Are Strigolactones Relevant for Arabidopsis Co-exposed to Heat and Salt Stress? – Exploring the Role of MAX2 and MAX3 in Stress Responses and Physiological Performance

Bruno Sousa; Pedro Nadais; Margarida Oliveira; Inês Garcês; Cristiano Soares; Ana Marta Pereira; Fernanda Fidalgo

doi:10.1007/s00344-026-12222-y

Are Strigolactones Relevant for Arabidopsis Co-exposed to Heat and Salt Stress? – Exploring the Role of MAX2 and MAX3 in Stress Responses and Physiological Performance

Bruno Sousa (Lead / Corresponding author)
, Pedro Nadais
, Margarida Oliveira
, Inês Garcês
, Cristiano Soares
, Ana Marta Pereira
, Fernanda Fidalgo

Plant Sciences

Research output: Contribution to journal › Article › peer-review

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Abstract

Under the current climatic context, understanding the complex dynamics of plant responses to stress conditions is a matter of special interest to properly develop sustainable mitigation strategies. The exogenous application of strigol actones (SLs) has been recently associated with improved stress tolerance. However, there has been limited focus on the role of endogenous SLs in modulating plant stress responses, especially under a combined stress scenario. To address this, two Arabidopsis T-DNA mutants deficient in either SL signaling (max2-4) or synthesis (max3-11) were exposed to salt (75 mM NaCl), heat (42 °C for 4 h d^{− 1}) and their combination for 14 days. The results highlight that while max3 presented the highest growth inhibition in response to heat, both genotypes presented an overall disruption in redox status, responding differently to the stressors, when compared to the wild-type. Thermotolerance appeared to be closely linked to SL biosynthesis, as max3 seedlings demonstrated higher susceptibility to both heat-related treatments, which was associated with increased membrane damage and a lower induction of antioxidant defenses. On the other hand, max2 mutants appeared more sensitive to salt conditions, lacking the activation of the SOS pathway and showing signs of lipid peroxidation, which were accompanied by a high accumulation of proline and the upsurge of the seedlings’ enzymatic antioxidant defenses. Overall, although the importance of endogenous SLs in regulating plant response to combined heat and salt is corroborated by the present research, the results also highlight the complexity of this regulation, with mutations at different points of the MAX pathway being associated with different responses.

Original language	English
Journal	Journal of Plant Growth Regulation
DOIs	https://doi.org/10.1007/s00344-026-12222-y
Publication status	Published - 12 May 2026

Keywords

Combined stress
Oxidative stress; phytohormones
Plant physiology
Strigolactones
T-DNA mutants

ASJC Scopus subject areas

Agronomy and Crop Science
Plant Science

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Cite this

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title = "Are Strigolactones Relevant for Arabidopsis Co-exposed to Heat and Salt Stress? – Exploring the Role of MAX2 and MAX3 in Stress Responses and Physiological Performance",

abstract = "Under the current climatic context, understanding the complex dynamics of plant responses to stress conditions is a matter of special interest to properly develop sustainable mitigation strategies. The exogenous application of strigol actones (SLs) has been recently associated with improved stress tolerance. However, there has been limited focus on the role of endogenous SLs in modulating plant stress responses, especially under a combined stress scenario. To address this, two Arabidopsis T-DNA mutants deficient in either SL signaling (max2-4) or synthesis (max3-11) were exposed to salt (75 mM NaCl), heat (42 °C for 4 h d− 1) and their combination for 14 days. The results highlight that while max3 presented the highest growth inhibition in response to heat, both genotypes presented an overall disruption in redox status, responding differently to the stressors, when compared to the wild-type. Thermotolerance appeared to be closely linked to SL biosynthesis, as max3 seedlings demonstrated higher susceptibility to both heat-related treatments, which was associated with increased membrane damage and a lower induction of antioxidant defenses. On the other hand, max2 mutants appeared more sensitive to salt conditions, lacking the activation of the SOS pathway and showing signs of lipid peroxidation, which were accompanied by a high accumulation of proline and the upsurge of the seedlings{\textquoteright} enzymatic antioxidant defenses. Overall, although the importance of endogenous SLs in regulating plant response to combined heat and salt is corroborated by the present research, the results also highlight the complexity of this regulation, with mutations at different points of the MAX pathway being associated with different responses.",

keywords = "Combined stress, Oxidative stress; phytohormones, Plant physiology, Strigolactones, T-DNA mutants",

author = "Bruno Sousa and Pedro Nadais and Margarida Oliveira and In{\^e}s Garc{\^e}s and Cristiano Soares and Pereira, \{Ana Marta\} and Fernanda Fidalgo",

note = "Publisher Copyright: {\textcopyright} The Author(s) 2026.",

year = "2026",

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doi = "10.1007/s00344-026-12222-y",

