Protein hydrolysate (PH)-based biostimulants offer a cost-effective and sustainable approach for the regulation of physiological processes in plants to stimulate growth and improve stress tolerance. Understanding the mode of action of PHs is challenging, but it is indispensable to improve existing candidates and to develop novel molecules with enhanced stimulatory effects. Hence, the present study aimed to understand the proteome level responses in the B73 maize roots treated with APR, a PH biostimulant, at two increasing concentrations and to compare and integrate it with the transcriptomic data obtained previously under identical experimental conditions. Results indicate that APR induced dose-dependent global changes in the transcriptome and proteome of maize roots. APR treatment altered the expression and abundance of several genes and proteins related to redox homeostasis, stress response, glycolysis, tricarboxylic acid cycle, pentose phosphate pathway, and other metabolic pathways of carbohydrates, amino acids, and lipids. Further, metabolic processes of phytohormone, secondary metabolites, especially phenylpropanoids, flavonoids, and terpenoids and transport, and cytoskeletal reorganization associated mechanisms were stimulated. Our results suggest that APR treatment altered the redox homeostasis and thus triggered an oxidative signal. This could be one of the key regulators of the cascade of downstream events involving multiple signaling, hormonal, and metabolic pathways, resulting in an altered physiological and metabolic state which consequently could lead to improved growth and stress adaptation observed in biostimulant—treated plants.

中文翻译：

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用蛋白质水解物处理的玉米根的定量蛋白质组学：与转录组学的比较研究突出了对生物刺激剂响应的分子机制。

基于蛋白水解物（PH）的生物刺激剂为调节植物的生理过程提供了一种经济高效且可持续的方法，以刺激植物生长并改善胁迫耐受性。理解PH的作用方式具有挑战性，但是改善现有候选物并开发具有增强刺激作用的新型分子是必不可少的。因此，本研究旨在了解以两种递增浓度的APR（PH生物刺激剂）处理过的B73玉米根中蛋白质组水平的反应，并将其与先前在相同实验条件下获得的转录组数据进行比较和整合。结果表明，APR诱导了玉米根转录组和蛋白质组中剂量依赖性的整体变化。APR处理改变了与氧化还原稳态，应激反应，糖酵解，三羧酸循环，戊糖磷酸途径以及其他碳水化合物，氨基酸和脂质代谢途径有关的基因和蛋白质的表达和丰度。此外，还刺激了植物激素，次生代谢产物（尤其是苯丙烷，类黄酮和萜类化合物）的代谢过程以及运输和细胞骨架重组相关的机制。我们的结果表明，APR处理改变了氧化还原稳态，因此触发了氧化信号。这可能是涉及多种信号，激素和代谢途径的下游事件级联的关键调控因素之一，