{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T20:06:58Z","timestamp":1792786018362,"version":"4.5.0"},"reference-count":56,"publisher":"Oxford University Press (OUP)","license":[{"start":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T00:00:00Z","timestamp":1789603200000},"content-version":"am","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/pages\/standard-publication-reuse-rights"}],"funder":[{"name":"Japan Society for the Promotion of Science","award":["24K01723)"],"award-info":[{"award-number":["24K01723)"]}],"id":[{"id":"https:\/\/ror.org\/00hhkn466","id-type":"ROR","asserted-by":"crossref"}]},{"name":"the Tokyo University of Science Research Grants","id":[{"id":"https:\/\/ror.org\/05sj3n476","id-type":"ROR","asserted-by":"crossref"}]},{"name":"the Fuji Foundation for Protein Research","id":[{"id":"https:\/\/ror.org\/01sdk1n29","id-type":"ROR","asserted-by":"crossref"}]},{"name":"the Asahi Group Foundation","id":[{"id":"https:\/\/ror.org\/01bd3ye13","id-type":"ROR","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>The environmental and ecological costs of chemical pesticide use have intensified the search for alternative crop protection strategies. Among these, plant defense activators (PDAs) are a distinct class of compounds that enhance plant resistance by activating or priming endogenous defense pathways, rather than through direct toxic effects on target organisms. However, current regulatory frameworks often classify such agents as plant protection products or equivalent regulatory categories, irrespective of their non-biocidal, host-mediated mode of action. In this review, we focus on a subset of PDAs whose primary effect is to activate or prime plant defense responses at non-biocidal concentrations, without relying on direct inhibition or mortality of target organisms. We examine major functional categories of PDAs, with particular emphasis on phytohormone analogs and priming agents, and plant volatile organic compounds (PVOCs), which represent well-characterized and practically relevant modes of defense activation. Based on these considerations, we propose that defense-activating agents operating through host-mediated processes align more appropriately with biostimulant-oriented frameworks. A mechanism-based classification could help resolve inconsistencies between biological modes of action and current regulatory classifications, supporting the development of sustainable, low-input crop protection strategies.<\/jats:p>","DOI":"10.1093\/jxb\/erag469","type":"journal-article","created":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T07:30:57Z","timestamp":1789630257000},"source":"Crossref","is-referenced-by-count":0,"title":["Plant defense activators for sustainable crop protection: a mechanism-based perspective on their regulatory positioning"],"prefix":"10.1093","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3371-0469","authenticated-orcid":false,"given":"Gen-ichiro","family":"Arimura","sequence":"first","affiliation":[{"name":"Department of Biological Science and Technology, Faculty of Advanced Engineering, Tokyo University of Science , Tokyo 125-8585 ,","place":["Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2026,9,17]]},"reference":[{"key":"2026100502465625500_erag469-B1","doi-asserted-by":"crossref","DOI":"10.1016\/j.envpol.2024.125526","article-title":"Beyond the field: how pesticide drift endangers biodiversity","volume":"366","author":"Albaseer","year":"2025","journal-title":"Environmental Pollution"},{"key":"2026100502465625500_erag469-B2","doi-asserted-by":"crossref","first-page":"911","DOI":"10.1093\/pcp\/pcp030","article-title":"Chemical and molecular ecology of herbivore-induced plant volatiles: proximate factors and their ultimate functions","volume":"50","author":"Arimura","year":"2009","journal-title":"Plant & Cell Physiology"},{"key":"2026100502465625500_erag469-B3","doi-asserted-by":"crossref","first-page":"288","DOI":"10.1016\/j.tplants.2020.11.001","article-title":"Making sense of the way plants sense herbivores","volume":"26","author":"Arimura","year":"2021","journal-title":"Trends in Plant Science"},{"key":"2026100502465625500_erag469-B4","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1016\/j.tplants.2024.09.005","article-title":"Cracking