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Are Strigolactones Relevant for Arabidopsis Co-exposed to Heat and Salt Stress? – Exploring the Role of MAX2 and MAX3 in Stress Responses and Physiological Performance. / Sousa, Bruno (Lead / Corresponding author); Nadais, Pedro; Oliveira, Margarida et al.
In: Journal of Plant Growth Regulation, 12.05.2026.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Are Strigolactones Relevant for Arabidopsis Co-exposed to Heat and Salt Stress? – Exploring the Role of MAX2 and MAX3 in Stress Responses and Physiological Performance

AU - Sousa, Bruno

AU - Nadais, Pedro

AU - Oliveira, Margarida

AU - Garcês, Inês

AU - Soares, Cristiano

AU - Pereira, Ana Marta

AU - Fidalgo, Fernanda

PY - 2026/5/12

Y1 - 2026/5/12

N2 - Under the current climatic context, understanding the complex dynamics of plant responses to stress conditions is a matter of special interest to properly develop sustainable mitigation strategies. The exogenous application of strigol actones (SLs) has been recently associated with improved stress tolerance. However, there has been limited focus on the role of endogenous SLs in modulating plant stress responses, especially under a combined stress scenario. To address this, two Arabidopsis T-DNA mutants deficient in either SL signaling (max2-4) or synthesis (max3-11) were exposed to salt (75 mM NaCl), heat (42 °C for 4 h d− 1) and their combination for 14 days. The results highlight that while max3 presented the highest growth inhibition in response to heat, both genotypes presented an overall disruption in redox status, responding differently to the stressors, when compared to the wild-type. Thermotolerance appeared to be closely linked to SL biosynthesis, as max3 seedlings demonstrated higher susceptibility to both heat-related treatments, which was associated with increased membrane damage and a lower induction of antioxidant defenses. On the other hand, max2 mutants appeared more sensitive to salt conditions, lacking the activation of the SOS pathway and showing signs of lipid peroxidation, which were accompanied by a high accumulation of proline and the upsurge of the seedlings’ enzymatic antioxidant defenses. Overall, although the importance of endogenous SLs in regulating plant response to combined heat and salt is corroborated by the present research, the results also highlight the complexity of this regulation, with mutations at different points of the MAX pathway being associated with different responses.

AB - Under the current climatic context, understanding the complex dynamics of plant responses to stress conditions is a matter of special interest to properly develop sustainable mitigation strategies. The exogenous application of strigol actones (SLs) has been recently associated with improved stress tolerance. However, there has been limited focus on the role of endogenous SLs in modulating plant stress responses, especially under a combined stress scenario. To address this, two Arabidopsis T-DNA mutants deficient in either SL signaling (max2-4) or synthesis (max3-11) were exposed to salt (75 mM NaCl), heat (42 °C for 4 h d− 1) and their combination for 14 days. The results highlight that while max3 presented the highest growth inhibition in response to heat, both genotypes presented an overall disruption in redox status, responding differently to the stressors, when compared to the wild-type. Thermotolerance appeared to be closely linked to SL biosynthesis, as max3 seedlings demonstrated higher susceptibility to both heat-related treatments, which was associated with increased membrane damage and a lower induction of antioxidant defenses. On the other hand, max2 mutants appeared more sensitive to salt conditions, lacking the activation of the SOS pathway and showing signs of lipid peroxidation, which were accompanied by a high accumulation of proline and the upsurge of the seedlings’ enzymatic antioxidant defenses. Overall, although the importance of endogenous SLs in regulating plant response to combined heat and salt is corroborated by the present research, the results also highlight the complexity of this regulation, with mutations at different points of the MAX pathway being associated with different responses.

KW - Combined stress

KW - Oxidative stress; phytohormones

KW - Plant physiology

KW - Strigolactones

KW - T-DNA mutants

UR - https://www.scopus.com/pages/publications/105039269354

U2 - 10.1007/s00344-026-12222-y

DO - 10.1007/s00344-026-12222-y

M3 - Article

AN - SCOPUS:105039269354

SN - 0721-7595

JO - Journal of Plant Growth Regulation

JF - Journal of Plant Growth Regulation

ER -

Are Strigolactones Relevant for Arabidopsis Co-exposed to Heat and Salt Stress? – Exploring the Role of MAX2 and MAX3 in Stress Responses and Physiological Performance

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Keywords

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