Quercus suber Roots Activate Antioxidant and Membrane Protective Processes in Response to High Salinity

Abstract

Cork oak (Quercus suber) is a species native to Mediterranean areas and its adaptation to the increasingly prevalent abiotic stresses, such as soil salinization, remain unknown. In sequence with recent studies on salt stress response in the leaf, it is fundamental to uncover the plasticity of roots directly exposed to high salinity to better understand how Q. suber copes with salt stress. In the present study we aimed to unveil the antioxidants and key-genes involved in the stress-responses (early vs. later responses) of Q. suber roots exposed to high salinity. Two-month-old Q. suber plants were watered with 300 mM NaCl solution and enzymatic and non-enzymatic antioxidants, lipid peroxidation and the relative expression of genes related to stress response were analysed 8 h and 6 days after salt treatment. After an 8 h of exposure, roots activated the expression of QsLTI30 and QsFAD7 genes involved in stress membrane protection, and QsRAV1 and QsCZF1 genes involved in tolerance and adaptation. As a result of the continued salinity stress (6 days), lipid peroxidation increased, which was associated with an upregulation of QsLTI30 gene. Moreover, other protective mechanisms were activated, such as the upregulation of genes related to antioxidant status, QsCSD1 and QsAPX2, and the increase of the antioxidant enzyme activities of superoxide dismutase, catalase, and ascorbate peroxidase, concomitantly with total antioxidant activity and phenols. These data suggest a response dependent on the time of salinity exposure, leading Q. suber roots to adopt protective complementary strategies to deal with salt stress.

Quercus suber L. Genetic Resources: Variability and Strategies for Its Conservation

“…As a follow-up to the above-mentioned study [85], Dias et al [84] studied the molecular mechanisms behind the salt stress response in cork oak roots. Two-month-old plants were watered with 300 mM NaCl.…”

“…Soil salinity is an abiotic factor that can limit cork oak tree growth and productivity [84]. Despite the relevance of soil salinization in many Mediterranean ecosystems [85], the knowledge about cork oak plasticity and resistance in response to high salinity also remains limited.…”

Strategies and prospects for biostimulants to alleviate abiotic stress in plants

“…As sessile organisms, plants developed sophisticated perception mechanisms, as well as signaling and acclimation strategies to cope with harsh environmental conditions, but at the cost of decreased growth and yield ( Zandalinas et al., 2020 ). These mechanisms include increased production of antioxidant metabolites (e.g., flavonoids, proline, and enzymes) that help in the control of reactive oxygen species (ROS) to avoid oxidative stress and changes in the levels of phytohormones (e.g., ABA and JA) ( Zandalinas et al., 2020 ; Ma et al., 2020 ; Dias et al., 2022 ; Dias et al., 2018 ). Hence, drought and salinity represent a major threat to plant productivity ( Daliakopoulos et al., 2016 ; de Oliveira et al., 2022 ).…”

Halophyte Nitraria billardieri CIPK25 mitigates salinity-induced cell damage by alleviating H2O2 accumulation

“…ROS signaling disruption causes defects during plant development ( Guillou et al, 2022 ; Zhang et al, 2022 ), activating detoxification pathways for remediation of salinity-induced damage ( Zhu, 2002 ). Therefore, for adaptive responses, plants have evolved specific mechanisms to regulate the production and scavenging of ROS through enzymatic and non-enzymatic antioxidative processes ( Nadarajah, 2020 ; Dias et al, 2022 ; Šoln and Koce, 2022 ).…”