Priming Treatments with Biostimulants to Cope the Short-Term Heat Stress Response: A Transcriptomic Profile Evaluation

• Published in: Plants (Basel) Vol. 11; no. 9; p. 1130
• Main Authors: Cocetta, Giacomo, Landoni, Michela, Pilu, Roberto, Repiso, Carlos, Nolasco, José, Alajarin, Marcos, Ugena, Lydia, Levy, Camila C B, Scatolino, Giacomo, Villa, Daniele, Ferrante, Antonio
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 21-04-2022; MDPI
• Subjects: Abiotic stress; Amino acids; Anthocyanins; Antioxidants; Arabidopsis thaliana; Ascophyllum nodosum; Biological activity; Cell membranes; Chlorophyll; Climate change; Crops; Drought; Exposure; Genes; Global warming; Heat; heat shock; Heat shock proteins; Heat stress; Heat tolerance; High temperature; HPS; Mode of action; Oxidative stress; Phenolic compounds; Phenols; Physiology; Plant growth; Plant protection; Plant stress; Plants (botany); Priming; Reactive oxygen species; Salinity; secondary metabolism; Seeds; Specific heat; Stress response; System effectiveness; Transcription activation; Transcription factors; Transcriptomics; Arabidopsis thaliana; secondary metabolism; heat shock; HPS; high temperature; Ascophyllum nodosum; abiotic stress
• ISSN: 2223-7747; 2223-7747
• 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.