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

Abstract

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 Ascophyllum nodosum extracts (named Phylgreen) and based on animal L-α amino acids (named Delfan Plus) were applied as priming treatments to Arabidopsis thaliana 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.

Effects of Date Palm Waste Compost Application on Root Proteome Changes of Barley (Hordeum vulgare L.)

“…In this study, endoplasmin and chaperonin CPN60-like were upregulated in the barley root-treated plants; however, heat shock protein (HSP 70) and small heat shock protein (sHSP) were downregulated. These results were consistent with those reported previously [ 64 ]. These authors noted that biostimulants based on Ascophyllum nodosum extracts (named Phylgreen) and based on animal L-amino acids (named Delfan Plus) induced the expression of some HSPs under control conditions, suggesting that they play a role during plant development, while other HSPs such as HSP 70 and small heat shock protein (sHSP) were upregulated under heat stress, suggesting that they perform a protective function against abiotic stress including heat stress.…”

Ascophyllum nodosum (L.) Le Jolis, a Pivotal Biostimulant toward Sustainable Agriculture: A Comprehensive Review

“…In AnE, the upregulation of defense pathway genes such as PinII (jasmonic acid), Etr1 (ethylene), and PR-1a (salicylic acid) enhanced the auxin-responsive proteins such as SAUR21 and indole-3-acetic acid-amido synthetase in AnE-treated tomatoes [172]. It was observed that the AnE alleviated the effect of heat stress by activating heat shock proteins (HPS), which mainly influenced the AtHSP17 family, particularly AtHPS17.4 and AtHPS17.6A and B, confirming the most significant changes [173].…”

Global Food Security and Sustainability Issues: The Road to 2030 from Nutrition and Sustainable Healthy Diets to Food Systems Change

“…A possible agronomic management measure for crops is the exploitation and exploration of the microbiota in agroecosystems in symbiosis with crop plants. Multiple benefits are underlined by this innovative strategy, such as coping with biotic and abiotic stressesfor instance, heat stress [136,137], drought [138,139], waterlogging [140,141], and the attack of pests [142] and diseases [143,144].…”