Ceccarelli Angela Valentina, Miras-Moreno Begoña, Buffagni Valentina, Senizza Biancamaria, Pii Youry, Cardarelli Mariateresa, Rouphael Youssef, Colla Giuseppe, Lucini Luigi
Department of Agriculture and Forest Sciences, University of Tuscia, 01100 Viterbo, Italy.
Department for Sustainable Food Process, Research Centre for Nutrigenomics and Proteomics, Università Cattolica del Sacro Cuore, 29122 Piacenza, Italy.
Plants (Basel). 2021 Feb 8;10(2):326. doi: 10.3390/plants10020326.
Despite the scientific evidence supporting their biostimulant activity, the molecular mechanism(s) underlying the activity of protein hydrolysates (PHs) and the specificity among different products are still poorly explored. This work tested five different protein hydrolysates, produced from different plant sources using the same enzymatic approach, for their ability to promote rooting in tomato cuttings following quick dipping. Provided that all the different PHs increased root length (45-93%) and some of them increased root number (37-56%), untargeted metabolomics followed by multivariate statistics and pathway analysis were used to unravel the molecular processes at the basis of the biostimulant activity. Distinct metabolomic signatures could be found in roots following the PHs treatments. In general, PHs shaped the phytohormone profile, modulating the complex interaction between cytokinins and auxins, an interplay playing a pivotal role in root development, and triggered a down accumulation of brassinosteroids. Concerning secondary metabolism, PHs induced the accumulation of aliphatic glucosinolates, alkaloids, and phenylpropanoids, potentially eliciting crop resilience to stress conditions. Here, we confirm that PHs may have a hormone-like activity, and that their application can modulate plant growth, likely interfering with signaling processes. Noteworthy, the heterogenicity of the botanical origin supported the distinctive and peculiar metabolomic responses we observed across the products tested. While supporting their biostimulant activity, these findings suggest that a generalized crop response to PHs cannot be defined and that specific effects are rather to be investigated.
尽管有科学证据支持其生物刺激活性，但蛋白质水解物（PHs）活性背后的分子机制以及不同产品之间的特异性仍未得到充分探索。这项工作测试了五种不同的蛋白质水解物，它们采用相同的酶法从不同植物来源生产，用于研究其在番茄插条快速蘸根后促进生根的能力。鉴于所有不同的PHs都增加了根长（45 - 93%），其中一些还增加了根数（37 - 56%），因此采用非靶向代谢组学结合多变量统计和通路分析来揭示生物刺激活性背后的分子过程。在PHs处理后的根中可以发现不同的代谢组学特征。总体而言，PHs塑造了植物激素谱，调节细胞分裂素和生长素之间的复杂相互作用，这种相互作用在根发育中起关键作用，并引发油菜素内酯的积累下降。关于次生代谢，PHs诱导了脂肪族芥子油苷、生物碱和苯丙烷类化合物的积累，可能引发作物对胁迫条件的抗性。在这里，我们证实PHs可能具有类似激素的活性，并且它们的应用可以调节植物生长，可能干扰信号传导过程。值得注意的是，植物来源的异质性支持了我们在测试产品中观察到的独特且特殊的代谢组学反应。在支持其生物刺激活性的同时，这些发现表明不能定义作物对PHs的普遍反应，而应研究其特定效果。
