MYC2b-regulated tyramine-derived phenolamides in maize defense against Spodoptera frugiperda
5 affiliations
- 1Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University
- 2State Key Laboratory of Agricultural and Forestry Biosecurity, College of Agriculture, Fujian Agriculture and Forestry University
- 3Key Laboratory of Crop Biotechnology of Fujian Higher Education Institutes, College of Agriculture, Fujian Agriculture and Forestry University
- 4Key Laboratory of Biological Breeding for Fujian and Taiwan Crops, College of Agriculture, Fujian Agriculture and Forestry University
- 5Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, School of Life Sciences, Huzhou Normal University
Abstract
Introduction: The fall armyworm Spodoptera frugiperda is a devastating pest of maize, capable of detoxifying the well-studied benzoxazinoid (BX) defenses. Whether maize deploys additional inducible defenses that complement BXs remains unclear.
Methods: We performed targeted alkaloid metabolomics, absolute quantification, artificial-diet bioassays, transcript profiling, hormone quantification, and genetic analysis using a myc2a myc2b double mutant to investigate phenolamide-mediated defense against FAW in maize.
Results: Upon S. frugiperda herbivory, maize leaves accumulated tyramine-derived phenolamides to levels that far exceeded those of BXs at 48 h after infestation. The two most abundant phenolamides, N-p- coumaroyltyramine and N-feruloyltyramine, reached over 50 mg/g fresh weight. N-feruloyltyramine significantly suppressed larval growth and survival, whereas N-p-coumaroyltyramine showed no significant effect; the methoxy group of the feruloyl side chain enhanced anti-insect activity. Phenolamide synthesis genes maintained high expression at 48 h, while BX biosynthetic genes were significantly downregulated at 24 h, accounting for the late-stage quantitative advantage of phenolamides. Herbivory activated jasmonate signaling. with MYC2b showing much stronger induction than MYC2a. The myc2a myc2b double mutant showed that both paralogs are required for phenolamide accumulation and tyramine hydroxycinnamoyl transferase ( THT ) expression. Given its stronger herbivory-responsive induction, MYC2b was selected for mechanistic verification.
Discussion: Our findings establish that MYC2a/MYC2b-dependent tyramine-derived phenolamides, with MYC2b directly activating THT3 transcription, constitute an important anti-herbivore specialized chemical defense.
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BibTeX
@article{zheng2026myc2bregulated,
title = {{MYC2b-regulated tyramine-derived phenolamides in maize defense against Spodoptera frugiperda}},
author = {Yingying Zheng and Na Sun and Zicha Wu and Jinyi Tian and Jing Chen and Xueyang Ju and Rensen Zeng and Yuanyuan Song and Dongmei Chen and Jie Wang},
journal = {Frontiers in Plant Science},
year = {2026},
month = oct,
doi = {10.3389/fpls.2026.1945110},
url = {https://www.frontiersin.org/articles/10.3389/fpls.2026.1945110/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - MYC2b-regulated tyramine-derived phenolamides in maize defense against Spodoptera frugiperda
AU - Yingying Zheng
AU - Na Sun
AU - Zicha Wu
AU - Jinyi Tian
AU - Jing Chen
AU - Xueyang Ju
AU - Rensen Zeng
AU - Yuanyuan Song
AU - Dongmei Chen
AU - Jie Wang
PY - 2026
DA - 2026/10/07
JO - Frontiers in Plant Science
DO - 10.3389/fpls.2026.1945110
UR - https://www.frontiersin.org/articles/10.3389/fpls.2026.1945110/full
AB - Introduction: The fall armyworm Spodoptera frugiperda is a devastating pest of maize, capable of detoxifying the well-studied benzoxazinoid (BX) defenses. Whether maize deploys additional inducible defenses that complement BXs remains unclear. Methods: We performed targeted alkaloid metabolomics, absolute quantification, artificial-diet bioassays, transcript profiling, hormone quantification, and genetic analysis using a myc2a myc2b double mutant to investigate phenolamide-mediated defense against FAW in maize. Results: Upon S. frugiperda herbivory, maize leaves accumulated tyramine-derived phenolamides to levels that far exceeded those of BXs at 48 h after infestation. The two most abundant phenolamides, N-p- coumaroyltyramine and N-feruloyltyramine, reached over 50 mg/g fresh weight. N-feruloyltyramine significantly suppressed larval growth and survival, whereas N-p-coumaroyltyramine showed no significant effect; the methoxy group of the feruloyl side chain enhanced anti-insect activity. Phenolamide synthesis genes maintained high expression at 48 h, while BX biosynthetic genes were significantly downregulated at 24 h, accounting for the late-stage quantitative advantage of phenolamides. Herbivory activated jasmonate signaling. with MYC2b showing much stronger induction than MYC2a. The myc2a myc2b double mutant showed that both paralogs are required for phenolamide accumulation and tyramine hydroxycinnamoyl transferase ( THT ) expression. Given its stronger herbivory-responsive induction, MYC2b was selected for mechanistic verification. Discussion: Our findings establish that MYC2a/MYC2b-dependent tyramine-derived phenolamides, with MYC2b directly activating THT3 transcription, constitute an important anti-herbivore specialized chemical defense.
SN - 1664-462X
ER -