The broad-leaf herbicide 2,4-dichlorophenoxyacetic acid turns rice into a living trap for a major insect pest and a parasitic wasp.
Synthetic chemical elicitors of plant defense have been touted as a powerful means for sustainable crop protection. Yet, they have never been successfully applied to control insect pests in the field. We developed a high-throughput chemical genetics screening system based on a herbivore-induced linalool synthase promoter fused to a β-glucuronidase (GUS) reporter construct to test synthetic compounds for their potential to induce rice defenses. We identified 2,4-dichlorophenoxyacetic acid (2,4-D), an auxin homolog and widely used herbicide in monocotyledonous crops, as a potent elicitor of rice defenses. Low doses of 2,4-D induced a strong defensive reaction upstream of the jasmonic acid and ethylene pathways, resulting in a marked increase in trypsin proteinase inhibitor activity and volatile production. Induced plants were more resistant to the striped stem borer Chilo suppressalis, but became highly attractive to the brown planthopper Nilaparvata lugens and its main egg parasitoid Anagrus nilaparvatae. In a field experiment, 2,4-D application turned rice plants into living traps for N. lugens by attracting parasitoids. Our findings demonstrate the potential of auxin homologs as defensive signals and show the potential of the herbicide to turn rice into a selective catch crop for an economically important pest.
National Key Laboratory of Rice Biology, Institute of Insect Science, Zhejiang University, Hangzhou 310029, China.
Zhaojun
Z
Xin
National Key Laboratory of Rice Biology, Institute of Insect Science, Zhejiang University, Hangzhou 310029, China.
Zhaonan
Z
Yu
Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745, Jena, Germany.
Matthias
M
Erb
Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, CP158, CH-2009, Neuchâtel, Switzerland.
Ted C J
TCJ
Turlings
National Key Laboratory of Rice Biology, Institute of Insect Science, Zhejiang University, Hangzhou 310029, China.
Baohui
B
Wang
National Key Laboratory of Rice Biology, Institute of Insect Science, Zhejiang University, Hangzhou 310029, China.
Jinfeng
J
Qi
National Key Laboratory of Rice Biology, Institute of Insect Science, Zhejiang University, Hangzhou 310029, China.
Shengning
S
Liu
National Key Laboratory of Rice Biology, Institute of Insect Science, Zhejiang University, Hangzhou 310029, China.
Yonggen
Y
Lou
D015084:2,4-Dichlorophenoxyacetic Acid / Q000633:toxicity*; D000818:Animals; D003517:Cyclopentanes / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006540:Herbicides / Q000633:toxicity*; D060434:Herbivory / Q000187:drug effects; D057166:High-Throughput Screening Assays; D007305:Insecticide Resistance / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D012275:Oryza / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000469:parasitology*; D054883:Oxylipins / Q000378:metabolism; D010571:Pest Control; D018515:Plant Leaves / Q000187:drug effects* / Q000469:parasitology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000378:metabolism; D014863:Wasps / Q000187:drug effects*
D003517:Cyclopentanes; D005030:Ethylenes; D006540:Herbicides; D054883:Oxylipins; D010940:Plant Proteins; D012333:RNA, Messenger; D014361:Trypsin Inhibitors; D055549:Volatile Organic Compounds; D015084:2,4-Dichlorophenoxyacetic Acid; C011006:jasmonic acid; C036216:ethylene; D020928:Mitogen-Activated Protein Kinases; D020156:Salicylic Acid