the plant VOC sensing code and its practical applications","volume":"30","author":"Arimura","year":"2025","journal-title":"Trends in Plant Science"},{"key":"2026100502465625500_erag469-B5","doi-asserted-by":"crossref","first-page":"401","DOI":"10.1146\/annurev-phyto-080516-035544","article-title":"Evolution of hormone signaling networks in plant defense","volume":"55","author":"Berens","year":"2017","journal-title":"Annual Review of Phytopathology"},{"key":"2026100502465625500_erag469-B6","doi-asserted-by":"crossref","first-page":"511","DOI":"10.1093\/jxb\/erab487","article-title":"Volatile-mediated plant-plant interactions: volatile organic compounds as modulators of receiver plant defence, growth, and reproduction","volume":"73","author":"Brosset","year":"2022","journal-title":"Journal of Experimental Botany"},{"key":"2026100502465625500_erag469-B7","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1146\/annurev-phyto-080614-120132","article-title":"Priming for enhanced defense","volume":"53","author":"Conrath","year":"2015","journal-title":"Annual Review of Phytopathology"},{"key":"2026100502465625500_erag469-B8","doi-asserted-by":"crossref","first-page":"804","DOI":"10.1111\/nph.18035","article-title":"Plant volatiles as regulators of hormone homeostasis","volume":"234","author":"Dani","year":"2022","journal-title":"New Phytologist"},{"key":"2026100502465625500_erag469-B9","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1016\/j.tplants.2009.12.002","article-title":"The evolutionary context for herbivore-induced plant volatiles: beyond the \u2018cry for help\u2019","volume":"15","author":"Dicke","year":"2010","journal-title":"Trends in Plant Science"},{"key":"2026100502465625500_erag469-B10","doi-asserted-by":"crossref","DOI":"10.3390\/ijms23052690","article-title":"Plant secondary metabolites as defense tools against herbivores for sustainable crop protection","volume":"23","author":"Divekar","year":"2022","journal-title":"International Journal of Molecular Sciences"},{"key":"2026100502465625500_erag469-B11","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1016\/j.scienta.2015.09.021","article-title":"Plant biostimulants: definition, concept, main categories and regulation","volume":"196","author":"du Jardin","year":"2015","journal-title":"Scientia Horticulturae"},{"key":"2026100502465625500_erag469-B12","author":"European Parliament and Council","year":"2009"},{"key":"2026100502465625500_erag469-B13","author":"European Parliament and Council","year":"2019"},{"key":"2026100502465625500_erag469-B14","doi-asserted-by":"crossref","first-page":"490","DOI":"10.1111\/j.1461-0248.2007.01043.x","article-title":"Within-plant signalling via volatiles overcomes vascular constraints on systemic signalling and primes responses against herbivores","volume":"10","author":"Frost","year":"2007","journal-title":"Ecology Letters"},{"key":"2026100502465625500_erag469-B15","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1016\/j.baae.2009.12.001","article-title":"Persistent negative effects of pesticides on biodiversity and biological control potential on European farmland","volume":"11","author":"Geiger","year":"2010","journal-title":"Basic and Applied Ecology"},{"key":"2026100502465625500_erag469-B16","doi-asserted-by":"crossref","DOI":"10.7554\/eLife.84988","article-title":"Plant secondary metabolite-dependent plant-soil feedbacks can improve crop yield in the field","volume":"12","author":"Gfeller","year":"2023","journal-title":"eLife"},{"key":"2026100502465625500_erag469-B17","doi-asserted-by":"crossref","DOI":"10.1126\/science.adv6675","article-title":"Linalool-triggered plant-soil feedback drives defense adaptation in dense maize plantings","volume":"389","author":"Guo","year":"2025","journal-title":"Science"},{"key":"2026100502465625500_erag469-B18","doi-asserted-by":"crossref","first-page":"5467","DOI":"10.1073\/pnas.0610266104","article-title":"Within-plant signaling by volatiles leads to induction and priming of an indirect plant defense in nature","volume":"104","author":"Heil","year":"2007","journal-title":"Proceedings of the National Academy of