Drought negatively affects the growth and yield of terrestrial crops. Seed priming, pre-exposing seed to a compound, could induce improved tolerance and adaptation to stress in germinated plants. To understand the effects and regulatory mechanism of seed priming with brassinosteroid (BR) on peanut plants, we treated seeds with five BR concentrations and examined dozens of physiological and biochemical features, and transcriptomic changes in leaves under well-watered and drought conditions. We found optimal 0.15 ppm BR priming could reduce inhibitions from drought and increase the yield of peanut, and priming effects are dependent on stage of plant development and duration of drought. BR priming induced fewer differentially expressed genes (DEGs) than no BR priming under well-watered condition. Drought with BR priming reduced the number of DEGs than drought only. These DEGs were enriched in varied gene ontologies and metabolism pathways. Downregulation of DEGs involved in both light perceiving and photosynthesis in leaves is consistent with low parameters of photosynthesis. Optimal BR priming partially rescued the levels of growth promoting auxin and gibberellin which were largely reduced by drought, and increased levels of defense associated abscisic acid and salicylic acid after long-term drought. BR priming induced many DEGs which function as kinase or transcription factor for signal cascade under drought. We proposed BR priming-induced regulatory responses will be memorized and recalled for fast adaptation in later drought stress. These results provide physiological and regulatory bases of effects of seed priming with BR, which can help to guide the framing improvement under drought stress.

中文翻译：

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油菜素类固醇引发通过消除对光合作用和激素信号转导基因的抑制来提高花生的耐旱性

干旱对陆生作物的生长和产量产生负面影响。种子引发，将种子预先暴露于化合物中，可以在发芽植物中诱导改善的耐受性和对胁迫的适应。为了了解油菜素类固醇 (BR) 种子引发对花生植物的影响和调控机制，我们用五种 BR 浓度处理种子，并检查了数十种生理和生化特征，以及在充足浇水和干旱条件下叶片的转录组变化。我们发现最佳的 0.15 ppm BR 引发可以减少干旱抑制并增加花生产量，引发效果取决于植物发育阶段和干旱持续时间。在充分浇水的条件下，BR 引发比没有 BR 引发诱导的差异表达基因 (DEG) 更少。与仅干旱相比，具有 BR 引发的干旱减少了 DEG 的数量。这些 DEG 富含各种基因本体和代谢途径。叶片中参与光感知和光合作用的 DEG 的下调与光合作用的低参数一致。最佳BR引发部分挽救了因干旱而大幅降低的促生长生长素和赤霉素的水平，并在长期干旱后增加了防御相关脱落酸和水杨酸的水平。BR 引发诱导了许多 DEG，它们在干旱条件下作为信号级联的激酶或转录因子起作用。我们建议 BR 启动诱导的调节反应将被记忆和召回，以便在以后的干旱胁迫中快速适应。这些结果提供了用 BR 引发种子的生理和调节基础，