Jasmonates, Salicylates, and Defense Signaling
Explain jasmonate and salicylate signaling, defense crosstalk, growth costs, and why elicitor claims require organism-, tissue-, dose-, and outcome-specific evidence.
Educational reference · evidence, sources, and limits shown below
Explain jasmonate and salicylate signaling, defense crosstalk, growth costs, and why elicitor claims require organism-, tissue-, dose-, and outcome-specific evidence.
Terms to know
- Jasmonate
- Lipid-derived signal involved in wounding, herbivory, reproduction, and defenses against many attackers.
- Salicylic acid
- Phenolic signal involved in local and systemic defense, especially against many biotrophic pathogens.
- Elicitor
- Stimulus that activates a plant response without necessarily providing durable protection.
- Crosstalk
- Interaction between signaling networks that can reinforce, redirect, or suppress responses.
Core science
Jasmonates rise after wounding and many herbivore or pathogen interactions and regulate defense genes, specialized metabolism, growth, and reproduction. Salicylic acid participates in local resistance, systemic signaling, stomatal and redox responses, and defense against many biotrophic pathogens. The common JA-versus-necrotroph and SA-versus-biotroph rule is a useful starting model, not a complete classifier.
Defense pathways interact with ethylene, ABA, auxin, light, sugars, circadian timing, and pathogen effectors. JA and SA can antagonize or cooperate depending on dose, order, tissue, and attacker. Defense activation consumes carbon, nitrogen, reducing power, and time; increased expression of one pathway is not proof of improved whole-crop resistance or yield.
Cannabis experiments show salicylic acid and other signals can alter promoter activity and cannabinoid-pathway expression. That is mechanistic evidence, not a universal instruction to spray elicitors. Transcript change, metabolite concentration, total metabolite yield, disease suppression, phytotoxicity, residue, and worker safety are separate endpoints.
Why this matters in cultivation
- Use sanitation, exclusion, scouting, identification, environment control, and lawful IPM as the foundation. Elicitors do not replace diagnosis or registered controls.
- When testing a signaling treatment, include untreated and carrier controls, defined disease or quality endpoints, tissue sampling, residue review, and total yield—not only one concentration result.
Measure and record
Trigger
Wound, pest, pathogen, mechanical treatment, compound, dose, formulation, and timing.
Biological identity
Pest/pathogen species or strain, confirmation method, disease stage, and inoculum pressure.
Defense response
Gene/metabolite method, tissue, sampling time, symptom score, and phytotoxicity.
Production response
Growth, leaf area, flower mass, cannabinoid/terpene concentration and total yield.
Compliance
Product label, legal status, PPE, preharvest interval, residue test, and waste handling.
Common misconceptions
Correction: Resources diverted to defense can reduce growth or reproduction.
Correction: Their interaction depends on tissue, attacker, timing, concentration, and other signals.
Correction: Transcript, concentration, total yield, maturity, and degradation are different endpoints.
Evidence limits
Cannabis signaling studies remain limited in genotypes and production contexts. Exogenous elicitor research cannot substitute for pesticide registration, residue limits, or controlled disease-efficacy trials.
Related encyclopedia topics
- THC-ENC-076–077, THC-ENC-079–080, THC-ENC-281–320, and THC-ENC-321–340.
Source notes
- Taiz L, Moller IM, Murphy A, and Zeiger E. Plant Physiology and Development. 7th ed. Oxford University Press, 2022. Publisher record
- Sands LB et al. Hormonal Control of Promoter Activities of Cannabis sativa Prenyltransferase 1 and 4 and Salicylic Acid-Mediated Regulation of Cannabinoid Biosynthesis. Scientific Reports. 2023;13:8620. Open source
- THC – Teaching Healthy Cultivation. Cannabis Plant Science Source Packet v1. May 2026. Project source packet.
- THC – Teaching Healthy Cultivation. Cultivation SOP Source Materials Packet v1. May 2026. Project source packet.
This lesson summarizes the source material and its evidence limits for education. Use direct measurement, controlled comparison, and the cited sources when conditions differ or a decision carries meaningful risk.