Sciences, USA"},{"key":"2026100502465625500_erag469-B19","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1016\/j.tree.2009.09.010","article-title":"Explaining evolution of plant communication by airborne signals","volume":"25","author":"Heil","year":"2010","journal-title":"Trends in Ecology & Evolution"},{"key":"2026100502465625500_erag469-B20","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1093\/bbb\/zbae156","article-title":"Eugenol and basil essential oil as priming agents for enhancing Arabidopsis immune response","volume":"89","author":"Hirose","year":"2024","journal-title":"Bioscience, Biotechnology, and Biochemistry"},{"key":"2026100502465625500_erag469-B21","doi-asserted-by":"crossref","first-page":"1267","DOI":"10.1093\/mp\/ssu049","article-title":"Growth-defense tradeoffs in plants: a balancing act to optimize fitness","volume":"7","author":"Huot","year":"2014","journal-title":"Molecular Plant"},{"key":"2026100502465625500_erag469-B22","doi-asserted-by":"crossref","first-page":"6526","DOI":"10.1021\/acs.jafc.3c08905","article-title":"Novel potential of rose essential oil as a powerful plant defense potentiator","volume":"72","author":"Kaneko","year":"2024","journal-title":"Journal of Agricultural and Food Chemistry"},{"key":"2026100502465625500_erag469-B23","doi-asserted-by":"crossref","first-page":"1820","DOI":"10.1111\/j.1365-3040.2006.01561.x","article-title":"On the induction of volatile organic compound emissions by plants as consequence of wounding or fluctuations of light and temperature","volume":"29","author":"Loreto","year":"2006","journal-title":"Plant, Cell & Environment"},{"key":"2026100502465625500_erag469-B24","volume-title":"National bioinputs program","author":"Ministry of Agriculture, Livestock and Supply, Brazil","year":"2020"},{"key":"2026100502465625500_erag469-B25","doi-asserted-by":"crossref","first-page":"431","DOI":"10.1146\/annurev-arplant-042110-103854","article-title":"Plant defense against herbivores: chemical aspects","volume":"63","author":"Mith\u00f6fer","year":"2012","journal-title":"Annual Review of Plant Biology"},{"key":"2026100502465625500_erag469-B26","article-title":"Development of menthyl esters of valine for pest control in tomato and lettuce crops","volume":"13","author":"Mori","year":"2024","journal-title":"Plants (Basel)"},{"key":"2026100502465625500_erag469-B27","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1016\/j.tplants.2021.08.012","article-title":"Plant immune networks","volume":"27","author":"Ngou","year":"2022","journal-title":"Trends in Plant Science"},{"key":"2026100502465625500_erag469-B28","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1093\/pcp\/pcu158","article-title":"Jasmonates induce both defense responses and communication in monocotyledonous and dicotyledonous plants","volume":"56","author":"Okada","year":"2015","journal-title":"Plant & Cell Physiology"},{"key":"2026100502465625500_erag469-B29","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1023\/A:1008760518772","article-title":"Induced disease resistance in plants by chemicals","volume":"107","author":"Oostendorp","year":"2001","journal-title":"European Journal of Plant Pathology"},{"key":"2026100502465625500_erag469-B30","doi-asserted-by":"crossref","first-page":"2231","DOI":"10.1007\/s10886-005-7099-7","article-title":"Herbivores, vascular pathways, and systemic induction: facts and artifacts","volume":"31","author":"Orians","year":"2005","journal-title":"Journal of Chemical Ecology"},{"key":"2026100502465625500_erag469-B31","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1016\/j.copbio.2013.12.006","article-title":"Push-pull farming systems","volume":"26","author":"Pickett","year":"2014","journal-title":"Current Opinion in Biotechnology"},{"key":"2026100502465625500_erag469-B32","doi-asserted-by":"crossref","first-page":"856","DOI":"10.1111\/nph.14274","article-title":"Plant volatile-mediated signalling and its application in agriculture: successes and challenges","volume":"212","author":"Pickett","year":"2016","journal-title":"New Phytologist"},{"key":"2026100502465625500_erag469-B33","doi-asserted-by":"crossref","first-page":"1571","DOI":"10.1093\/aob\/mcu205","article-title":"Sustainable intensification in agricultural