Simpson, R.J., 2011. Plant and microbial strategies to improve the phosphorus efficiency of agriculture. Plant and Soil349, 121–156.

[69] Rosado-Porto, D., Ratering, S., Moser, G., Deppe, M., Müller, C., Schnell, S., 2022. Soil metatranscriptome demonstrates a shift in C, N, and S metabolisms of a grassland ecosystem in response to elevated atmospheric CO₂. Frontiers in Microbiology13, 937021.

[70] Sessitsch, A., Pfaffenbichler, N., Mitter, B., 2019. Microbiome applications from lab to field: facing complexity. Trends in Plant Science24, 194–198.

[71] Shade, A., Handelsman, J., 2012. Beyond the Venn diagram: the hunt for a core microbiome. Environmental Microbiology14, 4–12.

[72] Shakya, M., Gottel, N., Castro, H., Yang, Z.K., Gunter, L., Labbé, J., Muchero, W., Bonito, G., Vilgalys, R., Tuskan, G., Podar, M., Schadt, C.W., 2013. A multifactor analysis of fungal and bacterial community structure in the root microbiome of mature Populus deltoides trees. PLoS One8, e76382.

[73] Shayanthan, A., Ordoñez, P.A.C., Oresnik, I.J., 2022. The role of synthetic microbial communities (SynCom) in sustainable agriculture. Frontiers in Agronomy4, 896307.

[74] Shetty, S.A., Hugenholtz, F., Lahti, L., Smidt, H., De Vos, W.M., 2017. Intestinal microbiome landscaping: insight in community assemblage and implications for microbial modulation strategies. FEMS Microbiology Reviews41, 182–199.

[75] Steele, J.A., Countway, P.D., Xia, L., Vigil, P.D., Beman, J.M., Kim, D.Y., Chow, C.E.T., Sachdeva, R., Jones, A.C., Schwalbach, M.S., Rose, J.M., Hewson, I., Patel, A., Sun, F.Z., Caron, D.A., Fuhrman, J.A., 2011. Marine bacterial, archaeal and protistan association networks reveal ecological linkages. The ISME Journal5, 1414–1425.

[76] Toju, H., Peay, K.G., Yamamichi, M., Narisawa, K., Hiruma, K., Naito, K., Fukuda, S., Ushio, M., Nakaoka, S., Onoda, Y., Yoshida, K., Schlaeppi, K., Bai, Y., Sugiura, R., Ichihashi, Y., Minamisawa, K., Kiers, E.T., 2018. Core microbiomes for sustainable agroecosystems. Nature Plants4, 247–257.

[77] Umaña, M.N., Zhang, C.C., Cao, M., Lin, L.X., Swenson, N.G., 2017. A core-transient framework for trait-based community ecology: an example from a tropical tree seedling community. Ecology Letters20, 619–628.

[78] Van Der Heijden, M.G.A., Bardgett, R.D., Van Straalen, N.M., 2008. The unseen majority: soil microbes as drivers of plant diversity and productivity in terrestrial ecosystems. Ecology Letters11, 296–310.

[79] Wagg, C., Schlaeppi, K., Banerjee, S., Kuramae, E.E., Van Der Heijden, M.G.A., 2019. Fungal-bacterial diversity and microbiome complexity predict ecosystem functioning. Nature Communications10, 4841.

[80] Walkley, A., Black, I.A., 1934. An examination of the degtjareff method for determining soil organic matter, and a proposed modification of the chromic acid titration method. Soil Science37, 29–38.

[81] Wang, X.Y., Bian, Q., Jiang, Y.J., Zhu, L.Y., Chen, Y., Liang, Y.T., Sun, B., 2021. Organic amendments drive shifts in microbial community structure and keystone taxa which increase C mineralization across aggregate size classes. Soil Biology and Biochemistry153, 108062.

[82] Wang, Y.S., Li, C.N., Kou, Y.P., Wang, J.J., Tu, B., Li, H., Li, X.Z., Wang, C.T., Yao, M.J., 2017. Soil pH is a major driver of soil diazotrophic community assembly in Qinghai-Tibet alpine meadows. Soil Biology and Biochemistry115, 547–555.

[83] Wei, X.T., Jiang, F.Y., Han, B., Zhang, H., Huang, D., Shao, X.Q., 2021. New insight into the divergent responses of plants to warming in the context of root endophytic bacterial and fungal communities. PeerJ9, e11340.

[84] Xie, H.J., Chai, Y.B., Liu, Z.Y., Hao, W.Y., Gai, J.P., 2024. Community assembly of endophytic bacteria and fungi differs in soil-root continuum of Carex cepillacea. Applied Soil Ecology194, 105206.

[85] Yeoh, Y.K., Dennis, P.G., Paungfoo-Lonhienne, C., Weber, L., Brackin, R., Ragan, M.A., Schmidt, S., Hugenholtz, P., 2017. Evolutionary conservation of a core root microbiome across plant phyla along a tropical soil chronosequence. Nature Communications8, 215.

[86] Zhang, A.L., Li, X.Y., Wu, S.X., Li, L., Jiang, Y., Wang, R.Z., Ahmed, Z.S., Zeng, F.J., Lin, L.S., Li, L., 2021. Spatial pattern of C:N:P stoichiometry characteristics of alpine grassland in the Altunshan Nature Reserve at North Qinghai-Tibet Plateau. CATENA207, 105691.

[87] Zhang, Y.J., Ding, M.J., Zhang, H., Wang, N.Y., Yu, Z.P., Xu, H., Huang, P., 2023. Degradation-driven bacterial homogenization closely associated with the loss of soil multifunctionality in alpine meadows. Agriculture, Ecosystems & Environment344, 108284.

[88] Zhu, Y.G., Zhu, D., R illig M.C., Yang, Y.F., Chu, H.Y., Chen, Q.L., Penuelas, J., Cui, H.L., Gillings, M., 2023. Ecosystem microbiome science. mLife2, 2–10.

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