Cocetta Giacomo, Landoni Michela, Pilu Roberto, Repiso Carlos, Nolasco José, Alajarin Marcos, Ugena Lydia, Levy Camila C B, Scatolino Giacomo, Villa Daniele, Ferrante Antonio
DISAA-Department of Agricultural and Environmental Sciences, Università degli Studi di Milano, Via Celoria 2, 20133 Milano, Italy.
Department of Bioscience, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.
Plants (Basel). 2022 Apr 21;11(9):1130. doi: 10.3390/plants11091130.
Plant stress induced by high temperature is a problem in wide areas of different regions in the world. The trend of global warming is going to enhance the effects of heat stress on crops in many cultivation areas. Heat stress impairs the stability of cell membranes and many biological processes involving both primary and secondary metabolism. Biostimulants are innovative agronomical tools that can be used as a strategy to counteract the detrimental effect of abiotic stresses, including heat stress. In this work, two biostimulants based on extracts (named Phylgreen) and based on animal L-α amino acids (named Delfan Plus) were applied as priming treatments to plants subjected to heat stress exposure. Plants at the vegetative stage were treated with biostimulants 12 h before high temperature exposure, which consisted of maintaining the plants at 37 ± 1 °C for 4 h. Transcriptional profiles, physiological, and biochemical analyses were performed to understand the mode of action of the biostimulants in protecting the plants exposed to short-term heat stress. At a physiological level, chlorophyll, chlorophyll a fluorescence, phenolic index, total anthocyanins, reactive oxygen species (ROS) were measured, and significant variations were observed immediately after stress. Both biostimulants were able to reduce the oxidative damage in leaves and cell membrane. Transcriptomic data revealed that upregulated genes were 626 in Phylgreen and 365 in Delfan Plus, while downregulated genes were 295 in Phylgreen and 312 in Delfan Plus. Bioinformatic analysis showed that the biostimulants protected the plants from heat stress by activating specific heat shock proteins (HPS), antioxidant systems, and ROS scavengers. The results revealed that the biostimulants effectively induced the activation of heat stress-associated genes belonging to different transcription factors and HSP families. Among the heat shock proteins, the most important was the AtHSP17 family and in particular, those influenced by treatments were AtHPS17.4 and AtHPS17.6A, B, showing the most relevant changes.
高温诱导的植物胁迫是世界不同地区广泛存在的问题。全球变暖趋势将增强许多种植区热胁迫对作物的影响。热胁迫会损害细胞膜的稳定性以及许多涉及初级和次级代谢的生物过程。生物刺激素是一种创新的农艺工具，可作为应对包括热胁迫在内的非生物胁迫有害影响的策略。在这项工作中，两种基于提取物（名为Phylgreen）和基于动物L-α氨基酸（名为Delfan Plus）的生物刺激素被用作引发处理，应用于遭受热胁迫的植物。营养生长阶段的植物在高温暴露前12小时用生物刺激素处理，高温暴露包括将植物在37±1°C下保持4小时。进行了转录谱、生理和生化分析，以了解生物刺激素在保护植物免受短期热胁迫方面的作用模式。在生理水平上，测量了叶绿素、叶绿素a荧光、酚类指数、总花青素、活性氧（ROS），并且在胁迫后立即观察到了显著变化。两种生物刺激素都能够减少叶片和细胞膜的氧化损伤。转录组数据显示，Phylgreen中上调的基因有626个，Delfan Plus中有365个，而Phylgreen中下调的基因有295个，Delfan Plus中有312个。生物信息学分析表明，生物刺激素通过激活特定的热休克蛋白（HPS）、抗氧化系统和ROS清除剂来保护植物免受热胁迫。结果表明，生物刺激素有效地诱导了属于不同转录因子和HSP家族的热胁迫相关基因的激活。在热休克蛋白中，最重要的是AtHSP17家族，特别是受处理影响的那些是AtHPS17.4和AtHPS17.6A、B，显示出最相关的变化。