systems","volume":"114","author":"Pretty","year":"2014","journal-title":"Annals of Botany"},{"key":"2026100502465625500_erag469-B34","doi-asserted-by":"crossref","first-page":"17542","DOI":"10.1021\/acs.jafc.5c05179","article-title":"Bush basil companion plants act as plant defense potentiators for cultivated plants","volume":"73","author":"Rahimian","year":"2025","journal-title":"Journal of Agricultural and Food Chemistry"},{"key":"2026100502465625500_erag469-B35","doi-asserted-by":"crossref","first-page":"494","DOI":"10.3389\/fpls.2019.00494","article-title":"General principles to justify plant biostimulant claims","volume":"10","author":"Ricci","year":"2019","journal-title":"Frontiers in Plant Science"},{"key":"2026100502465625500_erag469-B36","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1146\/annurev-phyto-073009-114447","article-title":"Hormone crosstalk in plant disease and defense: more than just jasmonate-salicylate antagonism","volume":"49","author":"Robert-Seilaniantz","year":"2011","journal-title":"Annual Review of Phytopathology"},{"key":"2026100502465625500_erag469-B37","doi-asserted-by":"crossref","first-page":"617","DOI":"10.1111\/tpj.15453","article-title":"Volatile terpenes\u2014mediators of plant-to-plant communication","volume":"108","author":"Rosenkranz","year":"2021","journal-title":"The Plant Journal"},{"key":"2026100502465625500_erag469-B38","doi-asserted-by":"crossref","first-page":"40","DOI":"10.3389\/fpls.2020.00040","article-title":"Editorial: biostimulants in agriculture","volume":"11","author":"Rouphael","year":"2020","journal-title":"Frontiers in Plant Science"},{"key":"2026100502465625500_erag469-B39","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.biocon.2019.01.020","article-title":"Worldwide decline of the entomofauna: a review of its drivers","volume":"232","author":"S\u00e1nchez-Bayo","year":"2019","journal-title":"Biological Conservation"},{"key":"2026100502465625500_erag469-B40","doi-asserted-by":"crossref","first-page":"283","DOI":"10.2503\/hortj.OKD-003","article-title":"Improvement in handpicking efficiency of Satsuma mandarin fruit with combination treatments of gibberellin, prohydrojasmon and ethephon","volume":"86","author":"Sato","year":"2017","journal-title":"The Horticulture Journal"},{"key":"2026100502465625500_erag469-B41","doi-asserted-by":"crossref","first-page":"399","DOI":"10.1007\/s11103-017-0659-8","article-title":"Forward genetic screens identify a role for the mitochondrial HER2 in E-2-hexenal responsiveness","volume":"95","author":"Scala","year":"2017","journal-title":"Plant Molecular Biology"},{"key":"2026100502465625500_erag469-B42","doi-asserted-by":"crossref","first-page":"653","DOI":"10.1073\/pnas.0811861106","article-title":"Phytohormone-based activity mapping of insect herbivore-produced elicitors","volume":"106","author":"Schmelz","year":"2009","journal-title":"Proceedings of the National Academy of Sciences, USA"},{"key":"2026100502465625500_erag469-B43","doi-asserted-by":"crossref","first-page":"5750","DOI":"10.1073\/pnas.1500232112","article-title":"Agricultural insecticides threaten surface waters at the global scale","volume":"112","author":"Stehle","year":"2015","journal-title":"Proceedings of the National Academy of Sciences, USA"},{"key":"2026100502465625500_erag469-B44","doi-asserted-by":"crossref","first-page":"31510","DOI":"10.1073\/pnas.2018415117","article-title":"A receptor-like protein mediates plant immune responses to herbivore-associated molecular patterns","volume":"117","author":"Steinbrenner","year":"2020","journal-title":"Proceedings of the National Academy of Sciences, USA"},{"key":"2026100502465625500_erag469-B45","doi-asserted-by":"crossref","first-page":"910","DOI":"10.1111\/tpj.14077","article-title":"Pest management using mint volatiles to elicit resistance in soy: mechanism and application potential","volume":"96","author":"Sukegawa","year":"2018","journal-title":"The Plant Journal"},{"key":"2026100502465625500_erag469-B46","doi-asserted-by":"crossref","first-page":"164","DOI":"10.1080\/17429145.2019.1605004","article-title":"Two arrays of defense strategies of Brassicaceae plants that eavesdrop on mint volatiles","volume":"14","author":"Sukegawa","year":"2019","journal-title":"Journal