ABA Positively Regulates SlAPX2-Mediated Tolerance to Heat and Cold in Tomato Plants

Tomato (<i>Solanum lycopersicum</i>) is highly susceptible to both high and low temperatures, which threaten its growth, yield, and quality. Ascorbate peroxidase (APX) plays a pivotal role in plant responses to abiotic stresses. In this study, we unveil the positive involvement of heat-...

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Main Authors: Kaimeng Liang, Xiulan Fan, Yuying Liu, Rongrong Tian, Meiling Wang, Zhihong Sun, Fei Ding
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Agronomy
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Online Access:https://www.mdpi.com/2073-4395/15/5/1206
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Summary:Tomato (<i>Solanum lycopersicum</i>) is highly susceptible to both high and low temperatures, which threaten its growth, yield, and quality. Ascorbate peroxidase (APX) plays a pivotal role in plant responses to abiotic stresses. In this study, we unveil the positive involvement of heat- and cold-induced <i>SlAPX2</i> in bolstering tomato resilience to temperature extremes. Knockout of <i>SlAPX2</i> using the CRISPR/Cas9 technique exacerbated oxidative stress under heat and cold conditions, as evidenced by reduced Fv/Fm and increased electrolyte leakage (REL), malondialdehyde (MDA) content, and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) levels. Furthermore, <i>SlAPX2</i> expression was modulated by abscisic acid (ABA), and the transcription factor ABF4 in the ABA signaling pathway positively regulated <i>SlAPX2</i> transcription. Using yeast one-hybrid (Y1H) and dual luciferase (LUC) assays, we found that ABF4 directly bound to the <i>SlAPX2</i> promoter, thereby activating its transcription. Additionally, silencing of <i>SlABF4</i> compromised tomato’s tolerance to heat or cold. Collectively, these findings reveal a regulatory module, SlABF4–SlAPX2, that enhances tomato tolerance to temperature extremes by detoxifying excessive reactive oxygen species (ROS). This study advances our understanding of ABA-mediated stress responses and highlights the SlABF4–SlAPX2 module as a promising target for breeding temperature-resilient tomato cultivars.
ISSN:2073-4395