Fujian Key Laboratory of Subtropical Plant Physiology and Biochemistry, Fujian Institute of Subtropical Botany, Xiamen, 361006, Fujian, China.
BMC Plant Biol. 2024 Aug 13;24(1):770. doi: 10.1186/s12870-024-05499-2.
Unfavorable temperatures significantly constrain the quality formation of Dendrobium officinale, severely limiting its food demand. Salicylic acid (SA) enhances the resistance of D. officinale to stress and possesses various analogs. The impact and mechanism of the SA family on improving the quality of D. officinale under adverse temperature conditions remains unclear.
Combined with molecular docking analysis, chlorophyll fluorescence and metabolic analysis after treatments with SA analogues or extreme temperatures are performed in this study. The results demonstrate that both heat and cold treatments impede several main parameters of chlorophyll fluorescence of D. officinale, including the ΦPSII parameter, a sensitive growth indicator. However, this inhibition is mitigated by SA or its chemically similar compounds. Comprehensive branch imaging of ΦPSII values revealed position-dependent improvement of tolerance. Molecular docking analysis using a crystal structure model of NPR4 protein reveals that the therapeutic effects of SA analogs are determined by their binding energy and the contact of certain residues. Metabolome analysis identifies 17 compounds are considered participating in the temperature-related SA signaling pathway. Moreover, several natural SA analogs such as 2-hydroxycinnamic acid, benzamide, 2-(formylamino) benzoic acid and 3-o-methylgallic acid, are further found to have high binding ability to NPR4 protein and probably enhance the tolerance of D. officinale against unfavorable temperatures through flavone and guanosine monophosphate degradation pathways.
These results reveal that the SA family with a high binding capability of NPR4 could improve the tolerance of D. officinale upon extreme temperature challenges. This study also highlights the collaborative role of SA-related natural compounds present in D. officinale in the mechanism of temperature resistance and offers a potential way to develop protective agents for the cultivation of D. officinale.
不利的温度会极大地限制铁皮石斛的品质形成，严重限制其食物需求。水杨酸（SA）可增强铁皮石斛对胁迫的抗性，且拥有多种类似物。SA 家族在改善不利温度条件下铁皮石斛品质方面的影响和机制尚不清楚。
本研究结合分子对接分析，在 SA 类似物或极端温度处理后，对铁皮石斛叶绿素荧光和代谢进行分析。结果表明，高温和低温处理均会抑制铁皮石斛叶绿素荧光的几个主要参数，包括 PSII 量子产量参数，这是一个敏感的生长指标。然而，SA 或其化学类似物可以减轻这种抑制。综合 PSII 值的分支成像揭示了位置依赖性的耐受性改善。使用 NPR4 蛋白晶体结构模型进行分子对接分析表明，SA 类似物的治疗效果取决于它们的结合能和某些残基的接触。代谢组学分析确定了 17 种化合物被认为参与了与温度相关的 SA 信号通路。此外，还发现几种天然的 SA 类似物，如 2-羟基肉桂酸、苯甲酰胺、2-（甲酰氨基）苯甲酸和 3-O-甲基没食子酸，对 NPR4 蛋白具有较高的结合能力，可能通过黄酮和鸟苷酸降解途径增强铁皮石斛对不利温度的耐受性。
这些结果表明，与 NPR4 具有高结合能力的 SA 家族可以提高铁皮石斛在极端温度挑战下的耐受性。本研究还强调了存在于铁皮石斛中的与 SA 相关的天然化合物在温度抗性机制中的协同作用，并为开发铁皮石斛栽培的保护剂提供了一种潜在途径。
