Unlocking the three-node regulatory axis: polyamines, antioxidants, and photosynthetic protection in stressed fruit crops
- 1Horticultural Sciences Department, North Florida Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida
- 2United States Horticultural Research Laboratory, United States Department of Agriculture, Agricultural Research Service
- 3Central Laboratories, King Faisal University
Abstract
Abiotic stresses, including drought, salinity, heat, and cold, disrupt cellular redox homeostasis and impair photosynthesis in fruit crops, directly threatening vegetative growth, fruit set, and marketable yield. While polyamines (PAs), mainly putrescine, spermidine, and spermine, are well-known mediators of environmental stress tolerance, their precise molecular roles in fruit crops remain fragmented. This review conceptualizes PA-mediated stress tolerance through a novel “three-node regulatory axis”. The first node governs cellular PA homeostasis through a tightly coordinated network of biosynthesis (via arginine decarboxylase [ADC], S-adenosylmethionine decarboxylase [SAMDC], and spermidine/spermine synthases [SPDS/SPMS]) and catabolism (via diamine and polyamine oxidases [DAO/PAO]). The second node involves antioxidant activation, where controlled PA catabolism generates signaling levels of hydrogen peroxide (H ₂ O ₂ ) that prime enzymatic and non-enzymatic defense mechanisms and preserve cellular and chloroplast redox poise. Beyond direct antioxidant activation, PA-dependent redox signals can interface with Ca² ⁺ -dependent pathways, MAPK cascades, nitric oxide, and hormone signaling to regulate stress-responsive gene expression. The third node encompasses photosynthetic protection, maintaining thylakoid membrane stability, protecting photosystem II (PSII) from photoinhibition, regulating stomatal behavior, and supporting carbon assimilation under stress. Although the model plant Arabidopsis thaliana provides a valuable reference framework, direct molecular extrapolation to fruit crops is limited. Fruit crops retain the ornithine decarboxylase (ODC) pathway (which is absent in Brassicaceae ), undergo complex perennial woody growth, exhibit fruit-specific hormone crosstalk (particularly PA–ethylene interactions during ripening), and face prolonged field stress conditions. Currently, critical molecular gaps remain in fruit crop research, particularly regarding the direct regulation of Calvin cycle gene expression (such as Rubisco, GAPDH, and SBPase), the functional characterization and regulation of PA transport systems across fruit crops, the direct validation of chloroplast-localized PA biosynthesis, and the upstream transcription factor modules coordinating these responses. To transition the field from physiological association to causal molecular mechanism, future research must prioritize time-resolved, multi-endpoint experimental designs integrating PA profiling, gas exchange, and transcriptomic or proteomic analyses in identical plant systems combined with long-term field evaluation to translate these physiological insights into robust, climate-resilient fruit production.
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BibTeX
@article{jan2026unlocking,
title = {{Unlocking the three-node regulatory axis: polyamines, antioxidants, and photosynthetic protection in stressed fruit crops}},
author = {Masood Jan and Carlos Eduardo Aucique-Perez and Matthew Mattia and Zafar Iqbal and Muhammad Adnan Shahid},
journal = {Frontiers in Plant Science},
year = {2026},
month = oct,
doi = {10.3389/fpls.2026.1984273},
url = {https://www.frontiersin.org/articles/10.3389/fpls.2026.1984273/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Unlocking the three-node regulatory axis: polyamines, antioxidants, and photosynthetic protection in stressed fruit crops
AU - Masood Jan
AU - Carlos Eduardo Aucique-Perez
AU - Matthew Mattia
AU - Zafar Iqbal
AU - Muhammad Adnan Shahid
PY - 2026
DA - 2026/10/21
JO - Frontiers in Plant Science
DO - 10.3389/fpls.2026.1984273
UR - https://www.frontiersin.org/articles/10.3389/fpls.2026.1984273/full
AB - Abiotic stresses, including drought, salinity, heat, and cold, disrupt cellular redox homeostasis and impair photosynthesis in fruit crops, directly threatening vegetative growth, fruit set, and marketable yield. While polyamines (PAs), mainly putrescine, spermidine, and spermine, are well-known mediators of environmental stress tolerance, their precise molecular roles in fruit crops remain fragmented. This review conceptualizes PA-mediated stress tolerance through a novel “three-node regulatory axis”. The first node governs cellular PA homeostasis through a tightly coordinated network of biosynthesis (via arginine decarboxylase [ADC], S-adenosylmethionine decarboxylase [SAMDC], and spermidine/spermine synthases [SPDS/SPMS]) and catabolism (via diamine and polyamine oxidases [DAO/PAO]). The second node involves antioxidant activation, where controlled PA catabolism generates signaling levels of hydrogen peroxide (H ₂ O ₂ ) that prime enzymatic and non-enzymatic defense mechanisms and preserve cellular and chloroplast redox poise. Beyond direct antioxidant activation, PA-dependent redox signals can interface with Ca² ⁺ -dependent pathways, MAPK cascades, nitric oxide, and hormone signaling to regulate stress-responsive gene expression. The third node encompasses photosynthetic protection, maintaining thylakoid membrane stability, protecting photosystem II (PSII) from photoinhibition, regulating stomatal behavior, and supporting carbon assimilation under stress. Although the model plant Arabidopsis thaliana provides a valuable reference framework, direct molecular extrapolation to fruit crops is limited. Fruit crops retain the ornithine decarboxylase (ODC) pathway (which is absent in Brassicaceae ), undergo complex perennial woody growth, exhibit fruit-specific hormone crosstalk (particularly PA–ethylene interactions during ripening), and face prolonged field stress conditions. Currently, critical molecular gaps remain in fruit crop research, particularly regarding the direct regulation of Calvin cycle gene expression (such as Rubisco, GAPDH, and SBPase), the functional characterization and regulation of PA transport systems across fruit crops, the direct validation of chloroplast-localized PA biosynthesis, and the upstream transcription factor modules coordinating these responses. To transition the field from physiological association to causal molecular mechanism, future research must prioritize time-resolved, multi-endpoint experimental designs integrating PA profiling, gas exchange, and transcriptomic or proteomic analyses in identical plant systems combined with long-term field evaluation to translate these physiological insights into robust, climate-resilient fruit production.
SN - 1664-462X
ER -