Departamento de Ingeniería Química, Instituto Universitario de Tecnología Cerámica. Universitat Jaume I, Castellón, Spain.
Departamento de Biología, Bioquímica y Ciencias Naturales. Universitat Jaume I, Castellón, Spain.
Physiol Plant. 2024 Jul-Aug;176(4):e14459. doi: 10.1111/ppl.14459.
Climate change induces significant abiotic stresses that adversely affect crop yields. One promising solution to improve plant resilience under adverse conditions is the application of exogenous salicylic acid (SA). However, its negative effects on growth and development are a concern. Encapsulation with protective materials like amorphous silica and chitosan has demonstrated a controlled release of SA, minimizing the detrimental impacts. In this work, we elucidate the physiological mechanisms behind this protective mechanism. We employed in vitro cultivation of Arabidopsis, comparing plant responses to both free and encapsulated SA under conditions of salt or mannitol stress, combined or not with high temperature (30°C). Plants treated with encapsulated SA displayed an enhanced tolerance to these stresses that was due, at least in part, to the maintenance of physiological endogenous SA levels, which in turn regulate indole-3-acetic acid (IAA) homeostasis. The activity of the Arabidopsis "DR5::GFP" reporter line supported this finding. Unlike plants treated with free SA (with altered DR5 activity under stress), those treated with encapsulated SA maintained similar activity levels to control plants. Moreover, stressed plants treated with free SA overexpressed genes involved in the SA biosynthesis pathway, leading to increased SA accumulation in roots and rosettes. In contrast, plants treated with encapsulated SA under stress did not exhibit increased expression of EDS1, PAL1, and NPR1 in roots, or of PAL1, PBS3, and NPR1 in rosettes. This indicates that these plants likely experienced lower stress levels, possibly because the encapsulated SA provided sufficient defense activation without triggering pleiotropic effects.
气候变化会引起显著的非生物胁迫，从而对作物产量产生不利影响。一种提高植物逆境适应能力的有前途的方法是施加外源性水杨酸（SA）。然而，其对生长和发育的负面影响令人担忧。用无定形二氧化硅和壳聚糖等保护材料进行封装可以实现 SA 的控制释放，从而最大限度地减少其有害影响。在这项工作中，我们阐明了这种保护机制的生理机制。我们通过体外培养拟南芥，比较了在盐或甘露醇胁迫下，结合或不结合高温（30°C）条件下，游离 SA 和包封 SA 对植物的影响。用包封 SA 处理的植物对这些胁迫的耐受性增强，这至少部分归因于维持了生理内源性 SA 水平，而 SA 水平又调节了吲哚-3-乙酸（IAA）的稳态。拟南芥“DR5::GFP”报告株系的活性支持了这一发现。与用游离 SA 处理的植物（在胁迫下 DR5 活性改变）不同，用包封 SA 处理的植物保持与对照植物相似的活性水平。此外，用游离 SA 处理的胁迫植物过表达了参与 SA 生物合成途径的基因，导致根和莲座叶中 SA 积累增加。相比之下，在胁迫下用包封 SA 处理的植物在根中未表现出 EDS1、PAL1 和 NPR1 或在莲座叶中 PAL1、PBS3 和 NPR1 的表达增加。这表明这些植物可能经历了较低的胁迫水平，可能是因为包封的 SA 提供了足够的防御激活，而没有引发多效性效应。