of Plant Interactions"},{"key":"2026100502465625500_erag469-B47","doi-asserted-by":"crossref","first-page":"523","DOI":"10.1007\/s11103-021-01150-y","article-title":"An amino acid ester of menthol elicits defense responses in plants","volume":"109","author":"Tsuzuki","year":"2022","journal-title":"Plant Molecular Biology"},{"key":"2026100502465625500_erag469-B48","doi-asserted-by":"crossref","first-page":"224","DOI":"10.1038\/s42003-020-0959-4","article-title":"Soy and Arabidopsis receptor-like kinases respond to polysaccharide signals from Spodoptera species and mediate herbivore resistance","volume":"3","author":"Uemura","year":"2020","journal-title":"Communications Biology"},{"key":"2026100502465625500_erag469-B49","volume-title":"Pesticide product label: Actigard 50WG","author":"US Environmental Protection Agency","year":"2023"},{"key":"2026100502465625500_erag469-B50","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s10526-011-9395-1","article-title":"The state of commercial augmentative biological control: plenty of natural enemies, but a frustrating lack of uptake","volume":"57","author":"van Lenteren","year":"2012","journal-title":"BioControl"},{"key":"2026100502465625500_erag469-B51","doi-asserted-by":"crossref","first-page":"1263","DOI":"10.1093\/jxb\/ert026","article-title":"Controlling crop diseases using induced resistance: challenges for the future","volume":"64","author":"Walters","year":"2013","journal-title":"Journal of Experimental Botany"},{"key":"2026100502465625500_erag469-B52","doi-asserted-by":"crossref","first-page":"4766","DOI":"10.1002\/jsfa.10535","article-title":"Preharvest application of prohydrojasmon affects color development, phenolic metabolism, and pigment-related gene expression in red pear (Pyrus ussuriensis)","volume":"100","author":"Wang","year":"2020","journal-title":"Journal of the Science of Food and Agriculture"},{"key":"2026100502465625500_erag469-B53","doi-asserted-by":"crossref","DOI":"10.3389\/fpls.2021.650132","article-title":"Biopesticide trunk injection into apple trees: a proof of concept for the systemic movement of mint and cinnamon essential oils","volume":"12","author":"Werrie","year":"2021","journal-title":"Frontiers in Plant Science"},{"key":"2026100502465625500_erag469-B54","doi-asserted-by":"crossref","DOI":"10.3389\/fpls.2016.02049","article-title":"Biostimulants in plant science: a global perspective","volume":"7","author":"Yakhin","year":"2017","journal-title":"Frontiers in Plant Science"},{"key":"2026100502465625500_erag469-B55","doi-asserted-by":"crossref","DOI":"10.1016\/j.emcon.2024.100410","article-title":"A comprehensive review on environmental and human health impacts of chemical pesticide usage","volume":"11","author":"Zhou","year":"2025","journal-title":"Emerging Contaminants"},{"key":"2026100502465625500_erag469-B56","doi-asserted-by":"crossref","first-page":"513","DOI":"10.1146\/annurev-arplant-042916-040856","article-title":"Trade-offs between plant growth and defense against insect herbivory: an emerging mechanistic synthesis","volume":"68","author":"Zust","year":"2017","journal-title":"Annual Review of Plant Biology"}],"container-title":["Journal of Experimental Botany"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/academic.oup.com\/jxb\/advance-article-pdf\/doi\/10.1093\/jxb\/erag469\/71179187\/erag469.pdf","content-type":"application\/pdf","content-version":"am","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/jxb\/advance-article-pdf\/doi\/10.1093\/jxb\/erag469\/71179187\/erag469.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T06:47:09Z","timestamp":1791182829000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/jxb\/advance-article\/doi\/10.1093\/jxb\/erag469\/8810616"}},"subtitle":[],"editor":[{"given":"Hilary","family":"Rogers","sequence":"additional","affiliation":[{"name":"Cardiff University ,","place":["UK"]}],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2026,9,17]]},"references-count":56,"URL":"https:\/\/doi.org\/10.1093\/jxb\/erag469","relation":{},"ISSN":["0022-0957","1460-2431"],"issn-type":[{"value":"0022-0957","type":"print"},{"value":"1460-2431","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,17]]},"article-number":"erag469"}}